[Proposal] Global temporary tables

diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index e954482..2f5f5ef 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -444,7 +444,7 @@ heapgetpage(TableScanDesc sscan, BlockNumber page)
 			if (all_visible)
 				valid = true;
 			else
-				valid = HeapTupleSatisfiesVisibility(&loctup, snapshot, buffer);
+				valid = HeapTupleSatisfiesVisibility(scan->rs_base.rs_rd, &loctup, snapshot, buffer);
 
 			CheckForSerializableConflictOut(valid, scan->rs_base.rs_rd,
 											&loctup, buffer, snapshot);
@@ -664,7 +664,8 @@ heapgettup(HeapScanDesc scan,
 				/*
 				 * if current tuple qualifies, return it.
 				 */
-				valid = HeapTupleSatisfiesVisibility(tuple,
+				valid = HeapTupleSatisfiesVisibility(scan->rs_base.rs_rd,
+													 tuple,
 													 snapshot,
 													 scan->rs_cbuf);
 
@@ -1474,7 +1475,7 @@ heap_fetch(Relation relation,
 	/*
 	 * check tuple visibility, then release lock
 	 */
-	valid = HeapTupleSatisfiesVisibility(tuple, snapshot, buffer);
+	valid = HeapTupleSatisfiesVisibility(relation, tuple, snapshot, buffer);
 
 	if (valid)
 		PredicateLockTuple(relation, tuple, snapshot);
@@ -1609,7 +1610,7 @@ heap_hot_search_buffer(ItemPointer tid, Relation relation, Buffer buffer,
 		if (!skip)
 		{
 			/* If it's visible per the snapshot, we must return it */
-			valid = HeapTupleSatisfiesVisibility(heapTuple, snapshot, buffer);
+			valid = HeapTupleSatisfiesVisibility(relation, heapTuple, snapshot, buffer);
 			CheckForSerializableConflictOut(valid, relation, heapTuple,
 											buffer, snapshot);
 
@@ -1749,7 +1750,7 @@ heap_get_latest_tid(TableScanDesc sscan,
 		 * Check tuple visibility; if visible, set it as the new result
 		 * candidate.
 		 */
-		valid = HeapTupleSatisfiesVisibility(&tp, snapshot, buffer);
+		valid = HeapTupleSatisfiesVisibility(relation, &tp, snapshot, buffer);
 		CheckForSerializableConflictOut(valid, relation, &tp, buffer, snapshot);
 		if (valid)
 			*tid = ctid;
@@ -1846,6 +1847,14 @@ ReleaseBulkInsertStatePin(BulkInsertState bistate)
 }
 
 
+static TransactionId
+GetTransactionId(Relation relation)
+{
+	return relation->rd_rel->relpersistence == RELPERSISTENCE_SESSION && RecoveryInProgress()
+		? GetReplicaTransactionId()
+		: GetCurrentTransactionId();
+}
+
 /*
  *	heap_insert		- insert tuple into a heap
  *
@@ -1868,7 +1877,7 @@ void
 heap_insert(Relation relation, HeapTuple tup, CommandId cid,
 			int options, BulkInsertState bistate)
 {
-	TransactionId xid = GetCurrentTransactionId();
+	TransactionId xid = GetTransactionId(relation);
 	HeapTuple	heaptup;
 	Buffer		buffer;
 	Buffer		vmbuffer = InvalidBuffer;
@@ -2105,7 +2114,7 @@ void
 heap_multi_insert(Relation relation, TupleTableSlot **slots, int ntuples,
 				  CommandId cid, int options, BulkInsertState bistate)
 {
-	TransactionId xid = GetCurrentTransactionId();
+	TransactionId xid = GetTransactionId(relation);
 	HeapTuple  *heaptuples;
 	int			i;
 	int			ndone;
@@ -2444,7 +2453,7 @@ heap_delete(Relation relation, ItemPointer tid,
 			TM_FailureData *tmfd, bool changingPart)
 {
 	TM_Result	result;
-	TransactionId xid = GetCurrentTransactionId();
+	TransactionId xid = GetTransactionId(relation);
 	ItemId		lp;
 	HeapTupleData tp;
 	Page		page;
@@ -2509,7 +2518,7 @@ heap_delete(Relation relation, ItemPointer tid,
 	tp.t_self = *tid;
 
 l1:
-	result = HeapTupleSatisfiesUpdate(&tp, cid, buffer);
+	result = HeapTupleSatisfiesUpdate(relation, &tp, cid, buffer);
 
 	if (result == TM_Invisible)
 	{
@@ -2628,7 +2637,7 @@ l1:
 	if (crosscheck != InvalidSnapshot && result == TM_Ok)
 	{
 		/* Perform additional check for transaction-snapshot mode RI updates */
-		if (!HeapTupleSatisfiesVisibility(&tp, crosscheck, buffer))
+		if (!HeapTupleSatisfiesVisibility(relation, &tp, crosscheck, buffer))
 			result = TM_Updated;
 	}
 
@@ -2895,7 +2904,7 @@ heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,
 			TM_FailureData *tmfd, LockTupleMode *lockmode)
 {
 	TM_Result	result;
-	TransactionId xid = GetCurrentTransactionId();
+	TransactionId xid = GetTransactionId(relation);
 	Bitmapset  *hot_attrs;
 	Bitmapset  *key_attrs;
 	Bitmapset  *id_attrs;
@@ -3065,7 +3074,7 @@ heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,
 l2:
 	checked_lockers = false;
 	locker_remains = false;
-	result = HeapTupleSatisfiesUpdate(&oldtup, cid, buffer);
+	result = HeapTupleSatisfiesUpdate(relation, &oldtup, cid, buffer);
 
 	/* see below about the "no wait" case */
 	Assert(result != TM_BeingModified || wait);
@@ -3258,7 +3267,7 @@ l2:
 	if (crosscheck != InvalidSnapshot && result == TM_Ok)
 	{
 		/* Perform additional check for transaction-snapshot mode RI updates */
-		if (!HeapTupleSatisfiesVisibility(&oldtup, crosscheck, buffer))
+		if (!HeapTupleSatisfiesVisibility(relation, &oldtup, crosscheck, buffer))
 		{
 			result = TM_Updated;
 			Assert(!ItemPointerEquals(&oldtup.t_self, &oldtup.t_data->t_ctid));
@@ -4014,7 +4023,7 @@ heap_lock_tuple(Relation relation, HeapTuple tuple,
 	tuple->t_tableOid = RelationGetRelid(relation);
 
 l3:
-	result = HeapTupleSatisfiesUpdate(tuple, cid, *buffer);
+	result = HeapTupleSatisfiesUpdate(relation, tuple, cid, *buffer);
 
 	if (result == TM_Invisible)
 	{
@@ -4189,7 +4198,7 @@ l3:
 					TM_Result	res;
 
 					res = heap_lock_updated_tuple(relation, tuple, &t_ctid,
-												  GetCurrentTransactionId(),
+												  GetTransactionId(relation),
 												  mode);
 					if (res != TM_Ok)
 					{
@@ -4437,7 +4446,7 @@ l3:
 				TM_Result	res;
 
 				res = heap_lock_updated_tuple(relation, tuple, &t_ctid,
-											  GetCurrentTransactionId(),
+											  GetTransactionId(relation),
 											  mode);
 				if (res != TM_Ok)
 				{
@@ -4546,7 +4555,7 @@ failed:
 	 * state if multixact.c elogs.
 	 */
 	compute_new_xmax_infomask(xmax, old_infomask, tuple->t_data->t_infomask2,
-							  GetCurrentTransactionId(), mode, false,
+							  GetTransactionId(relation), mode, false,
 							  &xid, &new_infomask, &new_infomask2);
 
 	START_CRIT_SECTION();
@@ -5566,7 +5575,7 @@ heap_finish_speculative(Relation relation, ItemPointer tid)
 void
 heap_abort_speculative(Relation relation, ItemPointer tid)
 {
-	TransactionId xid = GetCurrentTransactionId();
+	TransactionId xid = GetTransactionId(relation);
 	ItemId		lp;
 	HeapTupleData tp;
 	Page		page;
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 2dd8821..67a553a 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -226,7 +226,8 @@ heapam_tuple_satisfies_snapshot(Relation rel, TupleTableSlot *slot,
 	 * Caller should be holding pin, but not lock.
 	 */
 	LockBuffer(bslot->buffer, BUFFER_LOCK_SHARE);
-	res = HeapTupleSatisfiesVisibility(bslot->base.tuple, snapshot,
+
+	res = HeapTupleSatisfiesVisibility(rel, bslot->base.tuple, snapshot,
 									   bslot->buffer);
 	LockBuffer(bslot->buffer, BUFFER_LOCK_UNLOCK);
 
@@ -673,6 +674,7 @@ heapam_relation_copy_data(Relation rel, const RelFileNode *newrnode)
 			 * init fork of an unlogged relation.
 			 */
 			if (rel->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT ||
+				rel->rd_rel->relpersistence == RELPERSISTENCE_SESSION ||
 				(rel->rd_rel->relpersistence == RELPERSISTENCE_UNLOGGED &&
 				 forkNum == INIT_FORKNUM))
 				log_smgrcreate(newrnode, forkNum);
@@ -2162,7 +2164,7 @@ heapam_scan_bitmap_next_block(TableScanDesc scan,
 			loctup.t_len = ItemIdGetLength(lp);
 			loctup.t_tableOid = scan->rs_rd->rd_id;
 			ItemPointerSet(&loctup.t_self, page, offnum);
-			valid = HeapTupleSatisfiesVisibility(&loctup, snapshot, buffer);
+			valid = HeapTupleSatisfiesVisibility(scan->rs_rd, &loctup, snapshot, buffer);
 			if (valid)
 			{
 				hscan->rs_vistuples[ntup++] = offnum;
@@ -2482,7 +2484,7 @@ SampleHeapTupleVisible(TableScanDesc scan, Buffer buffer,
 	else
 	{
 		/* Otherwise, we have to check the tuple individually. */
-		return HeapTupleSatisfiesVisibility(tuple, scan->rs_snapshot,
+		return HeapTupleSatisfiesVisibility(scan->rs_rd, tuple, scan->rs_snapshot,
 											buffer);
 	}
 }
diff --git a/src/backend/access/heap/heapam_visibility.c b/src/backend/access/heap/heapam_visibility.c
index 537e681..3076f6a 100644
--- a/src/backend/access/heap/heapam_visibility.c
+++ b/src/backend/access/heap/heapam_visibility.c
@@ -77,6 +77,7 @@
 #include "utils/combocid.h"
 #include "utils/snapmgr.h"
 
+static bool TempTupleSatisfiesVisibility(HeapTuple htup, CommandId curcid, Buffer buffer);
 
 /*
  * SetHintBits()
@@ -454,7 +455,7 @@ HeapTupleSatisfiesToast(HeapTuple htup, Snapshot snapshot,
  *	test for it themselves.)
  */
 TM_Result
-HeapTupleSatisfiesUpdate(HeapTuple htup, CommandId curcid,
+HeapTupleSatisfiesUpdate(Relation relation, HeapTuple htup, CommandId curcid,
 						 Buffer buffer)
 {
 	HeapTupleHeader tuple = htup->t_data;
@@ -462,6 +463,13 @@ HeapTupleSatisfiesUpdate(HeapTuple htup, CommandId curcid,
 	Assert(ItemPointerIsValid(&htup->t_self));
 	Assert(htup->t_tableOid != InvalidOid);
 
+	if (relation->rd_rel->relpersistence == RELPERSISTENCE_SESSION && RecoveryInProgress())
+	{
+		AccessTempRelationAtReplica = true;
+		return TempTupleSatisfiesVisibility(htup, curcid, buffer) ? TM_Ok : TM_Invisible;
+	}
+	AccessTempRelationAtReplica = false;
+
 	if (!HeapTupleHeaderXminCommitted(tuple))
 	{
 		if (HeapTupleHeaderXminInvalid(tuple))
@@ -1677,6 +1685,59 @@ HeapTupleSatisfiesHistoricMVCC(HeapTuple htup, Snapshot snapshot,
 }
 
 /*
+ * TempTupleSatisfiesVisibility
+ *		True iff global temp table tuple is visible for the current transaction.
+ *
+ * Temporary tables are visible only for current backend, so there is no need to
+ * handle cases with tuples committed by other backends. We only need to exclude
+ * modifications done by aborted transactions or after start of table scan.
+ *
+ */
+static bool
+TempTupleSatisfiesVisibility(HeapTuple htup, CommandId curcid, Buffer buffer)
+{
+	HeapTupleHeader tuple = htup->t_data;
+	TransactionId xmin;
+	TransactionId xmax;
+
+	Assert(ItemPointerIsValid(&htup->t_self));
+	Assert(htup->t_tableOid != InvalidOid);
+
+	if (HeapTupleHeaderXminInvalid(tuple))
+		return false;
+
+	xmin = HeapTupleHeaderGetRawXmin(tuple);
+
+	if (IsReplicaTransactionAborted(xmin))
+		return false;
+
+	if (IsReplicaCurrentTransactionId(xmin)
+		&& HeapTupleHeaderGetCmin(tuple) >= curcid)
+	{
+		return false;	/* inserted after scan started */
+	}
+
+	if (tuple->t_infomask & HEAP_XMAX_INVALID)	/* xid invalid */
+		return true;
+
+	if (HEAP_XMAX_IS_LOCKED_ONLY(tuple->t_infomask))	/* not deleter */
+		return true;
+
+	xmax = (tuple->t_infomask & HEAP_XMAX_IS_MULTI)
+	    ? HeapTupleGetUpdateXid(tuple)
+		: HeapTupleHeaderGetRawXmax(tuple);
+
+	if (IsReplicaTransactionAborted(xmax))
+		return true; /* updating subtransaction aborted */
+
+	if (!IsReplicaCurrentTransactionId(xmax))
+		return false; /* updating transaction committed */
+
+	return (HeapTupleHeaderGetCmax(tuple) >= curcid);	/* updated after scan started */
+}
+
+
+/*
  * HeapTupleSatisfiesVisibility
  *		True iff heap tuple satisfies a time qual.
  *
@@ -1687,8 +1748,15 @@ HeapTupleSatisfiesHistoricMVCC(HeapTuple htup, Snapshot snapshot,
  *	if so, the indicated buffer is marked dirty.
  */
 bool
-HeapTupleSatisfiesVisibility(HeapTuple tup, Snapshot snapshot, Buffer buffer)
+HeapTupleSatisfiesVisibility(Relation relation, HeapTuple tup, Snapshot snapshot, Buffer buffer)
 {
+	if (relation->rd_rel->relpersistence == RELPERSISTENCE_SESSION && RecoveryInProgress())
+	{
+		AccessTempRelationAtReplica = true;
+		return TempTupleSatisfiesVisibility(tup, snapshot->curcid, buffer);
+	}
+	AccessTempRelationAtReplica = false;
+
 	switch (snapshot->snapshot_type)
 	{
 		case SNAPSHOT_MVCC:
diff --git a/src/backend/access/transam/transam.c b/src/backend/access/transam/transam.c
index 365ddfb..bce9c4a 100644
--- a/src/backend/access/transam/transam.c
+++ b/src/backend/access/transam/transam.c
@@ -22,6 +22,7 @@
 #include "access/clog.h"
 #include "access/subtrans.h"
 #include "access/transam.h"
+#include "access/xact.h"
 #include "utils/snapmgr.h"
 
 /*
@@ -126,6 +127,9 @@ TransactionIdDidCommit(TransactionId transactionId)
 {
 	XidStatus	xidstatus;
 
+	if (AccessTempRelationAtReplica)
+		return !IsReplicaCurrentTransactionId(transactionId) && !IsReplicaTransactionAborted(transactionId);
+
 	xidstatus = TransactionLogFetch(transactionId);
 
 	/*
@@ -182,6 +186,9 @@ TransactionIdDidAbort(TransactionId transactionId)
 {
 	XidStatus	xidstatus;
 
+	if (AccessTempRelationAtReplica)
+		return IsReplicaTransactionAborted(transactionId);
+
 	xidstatus = TransactionLogFetch(transactionId);
 
 	/*
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 9162286..cf6bf4e 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -192,6 +192,7 @@ typedef struct TransactionStateData
 	int			parallelModeLevel;	/* Enter/ExitParallelMode counter */
 	bool		chain;			/* start a new block after this one */
 	struct TransactionStateData *parent;	/* back link to parent */
+	TransactionId replicaTransactionId;    /* pseudo XID for inserting data in global temp tables at replica */
 } TransactionStateData;
 
 typedef TransactionStateData *TransactionState;
@@ -286,6 +287,12 @@ typedef struct XactCallbackItem
 
 static XactCallbackItem *Xact_callbacks = NULL;
 
+static TransactionId replicaTransIdCount = FirstNormalTransactionId;
+static TransactionId replicaTopTransId;
+static Bitmapset*    replicaAbortedXids;
+
+bool AccessTempRelationAtReplica;
+
 /*
  * List of add-on start- and end-of-subxact callbacks
  */
@@ -443,6 +450,48 @@ GetCurrentTransactionIdIfAny(void)
 }
 
 /*
+ * Transactions at replica can update only global temporary tables.
+ * Them are assigned backend-local XIDs which are independent from normal XIDs received from primary node.
+ * So tuples of temporary tables at replica requires special visibility rules.
+ *
+ * XIDs for such transactions at replica are created on demand (when tuple of temp table is updated).
+ * XID wrap-around and adjusting XID horizon is not supported. So number of such transactions at replica is
+ * limited by 2^32 and require up to 2^29 in-memory bitmap for marking aborted transactions.
+  */
+TransactionId
+GetReplicaTransactionId(void)
+{
+	TransactionState s = CurrentTransactionState;
+	if (!TransactionIdIsValid(s->replicaTransactionId))
+		s->replicaTransactionId = ++replicaTransIdCount;
+	return s->replicaTransactionId;
+}
+
+/*
+ * At replica transaction can update only temporary tables
+ * and them are assigned special XIDs (not related with normal XIDs received from primary node).
+ * As far as we see only own transaction it is not necessary to mark committed transactions.
+ * Only marking aborted ones is enough. All transactions which are not marked as aborted are treated as
+ * committed or self in-progress transactions.
+ */
+bool
+IsReplicaTransactionAborted(TransactionId xid)
+{
+	return bms_is_member(xid, replicaAbortedXids);
+}
+
+/*
+ * As far as XIDs for transactions at replica are generated individually for each backends,
+ * we can check that XID belongs to the current transaction or any of its subtransactions by
+ * just comparing it with XID of top transaction.
+ */
+bool
+IsReplicaCurrentTransactionId(TransactionId xid)
+{
+	return xid > replicaTopTransId;
+}
+
+/*
  *	GetTopFullTransactionId
  *
  * This will return the FullTransactionId of the main transaction, assigning
@@ -855,6 +904,9 @@ TransactionIdIsCurrentTransactionId(TransactionId xid)
 {
 	TransactionState s;
 
+	if (AccessTempRelationAtReplica)
+		return IsReplicaCurrentTransactionId(xid);
+
 	/*
 	 * We always say that BootstrapTransactionId is "not my transaction ID"
 	 * even when it is (ie, during bootstrap).  Along with the fact that
@@ -1206,7 +1258,7 @@ static TransactionId
 RecordTransactionCommit(void)
 {
 	TransactionId xid = GetTopTransactionIdIfAny();
-	bool		markXidCommitted = TransactionIdIsValid(xid);
+	bool		markXidCommitted = TransactionIdIsNormal(xid);
 	TransactionId latestXid = InvalidTransactionId;
 	int			nrels;
 	RelFileNode *rels;
@@ -1624,7 +1676,7 @@ RecordTransactionAbort(bool isSubXact)
 	 * rels to delete (note that this routine is not responsible for actually
 	 * deleting 'em).  We cannot have any child XIDs, either.
 	 */
-	if (!TransactionIdIsValid(xid))
+	if (!TransactionIdIsNormal(xid))
 	{
 		/* Reset XactLastRecEnd until the next transaction writes something */
 		if (!isSubXact)
@@ -1892,6 +1944,8 @@ StartTransaction(void)
 	s = &TopTransactionStateData;
 	CurrentTransactionState = s;
 
+	replicaTopTransId = replicaTransIdCount;
+
 	Assert(!FullTransactionIdIsValid(XactTopFullTransactionId));
 
 	/* check the current transaction state */
@@ -1905,6 +1959,7 @@ StartTransaction(void)
 	 */
 	s->state = TRANS_START;
 	s->fullTransactionId = InvalidFullTransactionId;	/* until assigned */
+	s->replicaTransactionId = InvalidTransactionId;	/* until assigned */
 
 	/* Determine if statements are logged in this transaction */
 	xact_is_sampled = log_xact_sample_rate != 0 &&
@@ -2570,6 +2625,14 @@ AbortTransaction(void)
 	/* Prevent cancel/die interrupt while cleaning up */
 	HOLD_INTERRUPTS();
 
+	/* Mark transactions involved global temp table at replica as aborted */
+	if (TransactionIdIsValid(s->replicaTransactionId))
+	{
+		MemoryContext ctx = MemoryContextSwitchTo(TopMemoryContext);
+		replicaAbortedXids = bms_add_member(replicaAbortedXids, s->replicaTransactionId);
+		MemoryContextSwitchTo(ctx);
+	}
+
 	/* Make sure we have a valid memory context and resource owner */
 	AtAbort_Memory();
 	AtAbort_ResourceOwner();
@@ -2991,6 +3054,9 @@ CommitTransactionCommand(void)
 			 * and then clean up.
 			 */
 		case TBLOCK_ABORT_PENDING:
+			if (GetCurrentTransactionIdIfAny() == FrozenTransactionId)
+				elog(FATAL, "Transaction is aborted at standby");
+
 			AbortTransaction();
 			CleanupTransaction();
 			s->blockState = TBLOCK_DEFAULT;
@@ -4880,6 +4946,14 @@ AbortSubTransaction(void)
 	/* Prevent cancel/die interrupt while cleaning up */
 	HOLD_INTERRUPTS();
 
+	/* Mark transactions involved global temp table at replica as aborted */
+	if (TransactionIdIsValid(s->replicaTransactionId))
+	{
+		MemoryContext ctx = MemoryContextSwitchTo(TopMemoryContext);
+		replicaAbortedXids = bms_add_member(replicaAbortedXids, s->replicaTransactionId);
+		MemoryContextSwitchTo(ctx);
+	}
+
 	/* Make sure we have a valid memory context and resource owner */
 	AtSubAbort_Memory();
 	AtSubAbort_ResourceOwner();

diff --git a/src/backend/access/brin/brin_revmap.c b/src/backend/access/brin/brin_revmap.c
index 647350c..ca5f22d 100644
--- a/src/backend/access/brin/brin_revmap.c
+++ b/src/backend/access/brin/brin_revmap.c
@@ -25,6 +25,7 @@
 #include "access/brin_revmap.h"
 #include "access/brin_tuple.h"
 #include "access/brin_xlog.h"
+#include "access/brin.h"
 #include "access/rmgr.h"
 #include "access/xloginsert.h"
 #include "miscadmin.h"
@@ -79,6 +80,11 @@ brinRevmapInitialize(Relation idxrel, BlockNumber *pagesPerRange,
 	meta = ReadBuffer(idxrel, BRIN_METAPAGE_BLKNO);
 	LockBuffer(meta, BUFFER_LOCK_SHARE);
 	page = BufferGetPage(meta);
+
+	if (GlobalTempRelationPageIsNotInitialized(idxrel, page))
+		brin_metapage_init(page, BrinGetPagesPerRange(idxrel),
+						   BRIN_CURRENT_VERSION);
+
 	TestForOldSnapshot(snapshot, idxrel, page);
 	metadata = (BrinMetaPageData *) PageGetContents(page);
 
diff --git a/src/backend/access/gin/ginfast.c b/src/backend/access/gin/ginfast.c
index 439a91b..8a6ac71 100644
--- a/src/backend/access/gin/ginfast.c
+++ b/src/backend/access/gin/ginfast.c
@@ -241,6 +241,16 @@ ginHeapTupleFastInsert(GinState *ginstate, GinTupleCollector *collector)
 	metabuffer = ReadBuffer(index, GIN_METAPAGE_BLKNO);
 	metapage = BufferGetPage(metabuffer);
 
+	if (GlobalTempRelationPageIsNotInitialized(index, metapage))
+	{
+		Buffer rootbuffer = ReadBuffer(index, GIN_ROOT_BLKNO);
+		LockBuffer(rootbuffer, BUFFER_LOCK_EXCLUSIVE);
+		GinInitMetabuffer(metabuffer);
+		GinInitBuffer(rootbuffer, GIN_LEAF);
+		MarkBufferDirty(rootbuffer);
+		UnlockReleaseBuffer(rootbuffer);
+	}
+
 	/*
 	 * An insertion to the pending list could logically belong anywhere in the
 	 * tree, so it conflicts with all serializable scans.  All scans acquire a
diff --git a/src/backend/access/gin/ginget.c b/src/backend/access/gin/ginget.c
index b18ae2b..41bab5d 100644
--- a/src/backend/access/gin/ginget.c
+++ b/src/backend/access/gin/ginget.c
@@ -1750,7 +1750,7 @@ collectMatchesForHeapRow(IndexScanDesc scan, pendingPosition *pos)
 /*
  * Collect all matched rows from pending list into bitmap.
  */
-static void
+static bool
 scanPendingInsert(IndexScanDesc scan, TIDBitmap *tbm, int64 *ntids)
 {
 	GinScanOpaque so = (GinScanOpaque) scan->opaque;
@@ -1774,6 +1774,12 @@ scanPendingInsert(IndexScanDesc scan, TIDBitmap *tbm, int64 *ntids)
 	LockBuffer(metabuffer, GIN_SHARE);
 	page = BufferGetPage(metabuffer);
 	TestForOldSnapshot(scan->xs_snapshot, scan->indexRelation, page);
+
+	if (GlobalTempRelationPageIsNotInitialized(scan->indexRelation, page))
+	{
+		UnlockReleaseBuffer(metabuffer);
+		return false;
+	}
 	blkno = GinPageGetMeta(page)->head;
 
 	/*
@@ -1784,7 +1790,7 @@ scanPendingInsert(IndexScanDesc scan, TIDBitmap *tbm, int64 *ntids)
 	{
 		/* No pending list, so proceed with normal scan */
 		UnlockReleaseBuffer(metabuffer);
-		return;
+		return true;
 	}
 
 	pos.pendingBuffer = ReadBuffer(scan->indexRelation, blkno);
@@ -1840,6 +1846,7 @@ scanPendingInsert(IndexScanDesc scan, TIDBitmap *tbm, int64 *ntids)
 	}
 
 	pfree(pos.hasMatchKey);
+	return true;
 }
 
 
@@ -1875,7 +1882,8 @@ gingetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
 	 * to scan the main index before the pending list, since concurrent
 	 * cleanup could then make us miss entries entirely.
 	 */
-	scanPendingInsert(scan, tbm, &ntids);
+	if (!scanPendingInsert(scan, tbm, &ntids))
+		return 0;
 
 	/*
 	 * Now scan the main index.
diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index 0cc8791..3215b6f 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -677,7 +677,10 @@ gistdoinsert(Relation r, IndexTuple itup, Size freespace,
 		if (!xlocked)
 		{
 			LockBuffer(stack->buffer, GIST_SHARE);
-			gistcheckpage(state.r, stack->buffer);
+			if (stack->blkno == GIST_ROOT_BLKNO && GlobalTempRelationPageIsNotInitialized(state.r, BufferGetPage(stack->buffer)))
+				GISTInitBuffer(stack->buffer, F_LEAF);
+			else
+				gistcheckpage(state.r, stack->buffer);
 		}
 
 		stack->page = (Page) BufferGetPage(stack->buffer);
diff --git a/src/backend/access/gist/gistget.c b/src/backend/access/gist/gistget.c
index 22d790d..4c52dbe 100644
--- a/src/backend/access/gist/gistget.c
+++ b/src/backend/access/gist/gistget.c
@@ -344,7 +344,10 @@ gistScanPage(IndexScanDesc scan, GISTSearchItem *pageItem,
 	buffer = ReadBuffer(scan->indexRelation, pageItem->blkno);
 	LockBuffer(buffer, GIST_SHARE);
 	PredicateLockPage(r, BufferGetBlockNumber(buffer), scan->xs_snapshot);
-	gistcheckpage(scan->indexRelation, buffer);
+	if (pageItem->blkno == GIST_ROOT_BLKNO && GlobalTempRelationPageIsNotInitialized(r, BufferGetPage(buffer)))
+		GISTInitBuffer(buffer, F_LEAF);
+	else
+		gistcheckpage(scan->indexRelation, buffer);
 	page = BufferGetPage(buffer);
 	TestForOldSnapshot(scan->xs_snapshot, r, page);
 	opaque = GistPageGetOpaque(page);
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index 45804d7..50b306a 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -1028,7 +1028,7 @@ gistGetFakeLSN(Relation rel)
 {
 	static XLogRecPtr counter = FirstNormalUnloggedLSN;
 
-	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	if (RelationHasSessionScope(rel))
 	{
 		/*
 		 * Temporary relations are only accessible in our session, so a simple
diff --git a/src/backend/access/hash/hashpage.c b/src/backend/access/hash/hashpage.c
index 838ee68..4f794b3 100644
--- a/src/backend/access/hash/hashpage.c
+++ b/src/backend/access/hash/hashpage.c
@@ -75,13 +75,20 @@ _hash_getbuf(Relation rel, BlockNumber blkno, int access, int flags)
 
 	buf = ReadBuffer(rel, blkno);
 
-	if (access != HASH_NOLOCK)
-		LockBuffer(buf, access);
-
 	/* ref count and lock type are correct */
 
-	_hash_checkpage(rel, buf, flags);
-
+	if (blkno == HASH_METAPAGE && GlobalTempRelationPageIsNotInitialized(rel, BufferGetPage(buf)))
+	{
+		_hash_init(rel, 0, MAIN_FORKNUM);
+		if (access != HASH_NOLOCK)
+			LockBuffer(buf, access);
+	}
+	else
+	{
+		if (access != HASH_NOLOCK)
+			LockBuffer(buf, access);
+		_hash_checkpage(rel, buf, flags);
+	}
 	return buf;
 }
 
@@ -339,7 +346,7 @@ _hash_init(Relation rel, double num_tuples, ForkNumber forkNum)
 	bool		use_wal;
 
 	/* safety check */
-	if (RelationGetNumberOfBlocksInFork(rel, forkNum) != 0)
+	if (rel->rd_rel->relpersistence != RELPERSISTENCE_SESSION && RelationGetNumberOfBlocksInFork(rel, forkNum) != 0)
 		elog(ERROR, "cannot initialize non-empty hash index \"%s\"",
 			 RelationGetRelationName(rel));
 
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 2dd8821..92df373 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -673,6 +673,7 @@ heapam_relation_copy_data(Relation rel, const RelFileNode *newrnode)
 			 * init fork of an unlogged relation.
 			 */
 			if (rel->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT ||
+				rel->rd_rel->relpersistence == RELPERSISTENCE_SESSION ||
 				(rel->rd_rel->relpersistence == RELPERSISTENCE_UNLOGGED &&
 				 forkNum == INIT_FORKNUM))
 				log_smgrcreate(newrnode, forkNum);
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index 268f869..ed3ab70 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -763,7 +763,11 @@ _bt_getbuf(Relation rel, BlockNumber blkno, int access)
 		/* Read an existing block of the relation */
 		buf = ReadBuffer(rel, blkno);
 		LockBuffer(buf, access);
-		_bt_checkpage(rel, buf);
+		/* Session temporary relation may be not yet initialized for this backend. */
+		if (blkno == BTREE_METAPAGE && GlobalTempRelationPageIsNotInitialized(rel, BufferGetPage(buf)))
+			_bt_initmetapage(BufferGetPage(buf), P_NONE, 0);
+		else
+			_bt_checkpage(rel, buf);
 	}
 	else
 	{
diff --git a/src/backend/access/spgist/spgutils.c b/src/backend/access/spgist/spgutils.c
index 45472db..a8497a2 100644
--- a/src/backend/access/spgist/spgutils.c
+++ b/src/backend/access/spgist/spgutils.c
@@ -106,6 +106,7 @@ spgGetCache(Relation index)
 		spgConfigIn in;
 		FmgrInfo   *procinfo;
 		Buffer		metabuffer;
+		Page        metapage;
 		SpGistMetaPageData *metadata;
 
 		cache = MemoryContextAllocZero(index->rd_indexcxt,
@@ -155,12 +156,32 @@ spgGetCache(Relation index)
 		metabuffer = ReadBuffer(index, SPGIST_METAPAGE_BLKNO);
 		LockBuffer(metabuffer, BUFFER_LOCK_SHARE);
 
-		metadata = SpGistPageGetMeta(BufferGetPage(metabuffer));
+		metapage = BufferGetPage(metabuffer);
+		metadata = SpGistPageGetMeta(metapage);
 
 		if (metadata->magicNumber != SPGIST_MAGIC_NUMBER)
-			elog(ERROR, "index \"%s\" is not an SP-GiST index",
-				 RelationGetRelationName(index));
+		{
+			if (GlobalTempRelationPageIsNotInitialized(index, metapage))
+			{
+				Buffer rootbuffer = ReadBuffer(index, SPGIST_ROOT_BLKNO);
+				Buffer nullbuffer = ReadBuffer(index, SPGIST_NULL_BLKNO);
+
+				SpGistInitMetapage(metapage);
+
+				LockBuffer(rootbuffer, BUFFER_LOCK_EXCLUSIVE);
+				SpGistInitPage(BufferGetPage(rootbuffer), SPGIST_LEAF);
+				MarkBufferDirty(rootbuffer);
+				UnlockReleaseBuffer(rootbuffer);
 
+				LockBuffer(nullbuffer, BUFFER_LOCK_EXCLUSIVE);
+				SpGistInitPage(BufferGetPage(nullbuffer), SPGIST_LEAF | SPGIST_NULLS);
+				MarkBufferDirty(nullbuffer);
+				UnlockReleaseBuffer(nullbuffer);
+			}
+			else
+				elog(ERROR, "index \"%s\" is not an SP-GiST index",
+					 RelationGetRelationName(index));
+		}
 		cache->lastUsedPages = metadata->lastUsedPages;
 
 		UnlockReleaseBuffer(metabuffer);
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index 1af31c2..e60bdb7 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -402,6 +402,9 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class, char relpersistence)
 		case RELPERSISTENCE_TEMP:
 			backend = BackendIdForTempRelations();
 			break;
+		case RELPERSISTENCE_SESSION:
+			backend = BackendIdForSessionRelations();
+			break;
 		case RELPERSISTENCE_UNLOGGED:
 		case RELPERSISTENCE_PERMANENT:
 			backend = InvalidBackendId;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index f6c31cc..d943b57 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3652,7 +3652,7 @@ reindex_relation(Oid relid, int flags, int options)
 		if (flags & REINDEX_REL_FORCE_INDEXES_UNLOGGED)
 			persistence = RELPERSISTENCE_UNLOGGED;
 		else if (flags & REINDEX_REL_FORCE_INDEXES_PERMANENT)
-			persistence = RELPERSISTENCE_PERMANENT;
+			persistence = rel->rd_rel->relpersistence == RELPERSISTENCE_SESSION ? RELPERSISTENCE_SESSION : RELPERSISTENCE_PERMANENT;
 		else
 			persistence = rel->rd_rel->relpersistence;
 
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index 625af8d..1e192fa 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -93,6 +93,10 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 			backend = InvalidBackendId;
 			needs_wal = false;
 			break;
+		case RELPERSISTENCE_SESSION:
+			backend = BackendIdForSessionRelations();
+			needs_wal = false;
+			break;
 		case RELPERSISTENCE_PERMANENT:
 			backend = InvalidBackendId;
 			needs_wal = true;
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index a23128d..5d131a7 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -1400,7 +1400,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
 	 */
 	if (newrelpersistence == RELPERSISTENCE_UNLOGGED)
 		reindex_flags |= REINDEX_REL_FORCE_INDEXES_UNLOGGED;
-	else if (newrelpersistence == RELPERSISTENCE_PERMANENT)
+	else if (newrelpersistence != RELPERSISTENCE_TEMP)
 		reindex_flags |= REINDEX_REL_FORCE_INDEXES_PERMANENT;
 
 	/* Report that we are now reindexing relations */
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index a13322b..be661a4 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -94,7 +94,7 @@ static HTAB *seqhashtab = NULL; /* hash table for SeqTable items */
  */
 static SeqTableData *last_used_seq = NULL;
 
-static void fill_seq_with_data(Relation rel, HeapTuple tuple);
+static void fill_seq_with_data(Relation rel, HeapTuple tuple, Buffer buf);
 static Relation lock_and_open_sequence(SeqTable seq);
 static void create_seq_hashtable(void);
 static void init_sequence(Oid relid, SeqTable *p_elm, Relation *p_rel);
@@ -222,7 +222,7 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 
 	/* now initialize the sequence's data */
 	tuple = heap_form_tuple(tupDesc, value, null);
-	fill_seq_with_data(rel, tuple);
+	fill_seq_with_data(rel, tuple, InvalidBuffer);
 
 	/* process OWNED BY if given */
 	if (owned_by)
@@ -327,7 +327,7 @@ ResetSequence(Oid seq_relid)
 	/*
 	 * Insert the modified tuple into the new storage file.
 	 */
-	fill_seq_with_data(seq_rel, tuple);
+	fill_seq_with_data(seq_rel, tuple, InvalidBuffer);
 
 	/* Clear local cache so that we don't think we have cached numbers */
 	/* Note that we do not change the currval() state */
@@ -340,18 +340,21 @@ ResetSequence(Oid seq_relid)
  * Initialize a sequence's relation with the specified tuple as content
  */
 static void
-fill_seq_with_data(Relation rel, HeapTuple tuple)
+fill_seq_with_data(Relation rel, HeapTuple tuple, Buffer buf)
 {
-	Buffer		buf;
 	Page		page;
 	sequence_magic *sm;
 	OffsetNumber offnum;
+	bool lockBuffer = false;
 
 	/* Initialize first page of relation with special magic number */
 
-	buf = ReadBuffer(rel, P_NEW);
-	Assert(BufferGetBlockNumber(buf) == 0);
-
+	if (buf == InvalidBuffer)
+	{
+		buf = ReadBuffer(rel, P_NEW);
+		Assert(BufferGetBlockNumber(buf) == 0);
+		lockBuffer = true;
+	}
 	page = BufferGetPage(buf);
 
 	PageInit(page, BufferGetPageSize(buf), sizeof(sequence_magic));
@@ -360,7 +363,8 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	/* Now insert sequence tuple */
 
-	LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
+	if (lockBuffer)
+		LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 
 	/*
 	 * Since VACUUM does not process sequences, we have to force the tuple to
@@ -410,7 +414,8 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	END_CRIT_SECTION();
 
-	UnlockReleaseBuffer(buf);
+	if (lockBuffer)
+		UnlockReleaseBuffer(buf);
 }
 
 /*
@@ -502,7 +507,7 @@ AlterSequence(ParseState *pstate, AlterSeqStmt *stmt)
 		/*
 		 * Insert the modified tuple into the new storage file.
 		 */
-		fill_seq_with_data(seqrel, newdatatuple);
+		fill_seq_with_data(seqrel, newdatatuple, InvalidBuffer);
 	}
 
 	/* process OWNED BY if given */
@@ -1178,6 +1183,17 @@ read_seq_tuple(Relation rel, Buffer *buf, HeapTuple seqdatatuple)
 	LockBuffer(*buf, BUFFER_LOCK_EXCLUSIVE);
 
 	page = BufferGetPage(*buf);
+	if (GlobalTempRelationPageIsNotInitialized(rel, page))
+	{
+		/* Initialize sequence for global temporary tables */
+		Datum		value[SEQ_COL_LASTCOL] = {0};
+		bool		null[SEQ_COL_LASTCOL] = {false};
+		HeapTuple tuple;
+		value[SEQ_COL_LASTVAL-1] = Int64GetDatumFast(1); /* start sequence with 1 */
+		tuple = heap_form_tuple(RelationGetDescr(rel), value, null);
+		fill_seq_with_data(rel, tuple, *buf);
+	}
+
 	sm = (sequence_magic *) PageGetSpecialPointer(page);
 
 	if (sm->magic != SEQ_MAGIC)
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 8d25d14..50d0402 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -587,7 +587,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	 * Check consistency of arguments
 	 */
 	if (stmt->oncommit != ONCOMMIT_NOOP
-		&& stmt->relation->relpersistence != RELPERSISTENCE_TEMP)
+		&& !IsLocalRelpersistence(stmt->relation->relpersistence))
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 				 errmsg("ON COMMIT can only be used on temporary tables")));
@@ -1772,7 +1772,8 @@ ExecuteTruncateGuts(List *explicit_rels, List *relids, List *relids_logged,
 		 * table or the current physical file to be thrown away anyway.
 		 */
 		if (rel->rd_createSubid == mySubid ||
-			rel->rd_newRelfilenodeSubid == mySubid)
+			rel->rd_newRelfilenodeSubid == mySubid ||
+			rel->rd_rel->relpersistence == RELPERSISTENCE_SESSION)
 		{
 			/* Immediate, non-rollbackable truncation is OK */
 			heap_truncate_one_rel(rel);
@@ -7708,6 +7709,12 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 						 errmsg("constraints on unlogged tables may reference only permanent or unlogged tables")));
 			break;
+		case RELPERSISTENCE_SESSION:
+			if (pkrel->rd_rel->relpersistence != RELPERSISTENCE_SESSION)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+						 errmsg("constraints on session tables may reference only session tables")));
+			break;
 		case RELPERSISTENCE_TEMP:
 			if (pkrel->rd_rel->relpersistence != RELPERSISTENCE_TEMP)
 				ereport(ERROR,
@@ -14140,6 +14147,13 @@ ATPrepChangePersistence(Relation rel, bool toLogged)
 							RelationGetRelationName(rel)),
 					 errtable(rel)));
 			break;
+		case RELPERSISTENCE_SESSION:
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					 errmsg("cannot change logged status of session table \"%s\"",
+							RelationGetRelationName(rel)),
+					 errtable(rel)));
+			break;
 		case RELPERSISTENCE_PERMANENT:
 			if (toLogged)
 				/* nothing to do */
@@ -14627,14 +14641,7 @@ PreCommit_on_commit_actions(void)
 				/* Do nothing (there shouldn't be such entries, actually) */
 				break;
 			case ONCOMMIT_DELETE_ROWS:
-
-				/*
-				 * If this transaction hasn't accessed any temporary
-				 * relations, we can skip truncating ON COMMIT DELETE ROWS
-				 * tables, as they must still be empty.
-				 */
-				if ((MyXactFlags & XACT_FLAGS_ACCESSEDTEMPNAMESPACE))
-					oids_to_truncate = lappend_oid(oids_to_truncate, oc->relid);
+				oids_to_truncate = lappend_oid(oids_to_truncate, oc->relid);
 				break;
 			case ONCOMMIT_DROP:
 				oids_to_drop = lappend_oid(oids_to_drop, oc->relid);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 3f67aaf..565c868 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3266,20 +3266,11 @@ OptTemp:	TEMPORARY					{ $$ = RELPERSISTENCE_TEMP; }
 			| TEMP						{ $$ = RELPERSISTENCE_TEMP; }
 			| LOCAL TEMPORARY			{ $$ = RELPERSISTENCE_TEMP; }
 			| LOCAL TEMP				{ $$ = RELPERSISTENCE_TEMP; }
-			| GLOBAL TEMPORARY
-				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
-				}
-			| GLOBAL TEMP
-				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
-				}
+			| GLOBAL TEMPORARY          { $$ = RELPERSISTENCE_SESSION; }
+			| GLOBAL TEMP               { $$ = RELPERSISTENCE_SESSION; }
+			| SESSION                   { $$ = RELPERSISTENCE_SESSION; }
+			| SESSION TEMPORARY         { $$ = RELPERSISTENCE_SESSION; }
+			| SESSION TEMP              { $$ = RELPERSISTENCE_SESSION; }
 			| UNLOGGED					{ $$ = RELPERSISTENCE_UNLOGGED; }
 			| /*EMPTY*/					{ $$ = RELPERSISTENCE_PERMANENT; }
 		;
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index ee47547..ea7fe4c 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -437,6 +437,14 @@ generateSerialExtraStmts(CreateStmtContext *cxt, ColumnDef *column,
 	seqstmt->options = seqoptions;
 
 	/*
+	 * Why we should not always use persistence of parent table?
+	 * Although it is prohibited to have unlogged sequences,
+	 * unlogged tables with SERIAL fields are accepted!
+	 */
+	if (cxt->relation->relpersistence != RELPERSISTENCE_UNLOGGED)
+		seqstmt->sequence->relpersistence = cxt->relation->relpersistence;
+
+	/*
 	 * If a sequence data type was specified, add it to the options.  Prepend
 	 * to the list rather than append; in case a user supplied their own AS
 	 * clause, the "redundant options" error will point to their occurrence,
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index c1dd816..dcfc134 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -2157,7 +2157,7 @@ do_autovacuum(void)
 		/*
 		 * We cannot safely process other backends' temp tables, so skip 'em.
 		 */
-		if (classForm->relpersistence == RELPERSISTENCE_TEMP)
+		if (IsLocalRelpersistence(classForm->relpersistence))
 			continue;
 
 		relid = classForm->oid;
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 07f3c93..5db79ec 100644
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -33,6 +33,7 @@
 #include "postmaster/bgwriter.h"
 #include "storage/fd.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/md.h"
 #include "storage/relfilenode.h"
 #include "storage/smgr.h"
@@ -87,6 +88,18 @@ typedef struct _MdfdVec
 
 static MemoryContext MdCxt;		/* context for all MdfdVec objects */
 
+/*
+ * Structure used to collect information created by this backend.
+ * Data of this related should be deleted on backend exit.
+ */
+typedef struct SessionRelation
+{
+	RelFileNodeBackend rnode;
+	struct SessionRelation* next;
+} SessionRelation;
+
+
+static SessionRelation* SessionRelations;
 
 /* Populate a file tag describing an md.c segment file. */
 #define INIT_MD_FILETAG(a,xx_rnode,xx_forknum,xx_segno) \
@@ -152,6 +165,45 @@ mdinit(void)
 								  ALLOCSET_DEFAULT_SIZES);
 }
 
+
+/*
+ * Delete all data of session relations and remove their pages from shared buffers.
+ * This function is called on backend exit.
+ */
+static void
+TruncateSessionRelations(int code, Datum arg)
+{
+	SessionRelation* rel;
+	for (rel = SessionRelations; rel != NULL; rel = rel->next)
+	{
+		/* Delete relation files */
+		mdunlink(rel->rnode, InvalidForkNumber, false);
+	}
+}
+
+/*
+ * Maintain information about session relations accessed by this backend.
+ * This list is needed to perform cleanup on backend exit.
+ * Session relation is linked in this list when this relation is created or opened and file doesn't exist.
+ * Such procedure guarantee that each relation is linked into list only once.
+ */
+static void
+RegisterSessionRelation(SMgrRelation reln)
+{
+	SessionRelation* rel = (SessionRelation*)MemoryContextAlloc(TopMemoryContext, sizeof(SessionRelation));
+
+	/*
+	 * Perform session relation cleanup on backend exit. We are using shared memory hook, because
+	 * cleanup should be performed before backend is disconnected from shared memory.
+	 */
+	if (SessionRelations == NULL)
+		on_shmem_exit(TruncateSessionRelations, 0);
+
+	rel->rnode = reln->smgr_rnode;
+	rel->next = SessionRelations;
+	SessionRelations = rel;
+}
+
 /*
  *	mdexists() -- Does the physical file exist?
  *
@@ -218,6 +270,8 @@ mdcreate(SMgrRelation reln, ForkNumber forkNum, bool isRedo)
 					 errmsg("could not create file \"%s\": %m", path)));
 		}
 	}
+	if (RelFileNodeBackendIsGlobalTemp(reln->smgr_rnode))
+		RegisterSessionRelation(reln);
 
 	pfree(path);
 
@@ -465,6 +519,19 @@ mdopenfork(SMgrRelation reln, ForkNumber forknum, int behavior)
 
 	if (fd < 0)
 	{
+		/*
+		 * In case of session relation access, there may be no yet files of this relation for this backend.
+		 * If so, then create file and register session relation for truncation on backend exit.
+		 */
+		if (RelFileNodeBackendIsGlobalTemp(reln->smgr_rnode))
+		{
+			fd = PathNameOpenFile(path, O_RDWR | PG_BINARY | O_CREAT);
+			if (fd >= 0)
+			{
+				RegisterSessionRelation(reln);
+				goto NewSegment;
+			}
+		}
 		if ((behavior & EXTENSION_RETURN_NULL) &&
 			FILE_POSSIBLY_DELETED(errno))
 		{
@@ -476,6 +543,7 @@ mdopenfork(SMgrRelation reln, ForkNumber forknum, int behavior)
 				 errmsg("could not open file \"%s\": %m", path)));
 	}
 
+  NewSegment:
 	pfree(path);
 
 	_fdvec_resize(reln, forknum, 1);
@@ -652,8 +720,13 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 		 * complaining.  This allows, for example, the case of trying to
 		 * update a block that was later truncated away.
 		 */
-		if (zero_damaged_pages || InRecovery)
+		if (zero_damaged_pages || InRecovery || RelFileNodeBackendIsGlobalTemp(reln->smgr_rnode))
+		{
 			MemSet(buffer, 0, BLCKSZ);
+			/* In case of session relation we need to write zero page to provide correct result of subsequent mdnblocks */
+			if (RelFileNodeBackendIsGlobalTemp(reln->smgr_rnode))
+				mdwrite(reln, forknum, blocknum, buffer, true);
+		}
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_DATA_CORRUPTED),
@@ -738,12 +811,18 @@ mdwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 BlockNumber
 mdnblocks(SMgrRelation reln, ForkNumber forknum)
 {
-	MdfdVec    *v = mdopenfork(reln, forknum, EXTENSION_FAIL);
+	/*
+	 * If we access session relation, there may be no files yet of this relation for this backend.
+	 * Pass EXTENSION_RETURN_NULL to make mdopen return NULL in this case instead of reporting error.
+	 */
+	MdfdVec    *v = mdopenfork(reln, forknum, RelFileNodeBackendIsGlobalTemp(reln->smgr_rnode)
+							   ? EXTENSION_RETURN_NULL : EXTENSION_FAIL);
 	BlockNumber nblocks;
 	BlockNumber segno = 0;
 
 	/* mdopen has opened the first segment */
-	Assert(reln->md_num_open_segs[forknum] > 0);
+	if (reln->md_num_open_segs[forknum] == 0)
+		return 0;
 
 	/*
 	 * Start from the last open segments, to avoid redundant seeks.  We have
diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c
index a87e721..2401361 100644
--- a/src/backend/utils/adt/dbsize.c
+++ b/src/backend/utils/adt/dbsize.c
@@ -994,6 +994,9 @@ pg_relation_filepath(PG_FUNCTION_ARGS)
 	/* Determine owning backend. */
 	switch (relform->relpersistence)
 	{
+		case RELPERSISTENCE_SESSION:
+			backend = BackendIdForSessionRelations();
+			break;
 		case RELPERSISTENCE_UNLOGGED:
 		case RELPERSISTENCE_PERMANENT:
 			backend = InvalidBackendId;
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 585dcee..ce8852c 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -1098,6 +1098,10 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
 	relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
 	switch (relation->rd_rel->relpersistence)
 	{
+		case RELPERSISTENCE_SESSION:
+			relation->rd_backend = BackendIdForSessionRelations();
+			relation->rd_islocaltemp = false;
+			break;
 		case RELPERSISTENCE_UNLOGGED:
 		case RELPERSISTENCE_PERMANENT:
 			relation->rd_backend = InvalidBackendId;
@@ -3301,6 +3305,10 @@ RelationBuildLocalRelation(const char *relname,
 	rel->rd_rel->relpersistence = relpersistence;
 	switch (relpersistence)
 	{
+		case RELPERSISTENCE_SESSION:
+			rel->rd_backend = BackendIdForSessionRelations();
+			rel->rd_islocaltemp = false;
+			break;
 		case RELPERSISTENCE_UNLOGGED:
 		case RELPERSISTENCE_PERMANENT:
 			rel->rd_backend = InvalidBackendId;
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index bf69adc..fa7479c 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15637,8 +15637,8 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 											 tbinfo->dobj.catId.oid, false);
 
 		appendPQExpBuffer(q, "CREATE %s%s %s",
-						  tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED ?
-						  "UNLOGGED " : "",
+						  tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED ? "UNLOGGED "
+						  : tbinfo->relpersistence == RELPERSISTENCE_SESSION ? "SESSION " : "",
 						  reltypename,
 						  qualrelname);
 
diff --git a/src/common/relpath.c b/src/common/relpath.c
index 62b9553..cef99d2 100644
--- a/src/common/relpath.c
+++ b/src/common/relpath.c
@@ -166,7 +166,18 @@ GetRelationPath(Oid dbNode, Oid spcNode, Oid relNode,
 		}
 		else
 		{
-			if (forkNumber != MAIN_FORKNUM)
+			/*
+			 * Session relations are distinguished from local temp relations by adding
+			 * SessionRelFirstBackendId offset to backendId.
+			 * These is no need to separate them at file system level, so just subtract SessionRelFirstBackendId
+			 * to avoid too long file names.
+			 * Segments of session relations have the same prefix (t%d_) as local temporary relations
+			 * to make it possible to cleanup them in the same way as local temporary relation files.
+			 */
+			 if (backendId >= SessionRelFirstBackendId)
+				 backendId -= SessionRelFirstBackendId;
+
+			 if (forkNumber != MAIN_FORKNUM)
 				path = psprintf("base/%u/t%d_%u_%s",
 								dbNode, backendId, relNode,
 								forkNames[forkNumber]);
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index 090b6ba..6a39663 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -165,6 +165,7 @@ typedef FormData_pg_class *Form_pg_class;
 #define		  RELPERSISTENCE_PERMANENT	'p' /* regular table */
 #define		  RELPERSISTENCE_UNLOGGED	'u' /* unlogged permanent table */
 #define		  RELPERSISTENCE_TEMP		't' /* temporary table */
+#define		  RELPERSISTENCE_SESSION	's' /* session table */
 
 /* default selection for replica identity (primary key or nothing) */
 #define		  REPLICA_IDENTITY_DEFAULT	'd'
diff --git a/src/include/storage/backendid.h b/src/include/storage/backendid.h
index 70ef8eb..f226e7c 100644
--- a/src/include/storage/backendid.h
+++ b/src/include/storage/backendid.h
@@ -22,6 +22,13 @@ typedef int BackendId;			/* unique currently active backend identifier */
 
 #define InvalidBackendId		(-1)
 
+/*
+ * We need to distinguish local and global temporary relations by RelFileNodeBackend.
+ * The least invasive change is to add some special bias value to backend id (since 
+ * maximal number of backed is limited by MaxBackends).
+ */
+#define SessionRelFirstBackendId (0x40000000)
+
 extern PGDLLIMPORT BackendId MyBackendId;	/* backend id of this backend */
 
 /* backend id of our parallel session leader, or InvalidBackendId if none */
@@ -34,4 +41,10 @@ extern PGDLLIMPORT BackendId ParallelMasterBackendId;
 #define BackendIdForTempRelations() \
 	(ParallelMasterBackendId == InvalidBackendId ? MyBackendId : ParallelMasterBackendId)
 
+
+#define BackendIdForSessionRelations() \
+	(BackendIdForTempRelations() + SessionRelFirstBackendId)
+
+#define IsSessionRelationBackendId(id) ((id) >= SessionRelFirstBackendId)
+
 #endif							/* BACKENDID_H */
diff --git a/src/include/storage/bufpage.h b/src/include/storage/bufpage.h
index 4ef6d8d..bac7a31 100644
--- a/src/include/storage/bufpage.h
+++ b/src/include/storage/bufpage.h
@@ -229,6 +229,13 @@ typedef PageHeaderData *PageHeader;
 #define PageIsNew(page) (((PageHeader) (page))->pd_upper == 0)
 
 /*
+ * Page of temporary relation is not initialized
+ */
+#define GlobalTempRelationPageIsNotInitialized(rel, page) \
+	((rel)->rd_rel->relpersistence == RELPERSISTENCE_SESSION && PageIsNew(page))
+
+
+/*
  * PageGetItemId
  *		Returns an item identifier of a page.
  */
diff --git a/src/include/storage/relfilenode.h b/src/include/storage/relfilenode.h
index 586500a..20aec72 100644
--- a/src/include/storage/relfilenode.h
+++ b/src/include/storage/relfilenode.h
@@ -75,10 +75,25 @@ typedef struct RelFileNodeBackend
 	BackendId	backend;
 } RelFileNodeBackend;
 
+/*
+ * Check whether it is local or global temporary relation, which data belongs only to one backend.
+ */
 #define RelFileNodeBackendIsTemp(rnode) \
 	((rnode).backend != InvalidBackendId)
 
 /*
+ * Check whether it is global temporary relation which metadata is shared by all sessions,
+ * but data is private for the current session.
+ */
+#define RelFileNodeBackendIsGlobalTemp(rnode) IsSessionRelationBackendId((rnode).backend)
+
+/*
+ * Check whether it is local temporary relation which exists only in this backend.
+ */
+#define RelFileNodeBackendIsLocalTemp(rnode) \
+	(RelFileNodeBackendIsTemp(rnode) && !RelFileNodeBackendIsGlobalTemp(rnode))
+
+/*
  * Note: RelFileNodeEquals and RelFileNodeBackendEquals compare relNode first
  * since that is most likely to be different in two unequal RelFileNodes.  It
  * is probably redundant to compare spcNode if the other fields are found equal,
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index a5cf804..d42830f 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -327,6 +327,18 @@ typedef struct StdRdOptions
 	((relation)->rd_options ? \
 	 ((StdRdOptions *) (relation)->rd_options)->parallel_workers : (defaultpw))
 
+/*
+ * Relation persistence is either TEMP either SESSION
+ */
+#define IsLocalRelpersistence(relpersistence) \
+	((relpersistence) == RELPERSISTENCE_TEMP || (relpersistence) == RELPERSISTENCE_SESSION)
+
+/*
+ * Relation is either global either local temp table
+ */
+#define RelationHasSessionScope(relation) \
+	IsLocalRelpersistence(((relation)->rd_rel->relpersistence))
+
 /* ViewOptions->check_option values */
 typedef enum ViewOptCheckOption
 {
@@ -335,6 +347,7 @@ typedef enum ViewOptCheckOption
 	VIEW_OPTION_CHECK_OPTION_CASCADED
 } ViewOptCheckOption;
 
+
 /*
  * ViewOptions
  *		Contents of rd_options for views
@@ -526,7 +539,7 @@ typedef struct ViewOptions
  *		True if relation's pages are stored in local buffers.
  */
 #define RelationUsesLocalBuffers(relation) \
-	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	RelationHasSessionScope(relation)
 
 /*
  * RELATION_IS_LOCAL
diff --git a/src/test/isolation/expected/inherit-global-temp.out b/src/test/isolation/expected/inherit-global-temp.out
new file mode 100644
index 0000000..6114f8c
--- /dev/null
+++ b/src/test/isolation/expected/inherit-global-temp.out
@@ -0,0 +1,218 @@
+Parsed test spec with 2 sessions
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s1_select_p s1_select_c s2_select_p s2_select_c
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s1_select_p: SELECT a FROM inh_global_parent;
+a              
+
+1              
+2              
+3              
+4              
+step s1_select_c: SELECT a FROM inh_global_temp_child_s1;
+a              
+
+3              
+4              
+step s2_select_p: SELECT a FROM inh_global_parent;
+a              
+
+1              
+2              
+5              
+6              
+step s2_select_c: SELECT a FROM inh_global_temp_child_s2;
+a              
+
+5              
+6              
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s1_update_p s1_update_c s1_select_p s1_select_c s2_select_p s2_select_c
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s1_update_p: UPDATE inh_global_parent SET a = 11 WHERE a = 1;
+step s1_update_c: UPDATE inh_global_parent SET a = 13 WHERE a IN (3, 5);
+step s1_select_p: SELECT a FROM inh_global_parent;
+a              
+
+2              
+11             
+4              
+13             
+step s1_select_c: SELECT a FROM inh_global_temp_child_s1;
+a              
+
+4              
+13             
+step s2_select_p: SELECT a FROM inh_global_parent;
+a              
+
+2              
+11             
+5              
+6              
+step s2_select_c: SELECT a FROM inh_global_temp_child_s2;
+a              
+
+5              
+6              
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s2_update_c s1_select_p s1_select_c s2_select_p s2_select_c
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s2_update_c: UPDATE inh_global_parent SET a = 15 WHERE a IN (3, 5);
+step s1_select_p: SELECT a FROM inh_global_parent;
+a              
+
+1              
+2              
+3              
+4              
+step s1_select_c: SELECT a FROM inh_global_temp_child_s1;
+a              
+
+3              
+4              
+step s2_select_p: SELECT a FROM inh_global_parent;
+a              
+
+1              
+2              
+6              
+15             
+step s2_select_c: SELECT a FROM inh_global_temp_child_s2;
+a              
+
+6              
+15             
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s1_delete_p s1_delete_c s1_select_p s1_select_c s2_select_p s2_select_c
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s1_delete_p: DELETE FROM inh_global_parent WHERE a = 2;
+step s1_delete_c: DELETE FROM inh_global_parent WHERE a IN (4, 6);
+step s1_select_p: SELECT a FROM inh_global_parent;
+a              
+
+1              
+3              
+step s1_select_c: SELECT a FROM inh_global_temp_child_s1;
+a              
+
+3              
+step s2_select_p: SELECT a FROM inh_global_parent;
+a              
+
+1              
+5              
+6              
+step s2_select_c: SELECT a FROM inh_global_temp_child_s2;
+a              
+
+5              
+6              
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s2_delete_c s1_select_p s1_select_c s2_select_p s2_select_c
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s2_delete_c: DELETE FROM inh_global_parent WHERE a IN (4, 6);
+step s1_select_p: SELECT a FROM inh_global_parent;
+a              
+
+1              
+2              
+3              
+4              
+step s1_select_c: SELECT a FROM inh_global_temp_child_s1;
+a              
+
+3              
+4              
+step s2_select_p: SELECT a FROM inh_global_parent;
+a              
+
+1              
+2              
+5              
+step s2_select_c: SELECT a FROM inh_global_temp_child_s2;
+a              
+
+5              
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s1_truncate_p s1_select_p s1_select_c s2_select_p s2_select_c
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s1_truncate_p: TRUNCATE inh_global_parent;
+step s1_select_p: SELECT a FROM inh_global_parent;
+a              
+
+step s1_select_c: SELECT a FROM inh_global_temp_child_s1;
+a              
+
+step s2_select_p: SELECT a FROM inh_global_parent;
+a              
+
+5              
+6              
+step s2_select_c: SELECT a FROM inh_global_temp_child_s2;
+a              
+
+5              
+6              
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s2_truncate_p s1_select_p s1_select_c s2_select_p s2_select_c
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s2_truncate_p: TRUNCATE inh_global_parent;
+step s1_select_p: SELECT a FROM inh_global_parent;
+a              
+
+3              
+4              
+step s1_select_c: SELECT a FROM inh_global_temp_child_s1;
+a              
+
+3              
+4              
+step s2_select_p: SELECT a FROM inh_global_parent;
+a              
+
+step s2_select_c: SELECT a FROM inh_global_temp_child_s2;
+a              
+
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s1_begin s1_truncate_p s2_select_p s1_commit
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s1_begin: BEGIN;
+step s1_truncate_p: TRUNCATE inh_global_parent;
+step s2_select_p: SELECT a FROM inh_global_parent; <waiting ...>
+step s1_commit: COMMIT;
+step s2_select_p: <... completed>
+a              
+
+5              
+6              
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s1_begin s1_truncate_p s2_select_c s1_commit
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s1_begin: BEGIN;
+step s1_truncate_p: TRUNCATE inh_global_parent;
+step s2_select_c: SELECT a FROM inh_global_temp_child_s2; <waiting ...>
+step s1_commit: COMMIT;
+step s2_select_c: <... completed>
+a              
+
+5              
+6              
diff --git a/src/test/isolation/isolation_schedule b/src/test/isolation/isolation_schedule
index a2fa192..ef7aa85 100644
--- a/src/test/isolation/isolation_schedule
+++ b/src/test/isolation/isolation_schedule
@@ -88,3 +88,4 @@ test: plpgsql-toast
 test: truncate-conflict
 test: serializable-parallel
 test: serializable-parallel-2
+test: inherit-global-temp
diff --git a/src/test/isolation/specs/inherit-global-temp.spec b/src/test/isolation/specs/inherit-global-temp.spec
new file mode 100644
index 0000000..5e95dd6
--- /dev/null
+++ b/src/test/isolation/specs/inherit-global-temp.spec
@@ -0,0 +1,73 @@
+# This is a copy of the inherit-temp test with little changes for global temporary tables.
+#
+
+setup
+{
+  CREATE TABLE inh_global_parent (a int);
+}
+
+teardown
+{
+  DROP TABLE inh_global_parent;
+}
+
+# Session 1 executes actions which act directly on both the parent and
+# its child.  Abbreviation "c" is used for queries working on the child
+# and "p" on the parent.
+session "s1"
+setup
+{
+  CREATE GLOBAL TEMPORARY TABLE inh_global_temp_child_s1 () INHERITS (inh_global_parent);
+}
+step "s1_begin" { BEGIN; }
+step "s1_truncate_p" { TRUNCATE inh_global_parent; }
+step "s1_select_p" { SELECT a FROM inh_global_parent; }
+step "s1_select_c" { SELECT a FROM inh_global_temp_child_s1; }
+step "s1_insert_p" { INSERT INTO inh_global_parent VALUES (1), (2); }
+step "s1_insert_c" { INSERT INTO inh_global_temp_child_s1 VALUES (3), (4); }
+step "s1_update_p" { UPDATE inh_global_parent SET a = 11 WHERE a = 1; }
+step "s1_update_c" { UPDATE inh_global_parent SET a = 13 WHERE a IN (3, 5); }
+step "s1_delete_p" { DELETE FROM inh_global_parent WHERE a = 2; }
+step "s1_delete_c" { DELETE FROM inh_global_parent WHERE a IN (4, 6); }
+step "s1_commit" { COMMIT; }
+teardown
+{
+  DROP TABLE inh_global_temp_child_s1;
+}
+
+# Session 2 executes actions on the parent which act only on the child.
+session "s2"
+setup
+{
+  CREATE GLOBAL TEMPORARY TABLE inh_global_temp_child_s2 () INHERITS (inh_global_parent);
+}
+step "s2_truncate_p" { TRUNCATE inh_global_parent; }
+step "s2_select_p" { SELECT a FROM inh_global_parent; }
+step "s2_select_c" { SELECT a FROM inh_global_temp_child_s2; }
+step "s2_insert_c" { INSERT INTO inh_global_temp_child_s2 VALUES (5), (6); }
+step "s2_update_c" { UPDATE inh_global_parent SET a = 15 WHERE a IN (3, 5); }
+step "s2_delete_c" { DELETE FROM inh_global_parent WHERE a IN (4, 6); }
+teardown
+{
+  DROP TABLE inh_global_temp_child_s2;
+}
+
+# Check INSERT behavior across sessions
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s1_select_p" "s1_select_c" "s2_select_p" "s2_select_c"
+
+# Check UPDATE behavior across sessions
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s1_update_p" "s1_update_c" "s1_select_p" "s1_select_c" "s2_select_p" "s2_select_c"
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s2_update_c" "s1_select_p" "s1_select_c" "s2_select_p" "s2_select_c"
+
+# Check DELETE behavior across sessions
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s1_delete_p" "s1_delete_c" "s1_select_p" "s1_select_c" "s2_select_p" "s2_select_c"
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s2_delete_c" "s1_select_p" "s1_select_c" "s2_select_p" "s2_select_c"
+
+# Check TRUNCATE behavior across sessions
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s1_truncate_p" "s1_select_p" "s1_select_c" "s2_select_p" "s2_select_c"
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s2_truncate_p" "s1_select_p" "s1_select_c" "s2_select_p" "s2_select_c"
+
+# TRUNCATE on a parent tree does not block access to temporary child relation
+# of another session, and blocks when scanning the parent.
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s1_begin" "s1_truncate_p" "s2_select_p" "s1_commit"
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s1_begin" "s1_truncate_p" "s2_select_c" "s1_commit"
diff --git a/src/test/regress/expected/global_temp.out b/src/test/regress/expected/global_temp.out
new file mode 100644
index 0000000..ae1adb6
--- /dev/null
+++ b/src/test/regress/expected/global_temp.out
@@ -0,0 +1,247 @@
+--
+-- GLOBAL TEMP
+-- Test global temp relations
+--
+-- Test ON COMMIT DELETE ROWS
+CREATE GLOBAL TEMP TABLE global_temptest(col int) ON COMMIT DELETE ROWS;
+BEGIN;
+INSERT INTO global_temptest VALUES (1);
+INSERT INTO global_temptest VALUES (2);
+SELECT * FROM global_temptest;
+ col 
+-----
+   1
+   2
+(2 rows)
+
+COMMIT;
+SELECT * FROM global_temptest;
+ col 
+-----
+(0 rows)
+
+DROP TABLE global_temptest;
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temptest(col) ON COMMIT DELETE ROWS AS SELECT 1;
+SELECT * FROM global_temptest;
+ col 
+-----
+   1
+(1 row)
+
+COMMIT;
+SELECT * FROM global_temptest;
+ col 
+-----
+(0 rows)
+
+DROP TABLE global_temptest;
+-- Test foreign keys
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temptest1(col int PRIMARY KEY);
+CREATE GLOBAL TEMP TABLE global_temptest2(col int REFERENCES global_temptest1)
+  ON COMMIT DELETE ROWS;
+INSERT INTO global_temptest1 VALUES (1);
+INSERT INTO global_temptest2 VALUES (1);
+COMMIT;
+SELECT * FROM global_temptest1;
+ col 
+-----
+   1
+(1 row)
+
+SELECT * FROM global_temptest2;
+ col 
+-----
+(0 rows)
+
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temptest3(col int PRIMARY KEY) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE global_temptest4(col int REFERENCES global_temptest3);
+COMMIT;
+ERROR:  unsupported ON COMMIT and foreign key combination
+DETAIL:  Table "global_temptest4" references "global_temptest3", but they do not have the same ON COMMIT setting.
+-- For partitioned temp tables, ON COMMIT actions ignore storage-less
+-- partitioned tables.
+BEGIN;
+CREATE GLOBAL TEMP TABLE temp_parted_oncommit (a int)
+  PARTITION BY LIST (a) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE temp_parted_oncommit_1
+  PARTITION OF temp_parted_oncommit
+  FOR VALUES IN (1) ON COMMIT DELETE ROWS;
+INSERT INTO temp_parted_oncommit VALUES (1);
+COMMIT;
+-- partitions are emptied by the previous commit
+SELECT * FROM temp_parted_oncommit;
+ a 
+---
+(0 rows)
+
+DROP TABLE temp_parted_oncommit;
+-- Using ON COMMIT DELETE on a partitioned table does not remove
+-- all rows if partitions preserve their data.
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temp_parted_oncommit_test (a int)
+  PARTITION BY LIST (a) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE global_temp_parted_oncommit_test1
+  PARTITION OF global_temp_parted_oncommit_test
+  FOR VALUES IN (1) ON COMMIT PRESERVE ROWS;
+INSERT INTO global_temp_parted_oncommit_test VALUES (1);
+COMMIT;
+-- Data from the remaining partition is still here as its rows are
+-- preserved.
+SELECT * FROM global_temp_parted_oncommit_test;
+ a 
+---
+ 1
+(1 row)
+
+-- two relations remain in this case.
+SELECT relname FROM pg_class WHERE relname LIKE 'global_temp_parted_oncommit_test%';
+              relname              
+-----------------------------------
+ global_temp_parted_oncommit_test
+ global_temp_parted_oncommit_test1
+(2 rows)
+
+DROP TABLE global_temp_parted_oncommit_test;
+-- Check dependencies between ON COMMIT actions with inheritance trees.
+-- Data on the parent is removed, and the child goes away.
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temp_inh_oncommit_test (a int) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE global_temp_inh_oncommit_test1 ()
+  INHERITS(global_temp_inh_oncommit_test) ON COMMIT PRESERVE ROWS;
+INSERT INTO global_temp_inh_oncommit_test1 VALUES (1);
+INSERT INTO global_temp_inh_oncommit_test VALUES (1);
+COMMIT;
+SELECT * FROM global_temp_inh_oncommit_test;
+ a 
+---
+ 1
+(1 row)
+
+-- two relations remain
+SELECT relname FROM pg_class WHERE relname LIKE 'global_temp_inh_oncommit_test%';
+            relname             
+--------------------------------
+ global_temp_inh_oncommit_test
+ global_temp_inh_oncommit_test1
+(2 rows)
+
+DROP TABLE global_temp_inh_oncommit_test1;
+DROP TABLE global_temp_inh_oncommit_test;
+-- Global temp table cannot inherit from temporary relation
+BEGIN;
+CREATE TEMP TABLE global_temp_table (a int) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE global_temp_table1 ()
+  INHERITS(global_temp_table) ON COMMIT PRESERVE ROWS;
+ERROR:  cannot inherit from temporary relation "global_temp_table"
+ROLLBACK;
+-- Temp table can inherit from global temporary relation
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temp_table (a int) ON COMMIT DELETE ROWS;
+CREATE TEMP TABLE temp_table1 ()
+  INHERITS(global_temp_table) ON COMMIT PRESERVE ROWS;
+CREATE TEMP TABLE temp_table2 ()
+  INHERITS(global_temp_table) ON COMMIT DELETE ROWS;
+INSERT INTO temp_table2 VALUES (2);
+INSERT INTO temp_table1 VALUES (1);
+INSERT INTO global_temp_table VALUES (0);
+SELECT * FROM global_temp_table;
+ a 
+---
+ 0
+ 1
+ 2
+(3 rows)
+
+COMMIT;
+SELECT * FROM global_temp_table;
+ a 
+---
+ 1
+(1 row)
+
+DROP TABLE temp_table2;
+DROP TABLE temp_table1;
+DROP TABLE global_temp_table;
+-- Global temp table can inherit from normal relation
+BEGIN;
+CREATE TABLE normal_table (a int);
+CREATE GLOBAL TEMP TABLE temp_table1 ()
+  INHERITS(normal_table) ON COMMIT PRESERVE ROWS;
+CREATE GLOBAL TEMP TABLE temp_table2 ()
+  INHERITS(normal_table) ON COMMIT DELETE ROWS;
+INSERT INTO temp_table2 VALUES (2);
+INSERT INTO temp_table1 VALUES (1);
+INSERT INTO normal_table VALUES (0);
+SELECT * FROM normal_table;
+ a 
+---
+ 0
+ 1
+ 2
+(3 rows)
+
+COMMIT;
+SELECT * FROM normal_table;
+ a 
+---
+ 0
+ 1
+(2 rows)
+
+DROP TABLE temp_table2;
+DROP TABLE temp_table1;
+DROP TABLE normal_table;
+-- Check SERIAL and BIGSERIAL pseudo-types
+CREATE GLOBAL TEMP TABLE global_temp_table ( aid BIGSERIAL, bid SERIAL );
+CREATE SEQUENCE test_sequence;
+INSERT INTO global_temp_table DEFAULT VALUES;
+INSERT INTO global_temp_table DEFAULT VALUES;
+INSERT INTO global_temp_table DEFAULT VALUES;
+SELECT * FROM global_temp_table;
+ aid | bid 
+-----+-----
+   1 |   1
+   2 |   2
+   3 |   3
+(3 rows)
+
+SELECT NEXTVAL( 'test_sequence' );
+ nextval 
+---------
+       1
+(1 row)
+
+\c
+SELECT * FROM global_temp_table;
+ aid | bid 
+-----+-----
+(0 rows)
+
+SELECT NEXTVAL( 'test_sequence' );
+ nextval 
+---------
+       2
+(1 row)
+
+INSERT INTO global_temp_table DEFAULT VALUES;
+INSERT INTO global_temp_table DEFAULT VALUES;
+INSERT INTO global_temp_table DEFAULT VALUES;
+SELECT * FROM global_temp_table;
+ aid | bid 
+-----+-----
+   1 |   1
+   2 |   2
+   3 |   3
+(3 rows)
+
+SELECT NEXTVAL( 'test_sequence' );
+ nextval 
+---------
+       3
+(1 row)
+
+DROP TABLE global_temp_table;
+DROP SEQUENCE test_sequence;
diff --git a/src/test/regress/expected/session_table.out b/src/test/regress/expected/session_table.out
new file mode 100644
index 0000000..1b9b3f4
--- /dev/null
+++ b/src/test/regress/expected/session_table.out
@@ -0,0 +1,64 @@
+create session table my_private_table(x integer primary key, y integer);
+insert into my_private_table values (generate_series(1,10000), generate_series(1,10000));
+select count(*) from my_private_table;
+ count 
+-------
+ 10000
+(1 row)
+
+\c
+select count(*) from my_private_table;
+ count 
+-------
+     0
+(1 row)
+
+select * from my_private_table where x=10001;
+ x | y 
+---+---
+(0 rows)
+
+insert into my_private_table values (generate_series(1,100000), generate_series(1,100000));
+create index on my_private_table(y);
+select * from my_private_table where x=10001;
+   x   |   y   
+-------+-------
+ 10001 | 10001
+(1 row)
+
+select * from my_private_table where y=10001;
+   x   |   y   
+-------+-------
+ 10001 | 10001
+(1 row)
+
+select count(*) from my_private_table;
+ count  
+--------
+ 100000
+(1 row)
+
+\c
+select * from my_private_table where x=100001;
+ x | y 
+---+---
+(0 rows)
+
+select * from my_private_table order by y desc limit 1;
+ x | y 
+---+---
+(0 rows)
+
+insert into my_private_table values (generate_series(1,100000), generate_series(1,100000));
+select * from my_private_table where x=100001;
+ x | y 
+---+---
+(0 rows)
+
+select * from my_private_table order by y desc limit 1;
+   x    |   y    
+--------+--------
+ 100000 | 100000
+(1 row)
+
+drop table  my_private_table;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index fc0f141..507cf7d 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -107,7 +107,7 @@ test: json jsonb json_encoding jsonpath jsonpath_encoding jsonb_jsonpath
 # NB: temp.sql does a reconnect which transiently uses 2 connections,
 # so keep this parallel group to at most 19 tests
 # ----------
-test: plancache limit plpgsql copy2 temp domain rangefuncs prepare conversion truncate alter_table sequence polymorphism rowtypes returning largeobject with xml
+test: plancache limit plpgsql copy2 temp global_temp session_table domain rangefuncs prepare conversion truncate alter_table sequence polymorphism rowtypes returning largeobject with xml
 
 # ----------
 # Another group of parallel tests
diff --git a/src/test/regress/serial_schedule b/src/test/regress/serial_schedule
index 68ac56a..3890777 100644
--- a/src/test/regress/serial_schedule
+++ b/src/test/regress/serial_schedule
@@ -172,6 +172,8 @@ test: limit
 test: plpgsql
 test: copy2
 test: temp
+test: global_temp
+test: session_table
 test: domain
 test: rangefuncs
 test: prepare
diff --git a/src/test/regress/sql/global_temp.sql b/src/test/regress/sql/global_temp.sql
new file mode 100644
index 0000000..3058b9b
--- /dev/null
+++ b/src/test/regress/sql/global_temp.sql
@@ -0,0 +1,151 @@
+--
+-- GLOBAL TEMP
+-- Test global temp relations
+--
+
+-- Test ON COMMIT DELETE ROWS
+
+CREATE GLOBAL TEMP TABLE global_temptest(col int) ON COMMIT DELETE ROWS;
+
+BEGIN;
+INSERT INTO global_temptest VALUES (1);
+INSERT INTO global_temptest VALUES (2);
+
+SELECT * FROM global_temptest;
+COMMIT;
+
+SELECT * FROM global_temptest;
+
+DROP TABLE global_temptest;
+
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temptest(col) ON COMMIT DELETE ROWS AS SELECT 1;
+
+SELECT * FROM global_temptest;
+COMMIT;
+
+SELECT * FROM global_temptest;
+
+DROP TABLE global_temptest;
+
+-- Test foreign keys
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temptest1(col int PRIMARY KEY);
+CREATE GLOBAL TEMP TABLE global_temptest2(col int REFERENCES global_temptest1)
+  ON COMMIT DELETE ROWS;
+INSERT INTO global_temptest1 VALUES (1);
+INSERT INTO global_temptest2 VALUES (1);
+COMMIT;
+SELECT * FROM global_temptest1;
+SELECT * FROM global_temptest2;
+
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temptest3(col int PRIMARY KEY) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE global_temptest4(col int REFERENCES global_temptest3);
+COMMIT;
+
+-- For partitioned temp tables, ON COMMIT actions ignore storage-less
+-- partitioned tables.
+BEGIN;
+CREATE GLOBAL TEMP TABLE temp_parted_oncommit (a int)
+  PARTITION BY LIST (a) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE temp_parted_oncommit_1
+  PARTITION OF temp_parted_oncommit
+  FOR VALUES IN (1) ON COMMIT DELETE ROWS;
+INSERT INTO temp_parted_oncommit VALUES (1);
+COMMIT;
+-- partitions are emptied by the previous commit
+SELECT * FROM temp_parted_oncommit;
+DROP TABLE temp_parted_oncommit;
+
+-- Using ON COMMIT DELETE on a partitioned table does not remove
+-- all rows if partitions preserve their data.
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temp_parted_oncommit_test (a int)
+  PARTITION BY LIST (a) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE global_temp_parted_oncommit_test1
+  PARTITION OF global_temp_parted_oncommit_test
+  FOR VALUES IN (1) ON COMMIT PRESERVE ROWS;
+INSERT INTO global_temp_parted_oncommit_test VALUES (1);
+COMMIT;
+-- Data from the remaining partition is still here as its rows are
+-- preserved.
+SELECT * FROM global_temp_parted_oncommit_test;
+-- two relations remain in this case.
+SELECT relname FROM pg_class WHERE relname LIKE 'global_temp_parted_oncommit_test%';
+DROP TABLE global_temp_parted_oncommit_test;
+
+-- Check dependencies between ON COMMIT actions with inheritance trees.
+-- Data on the parent is removed, and the child goes away.
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temp_inh_oncommit_test (a int) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE global_temp_inh_oncommit_test1 ()
+  INHERITS(global_temp_inh_oncommit_test) ON COMMIT PRESERVE ROWS;
+INSERT INTO global_temp_inh_oncommit_test1 VALUES (1);
+INSERT INTO global_temp_inh_oncommit_test VALUES (1);
+COMMIT;
+SELECT * FROM global_temp_inh_oncommit_test;
+-- two relations remain
+SELECT relname FROM pg_class WHERE relname LIKE 'global_temp_inh_oncommit_test%';
+DROP TABLE global_temp_inh_oncommit_test1;
+DROP TABLE global_temp_inh_oncommit_test;
+
+-- Global temp table cannot inherit from temporary relation
+BEGIN;
+CREATE TEMP TABLE global_temp_table (a int) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE global_temp_table1 ()
+  INHERITS(global_temp_table) ON COMMIT PRESERVE ROWS;
+ROLLBACK;
+
+-- Temp table can inherit from global temporary relation
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temp_table (a int) ON COMMIT DELETE ROWS;
+CREATE TEMP TABLE temp_table1 ()
+  INHERITS(global_temp_table) ON COMMIT PRESERVE ROWS;
+CREATE TEMP TABLE temp_table2 ()
+  INHERITS(global_temp_table) ON COMMIT DELETE ROWS;
+INSERT INTO temp_table2 VALUES (2);
+INSERT INTO temp_table1 VALUES (1);
+INSERT INTO global_temp_table VALUES (0);
+SELECT * FROM global_temp_table;
+COMMIT;
+SELECT * FROM global_temp_table;
+DROP TABLE temp_table2;
+DROP TABLE temp_table1;
+DROP TABLE global_temp_table;
+
+-- Global temp table can inherit from normal relation
+BEGIN;
+CREATE TABLE normal_table (a int);
+CREATE GLOBAL TEMP TABLE temp_table1 ()
+  INHERITS(normal_table) ON COMMIT PRESERVE ROWS;
+CREATE GLOBAL TEMP TABLE temp_table2 ()
+  INHERITS(normal_table) ON COMMIT DELETE ROWS;
+INSERT INTO temp_table2 VALUES (2);
+INSERT INTO temp_table1 VALUES (1);
+INSERT INTO normal_table VALUES (0);
+SELECT * FROM normal_table;
+COMMIT;
+SELECT * FROM normal_table;
+DROP TABLE temp_table2;
+DROP TABLE temp_table1;
+DROP TABLE normal_table;
+
+-- Check SERIAL and BIGSERIAL pseudo-types
+CREATE GLOBAL TEMP TABLE global_temp_table ( aid BIGSERIAL, bid SERIAL );
+CREATE SEQUENCE test_sequence;
+INSERT INTO global_temp_table DEFAULT VALUES;
+INSERT INTO global_temp_table DEFAULT VALUES;
+INSERT INTO global_temp_table DEFAULT VALUES;
+SELECT * FROM global_temp_table;
+SELECT NEXTVAL( 'test_sequence' );
+\c
+SELECT * FROM global_temp_table;
+SELECT NEXTVAL( 'test_sequence' );
+INSERT INTO global_temp_table DEFAULT VALUES;
+INSERT INTO global_temp_table DEFAULT VALUES;
+INSERT INTO global_temp_table DEFAULT VALUES;
+SELECT * FROM global_temp_table;
+SELECT NEXTVAL( 'test_sequence' );
+DROP TABLE global_temp_table;
+DROP SEQUENCE test_sequence;
diff --git a/src/test/regress/sql/session_table.sql b/src/test/regress/sql/session_table.sql
new file mode 100644
index 0000000..c6663dc
--- /dev/null
+++ b/src/test/regress/sql/session_table.sql
@@ -0,0 +1,18 @@
+create session table my_private_table(x integer primary key, y integer);
+insert into my_private_table values (generate_series(1,10000), generate_series(1,10000));
+select count(*) from my_private_table;
+\c
+select count(*) from my_private_table;
+select * from my_private_table where x=10001;
+insert into my_private_table values (generate_series(1,100000), generate_series(1,100000));
+create index on my_private_table(y);
+select * from my_private_table where x=10001;
+select * from my_private_table where y=10001;
+select count(*) from my_private_table;
+\c
+select * from my_private_table where x=100001;
+select * from my_private_table order by y desc limit 1;
+insert into my_private_table values (generate_series(1,100000), generate_series(1,100000));
+select * from my_private_table where x=100001;
+select * from my_private_table order by y desc limit 1;
+drop table  my_private_table;

diff --git a/src/backend/access/brin/brin_revmap.c b/src/backend/access/brin/brin_revmap.c
index 647350c..ca5f22d 100644
--- a/src/backend/access/brin/brin_revmap.c
+++ b/src/backend/access/brin/brin_revmap.c
@@ -25,6 +25,7 @@
 #include "access/brin_revmap.h"
 #include "access/brin_tuple.h"
 #include "access/brin_xlog.h"
+#include "access/brin.h"
 #include "access/rmgr.h"
 #include "access/xloginsert.h"
 #include "miscadmin.h"
@@ -79,6 +80,11 @@ brinRevmapInitialize(Relation idxrel, BlockNumber *pagesPerRange,
 	meta = ReadBuffer(idxrel, BRIN_METAPAGE_BLKNO);
 	LockBuffer(meta, BUFFER_LOCK_SHARE);
 	page = BufferGetPage(meta);
+
+	if (GlobalTempRelationPageIsNotInitialized(idxrel, page))
+		brin_metapage_init(page, BrinGetPagesPerRange(idxrel),
+						   BRIN_CURRENT_VERSION);
+
 	TestForOldSnapshot(snapshot, idxrel, page);
 	metadata = (BrinMetaPageData *) PageGetContents(page);
 
diff --git a/src/backend/access/gin/ginfast.c b/src/backend/access/gin/ginfast.c
index 439a91b..8a6ac71 100644
--- a/src/backend/access/gin/ginfast.c
+++ b/src/backend/access/gin/ginfast.c
@@ -241,6 +241,16 @@ ginHeapTupleFastInsert(GinState *ginstate, GinTupleCollector *collector)
 	metabuffer = ReadBuffer(index, GIN_METAPAGE_BLKNO);
 	metapage = BufferGetPage(metabuffer);
 
+	if (GlobalTempRelationPageIsNotInitialized(index, metapage))
+	{
+		Buffer rootbuffer = ReadBuffer(index, GIN_ROOT_BLKNO);
+		LockBuffer(rootbuffer, BUFFER_LOCK_EXCLUSIVE);
+		GinInitMetabuffer(metabuffer);
+		GinInitBuffer(rootbuffer, GIN_LEAF);
+		MarkBufferDirty(rootbuffer);
+		UnlockReleaseBuffer(rootbuffer);
+	}
+
 	/*
 	 * An insertion to the pending list could logically belong anywhere in the
 	 * tree, so it conflicts with all serializable scans.  All scans acquire a
diff --git a/src/backend/access/gin/ginget.c b/src/backend/access/gin/ginget.c
index b18ae2b..41bab5d 100644
--- a/src/backend/access/gin/ginget.c
+++ b/src/backend/access/gin/ginget.c
@@ -1750,7 +1750,7 @@ collectMatchesForHeapRow(IndexScanDesc scan, pendingPosition *pos)
 /*
  * Collect all matched rows from pending list into bitmap.
  */
-static void
+static bool
 scanPendingInsert(IndexScanDesc scan, TIDBitmap *tbm, int64 *ntids)
 {
 	GinScanOpaque so = (GinScanOpaque) scan->opaque;
@@ -1774,6 +1774,12 @@ scanPendingInsert(IndexScanDesc scan, TIDBitmap *tbm, int64 *ntids)
 	LockBuffer(metabuffer, GIN_SHARE);
 	page = BufferGetPage(metabuffer);
 	TestForOldSnapshot(scan->xs_snapshot, scan->indexRelation, page);
+
+	if (GlobalTempRelationPageIsNotInitialized(scan->indexRelation, page))
+	{
+		UnlockReleaseBuffer(metabuffer);
+		return false;
+	}
 	blkno = GinPageGetMeta(page)->head;
 
 	/*
@@ -1784,7 +1790,7 @@ scanPendingInsert(IndexScanDesc scan, TIDBitmap *tbm, int64 *ntids)
 	{
 		/* No pending list, so proceed with normal scan */
 		UnlockReleaseBuffer(metabuffer);
-		return;
+		return true;
 	}
 
 	pos.pendingBuffer = ReadBuffer(scan->indexRelation, blkno);
@@ -1840,6 +1846,7 @@ scanPendingInsert(IndexScanDesc scan, TIDBitmap *tbm, int64 *ntids)
 	}
 
 	pfree(pos.hasMatchKey);
+	return true;
 }
 
 
@@ -1875,7 +1882,8 @@ gingetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
 	 * to scan the main index before the pending list, since concurrent
 	 * cleanup could then make us miss entries entirely.
 	 */
-	scanPendingInsert(scan, tbm, &ntids);
+	if (!scanPendingInsert(scan, tbm, &ntids))
+		return 0;
 
 	/*
 	 * Now scan the main index.
diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index 0cc8791..3215b6f 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -677,7 +677,10 @@ gistdoinsert(Relation r, IndexTuple itup, Size freespace,
 		if (!xlocked)
 		{
 			LockBuffer(stack->buffer, GIST_SHARE);
-			gistcheckpage(state.r, stack->buffer);
+			if (stack->blkno == GIST_ROOT_BLKNO && GlobalTempRelationPageIsNotInitialized(state.r, BufferGetPage(stack->buffer)))
+				GISTInitBuffer(stack->buffer, F_LEAF);
+			else
+				gistcheckpage(state.r, stack->buffer);
 		}
 
 		stack->page = (Page) BufferGetPage(stack->buffer);
diff --git a/src/backend/access/gist/gistget.c b/src/backend/access/gist/gistget.c
index 22d790d..4c52dbe 100644
--- a/src/backend/access/gist/gistget.c
+++ b/src/backend/access/gist/gistget.c
@@ -344,7 +344,10 @@ gistScanPage(IndexScanDesc scan, GISTSearchItem *pageItem,
 	buffer = ReadBuffer(scan->indexRelation, pageItem->blkno);
 	LockBuffer(buffer, GIST_SHARE);
 	PredicateLockPage(r, BufferGetBlockNumber(buffer), scan->xs_snapshot);
-	gistcheckpage(scan->indexRelation, buffer);
+	if (pageItem->blkno == GIST_ROOT_BLKNO && GlobalTempRelationPageIsNotInitialized(r, BufferGetPage(buffer)))
+		GISTInitBuffer(buffer, F_LEAF);
+	else
+		gistcheckpage(scan->indexRelation, buffer);
 	page = BufferGetPage(buffer);
 	TestForOldSnapshot(scan->xs_snapshot, r, page);
 	opaque = GistPageGetOpaque(page);
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index 45804d7..50b306a 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -1028,7 +1028,7 @@ gistGetFakeLSN(Relation rel)
 {
 	static XLogRecPtr counter = FirstNormalUnloggedLSN;
 
-	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	if (RelationHasSessionScope(rel))
 	{
 		/*
 		 * Temporary relations are only accessible in our session, so a simple
diff --git a/src/backend/access/hash/hashpage.c b/src/backend/access/hash/hashpage.c
index 838ee68..4f794b3 100644
--- a/src/backend/access/hash/hashpage.c
+++ b/src/backend/access/hash/hashpage.c
@@ -75,13 +75,20 @@ _hash_getbuf(Relation rel, BlockNumber blkno, int access, int flags)
 
 	buf = ReadBuffer(rel, blkno);
 
-	if (access != HASH_NOLOCK)
-		LockBuffer(buf, access);
-
 	/* ref count and lock type are correct */
 
-	_hash_checkpage(rel, buf, flags);
-
+	if (blkno == HASH_METAPAGE && GlobalTempRelationPageIsNotInitialized(rel, BufferGetPage(buf)))
+	{
+		_hash_init(rel, 0, MAIN_FORKNUM);
+		if (access != HASH_NOLOCK)
+			LockBuffer(buf, access);
+	}
+	else
+	{
+		if (access != HASH_NOLOCK)
+			LockBuffer(buf, access);
+		_hash_checkpage(rel, buf, flags);
+	}
 	return buf;
 }
 
@@ -339,7 +346,7 @@ _hash_init(Relation rel, double num_tuples, ForkNumber forkNum)
 	bool		use_wal;
 
 	/* safety check */
-	if (RelationGetNumberOfBlocksInFork(rel, forkNum) != 0)
+	if (rel->rd_rel->relpersistence != RELPERSISTENCE_SESSION && RelationGetNumberOfBlocksInFork(rel, forkNum) != 0)
 		elog(ERROR, "cannot initialize non-empty hash index \"%s\"",
 			 RelationGetRelationName(rel));
 
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 2dd8821..92df373 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -673,6 +673,7 @@ heapam_relation_copy_data(Relation rel, const RelFileNode *newrnode)
 			 * init fork of an unlogged relation.
 			 */
 			if (rel->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT ||
+				rel->rd_rel->relpersistence == RELPERSISTENCE_SESSION ||
 				(rel->rd_rel->relpersistence == RELPERSISTENCE_UNLOGGED &&
 				 forkNum == INIT_FORKNUM))
 				log_smgrcreate(newrnode, forkNum);
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index 268f869..ed3ab70 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -763,7 +763,11 @@ _bt_getbuf(Relation rel, BlockNumber blkno, int access)
 		/* Read an existing block of the relation */
 		buf = ReadBuffer(rel, blkno);
 		LockBuffer(buf, access);
-		_bt_checkpage(rel, buf);
+		/* Session temporary relation may be not yet initialized for this backend. */
+		if (blkno == BTREE_METAPAGE && GlobalTempRelationPageIsNotInitialized(rel, BufferGetPage(buf)))
+			_bt_initmetapage(BufferGetPage(buf), P_NONE, 0);
+		else
+			_bt_checkpage(rel, buf);
 	}
 	else
 	{
diff --git a/src/backend/access/spgist/spgutils.c b/src/backend/access/spgist/spgutils.c
index 45472db..a8497a2 100644
--- a/src/backend/access/spgist/spgutils.c
+++ b/src/backend/access/spgist/spgutils.c
@@ -106,6 +106,7 @@ spgGetCache(Relation index)
 		spgConfigIn in;
 		FmgrInfo   *procinfo;
 		Buffer		metabuffer;
+		Page        metapage;
 		SpGistMetaPageData *metadata;
 
 		cache = MemoryContextAllocZero(index->rd_indexcxt,
@@ -155,12 +156,32 @@ spgGetCache(Relation index)
 		metabuffer = ReadBuffer(index, SPGIST_METAPAGE_BLKNO);
 		LockBuffer(metabuffer, BUFFER_LOCK_SHARE);
 
-		metadata = SpGistPageGetMeta(BufferGetPage(metabuffer));
+		metapage = BufferGetPage(metabuffer);
+		metadata = SpGistPageGetMeta(metapage);
 
 		if (metadata->magicNumber != SPGIST_MAGIC_NUMBER)
-			elog(ERROR, "index \"%s\" is not an SP-GiST index",
-				 RelationGetRelationName(index));
+		{
+			if (GlobalTempRelationPageIsNotInitialized(index, metapage))
+			{
+				Buffer rootbuffer = ReadBuffer(index, SPGIST_ROOT_BLKNO);
+				Buffer nullbuffer = ReadBuffer(index, SPGIST_NULL_BLKNO);
+
+				SpGistInitMetapage(metapage);
+
+				LockBuffer(rootbuffer, BUFFER_LOCK_EXCLUSIVE);
+				SpGistInitPage(BufferGetPage(rootbuffer), SPGIST_LEAF);
+				MarkBufferDirty(rootbuffer);
+				UnlockReleaseBuffer(rootbuffer);
 
+				LockBuffer(nullbuffer, BUFFER_LOCK_EXCLUSIVE);
+				SpGistInitPage(BufferGetPage(nullbuffer), SPGIST_LEAF | SPGIST_NULLS);
+				MarkBufferDirty(nullbuffer);
+				UnlockReleaseBuffer(nullbuffer);
+			}
+			else
+				elog(ERROR, "index \"%s\" is not an SP-GiST index",
+					 RelationGetRelationName(index));
+		}
 		cache->lastUsedPages = metadata->lastUsedPages;
 
 		UnlockReleaseBuffer(metabuffer);
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index 1af31c2..e60bdb7 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -402,6 +402,9 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class, char relpersistence)
 		case RELPERSISTENCE_TEMP:
 			backend = BackendIdForTempRelations();
 			break;
+		case RELPERSISTENCE_SESSION:
+			backend = BackendIdForSessionRelations();
+			break;
 		case RELPERSISTENCE_UNLOGGED:
 		case RELPERSISTENCE_PERMANENT:
 			backend = InvalidBackendId;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index f6c31cc..d943b57 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3652,7 +3652,7 @@ reindex_relation(Oid relid, int flags, int options)
 		if (flags & REINDEX_REL_FORCE_INDEXES_UNLOGGED)
 			persistence = RELPERSISTENCE_UNLOGGED;
 		else if (flags & REINDEX_REL_FORCE_INDEXES_PERMANENT)
-			persistence = RELPERSISTENCE_PERMANENT;
+			persistence = rel->rd_rel->relpersistence == RELPERSISTENCE_SESSION ? RELPERSISTENCE_SESSION : RELPERSISTENCE_PERMANENT;
 		else
 			persistence = rel->rd_rel->relpersistence;
 
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index 625af8d..1e192fa 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -93,6 +93,10 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 			backend = InvalidBackendId;
 			needs_wal = false;
 			break;
+		case RELPERSISTENCE_SESSION:
+			backend = BackendIdForSessionRelations();
+			needs_wal = false;
+			break;
 		case RELPERSISTENCE_PERMANENT:
 			backend = InvalidBackendId;
 			needs_wal = true;
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 7accb95..9f2ea48 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -102,7 +102,7 @@ static int	acquire_inherited_sample_rows(Relation onerel, int elevel,
 										  HeapTuple *rows, int targrows,
 										  double *totalrows, double *totaldeadrows);
 static void update_attstats(Oid relid, bool inh,
-							int natts, VacAttrStats **vacattrstats);
+							int natts, VacAttrStats **vacattrstats, bool is_global_temp);
 static Datum std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 static Datum ind_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 
@@ -318,6 +318,7 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
+	bool        is_global_temp = onerel->rd_rel->relpersistence == RELPERSISTENCE_SESSION;
 
 	if (inh)
 		ereport(elevel,
@@ -575,14 +576,14 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 		 * pg_statistic for columns we didn't process, we leave them alone.)
 		 */
 		update_attstats(RelationGetRelid(onerel), inh,
-						attr_cnt, vacattrstats);
+						attr_cnt, vacattrstats, is_global_temp);
 
 		for (ind = 0; ind < nindexes; ind++)
 		{
 			AnlIndexData *thisdata = &indexdata[ind];
 
 			update_attstats(RelationGetRelid(Irel[ind]), false,
-							thisdata->attr_cnt, thisdata->vacattrstats);
+							thisdata->attr_cnt, thisdata->vacattrstats, is_global_temp);
 		}
 
 		/*
@@ -1425,7 +1426,7 @@ acquire_inherited_sample_rows(Relation onerel, int elevel,
  *		by taking a self-exclusive lock on the relation in analyze_rel().
  */
 static void
-update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
+update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats, bool is_global_temp)
 {
 	Relation	sd;
 	int			attno;
@@ -1527,30 +1528,42 @@ update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
 			}
 		}
 
-		/* Is there already a pg_statistic tuple for this attribute? */
-		oldtup = SearchSysCache3(STATRELATTINH,
-								 ObjectIdGetDatum(relid),
-								 Int16GetDatum(stats->attr->attnum),
-								 BoolGetDatum(inh));
-
-		if (HeapTupleIsValid(oldtup))
+		if (is_global_temp)
 		{
-			/* Yes, replace it */
-			stup = heap_modify_tuple(oldtup,
-									 RelationGetDescr(sd),
-									 values,
-									 nulls,
-									 replaces);
-			ReleaseSysCache(oldtup);
-			CatalogTupleUpdate(sd, &stup->t_self, stup);
+			stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
+			InsertSysCache(STATRELATTINH,
+						   ObjectIdGetDatum(relid),
+						   Int16GetDatum(stats->attr->attnum),
+						   BoolGetDatum(inh),
+						   0,
+						   stup);
 		}
 		else
 		{
-			/* No, insert new tuple */
-			stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
-			CatalogTupleInsert(sd, stup);
-		}
+			/* Is there already a pg_statistic tuple for this attribute? */
+			oldtup = SearchSysCache3(STATRELATTINH,
+									 ObjectIdGetDatum(relid),
+									 Int16GetDatum(stats->attr->attnum),
+									 BoolGetDatum(inh));
 
+			if (HeapTupleIsValid(oldtup))
+			{
+				/* Yes, replace it */
+				stup = heap_modify_tuple(oldtup,
+										 RelationGetDescr(sd),
+										 values,
+										 nulls,
+										 replaces);
+				ReleaseSysCache(oldtup);
+				CatalogTupleUpdate(sd, &stup->t_self, stup);
+			}
+			else
+			{
+				/* No, insert new tuple */
+				stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
+				CatalogTupleInsert(sd, stup);
+			}
+		}
 		heap_freetuple(stup);
 	}
 
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index a23128d..5d131a7 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -1400,7 +1400,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
 	 */
 	if (newrelpersistence == RELPERSISTENCE_UNLOGGED)
 		reindex_flags |= REINDEX_REL_FORCE_INDEXES_UNLOGGED;
-	else if (newrelpersistence == RELPERSISTENCE_PERMANENT)
+	else if (newrelpersistence != RELPERSISTENCE_TEMP)
 		reindex_flags |= REINDEX_REL_FORCE_INDEXES_PERMANENT;
 
 	/* Report that we are now reindexing relations */
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index a13322b..be661a4 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -94,7 +94,7 @@ static HTAB *seqhashtab = NULL; /* hash table for SeqTable items */
  */
 static SeqTableData *last_used_seq = NULL;
 
-static void fill_seq_with_data(Relation rel, HeapTuple tuple);
+static void fill_seq_with_data(Relation rel, HeapTuple tuple, Buffer buf);
 static Relation lock_and_open_sequence(SeqTable seq);
 static void create_seq_hashtable(void);
 static void init_sequence(Oid relid, SeqTable *p_elm, Relation *p_rel);
@@ -222,7 +222,7 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 
 	/* now initialize the sequence's data */
 	tuple = heap_form_tuple(tupDesc, value, null);
-	fill_seq_with_data(rel, tuple);
+	fill_seq_with_data(rel, tuple, InvalidBuffer);
 
 	/* process OWNED BY if given */
 	if (owned_by)
@@ -327,7 +327,7 @@ ResetSequence(Oid seq_relid)
 	/*
 	 * Insert the modified tuple into the new storage file.
 	 */
-	fill_seq_with_data(seq_rel, tuple);
+	fill_seq_with_data(seq_rel, tuple, InvalidBuffer);
 
 	/* Clear local cache so that we don't think we have cached numbers */
 	/* Note that we do not change the currval() state */
@@ -340,18 +340,21 @@ ResetSequence(Oid seq_relid)
  * Initialize a sequence's relation with the specified tuple as content
  */
 static void
-fill_seq_with_data(Relation rel, HeapTuple tuple)
+fill_seq_with_data(Relation rel, HeapTuple tuple, Buffer buf)
 {
-	Buffer		buf;
 	Page		page;
 	sequence_magic *sm;
 	OffsetNumber offnum;
+	bool lockBuffer = false;
 
 	/* Initialize first page of relation with special magic number */
 
-	buf = ReadBuffer(rel, P_NEW);
-	Assert(BufferGetBlockNumber(buf) == 0);
-
+	if (buf == InvalidBuffer)
+	{
+		buf = ReadBuffer(rel, P_NEW);
+		Assert(BufferGetBlockNumber(buf) == 0);
+		lockBuffer = true;
+	}
 	page = BufferGetPage(buf);
 
 	PageInit(page, BufferGetPageSize(buf), sizeof(sequence_magic));
@@ -360,7 +363,8 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	/* Now insert sequence tuple */
 
-	LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
+	if (lockBuffer)
+		LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 
 	/*
 	 * Since VACUUM does not process sequences, we have to force the tuple to
@@ -410,7 +414,8 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	END_CRIT_SECTION();
 
-	UnlockReleaseBuffer(buf);
+	if (lockBuffer)
+		UnlockReleaseBuffer(buf);
 }
 
 /*
@@ -502,7 +507,7 @@ AlterSequence(ParseState *pstate, AlterSeqStmt *stmt)
 		/*
 		 * Insert the modified tuple into the new storage file.
 		 */
-		fill_seq_with_data(seqrel, newdatatuple);
+		fill_seq_with_data(seqrel, newdatatuple, InvalidBuffer);
 	}
 
 	/* process OWNED BY if given */
@@ -1178,6 +1183,17 @@ read_seq_tuple(Relation rel, Buffer *buf, HeapTuple seqdatatuple)
 	LockBuffer(*buf, BUFFER_LOCK_EXCLUSIVE);
 
 	page = BufferGetPage(*buf);
+	if (GlobalTempRelationPageIsNotInitialized(rel, page))
+	{
+		/* Initialize sequence for global temporary tables */
+		Datum		value[SEQ_COL_LASTCOL] = {0};
+		bool		null[SEQ_COL_LASTCOL] = {false};
+		HeapTuple tuple;
+		value[SEQ_COL_LASTVAL-1] = Int64GetDatumFast(1); /* start sequence with 1 */
+		tuple = heap_form_tuple(RelationGetDescr(rel), value, null);
+		fill_seq_with_data(rel, tuple, *buf);
+	}
+
 	sm = (sequence_magic *) PageGetSpecialPointer(page);
 
 	if (sm->magic != SEQ_MAGIC)
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 8d25d14..50d0402 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -587,7 +587,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	 * Check consistency of arguments
 	 */
 	if (stmt->oncommit != ONCOMMIT_NOOP
-		&& stmt->relation->relpersistence != RELPERSISTENCE_TEMP)
+		&& !IsLocalRelpersistence(stmt->relation->relpersistence))
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 				 errmsg("ON COMMIT can only be used on temporary tables")));
@@ -1772,7 +1772,8 @@ ExecuteTruncateGuts(List *explicit_rels, List *relids, List *relids_logged,
 		 * table or the current physical file to be thrown away anyway.
 		 */
 		if (rel->rd_createSubid == mySubid ||
-			rel->rd_newRelfilenodeSubid == mySubid)
+			rel->rd_newRelfilenodeSubid == mySubid ||
+			rel->rd_rel->relpersistence == RELPERSISTENCE_SESSION)
 		{
 			/* Immediate, non-rollbackable truncation is OK */
 			heap_truncate_one_rel(rel);
@@ -7708,6 +7709,12 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 						 errmsg("constraints on unlogged tables may reference only permanent or unlogged tables")));
 			break;
+		case RELPERSISTENCE_SESSION:
+			if (pkrel->rd_rel->relpersistence != RELPERSISTENCE_SESSION)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+						 errmsg("constraints on session tables may reference only session tables")));
+			break;
 		case RELPERSISTENCE_TEMP:
 			if (pkrel->rd_rel->relpersistence != RELPERSISTENCE_TEMP)
 				ereport(ERROR,
@@ -14140,6 +14147,13 @@ ATPrepChangePersistence(Relation rel, bool toLogged)
 							RelationGetRelationName(rel)),
 					 errtable(rel)));
 			break;
+		case RELPERSISTENCE_SESSION:
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					 errmsg("cannot change logged status of session table \"%s\"",
+							RelationGetRelationName(rel)),
+					 errtable(rel)));
+			break;
 		case RELPERSISTENCE_PERMANENT:
 			if (toLogged)
 				/* nothing to do */
@@ -14627,14 +14641,7 @@ PreCommit_on_commit_actions(void)
 				/* Do nothing (there shouldn't be such entries, actually) */
 				break;
 			case ONCOMMIT_DELETE_ROWS:
-
-				/*
-				 * If this transaction hasn't accessed any temporary
-				 * relations, we can skip truncating ON COMMIT DELETE ROWS
-				 * tables, as they must still be empty.
-				 */
-				if ((MyXactFlags & XACT_FLAGS_ACCESSEDTEMPNAMESPACE))
-					oids_to_truncate = lappend_oid(oids_to_truncate, oc->relid);
+				oids_to_truncate = lappend_oid(oids_to_truncate, oc->relid);
 				break;
 			case ONCOMMIT_DROP:
 				oids_to_drop = lappend_oid(oids_to_drop, oc->relid);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 3f67aaf..565c868 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3266,20 +3266,11 @@ OptTemp:	TEMPORARY					{ $$ = RELPERSISTENCE_TEMP; }
 			| TEMP						{ $$ = RELPERSISTENCE_TEMP; }
 			| LOCAL TEMPORARY			{ $$ = RELPERSISTENCE_TEMP; }
 			| LOCAL TEMP				{ $$ = RELPERSISTENCE_TEMP; }
-			| GLOBAL TEMPORARY
-				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
-				}
-			| GLOBAL TEMP
-				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
-				}
+			| GLOBAL TEMPORARY          { $$ = RELPERSISTENCE_SESSION; }
+			| GLOBAL TEMP               { $$ = RELPERSISTENCE_SESSION; }
+			| SESSION                   { $$ = RELPERSISTENCE_SESSION; }
+			| SESSION TEMPORARY         { $$ = RELPERSISTENCE_SESSION; }
+			| SESSION TEMP              { $$ = RELPERSISTENCE_SESSION; }
 			| UNLOGGED					{ $$ = RELPERSISTENCE_UNLOGGED; }
 			| /*EMPTY*/					{ $$ = RELPERSISTENCE_PERMANENT; }
 		;
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index ee47547..ea7fe4c 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -437,6 +437,14 @@ generateSerialExtraStmts(CreateStmtContext *cxt, ColumnDef *column,
 	seqstmt->options = seqoptions;
 
 	/*
+	 * Why we should not always use persistence of parent table?
+	 * Although it is prohibited to have unlogged sequences,
+	 * unlogged tables with SERIAL fields are accepted!
+	 */
+	if (cxt->relation->relpersistence != RELPERSISTENCE_UNLOGGED)
+		seqstmt->sequence->relpersistence = cxt->relation->relpersistence;
+
+	/*
 	 * If a sequence data type was specified, add it to the options.  Prepend
 	 * to the list rather than append; in case a user supplied their own AS
 	 * clause, the "redundant options" error will point to their occurrence,
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index c1dd816..dcfc134 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -2157,7 +2157,7 @@ do_autovacuum(void)
 		/*
 		 * We cannot safely process other backends' temp tables, so skip 'em.
 		 */
-		if (classForm->relpersistence == RELPERSISTENCE_TEMP)
+		if (IsLocalRelpersistence(classForm->relpersistence))
 			continue;
 
 		relid = classForm->oid;
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 07f3c93..5db79ec 100644
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -33,6 +33,7 @@
 #include "postmaster/bgwriter.h"
 #include "storage/fd.h"
 #include "storage/bufmgr.h"
+#include "storage/ipc.h"
 #include "storage/md.h"
 #include "storage/relfilenode.h"
 #include "storage/smgr.h"
@@ -87,6 +88,18 @@ typedef struct _MdfdVec
 
 static MemoryContext MdCxt;		/* context for all MdfdVec objects */
 
+/*
+ * Structure used to collect information created by this backend.
+ * Data of this related should be deleted on backend exit.
+ */
+typedef struct SessionRelation
+{
+	RelFileNodeBackend rnode;
+	struct SessionRelation* next;
+} SessionRelation;
+
+
+static SessionRelation* SessionRelations;
 
 /* Populate a file tag describing an md.c segment file. */
 #define INIT_MD_FILETAG(a,xx_rnode,xx_forknum,xx_segno) \
@@ -152,6 +165,45 @@ mdinit(void)
 								  ALLOCSET_DEFAULT_SIZES);
 }
 
+
+/*
+ * Delete all data of session relations and remove their pages from shared buffers.
+ * This function is called on backend exit.
+ */
+static void
+TruncateSessionRelations(int code, Datum arg)
+{
+	SessionRelation* rel;
+	for (rel = SessionRelations; rel != NULL; rel = rel->next)
+	{
+		/* Delete relation files */
+		mdunlink(rel->rnode, InvalidForkNumber, false);
+	}
+}
+
+/*
+ * Maintain information about session relations accessed by this backend.
+ * This list is needed to perform cleanup on backend exit.
+ * Session relation is linked in this list when this relation is created or opened and file doesn't exist.
+ * Such procedure guarantee that each relation is linked into list only once.
+ */
+static void
+RegisterSessionRelation(SMgrRelation reln)
+{
+	SessionRelation* rel = (SessionRelation*)MemoryContextAlloc(TopMemoryContext, sizeof(SessionRelation));
+
+	/*
+	 * Perform session relation cleanup on backend exit. We are using shared memory hook, because
+	 * cleanup should be performed before backend is disconnected from shared memory.
+	 */
+	if (SessionRelations == NULL)
+		on_shmem_exit(TruncateSessionRelations, 0);
+
+	rel->rnode = reln->smgr_rnode;
+	rel->next = SessionRelations;
+	SessionRelations = rel;
+}
+
 /*
  *	mdexists() -- Does the physical file exist?
  *
@@ -218,6 +270,8 @@ mdcreate(SMgrRelation reln, ForkNumber forkNum, bool isRedo)
 					 errmsg("could not create file \"%s\": %m", path)));
 		}
 	}
+	if (RelFileNodeBackendIsGlobalTemp(reln->smgr_rnode))
+		RegisterSessionRelation(reln);
 
 	pfree(path);
 
@@ -465,6 +519,19 @@ mdopenfork(SMgrRelation reln, ForkNumber forknum, int behavior)
 
 	if (fd < 0)
 	{
+		/*
+		 * In case of session relation access, there may be no yet files of this relation for this backend.
+		 * If so, then create file and register session relation for truncation on backend exit.
+		 */
+		if (RelFileNodeBackendIsGlobalTemp(reln->smgr_rnode))
+		{
+			fd = PathNameOpenFile(path, O_RDWR | PG_BINARY | O_CREAT);
+			if (fd >= 0)
+			{
+				RegisterSessionRelation(reln);
+				goto NewSegment;
+			}
+		}
 		if ((behavior & EXTENSION_RETURN_NULL) &&
 			FILE_POSSIBLY_DELETED(errno))
 		{
@@ -476,6 +543,7 @@ mdopenfork(SMgrRelation reln, ForkNumber forknum, int behavior)
 				 errmsg("could not open file \"%s\": %m", path)));
 	}
 
+  NewSegment:
 	pfree(path);
 
 	_fdvec_resize(reln, forknum, 1);
@@ -652,8 +720,13 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 		 * complaining.  This allows, for example, the case of trying to
 		 * update a block that was later truncated away.
 		 */
-		if (zero_damaged_pages || InRecovery)
+		if (zero_damaged_pages || InRecovery || RelFileNodeBackendIsGlobalTemp(reln->smgr_rnode))
+		{
 			MemSet(buffer, 0, BLCKSZ);
+			/* In case of session relation we need to write zero page to provide correct result of subsequent mdnblocks */
+			if (RelFileNodeBackendIsGlobalTemp(reln->smgr_rnode))
+				mdwrite(reln, forknum, blocknum, buffer, true);
+		}
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_DATA_CORRUPTED),
@@ -738,12 +811,18 @@ mdwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 BlockNumber
 mdnblocks(SMgrRelation reln, ForkNumber forknum)
 {
-	MdfdVec    *v = mdopenfork(reln, forknum, EXTENSION_FAIL);
+	/*
+	 * If we access session relation, there may be no files yet of this relation for this backend.
+	 * Pass EXTENSION_RETURN_NULL to make mdopen return NULL in this case instead of reporting error.
+	 */
+	MdfdVec    *v = mdopenfork(reln, forknum, RelFileNodeBackendIsGlobalTemp(reln->smgr_rnode)
+							   ? EXTENSION_RETURN_NULL : EXTENSION_FAIL);
 	BlockNumber nblocks;
 	BlockNumber segno = 0;
 
 	/* mdopen has opened the first segment */
-	Assert(reln->md_num_open_segs[forknum] > 0);
+	if (reln->md_num_open_segs[forknum] == 0)
+		return 0;
 
 	/*
 	 * Start from the last open segments, to avoid redundant seeks.  We have
diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c
index a87e721..2401361 100644
--- a/src/backend/utils/adt/dbsize.c
+++ b/src/backend/utils/adt/dbsize.c
@@ -994,6 +994,9 @@ pg_relation_filepath(PG_FUNCTION_ARGS)
 	/* Determine owning backend. */
 	switch (relform->relpersistence)
 	{
+		case RELPERSISTENCE_SESSION:
+			backend = BackendIdForSessionRelations();
+			break;
 		case RELPERSISTENCE_UNLOGGED:
 		case RELPERSISTENCE_PERMANENT:
 			backend = InvalidBackendId;
diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c
index c3e7d94..6d86c28 100644
--- a/src/backend/utils/cache/catcache.c
+++ b/src/backend/utils/cache/catcache.c
@@ -1191,6 +1191,111 @@ SearchCatCache4(CatCache *cache,
 	return SearchCatCacheInternal(cache, 4, v1, v2, v3, v4);
 }
 
+
+void InsertCatCache(CatCache *cache,
+					Datum v1, Datum v2, Datum v3, Datum v4,
+					HeapTuple tuple)
+{
+	Datum		arguments[CATCACHE_MAXKEYS];
+	uint32		hashValue;
+	Index		hashIndex;
+	CatCTup    *ct;
+	dlist_iter	iter;
+	dlist_head *bucket;
+	int         nkeys = cache->cc_nkeys;
+	MemoryContext oldcxt;
+	int         i;
+
+	/*
+	 * one-time startup overhead for each cache
+	 */
+	if (unlikely(cache->cc_tupdesc == NULL))
+		CatalogCacheInitializeCache(cache);
+
+	/* Initialize local parameter array */
+	arguments[0] = v1;
+	arguments[1] = v2;
+	arguments[2] = v3;
+	arguments[3] = v4;
+	/*
+	 * find the hash bucket in which to look for the tuple
+	 */
+	hashValue = CatalogCacheComputeHashValue(cache, nkeys, v1, v2, v3, v4);
+	hashIndex = HASH_INDEX(hashValue, cache->cc_nbuckets);
+
+	/*
+	 * scan the hash bucket until we find a match or exhaust our tuples
+	 *
+	 * Note: it's okay to use dlist_foreach here, even though we modify the
+	 * dlist within the loop, because we don't continue the loop afterwards.
+	 */
+	bucket = &cache->cc_bucket[hashIndex];
+	dlist_foreach(iter, bucket)
+	{
+		ct = dlist_container(CatCTup, cache_elem, iter.cur);
+
+		if (ct->dead)
+			continue;			/* ignore dead entries */
+
+		if (ct->hash_value != hashValue)
+			continue;			/* quickly skip entry if wrong hash val */
+
+		if (!CatalogCacheCompareTuple(cache, nkeys, ct->keys, arguments))
+			continue;
+
+		/*
+		 * If it's a positive entry, bump its refcount and return it. If it's
+		 * negative, we can report failure to the caller.
+		 */
+		if (ct->tuple.t_len == tuple->t_len)
+		{
+			memcpy((char *) ct->tuple.t_data,
+				   (const char *) tuple->t_data,
+				   tuple->t_len);
+			return;
+		}
+		dlist_delete(&ct->cache_elem);
+		pfree(ct);
+		cache->cc_ntup -= 1;
+		CacheHdr->ch_ntup -= 1;
+		break;
+	}
+	/* Allocate memory for CatCTup and the cached tuple in one go */
+	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
+
+	ct = (CatCTup *) palloc(sizeof(CatCTup) +
+							MAXIMUM_ALIGNOF + tuple->t_len);
+	ct->tuple.t_len = tuple->t_len;
+	ct->tuple.t_self = tuple->t_self;
+	ct->tuple.t_tableOid = tuple->t_tableOid;
+	ct->tuple.t_data = (HeapTupleHeader)
+		MAXALIGN(((char *) ct) + sizeof(CatCTup));
+	/* copy tuple contents */
+	memcpy((char *) ct->tuple.t_data,
+		   (const char *) tuple->t_data,
+		   tuple->t_len);
+	ct->ct_magic = CT_MAGIC;
+	ct->my_cache = cache;
+	ct->c_list = NULL;
+	ct->refcount = 1;			/* pinned*/
+	ct->dead = false;
+	ct->negative = false;
+	ct->hash_value = hashValue;
+	dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem);
+	memcpy(ct->keys, arguments, nkeys*sizeof(Datum));
+
+	cache->cc_ntup++;
+	CacheHdr->ch_ntup++;
+	MemoryContextSwitchTo(oldcxt);
+
+	/*
+	 * If the hash table has become too full, enlarge the buckets array. Quite
+	 * arbitrarily, we enlarge when fill factor > 2.
+	 */
+	if (cache->cc_ntup > cache->cc_nbuckets * 2)
+		RehashCatCache(cache);
+}
+
 /*
  * Work-horse for SearchCatCache/SearchCatCacheN.
  */
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 585dcee..ce8852c 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -1098,6 +1098,10 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
 	relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
 	switch (relation->rd_rel->relpersistence)
 	{
+		case RELPERSISTENCE_SESSION:
+			relation->rd_backend = BackendIdForSessionRelations();
+			relation->rd_islocaltemp = false;
+			break;
 		case RELPERSISTENCE_UNLOGGED:
 		case RELPERSISTENCE_PERMANENT:
 			relation->rd_backend = InvalidBackendId;
@@ -3301,6 +3305,10 @@ RelationBuildLocalRelation(const char *relname,
 	rel->rd_rel->relpersistence = relpersistence;
 	switch (relpersistence)
 	{
+		case RELPERSISTENCE_SESSION:
+			rel->rd_backend = BackendIdForSessionRelations();
+			rel->rd_islocaltemp = false;
+			break;
 		case RELPERSISTENCE_UNLOGGED:
 		case RELPERSISTENCE_PERMANENT:
 			rel->rd_backend = InvalidBackendId;
diff --git a/src/backend/utils/cache/syscache.c b/src/backend/utils/cache/syscache.c
index 16297a5..e7a4d3c 100644
--- a/src/backend/utils/cache/syscache.c
+++ b/src/backend/utils/cache/syscache.c
@@ -1164,6 +1164,16 @@ SearchSysCache4(int cacheId,
 	return SearchCatCache4(SysCache[cacheId], key1, key2, key3, key4);
 }
 
+void
+InsertSysCache(int cacheId,
+			   Datum key1, Datum key2, Datum key3, Datum key4,
+			   HeapTuple value)
+{
+	Assert(cacheId >= 0 && cacheId < SysCacheSize &&
+		   PointerIsValid(SysCache[cacheId]));
+	InsertCatCache(SysCache[cacheId], key1, key2, key3, key4, value);
+}
+
 /*
  * ReleaseSysCache
  *		Release previously grabbed reference count on a tuple
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index bf69adc..fa7479c 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15637,8 +15637,8 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 											 tbinfo->dobj.catId.oid, false);
 
 		appendPQExpBuffer(q, "CREATE %s%s %s",
-						  tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED ?
-						  "UNLOGGED " : "",
+						  tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED ? "UNLOGGED "
+						  : tbinfo->relpersistence == RELPERSISTENCE_SESSION ? "SESSION " : "",
 						  reltypename,
 						  qualrelname);
 
diff --git a/src/common/relpath.c b/src/common/relpath.c
index 62b9553..cef99d2 100644
--- a/src/common/relpath.c
+++ b/src/common/relpath.c
@@ -166,7 +166,18 @@ GetRelationPath(Oid dbNode, Oid spcNode, Oid relNode,
 		}
 		else
 		{
-			if (forkNumber != MAIN_FORKNUM)
+			/*
+			 * Session relations are distinguished from local temp relations by adding
+			 * SessionRelFirstBackendId offset to backendId.
+			 * These is no need to separate them at file system level, so just subtract SessionRelFirstBackendId
+			 * to avoid too long file names.
+			 * Segments of session relations have the same prefix (t%d_) as local temporary relations
+			 * to make it possible to cleanup them in the same way as local temporary relation files.
+			 */
+			 if (backendId >= SessionRelFirstBackendId)
+				 backendId -= SessionRelFirstBackendId;
+
+			 if (forkNumber != MAIN_FORKNUM)
 				path = psprintf("base/%u/t%d_%u_%s",
 								dbNode, backendId, relNode,
 								forkNames[forkNumber]);
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index 090b6ba..6a39663 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -165,6 +165,7 @@ typedef FormData_pg_class *Form_pg_class;
 #define		  RELPERSISTENCE_PERMANENT	'p' /* regular table */
 #define		  RELPERSISTENCE_UNLOGGED	'u' /* unlogged permanent table */
 #define		  RELPERSISTENCE_TEMP		't' /* temporary table */
+#define		  RELPERSISTENCE_SESSION	's' /* session table */
 
 /* default selection for replica identity (primary key or nothing) */
 #define		  REPLICA_IDENTITY_DEFAULT	'd'
diff --git a/src/include/storage/backendid.h b/src/include/storage/backendid.h
index 70ef8eb..f226e7c 100644
--- a/src/include/storage/backendid.h
+++ b/src/include/storage/backendid.h
@@ -22,6 +22,13 @@ typedef int BackendId;			/* unique currently active backend identifier */
 
 #define InvalidBackendId		(-1)
 
+/*
+ * We need to distinguish local and global temporary relations by RelFileNodeBackend.
+ * The least invasive change is to add some special bias value to backend id (since 
+ * maximal number of backed is limited by MaxBackends).
+ */
+#define SessionRelFirstBackendId (0x40000000)
+
 extern PGDLLIMPORT BackendId MyBackendId;	/* backend id of this backend */
 
 /* backend id of our parallel session leader, or InvalidBackendId if none */
@@ -34,4 +41,10 @@ extern PGDLLIMPORT BackendId ParallelMasterBackendId;
 #define BackendIdForTempRelations() \
 	(ParallelMasterBackendId == InvalidBackendId ? MyBackendId : ParallelMasterBackendId)
 
+
+#define BackendIdForSessionRelations() \
+	(BackendIdForTempRelations() + SessionRelFirstBackendId)
+
+#define IsSessionRelationBackendId(id) ((id) >= SessionRelFirstBackendId)
+
 #endif							/* BACKENDID_H */
diff --git a/src/include/storage/bufpage.h b/src/include/storage/bufpage.h
index 4ef6d8d..bac7a31 100644
--- a/src/include/storage/bufpage.h
+++ b/src/include/storage/bufpage.h
@@ -229,6 +229,13 @@ typedef PageHeaderData *PageHeader;
 #define PageIsNew(page) (((PageHeader) (page))->pd_upper == 0)
 
 /*
+ * Page of temporary relation is not initialized
+ */
+#define GlobalTempRelationPageIsNotInitialized(rel, page) \
+	((rel)->rd_rel->relpersistence == RELPERSISTENCE_SESSION && PageIsNew(page))
+
+
+/*
  * PageGetItemId
  *		Returns an item identifier of a page.
  */
diff --git a/src/include/storage/relfilenode.h b/src/include/storage/relfilenode.h
index 586500a..20aec72 100644
--- a/src/include/storage/relfilenode.h
+++ b/src/include/storage/relfilenode.h
@@ -75,10 +75,25 @@ typedef struct RelFileNodeBackend
 	BackendId	backend;
 } RelFileNodeBackend;
 
+/*
+ * Check whether it is local or global temporary relation, which data belongs only to one backend.
+ */
 #define RelFileNodeBackendIsTemp(rnode) \
 	((rnode).backend != InvalidBackendId)
 
 /*
+ * Check whether it is global temporary relation which metadata is shared by all sessions,
+ * but data is private for the current session.
+ */
+#define RelFileNodeBackendIsGlobalTemp(rnode) IsSessionRelationBackendId((rnode).backend)
+
+/*
+ * Check whether it is local temporary relation which exists only in this backend.
+ */
+#define RelFileNodeBackendIsLocalTemp(rnode) \
+	(RelFileNodeBackendIsTemp(rnode) && !RelFileNodeBackendIsGlobalTemp(rnode))
+
+/*
  * Note: RelFileNodeEquals and RelFileNodeBackendEquals compare relNode first
  * since that is most likely to be different in two unequal RelFileNodes.  It
  * is probably redundant to compare spcNode if the other fields are found equal,
diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h
index ff1faba..31f615d 100644
--- a/src/include/utils/catcache.h
+++ b/src/include/utils/catcache.h
@@ -228,4 +228,8 @@ extern void PrepareToInvalidateCacheTuple(Relation relation,
 extern void PrintCatCacheLeakWarning(HeapTuple tuple);
 extern void PrintCatCacheListLeakWarning(CatCList *list);
 
+extern void InsertCatCache(CatCache *cache,
+						   Datum v1, Datum v2, Datum v3, Datum v4,
+						   HeapTuple tuple);
+
 #endif							/* CATCACHE_H */
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index a5cf804..d42830f 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -327,6 +327,18 @@ typedef struct StdRdOptions
 	((relation)->rd_options ? \
 	 ((StdRdOptions *) (relation)->rd_options)->parallel_workers : (defaultpw))
 
+/*
+ * Relation persistence is either TEMP either SESSION
+ */
+#define IsLocalRelpersistence(relpersistence) \
+	((relpersistence) == RELPERSISTENCE_TEMP || (relpersistence) == RELPERSISTENCE_SESSION)
+
+/*
+ * Relation is either global either local temp table
+ */
+#define RelationHasSessionScope(relation) \
+	IsLocalRelpersistence(((relation)->rd_rel->relpersistence))
+
 /* ViewOptions->check_option values */
 typedef enum ViewOptCheckOption
 {
@@ -335,6 +347,7 @@ typedef enum ViewOptCheckOption
 	VIEW_OPTION_CHECK_OPTION_CASCADED
 } ViewOptCheckOption;
 
+
 /*
  * ViewOptions
  *		Contents of rd_options for views
@@ -526,7 +539,7 @@ typedef struct ViewOptions
  *		True if relation's pages are stored in local buffers.
  */
 #define RelationUsesLocalBuffers(relation) \
-	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	RelationHasSessionScope(relation)
 
 /*
  * RELATION_IS_LOCAL
diff --git a/src/include/utils/syscache.h b/src/include/utils/syscache.h
index 918765c..5b1598b 100644
--- a/src/include/utils/syscache.h
+++ b/src/include/utils/syscache.h
@@ -216,4 +216,8 @@ extern bool RelationSupportsSysCache(Oid relid);
 
 #define ReleaseSysCacheList(x)	ReleaseCatCacheList(x)
 
+
+extern void InsertSysCache(int cacheId, 
+						   Datum v1, Datum v2, Datum v3, Datum v4,
+						   HeapTuple tuple);
 #endif							/* SYSCACHE_H */
diff --git a/src/test/isolation/expected/inherit-global-temp.out b/src/test/isolation/expected/inherit-global-temp.out
new file mode 100644
index 0000000..6114f8c
--- /dev/null
+++ b/src/test/isolation/expected/inherit-global-temp.out
@@ -0,0 +1,218 @@
+Parsed test spec with 2 sessions
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s1_select_p s1_select_c s2_select_p s2_select_c
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s1_select_p: SELECT a FROM inh_global_parent;
+a              
+
+1              
+2              
+3              
+4              
+step s1_select_c: SELECT a FROM inh_global_temp_child_s1;
+a              
+
+3              
+4              
+step s2_select_p: SELECT a FROM inh_global_parent;
+a              
+
+1              
+2              
+5              
+6              
+step s2_select_c: SELECT a FROM inh_global_temp_child_s2;
+a              
+
+5              
+6              
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s1_update_p s1_update_c s1_select_p s1_select_c s2_select_p s2_select_c
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s1_update_p: UPDATE inh_global_parent SET a = 11 WHERE a = 1;
+step s1_update_c: UPDATE inh_global_parent SET a = 13 WHERE a IN (3, 5);
+step s1_select_p: SELECT a FROM inh_global_parent;
+a              
+
+2              
+11             
+4              
+13             
+step s1_select_c: SELECT a FROM inh_global_temp_child_s1;
+a              
+
+4              
+13             
+step s2_select_p: SELECT a FROM inh_global_parent;
+a              
+
+2              
+11             
+5              
+6              
+step s2_select_c: SELECT a FROM inh_global_temp_child_s2;
+a              
+
+5              
+6              
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s2_update_c s1_select_p s1_select_c s2_select_p s2_select_c
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s2_update_c: UPDATE inh_global_parent SET a = 15 WHERE a IN (3, 5);
+step s1_select_p: SELECT a FROM inh_global_parent;
+a              
+
+1              
+2              
+3              
+4              
+step s1_select_c: SELECT a FROM inh_global_temp_child_s1;
+a              
+
+3              
+4              
+step s2_select_p: SELECT a FROM inh_global_parent;
+a              
+
+1              
+2              
+6              
+15             
+step s2_select_c: SELECT a FROM inh_global_temp_child_s2;
+a              
+
+6              
+15             
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s1_delete_p s1_delete_c s1_select_p s1_select_c s2_select_p s2_select_c
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s1_delete_p: DELETE FROM inh_global_parent WHERE a = 2;
+step s1_delete_c: DELETE FROM inh_global_parent WHERE a IN (4, 6);
+step s1_select_p: SELECT a FROM inh_global_parent;
+a              
+
+1              
+3              
+step s1_select_c: SELECT a FROM inh_global_temp_child_s1;
+a              
+
+3              
+step s2_select_p: SELECT a FROM inh_global_parent;
+a              
+
+1              
+5              
+6              
+step s2_select_c: SELECT a FROM inh_global_temp_child_s2;
+a              
+
+5              
+6              
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s2_delete_c s1_select_p s1_select_c s2_select_p s2_select_c
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s2_delete_c: DELETE FROM inh_global_parent WHERE a IN (4, 6);
+step s1_select_p: SELECT a FROM inh_global_parent;
+a              
+
+1              
+2              
+3              
+4              
+step s1_select_c: SELECT a FROM inh_global_temp_child_s1;
+a              
+
+3              
+4              
+step s2_select_p: SELECT a FROM inh_global_parent;
+a              
+
+1              
+2              
+5              
+step s2_select_c: SELECT a FROM inh_global_temp_child_s2;
+a              
+
+5              
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s1_truncate_p s1_select_p s1_select_c s2_select_p s2_select_c
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s1_truncate_p: TRUNCATE inh_global_parent;
+step s1_select_p: SELECT a FROM inh_global_parent;
+a              
+
+step s1_select_c: SELECT a FROM inh_global_temp_child_s1;
+a              
+
+step s2_select_p: SELECT a FROM inh_global_parent;
+a              
+
+5              
+6              
+step s2_select_c: SELECT a FROM inh_global_temp_child_s2;
+a              
+
+5              
+6              
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s2_truncate_p s1_select_p s1_select_c s2_select_p s2_select_c
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s2_truncate_p: TRUNCATE inh_global_parent;
+step s1_select_p: SELECT a FROM inh_global_parent;
+a              
+
+3              
+4              
+step s1_select_c: SELECT a FROM inh_global_temp_child_s1;
+a              
+
+3              
+4              
+step s2_select_p: SELECT a FROM inh_global_parent;
+a              
+
+step s2_select_c: SELECT a FROM inh_global_temp_child_s2;
+a              
+
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s1_begin s1_truncate_p s2_select_p s1_commit
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s1_begin: BEGIN;
+step s1_truncate_p: TRUNCATE inh_global_parent;
+step s2_select_p: SELECT a FROM inh_global_parent; <waiting ...>
+step s1_commit: COMMIT;
+step s2_select_p: <... completed>
+a              
+
+5              
+6              
+
+starting permutation: s1_insert_p s1_insert_c s2_insert_c s1_begin s1_truncate_p s2_select_c s1_commit
+step s1_insert_p: INSERT INTO inh_global_parent VALUES (1), (2);
+step s1_insert_c: INSERT INTO inh_global_temp_child_s1 VALUES (3), (4);
+step s2_insert_c: INSERT INTO inh_global_temp_child_s2 VALUES (5), (6);
+step s1_begin: BEGIN;
+step s1_truncate_p: TRUNCATE inh_global_parent;
+step s2_select_c: SELECT a FROM inh_global_temp_child_s2; <waiting ...>
+step s1_commit: COMMIT;
+step s2_select_c: <... completed>
+a              
+
+5              
+6              
diff --git a/src/test/isolation/isolation_schedule b/src/test/isolation/isolation_schedule
index a2fa192..ef7aa85 100644
--- a/src/test/isolation/isolation_schedule
+++ b/src/test/isolation/isolation_schedule
@@ -88,3 +88,4 @@ test: plpgsql-toast
 test: truncate-conflict
 test: serializable-parallel
 test: serializable-parallel-2
+test: inherit-global-temp
diff --git a/src/test/isolation/specs/inherit-global-temp.spec b/src/test/isolation/specs/inherit-global-temp.spec
new file mode 100644
index 0000000..5e95dd6
--- /dev/null
+++ b/src/test/isolation/specs/inherit-global-temp.spec
@@ -0,0 +1,73 @@
+# This is a copy of the inherit-temp test with little changes for global temporary tables.
+#
+
+setup
+{
+  CREATE TABLE inh_global_parent (a int);
+}
+
+teardown
+{
+  DROP TABLE inh_global_parent;
+}
+
+# Session 1 executes actions which act directly on both the parent and
+# its child.  Abbreviation "c" is used for queries working on the child
+# and "p" on the parent.
+session "s1"
+setup
+{
+  CREATE GLOBAL TEMPORARY TABLE inh_global_temp_child_s1 () INHERITS (inh_global_parent);
+}
+step "s1_begin" { BEGIN; }
+step "s1_truncate_p" { TRUNCATE inh_global_parent; }
+step "s1_select_p" { SELECT a FROM inh_global_parent; }
+step "s1_select_c" { SELECT a FROM inh_global_temp_child_s1; }
+step "s1_insert_p" { INSERT INTO inh_global_parent VALUES (1), (2); }
+step "s1_insert_c" { INSERT INTO inh_global_temp_child_s1 VALUES (3), (4); }
+step "s1_update_p" { UPDATE inh_global_parent SET a = 11 WHERE a = 1; }
+step "s1_update_c" { UPDATE inh_global_parent SET a = 13 WHERE a IN (3, 5); }
+step "s1_delete_p" { DELETE FROM inh_global_parent WHERE a = 2; }
+step "s1_delete_c" { DELETE FROM inh_global_parent WHERE a IN (4, 6); }
+step "s1_commit" { COMMIT; }
+teardown
+{
+  DROP TABLE inh_global_temp_child_s1;
+}
+
+# Session 2 executes actions on the parent which act only on the child.
+session "s2"
+setup
+{
+  CREATE GLOBAL TEMPORARY TABLE inh_global_temp_child_s2 () INHERITS (inh_global_parent);
+}
+step "s2_truncate_p" { TRUNCATE inh_global_parent; }
+step "s2_select_p" { SELECT a FROM inh_global_parent; }
+step "s2_select_c" { SELECT a FROM inh_global_temp_child_s2; }
+step "s2_insert_c" { INSERT INTO inh_global_temp_child_s2 VALUES (5), (6); }
+step "s2_update_c" { UPDATE inh_global_parent SET a = 15 WHERE a IN (3, 5); }
+step "s2_delete_c" { DELETE FROM inh_global_parent WHERE a IN (4, 6); }
+teardown
+{
+  DROP TABLE inh_global_temp_child_s2;
+}
+
+# Check INSERT behavior across sessions
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s1_select_p" "s1_select_c" "s2_select_p" "s2_select_c"
+
+# Check UPDATE behavior across sessions
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s1_update_p" "s1_update_c" "s1_select_p" "s1_select_c" "s2_select_p" "s2_select_c"
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s2_update_c" "s1_select_p" "s1_select_c" "s2_select_p" "s2_select_c"
+
+# Check DELETE behavior across sessions
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s1_delete_p" "s1_delete_c" "s1_select_p" "s1_select_c" "s2_select_p" "s2_select_c"
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s2_delete_c" "s1_select_p" "s1_select_c" "s2_select_p" "s2_select_c"
+
+# Check TRUNCATE behavior across sessions
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s1_truncate_p" "s1_select_p" "s1_select_c" "s2_select_p" "s2_select_c"
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s2_truncate_p" "s1_select_p" "s1_select_c" "s2_select_p" "s2_select_c"
+
+# TRUNCATE on a parent tree does not block access to temporary child relation
+# of another session, and blocks when scanning the parent.
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s1_begin" "s1_truncate_p" "s2_select_p" "s1_commit"
+permutation "s1_insert_p" "s1_insert_c" "s2_insert_c" "s1_begin" "s1_truncate_p" "s2_select_c" "s1_commit"
diff --git a/src/test/regress/expected/global_temp.out b/src/test/regress/expected/global_temp.out
new file mode 100644
index 0000000..ae1adb6
--- /dev/null
+++ b/src/test/regress/expected/global_temp.out
@@ -0,0 +1,247 @@
+--
+-- GLOBAL TEMP
+-- Test global temp relations
+--
+-- Test ON COMMIT DELETE ROWS
+CREATE GLOBAL TEMP TABLE global_temptest(col int) ON COMMIT DELETE ROWS;
+BEGIN;
+INSERT INTO global_temptest VALUES (1);
+INSERT INTO global_temptest VALUES (2);
+SELECT * FROM global_temptest;
+ col 
+-----
+   1
+   2
+(2 rows)
+
+COMMIT;
+SELECT * FROM global_temptest;
+ col 
+-----
+(0 rows)
+
+DROP TABLE global_temptest;
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temptest(col) ON COMMIT DELETE ROWS AS SELECT 1;
+SELECT * FROM global_temptest;
+ col 
+-----
+   1
+(1 row)
+
+COMMIT;
+SELECT * FROM global_temptest;
+ col 
+-----
+(0 rows)
+
+DROP TABLE global_temptest;
+-- Test foreign keys
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temptest1(col int PRIMARY KEY);
+CREATE GLOBAL TEMP TABLE global_temptest2(col int REFERENCES global_temptest1)
+  ON COMMIT DELETE ROWS;
+INSERT INTO global_temptest1 VALUES (1);
+INSERT INTO global_temptest2 VALUES (1);
+COMMIT;
+SELECT * FROM global_temptest1;
+ col 
+-----
+   1
+(1 row)
+
+SELECT * FROM global_temptest2;
+ col 
+-----
+(0 rows)
+
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temptest3(col int PRIMARY KEY) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE global_temptest4(col int REFERENCES global_temptest3);
+COMMIT;
+ERROR:  unsupported ON COMMIT and foreign key combination
+DETAIL:  Table "global_temptest4" references "global_temptest3", but they do not have the same ON COMMIT setting.
+-- For partitioned temp tables, ON COMMIT actions ignore storage-less
+-- partitioned tables.
+BEGIN;
+CREATE GLOBAL TEMP TABLE temp_parted_oncommit (a int)
+  PARTITION BY LIST (a) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE temp_parted_oncommit_1
+  PARTITION OF temp_parted_oncommit
+  FOR VALUES IN (1) ON COMMIT DELETE ROWS;
+INSERT INTO temp_parted_oncommit VALUES (1);
+COMMIT;
+-- partitions are emptied by the previous commit
+SELECT * FROM temp_parted_oncommit;
+ a 
+---
+(0 rows)
+
+DROP TABLE temp_parted_oncommit;
+-- Using ON COMMIT DELETE on a partitioned table does not remove
+-- all rows if partitions preserve their data.
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temp_parted_oncommit_test (a int)
+  PARTITION BY LIST (a) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE global_temp_parted_oncommit_test1
+  PARTITION OF global_temp_parted_oncommit_test
+  FOR VALUES IN (1) ON COMMIT PRESERVE ROWS;
+INSERT INTO global_temp_parted_oncommit_test VALUES (1);
+COMMIT;
+-- Data from the remaining partition is still here as its rows are
+-- preserved.
+SELECT * FROM global_temp_parted_oncommit_test;
+ a 
+---
+ 1
+(1 row)
+
+-- two relations remain in this case.
+SELECT relname FROM pg_class WHERE relname LIKE 'global_temp_parted_oncommit_test%';
+              relname              
+-----------------------------------
+ global_temp_parted_oncommit_test
+ global_temp_parted_oncommit_test1
+(2 rows)
+
+DROP TABLE global_temp_parted_oncommit_test;
+-- Check dependencies between ON COMMIT actions with inheritance trees.
+-- Data on the parent is removed, and the child goes away.
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temp_inh_oncommit_test (a int) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE global_temp_inh_oncommit_test1 ()
+  INHERITS(global_temp_inh_oncommit_test) ON COMMIT PRESERVE ROWS;
+INSERT INTO global_temp_inh_oncommit_test1 VALUES (1);
+INSERT INTO global_temp_inh_oncommit_test VALUES (1);
+COMMIT;
+SELECT * FROM global_temp_inh_oncommit_test;
+ a 
+---
+ 1
+(1 row)
+
+-- two relations remain
+SELECT relname FROM pg_class WHERE relname LIKE 'global_temp_inh_oncommit_test%';
+            relname             
+--------------------------------
+ global_temp_inh_oncommit_test
+ global_temp_inh_oncommit_test1
+(2 rows)
+
+DROP TABLE global_temp_inh_oncommit_test1;
+DROP TABLE global_temp_inh_oncommit_test;
+-- Global temp table cannot inherit from temporary relation
+BEGIN;
+CREATE TEMP TABLE global_temp_table (a int) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE global_temp_table1 ()
+  INHERITS(global_temp_table) ON COMMIT PRESERVE ROWS;
+ERROR:  cannot inherit from temporary relation "global_temp_table"
+ROLLBACK;
+-- Temp table can inherit from global temporary relation
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temp_table (a int) ON COMMIT DELETE ROWS;
+CREATE TEMP TABLE temp_table1 ()
+  INHERITS(global_temp_table) ON COMMIT PRESERVE ROWS;
+CREATE TEMP TABLE temp_table2 ()
+  INHERITS(global_temp_table) ON COMMIT DELETE ROWS;
+INSERT INTO temp_table2 VALUES (2);
+INSERT INTO temp_table1 VALUES (1);
+INSERT INTO global_temp_table VALUES (0);
+SELECT * FROM global_temp_table;
+ a 
+---
+ 0
+ 1
+ 2
+(3 rows)
+
+COMMIT;
+SELECT * FROM global_temp_table;
+ a 
+---
+ 1
+(1 row)
+
+DROP TABLE temp_table2;
+DROP TABLE temp_table1;
+DROP TABLE global_temp_table;
+-- Global temp table can inherit from normal relation
+BEGIN;
+CREATE TABLE normal_table (a int);
+CREATE GLOBAL TEMP TABLE temp_table1 ()
+  INHERITS(normal_table) ON COMMIT PRESERVE ROWS;
+CREATE GLOBAL TEMP TABLE temp_table2 ()
+  INHERITS(normal_table) ON COMMIT DELETE ROWS;
+INSERT INTO temp_table2 VALUES (2);
+INSERT INTO temp_table1 VALUES (1);
+INSERT INTO normal_table VALUES (0);
+SELECT * FROM normal_table;
+ a 
+---
+ 0
+ 1
+ 2
+(3 rows)
+
+COMMIT;
+SELECT * FROM normal_table;
+ a 
+---
+ 0
+ 1
+(2 rows)
+
+DROP TABLE temp_table2;
+DROP TABLE temp_table1;
+DROP TABLE normal_table;
+-- Check SERIAL and BIGSERIAL pseudo-types
+CREATE GLOBAL TEMP TABLE global_temp_table ( aid BIGSERIAL, bid SERIAL );
+CREATE SEQUENCE test_sequence;
+INSERT INTO global_temp_table DEFAULT VALUES;
+INSERT INTO global_temp_table DEFAULT VALUES;
+INSERT INTO global_temp_table DEFAULT VALUES;
+SELECT * FROM global_temp_table;
+ aid | bid 
+-----+-----
+   1 |   1
+   2 |   2
+   3 |   3
+(3 rows)
+
+SELECT NEXTVAL( 'test_sequence' );
+ nextval 
+---------
+       1
+(1 row)
+
+\c
+SELECT * FROM global_temp_table;
+ aid | bid 
+-----+-----
+(0 rows)
+
+SELECT NEXTVAL( 'test_sequence' );
+ nextval 
+---------
+       2
+(1 row)
+
+INSERT INTO global_temp_table DEFAULT VALUES;
+INSERT INTO global_temp_table DEFAULT VALUES;
+INSERT INTO global_temp_table DEFAULT VALUES;
+SELECT * FROM global_temp_table;
+ aid | bid 
+-----+-----
+   1 |   1
+   2 |   2
+   3 |   3
+(3 rows)
+
+SELECT NEXTVAL( 'test_sequence' );
+ nextval 
+---------
+       3
+(1 row)
+
+DROP TABLE global_temp_table;
+DROP SEQUENCE test_sequence;
diff --git a/src/test/regress/expected/session_table.out b/src/test/regress/expected/session_table.out
new file mode 100644
index 0000000..1b9b3f4
--- /dev/null
+++ b/src/test/regress/expected/session_table.out
@@ -0,0 +1,64 @@
+create session table my_private_table(x integer primary key, y integer);
+insert into my_private_table values (generate_series(1,10000), generate_series(1,10000));
+select count(*) from my_private_table;
+ count 
+-------
+ 10000
+(1 row)
+
+\c
+select count(*) from my_private_table;
+ count 
+-------
+     0
+(1 row)
+
+select * from my_private_table where x=10001;
+ x | y 
+---+---
+(0 rows)
+
+insert into my_private_table values (generate_series(1,100000), generate_series(1,100000));
+create index on my_private_table(y);
+select * from my_private_table where x=10001;
+   x   |   y   
+-------+-------
+ 10001 | 10001
+(1 row)
+
+select * from my_private_table where y=10001;
+   x   |   y   
+-------+-------
+ 10001 | 10001
+(1 row)
+
+select count(*) from my_private_table;
+ count  
+--------
+ 100000
+(1 row)
+
+\c
+select * from my_private_table where x=100001;
+ x | y 
+---+---
+(0 rows)
+
+select * from my_private_table order by y desc limit 1;
+ x | y 
+---+---
+(0 rows)
+
+insert into my_private_table values (generate_series(1,100000), generate_series(1,100000));
+select * from my_private_table where x=100001;
+ x | y 
+---+---
+(0 rows)
+
+select * from my_private_table order by y desc limit 1;
+   x    |   y    
+--------+--------
+ 100000 | 100000
+(1 row)
+
+drop table  my_private_table;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index fc0f141..507cf7d 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -107,7 +107,7 @@ test: json jsonb json_encoding jsonpath jsonpath_encoding jsonb_jsonpath
 # NB: temp.sql does a reconnect which transiently uses 2 connections,
 # so keep this parallel group to at most 19 tests
 # ----------
-test: plancache limit plpgsql copy2 temp domain rangefuncs prepare conversion truncate alter_table sequence polymorphism rowtypes returning largeobject with xml
+test: plancache limit plpgsql copy2 temp global_temp session_table domain rangefuncs prepare conversion truncate alter_table sequence polymorphism rowtypes returning largeobject with xml
 
 # ----------
 # Another group of parallel tests
diff --git a/src/test/regress/serial_schedule b/src/test/regress/serial_schedule
index 68ac56a..3890777 100644
--- a/src/test/regress/serial_schedule
+++ b/src/test/regress/serial_schedule
@@ -172,6 +172,8 @@ test: limit
 test: plpgsql
 test: copy2
 test: temp
+test: global_temp
+test: session_table
 test: domain
 test: rangefuncs
 test: prepare
diff --git a/src/test/regress/sql/global_temp.sql b/src/test/regress/sql/global_temp.sql
new file mode 100644
index 0000000..3058b9b
--- /dev/null
+++ b/src/test/regress/sql/global_temp.sql
@@ -0,0 +1,151 @@
+--
+-- GLOBAL TEMP
+-- Test global temp relations
+--
+
+-- Test ON COMMIT DELETE ROWS
+
+CREATE GLOBAL TEMP TABLE global_temptest(col int) ON COMMIT DELETE ROWS;
+
+BEGIN;
+INSERT INTO global_temptest VALUES (1);
+INSERT INTO global_temptest VALUES (2);
+
+SELECT * FROM global_temptest;
+COMMIT;
+
+SELECT * FROM global_temptest;
+
+DROP TABLE global_temptest;
+
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temptest(col) ON COMMIT DELETE ROWS AS SELECT 1;
+
+SELECT * FROM global_temptest;
+COMMIT;
+
+SELECT * FROM global_temptest;
+
+DROP TABLE global_temptest;
+
+-- Test foreign keys
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temptest1(col int PRIMARY KEY);
+CREATE GLOBAL TEMP TABLE global_temptest2(col int REFERENCES global_temptest1)
+  ON COMMIT DELETE ROWS;
+INSERT INTO global_temptest1 VALUES (1);
+INSERT INTO global_temptest2 VALUES (1);
+COMMIT;
+SELECT * FROM global_temptest1;
+SELECT * FROM global_temptest2;
+
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temptest3(col int PRIMARY KEY) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE global_temptest4(col int REFERENCES global_temptest3);
+COMMIT;
+
+-- For partitioned temp tables, ON COMMIT actions ignore storage-less
+-- partitioned tables.
+BEGIN;
+CREATE GLOBAL TEMP TABLE temp_parted_oncommit (a int)
+  PARTITION BY LIST (a) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE temp_parted_oncommit_1
+  PARTITION OF temp_parted_oncommit
+  FOR VALUES IN (1) ON COMMIT DELETE ROWS;
+INSERT INTO temp_parted_oncommit VALUES (1);
+COMMIT;
+-- partitions are emptied by the previous commit
+SELECT * FROM temp_parted_oncommit;
+DROP TABLE temp_parted_oncommit;
+
+-- Using ON COMMIT DELETE on a partitioned table does not remove
+-- all rows if partitions preserve their data.
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temp_parted_oncommit_test (a int)
+  PARTITION BY LIST (a) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE global_temp_parted_oncommit_test1
+  PARTITION OF global_temp_parted_oncommit_test
+  FOR VALUES IN (1) ON COMMIT PRESERVE ROWS;
+INSERT INTO global_temp_parted_oncommit_test VALUES (1);
+COMMIT;
+-- Data from the remaining partition is still here as its rows are
+-- preserved.
+SELECT * FROM global_temp_parted_oncommit_test;
+-- two relations remain in this case.
+SELECT relname FROM pg_class WHERE relname LIKE 'global_temp_parted_oncommit_test%';
+DROP TABLE global_temp_parted_oncommit_test;
+
+-- Check dependencies between ON COMMIT actions with inheritance trees.
+-- Data on the parent is removed, and the child goes away.
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temp_inh_oncommit_test (a int) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE global_temp_inh_oncommit_test1 ()
+  INHERITS(global_temp_inh_oncommit_test) ON COMMIT PRESERVE ROWS;
+INSERT INTO global_temp_inh_oncommit_test1 VALUES (1);
+INSERT INTO global_temp_inh_oncommit_test VALUES (1);
+COMMIT;
+SELECT * FROM global_temp_inh_oncommit_test;
+-- two relations remain
+SELECT relname FROM pg_class WHERE relname LIKE 'global_temp_inh_oncommit_test%';
+DROP TABLE global_temp_inh_oncommit_test1;
+DROP TABLE global_temp_inh_oncommit_test;
+
+-- Global temp table cannot inherit from temporary relation
+BEGIN;
+CREATE TEMP TABLE global_temp_table (a int) ON COMMIT DELETE ROWS;
+CREATE GLOBAL TEMP TABLE global_temp_table1 ()
+  INHERITS(global_temp_table) ON COMMIT PRESERVE ROWS;
+ROLLBACK;
+
+-- Temp table can inherit from global temporary relation
+BEGIN;
+CREATE GLOBAL TEMP TABLE global_temp_table (a int) ON COMMIT DELETE ROWS;
+CREATE TEMP TABLE temp_table1 ()
+  INHERITS(global_temp_table) ON COMMIT PRESERVE ROWS;
+CREATE TEMP TABLE temp_table2 ()
+  INHERITS(global_temp_table) ON COMMIT DELETE ROWS;
+INSERT INTO temp_table2 VALUES (2);
+INSERT INTO temp_table1 VALUES (1);
+INSERT INTO global_temp_table VALUES (0);
+SELECT * FROM global_temp_table;
+COMMIT;
+SELECT * FROM global_temp_table;
+DROP TABLE temp_table2;
+DROP TABLE temp_table1;
+DROP TABLE global_temp_table;
+
+-- Global temp table can inherit from normal relation
+BEGIN;
+CREATE TABLE normal_table (a int);
+CREATE GLOBAL TEMP TABLE temp_table1 ()
+  INHERITS(normal_table) ON COMMIT PRESERVE ROWS;
+CREATE GLOBAL TEMP TABLE temp_table2 ()
+  INHERITS(normal_table) ON COMMIT DELETE ROWS;
+INSERT INTO temp_table2 VALUES (2);
+INSERT INTO temp_table1 VALUES (1);
+INSERT INTO normal_table VALUES (0);
+SELECT * FROM normal_table;
+COMMIT;
+SELECT * FROM normal_table;
+DROP TABLE temp_table2;
+DROP TABLE temp_table1;
+DROP TABLE normal_table;
+
+-- Check SERIAL and BIGSERIAL pseudo-types
+CREATE GLOBAL TEMP TABLE global_temp_table ( aid BIGSERIAL, bid SERIAL );
+CREATE SEQUENCE test_sequence;
+INSERT INTO global_temp_table DEFAULT VALUES;
+INSERT INTO global_temp_table DEFAULT VALUES;
+INSERT INTO global_temp_table DEFAULT VALUES;
+SELECT * FROM global_temp_table;
+SELECT NEXTVAL( 'test_sequence' );
+\c
+SELECT * FROM global_temp_table;
+SELECT NEXTVAL( 'test_sequence' );
+INSERT INTO global_temp_table DEFAULT VALUES;
+INSERT INTO global_temp_table DEFAULT VALUES;
+INSERT INTO global_temp_table DEFAULT VALUES;
+SELECT * FROM global_temp_table;
+SELECT NEXTVAL( 'test_sequence' );
+DROP TABLE global_temp_table;
+DROP SEQUENCE test_sequence;
diff --git a/src/test/regress/sql/session_table.sql b/src/test/regress/sql/session_table.sql
new file mode 100644
index 0000000..c6663dc
--- /dev/null
+++ b/src/test/regress/sql/session_table.sql
@@ -0,0 +1,18 @@
+create session table my_private_table(x integer primary key, y integer);
+insert into my_private_table values (generate_series(1,10000), generate_series(1,10000));
+select count(*) from my_private_table;
+\c
+select count(*) from my_private_table;
+select * from my_private_table where x=10001;
+insert into my_private_table values (generate_series(1,100000), generate_series(1,100000));
+create index on my_private_table(y);
+select * from my_private_table where x=10001;
+select * from my_private_table where y=10001;
+select count(*) from my_private_table;
+\c
+select * from my_private_table where x=100001;
+select * from my_private_table order by y desc limit 1;
+insert into my_private_table values (generate_series(1,100000), generate_series(1,100000));
+select * from my_private_table where x=100001;
+select * from my_private_table order by y desc limit 1;
+drop table  my_private_table;

From fbe31fe0202bd3563235963b00050193bb32b618 Mon Sep 17 00:00:00 2001
From: wenjing.zwj <wenjing.zwj@alibaba-inc.com>
Date: Tue, 25 Jun 2019 17:44:26 +0800
Subject: [PATCH] support global temp table

---
 contrib/Makefile                             |   3 ++-
 contrib/pg_gtt/Makefile                      |  22 ++++++++++++++++++++++
 contrib/pg_gtt/pg_gtt--1.0.sql               |  28 ++++++++++++++++++++++++++++
 contrib/pg_gtt/pg_gtt.c                      | 474 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 contrib/pg_gtt/pg_gtt.control                |   4 ++++
 src/backend/access/common/reloptions.c       |  17 +++++++++++++++++
 src/backend/access/gist/gistutil.c           |   4 +++-
 src/backend/access/hash/hash.c               |   4 +++-
 src/backend/access/heap/heapam_handler.c     |   4 ++--
 src/backend/access/heap/vacuumlazy.c         |  22 ++++++++++++++++++----
 src/backend/access/nbtree/nbtpage.c          |   9 ++++++++-
 src/backend/access/transam/xlog.c            |   4 ++++
 src/backend/catalog/Makefile                 |   2 ++
 src/backend/catalog/catalog.c                |   2 ++
 src/backend/catalog/heap.c                   |  86 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------
 src/backend/catalog/index.c                  |  87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------------
 src/backend/catalog/namespace.c              |   7 +++++++
 src/backend/catalog/storage.c                |  17 ++++++++++++++++-
 src/backend/catalog/storage_gtt.c            | 814 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/backend/commands/analyze.c               |  75 ++++++++++++++++++++++++++++++++++++++++++++++++++-------------------------
 src/backend/commands/cluster.c               |   6 ++++++
 src/backend/commands/indexcmds.c             |  10 ++++++++++
 src/backend/commands/lockcmds.c              |   3 ++-
 src/backend/commands/tablecmds.c             | 111 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 src/backend/commands/vacuum.c                | 140 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------------------------------------
 src/backend/optimizer/path/allpaths.c        |   8 +++++++-
 src/backend/optimizer/plan/planner.c         |   2 ++
 src/backend/optimizer/util/plancat.c         |  33 ++++++++++++++++++++-------------
 src/backend/parser/analyze.c                 |   5 +++++
 src/backend/parser/gram.y                    |  20 ++++----------------
 src/backend/parser/parse_relation.c          |  47 +++++++++++++++++++++++++++++++++++++++++++++++
 src/backend/parser/parse_utilcmd.c           |   7 +++++++
 src/backend/postmaster/autovacuum.c          |   9 ++++++++-
 src/backend/storage/buffer/bufmgr.c          |  31 +++++++++++++++++++++++++++----
 src/backend/storage/ipc/ipci.c               |   4 ++++
 src/backend/storage/ipc/procarray.c          |  75 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/backend/storage/lmgr/proc.c              |   2 ++
 src/backend/storage/smgr/md.c                |   6 ++++++
 src/backend/utils/adt/dbsize.c               |   4 ++++
 src/backend/utils/adt/selfuncs.c             |  93 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---------------
 src/backend/utils/cache/lsyscache.c          |  14 ++++++++++++++
 src/backend/utils/cache/relcache.c           |  19 ++++++++++++++++++-
 src/backend/utils/misc/guc.c                 |  21 +++++++++++++++++++++
 src/bin/pg_dump/pg_dump.c                    |  11 +++++++++--
 src/include/catalog/pg_class.h               |   1 +
 src/include/catalog/storage.h                |   2 +-
 src/include/catalog/storage_gtt.h            |  39 +++++++++++++++++++++++++++++++++++++++
 src/include/parser/parse_relation.h          |   3 +++
 src/include/storage/lwlock.h                 |   1 +
 src/include/storage/proc.h                   |   2 ++
 src/include/storage/procarray.h              |   2 ++
 src/include/utils/guc.h                      |   4 ++++
 src/include/utils/rel.h                      |  15 ++++++++++++++-
 src/test/regress/expected/gtt_clean.out      |   7 +++++++
 src/test/regress/expected/gtt_error.out      | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/expected/gtt_parallel_1.out |  84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/expected/gtt_parallel_2.out | 142 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/expected/gtt_prepare.out    |   7 +++++++
 src/test/regress/parallel_schedule           |   6 ++++++
 src/test/regress/sql/gtt_clean.sql           |   6 ++++++
 src/test/regress/sql/gtt_error.sql           | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/sql/gtt_parallel_1.sql      |  42 ++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/sql/gtt_parallel_2.sql      |  62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/sql/gtt_prepare.sql         |  15 +++++++++++++++
 64 files changed, 2848 insertions(+), 170 deletions(-)
 create mode 100644 contrib/pg_gtt/Makefile
 create mode 100644 contrib/pg_gtt/pg_gtt--1.0.sql
 create mode 100644 contrib/pg_gtt/pg_gtt.c
 create mode 100644 contrib/pg_gtt/pg_gtt.control
 create mode 100644 src/backend/catalog/storage_gtt.c
 create mode 100644 src/include/catalog/storage_gtt.h
 create mode 100644 src/test/regress/expected/gtt_clean.out
 create mode 100644 src/test/regress/expected/gtt_error.out
 create mode 100644 src/test/regress/expected/gtt_parallel_1.out
 create mode 100644 src/test/regress/expected/gtt_parallel_2.out
 create mode 100644 src/test/regress/expected/gtt_prepare.out
 create mode 100644 src/test/regress/sql/gtt_clean.sql
 create mode 100644 src/test/regress/sql/gtt_error.sql
 create mode 100644 src/test/regress/sql/gtt_parallel_1.sql
 create mode 100644 src/test/regress/sql/gtt_parallel_2.sql
 create mode 100644 src/test/regress/sql/gtt_prepare.sql

diff --git a/contrib/Makefile b/contrib/Makefile
index 92184ed..4b1a596 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -48,7 +48,8 @@ SUBDIRS = \
 		tsm_system_rows \
 		tsm_system_time \
 		unaccent	\
-		vacuumlo
+		vacuumlo	\
+		pg_gtt
 
 ifeq ($(with_openssl),yes)
 SUBDIRS += sslinfo
diff --git a/contrib/pg_gtt/Makefile b/contrib/pg_gtt/Makefile
new file mode 100644
index 0000000..1d2ef64
--- /dev/null
+++ b/contrib/pg_gtt/Makefile
@@ -0,0 +1,22 @@
+# contrib/pg_gtt/Makefile
+
+MODULE_big = pg_gtt
+OBJS = pg_gtt.o
+
+EXTENSION = pg_gtt
+DATA = pg_gtt--1.0.sql
+
+LDFLAGS_SL += $(filter -lm, $(LIBS))
+
+NO_INSTALLCHECK = 1
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/pg_pfs
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/contrib/pg_gtt/pg_gtt--1.0.sql b/contrib/pg_gtt/pg_gtt--1.0.sql
new file mode 100644
index 0000000..3f794d7
--- /dev/null
+++ b/contrib/pg_gtt/pg_gtt--1.0.sql
@@ -0,0 +1,28 @@
+/* contrib/pg_gtt/pg_gtt--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION pg_gtt" to load this file. \quit
+
+
+CREATE FUNCTION pg_gtt_att_statistic(text, text, int)
+RETURNS setof pg_statistic
+AS 'MODULE_PATHNAME','pg_gtt_att_statistic'
+LANGUAGE C STRICT;
+
+CREATE TYPE relstats_type AS (relpages int4, reltuples float4, relallvisible int4, relfrozenxid xid, relminmxid xid);
+CREATE TYPE rel_vac_type AS (pid int4, relfrozenxid xid, relminmxid xid);
+
+CREATE FUNCTION pg_gtt_relstats(text, text)
+RETURNS relstats_type
+AS 'MODULE_PATHNAME','pg_gtt_relstats'
+LANGUAGE C STRICT;
+
+CREATE FUNCTION pg_gtt_attached_pid(text, text)
+RETURNS setof int4
+AS 'MODULE_PATHNAME','pg_gtt_attached_pid'
+LANGUAGE C STRICT;
+
+CREATE FUNCTION pg_list_gtt_relfrozenxids()
+RETURNS setof rel_vac_type
+AS 'MODULE_PATHNAME','pg_list_gtt_relfrozenxids'
+LANGUAGE C STRICT;
diff --git a/contrib/pg_gtt/pg_gtt.c b/contrib/pg_gtt/pg_gtt.c
new file mode 100644
index 0000000..19e1ec0
--- /dev/null
+++ b/contrib/pg_gtt/pg_gtt.c
@@ -0,0 +1,474 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_gtt.c
+ *	code to management function for global temparary table
+ *
+ * IDENTIFICATION
+ *	  contrib/pg_gtt/pg_gtt.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <unistd.h>
+#include <sys/time.h>
+#include "port.h"
+#include "access/htup_details.h"
+#include "access/table.h"
+#include "access/xlog.h"
+#include "catalog/pg_type.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/namespace.h"
+#include "catalog/pg_class.h"
+#include "funcapi.h"
+#include "storage/ipc.h"
+#include "storage/shmem.h"
+#include "storage/lwlock.h"
+#include "storage/procarray.h"
+#include "storage/proc.h"
+#include "tcop/utility.h"
+#include "utils/builtins.h"
+#include "utils/memutils.h"
+#include "utils/timeout.h"
+#include "utils/guc.h"
+#include "utils/lsyscache.h"
+#include "utils/rel.h"
+#include <nodes/makefuncs.h>
+#include "storage/sinvaladt.h"
+#include "miscadmin.h"
+
+PG_MODULE_MAGIC;
+
+static Oid pg_get_relid(const char *relname, char *schema);
+
+Datum pg_gtt_att_statistic(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(pg_gtt_att_statistic);
+
+Datum pg_gtt_relstats(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(pg_gtt_relstats);
+
+Datum pg_gtt_attached_pid(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(pg_gtt_attached_pid);
+
+Datum pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(pg_list_gtt_relfrozenxids);
+
+void		_PG_init(void);
+void		_PG_fini(void);
+
+void
+_PG_init(void)
+{
+	return;
+}
+
+void
+_PG_fini(void)
+{
+	return;
+}
+
+static Oid
+pg_get_relid(const char *relname, char *schema)
+{
+	Oid			relid;
+	RangeVar   *rv = makeRangeVar(schema, (char *)relname, -1);
+
+	relid = RangeVarGetRelid(rv, NoLock, true);
+
+	pfree(rv);
+	return relid;
+}
+
+Datum
+pg_gtt_att_statistic(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc		tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple		tuple;
+	Relation	rel = NULL;
+	char	*relname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	char	*schema = text_to_cstring(PG_GETARG_TEXT_PP(1));
+	int		attnum = PG_GETARG_INT32(2);
+	Oid		reloid;
+	char	rel_persistence;
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = NULL;
+	rsinfo->setDesc = NULL;
+
+	tupdesc = CreateTemplateTupleDesc(31);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "starelid",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "staattnum",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 3, "stainherit",
+						BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 4, "stanullfrac",
+						FLOAT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "stawidth",
+						INT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "stadistinct",
+						FLOAT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 7, "stakind1",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 8, "stakind2",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 9, "stakind3",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 10, "stakind4",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 11, "stakind5",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 12, "staop1",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 13, "staop2",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 14, "staop3",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 15, "staop4",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 16, "staop5",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 17, "stacoll1",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 18, "stacoll2",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 19, "stacoll3",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 20, "stacoll4",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 21, "stacoll5",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 22, "stanumbers1",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 23, "stanumbers2",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 24, "stanumbers3",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 25, "stanumbers4",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 26, "stanumbers5",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 27, "stavalues1",
+						ANYARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 28, "stavalues2",
+						ANYARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 29, "stavalues3",
+						ANYARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 30, "stavalues4",
+						ANYARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 31, "stavalues5",
+						ANYARRAYOID, -1, 0);
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (schema == NULL)
+		schema = "public";
+
+	reloid = pg_get_relid(relname, schema);
+	if (reloid == InvalidOid)
+	{
+		elog(WARNING, "relation %s.%s does not exist", schema, relname);
+		return (Datum) 0;
+	}
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation %s.%s not global temp table", schema, relname);
+		return (Datum) 0;
+	}
+
+	tuple = get_gtt_att_statistic(reloid, attnum, false);
+	if (tuple)
+	{
+		HeapTuple tp = heap_copytuple(tuple);
+		tuplestore_puttuple(tupstore, tp);
+	}
+	tuplestore_donestoring(tupstore);
+
+	table_close(rel, NoLock);
+	return (Datum) 0;
+}
+
+Datum
+pg_gtt_relstats(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	char	*relname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	char	*schema = text_to_cstring(PG_GETARG_TEXT_PP(1));
+	Oid	reloid;
+	char	rel_persistence;
+	Datum	values[5];
+	bool	isnull[5];
+	BlockNumber	relpages = 0;
+	double		reltuples = 0;
+	BlockNumber	relallvisible = 0;
+	uint32		relfrozenxid = 0;
+	uint32		relminmxid = 0;
+	Relation	rel = NULL;
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = NULL;
+	rsinfo->setDesc = NULL;
+
+	tupdesc = CreateTemplateTupleDesc(5);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "relpages",
+						INT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "reltuples",
+						FLOAT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 3, "relallvisible",
+						INT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 4, "relfrozenxid",
+						XIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "relminmxid",
+						XIDOID, -1, 0);
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (schema == NULL)
+		schema = "public";
+
+	reloid = pg_get_relid(relname, schema);
+	if (reloid == InvalidOid)
+	{
+		elog(WARNING, "relation %s.%s does not exist", schema, relname);
+		return (Datum) 0;
+	}
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation %s.%s not global temp table", schema, relname);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	get_gtt_relstats(reloid,
+					&relpages, &reltuples, &relallvisible,
+					&relfrozenxid, &relminmxid);
+
+	memset(isnull, false, sizeof(isnull));
+	memset(values, 0, sizeof(values));
+	values[0] = Int32GetDatum(relpages);
+	values[1] = Float4GetDatum((float4)reltuples);
+	values[2] = Int32GetDatum(relallvisible);
+	values[3] = UInt32GetDatum(relfrozenxid);
+	values[4] = UInt32GetDatum(relminmxid);
+	tuple = heap_form_tuple(tupdesc, values, isnull);
+	tuplestore_puttuple(tupstore, tuple);
+	tuplestore_donestoring(tupstore);
+
+	table_close(rel, NoLock);
+	return (Datum) 0;
+}
+
+Datum
+pg_gtt_attached_pid(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	char	*relname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	char	*schema = text_to_cstring(PG_GETARG_TEXT_PP(1));
+	Oid	reloid;
+	char	rel_persistence;
+	Datum	values[1];
+	bool	isnull[1];
+	Relation	rel = NULL;
+	PGPROC		*proc = NULL;
+	Bitmapset	*map = NULL;
+	pid_t		pid = 0;
+	int			backendid = 0;
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = NULL;
+	rsinfo->setDesc = NULL;
+
+	tupdesc = CreateTemplateTupleDesc(1);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "pid",
+						INT4OID, -1, 0);
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (schema == NULL)
+		schema = "public";
+
+	reloid = pg_get_relid(relname, schema);
+	if (reloid == InvalidOid)
+	{
+		elog(WARNING, "relation %s.%s does not exist", schema, relname);
+		return (Datum) 0;
+	}
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation %s.%s not global temp table", schema, relname);
+		return (Datum) 0;
+	}
+
+	map = copy_active_gtt_bitmap(rel->rd_node);
+	if (map)
+	{
+		backendid = bms_first_member(map);
+
+		do
+		{
+			proc = BackendIdGetProc(backendid);
+			pid = proc->pid;
+			if (pid > 0)
+			{
+				memset(isnull, false, sizeof(isnull));
+				memset(values, 0, sizeof(values));
+				values[0] = Int32GetDatum(pid);
+				tuple = heap_form_tuple(tupdesc, values, isnull);
+				tuplestore_puttuple(tupstore, tuple);
+			}
+			backendid = bms_next_member(map, backendid);
+		} while (backendid > 0);
+
+		pfree(map);
+	}
+
+	tuplestore_donestoring(tupstore);
+	table_close(rel, NoLock);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	Datum	values[3];
+	bool	isnull[3];
+	int			num_xid = MaxBackends + 1;
+	int			*pids = NULL;
+	uint32		*xids = NULL;
+	int			i = 0;
+	int			j = 0;
+	uint32		oldest = 0;
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = NULL;
+	rsinfo->setDesc = NULL;
+
+	tupdesc = CreateTemplateTupleDesc(3);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "pid",
+						INT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "relfrozenxid",
+						XIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 3, "relminmxid",
+						XIDOID, -1, 0);
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (max_active_gtt <= 0)
+		return (Datum) 0;
+
+	if (RecoveryInProgress())
+		return (Datum) 0;
+
+	pids = palloc0(sizeof(int) * num_xid);
+	xids = palloc0(sizeof(int) * num_xid);
+	oldest = list_all_session_gtt_frozenxids(num_xid, pids, xids, &i);
+	if (i > 0)
+	{
+		if (i > 0)
+		{
+			pids[i] = 0;
+			xids[i] = oldest;
+			i++;
+		}
+
+		for(j = 0; j < i; j++)
+		{
+			memset(isnull, false, sizeof(isnull));
+			memset(values, 0, sizeof(values));
+			values[0] = Int32GetDatum(pids[j]);
+			values[1] = UInt32GetDatum(xids[j]);
+			values[2] = UInt32GetDatum(0);
+			tuple = heap_form_tuple(tupdesc, values, isnull);
+			tuplestore_puttuple(tupstore, tuple);
+		}
+	}
+	tuplestore_donestoring(tupstore);
+	pfree(pids);
+	pfree(xids);
+
+	return (Datum) 0;
+}
+
diff --git a/contrib/pg_gtt/pg_gtt.control b/contrib/pg_gtt/pg_gtt.control
new file mode 100644
index 0000000..342af1d
--- /dev/null
+++ b/contrib/pg_gtt/pg_gtt.control
@@ -0,0 +1,4 @@
+comment = 'pg_gtt'
+default_version = '1.0'
+module_pathname = '$libdir/pg_gtt'
+relocatable = true
diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c
index 2e1dcb9..3eb57df 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -158,6 +158,19 @@ static relopt_bool boolRelOpts[] =
 		},
 		true
 	},
+	/*
+	 * For global temp table only
+	 * use AccessExclusiveLock for ensure safety
+	 */
+	{
+		{
+			"on_commit_delete_rows",
+			"global temp table on commit options",
+			RELOPT_KIND_HEAP,
+			ShareUpdateExclusiveLock
+		},
+		true
+	},	
 	/* list terminator */
 	{{NULL}}
 };
@@ -1378,7 +1391,11 @@ default_reloptions(Datum reloptions, bool validate, relopt_kind kind)
 	relopt_value *options;
 	StdRdOptions *rdopts;
 	int			numoptions;
+
+	/* add on_commit_delete_rows for global temp table */
 	static const relopt_parse_elt tab[] = {
+		{"on_commit_delete_rows", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, on_commit_delete_rows)},
 		{"fillfactor", RELOPT_TYPE_INT, offsetof(StdRdOptions, fillfactor)},
 		{"autovacuum_enabled", RELOPT_TYPE_BOOL,
 		offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, enabled)},
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index f428729..6c9b052 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -1028,7 +1028,9 @@ gistGetFakeLSN(Relation rel)
 {
 	static XLogRecPtr counter = FirstNormalUnloggedLSN;
 
-	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	/* global temp is same as local temp table */
+	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		rel->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 	{
 		/*
 		 * Temporary relations are only accessible in our session, so a simple
diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index 5cc30da..49b7d2e 100644
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -148,7 +148,9 @@ hashbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	 * metapage, nor the first bitmap page.
 	 */
 	sort_threshold = (maintenance_work_mem * 1024L) / BLCKSZ;
-	if (index->rd_rel->relpersistence != RELPERSISTENCE_TEMP)
+	/* global temp table is same as local temp table */
+	if (!(index->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		index->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		sort_threshold = Min(sort_threshold, NBuffers);
 	else
 		sort_threshold = Min(sort_threshold, NLocBuffer);
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index fc19f40..681521a 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -602,7 +602,7 @@ heapam_relation_set_new_filenode(Relation rel,
 	 */
 	*minmulti = GetOldestMultiXactId();
 
-	srel = RelationCreateStorage(*newrnode, persistence);
+	srel = RelationCreateStorage(*newrnode, persistence, rel);
 
 	/*
 	 * If required, set up an init fork for an unlogged table so that it can
@@ -655,7 +655,7 @@ heapam_relation_copy_data(Relation rel, const RelFileNode *newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index a3c4a1d..03fac55 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -60,6 +60,7 @@
 #include "utils/pg_rusage.h"
 #include "utils/timestamp.h"
 
+#include "catalog/storage_gtt.h"
 
 /*
  * Space/time tradeoff parameters: do these need to be user-tunable?
@@ -214,8 +215,10 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 	Assert(params->truncate != VACOPT_TERNARY_DEFAULT);
 
 	/* not every AM requires these to be valid, but heap does */
-	Assert(TransactionIdIsNormal(onerel->rd_rel->relfrozenxid));
-	Assert(MultiXactIdIsValid(onerel->rd_rel->relminmxid));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relfrozenxid == InvalidTransactionId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && TransactionIdIsNormal(onerel->rd_rel->relfrozenxid)));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relminmxid == InvalidMultiXactId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && MultiXactIdIsValid(onerel->rd_rel->relminmxid)));
 
 	/* measure elapsed time iff autovacuum logging requires it */
 	if (IsAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
@@ -274,8 +277,19 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 
 	vacrelstats = (LVRelStats *) palloc0(sizeof(LVRelStats));
 
-	vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
-	vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
+	/* get relstat from gtt localhash */
+	if (RELATION_IS_GLOBAL_TEMP(onerel))
+	{
+		get_gtt_relstats(RelationGetRelid(onerel),
+						&vacrelstats->old_rel_pages,
+						&vacrelstats->old_live_tuples,
+						NULL, NULL, NULL);
+	}
+	else
+	{
+		vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
+		vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
+	}
 	vacrelstats->num_index_scans = 0;
 	vacrelstats->pages_removed = 0;
 	vacrelstats->lock_waiter_detected = false;
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index 6b2655c..dcb5acb 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -765,7 +765,14 @@ _bt_getbuf(Relation rel, BlockNumber blkno, int access)
 		/* Read an existing block of the relation */
 		buf = ReadBuffer(rel, blkno);
 		LockBuffer(buf, access);
-		_bt_checkpage(rel, buf);
+
+		/* global temp table may be not yet initialized for this backend. */
+		if (RELATION_IS_GLOBAL_TEMP(rel) &&
+			blkno == BTREE_METAPAGE &&
+			PageIsNew(BufferGetPage(buf)))
+			_bt_initmetapage(BufferGetPage(buf), P_NONE, 0);
+		else
+			_bt_checkpage(rel, buf);
 	}
 	else
 	{
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 77ad765..9ff98ff 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6319,6 +6319,10 @@ StartupXLOG(void)
 	else
 		recoveryTargetTLI = ControlFile->checkPointCopy.ThisTimeLineID;
 
+	/* clean temp relation files */
+	if (max_active_gtt > 0)
+		RemovePgTempFiles();
+
 	/*
 	 * Check for signal files, and if so set up state for offline recovery
 	 */
diff --git a/src/backend/catalog/Makefile b/src/backend/catalog/Makefile
index 8bece07..470683b 100644
--- a/src/backend/catalog/Makefile
+++ b/src/backend/catalog/Makefile
@@ -21,6 +21,8 @@ OBJS = catalog.o dependency.o heap.o index.o indexing.o namespace.o aclchk.o \
 	   pg_db_role_setting.o pg_shdepend.o pg_subscription.o pg_type.o \
 	   storage.o toasting.o
 
+OBJS += storage_gtt.o
+
 BKIFILES = postgres.bki postgres.description postgres.shdescription
 
 include $(top_srcdir)/src/backend/common.mk
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index a065419..db86aa6 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -406,7 +406,9 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class, char relpersistence)
 
 	switch (relpersistence)
 	{
+		/* global temp table is same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			break;
 		case RELPERSISTENCE_UNLOGGED:
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index b8b4768..832a3f1 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -61,6 +61,7 @@
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "commands/tablecmds.h"
 #include "commands/typecmds.h"
 #include "executor/executor.h"
@@ -100,6 +101,7 @@ static void AddNewRelationTuple(Relation pg_class_desc,
 								Oid reloftype,
 								Oid relowner,
 								char relkind,
+								char relpersistence,
 								TransactionId relfrozenxid,
 								TransactionId relminmxid,
 								Datum relacl,
@@ -406,6 +408,10 @@ heap_create(const char *relname,
 									 relpersistence,
 									 relkind);
 
+	/* global temp table not create storage file when catalog create */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		create_storage = false;
+
 	/*
 	 * Have the storage manager create the relation's disk file, if needed.
 	 *
@@ -429,7 +435,7 @@ heap_create(const char *relname,
 
 			case RELKIND_INDEX:
 			case RELKIND_SEQUENCE:
-				RelationCreateStorage(rel->rd_node, relpersistence);
+				RelationCreateStorage(rel->rd_node, relpersistence, rel);
 				break;
 
 			case RELKIND_RELATION:
@@ -926,6 +932,7 @@ AddNewRelationTuple(Relation pg_class_desc,
 					Oid reloftype,
 					Oid relowner,
 					char relkind,
+					char relpersistence,
 					TransactionId relfrozenxid,
 					TransactionId relminmxid,
 					Datum relacl,
@@ -964,8 +971,18 @@ AddNewRelationTuple(Relation pg_class_desc,
 			break;
 	}
 
-	new_rel_reltup->relfrozenxid = relfrozenxid;
-	new_rel_reltup->relminmxid = relminmxid;
+	/* global temp table not remember transaction info in catalog */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		new_rel_reltup->relfrozenxid = InvalidTransactionId;
+		new_rel_reltup->relminmxid = InvalidMultiXactId;
+	}
+	else
+	{
+		new_rel_reltup->relfrozenxid = relfrozenxid;
+		new_rel_reltup->relminmxid = relminmxid;
+	}
+
 	new_rel_reltup->relowner = relowner;
 	new_rel_reltup->reltype = new_type_oid;
 	new_rel_reltup->reloftype = reloftype;
@@ -1327,6 +1344,7 @@ heap_create_with_catalog(const char *relname,
 						reloftypeid,
 						ownerid,
 						relkind,
+						relpersistence,
 						relfrozenxid,
 						relminmxid,
 						PointerGetDatum(relacl),
@@ -1411,11 +1429,15 @@ heap_create_with_catalog(const char *relname,
 	 */
 	StoreConstraints(new_rel_desc, cooked_constraints, is_internal);
 
-	/*
-	 * If there's a special on-commit action, remember it
-	 */
-	if (oncommit != ONCOMMIT_NOOP)
-		register_on_commit_action(relid, oncommit);
+	/* global temp table register action when storage init */
+	if (relpersistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		/*
+		 * If there's a special on-commit action, remember it
+		 */
+		if (oncommit != ONCOMMIT_NOOP)
+			register_on_commit_action(relid, oncommit);
+	}
 
 	/*
 	 * ok, the relation has been cataloged, so close our relations and return
@@ -1907,6 +1929,13 @@ heap_drop_with_catalog(Oid relid)
 	if (relid == defaultPartOid)
 		update_default_partition_oid(parentOid, InvalidOid);
 
+	/* We allow to drop global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (is_other_backend_use_gtt(rel->rd_node))
+			elog(ERROR, "can not drop relation when other backend attached this global temp table");
+	}
+
 	/*
 	 * Schedule unlinking of the relation's physical files at commit.
 	 */
@@ -3133,9 +3162,10 @@ RemoveStatistics(Oid relid, AttrNumber attnum)
  *
  * The routine will truncate and then reconstruct the indexes on
  * the specified relation.  Caller must hold exclusive lock on rel.
+ *
  */
 static void
-RelationTruncateIndexes(Relation heapRelation)
+RelationTruncateIndexes(Relation heapRelation, LOCKMODE lockmode)
 {
 	ListCell   *indlist;
 
@@ -3147,7 +3177,7 @@ RelationTruncateIndexes(Relation heapRelation)
 		IndexInfo  *indexInfo;
 
 		/* Open the index relation; use exclusive lock, just to be sure */
-		currentIndex = index_open(indexId, AccessExclusiveLock);
+		currentIndex = index_open(indexId, lockmode);
 
 		/* Fetch info needed for index_build */
 		indexInfo = BuildIndexInfo(currentIndex);
@@ -3186,8 +3216,13 @@ heap_truncate(List *relids)
 	{
 		Oid			rid = lfirst_oid(cell);
 		Relation	rel;
+		LOCKMODE	lockmode = AccessExclusiveLock;
 
-		rel = table_open(rid, AccessExclusiveLock);
+		/* truncate global temp table only need RowExclusiveLock */
+		if (get_rel_persistence(rid) == RELPERSISTENCE_GLOBAL_TEMP)
+			lockmode = RowExclusiveLock;
+
+		rel = table_open(rid, lockmode);
 		relations = lappend(relations, rel);
 	}
 
@@ -3220,6 +3255,8 @@ void
 heap_truncate_one_rel(Relation rel)
 {
 	Oid			toastrelid;
+	LOCKMODE	lockmode = AccessExclusiveLock;
+	bool		truncate_toastrel = false;
 
 	/*
 	 * Truncate the relation.  Partitioned tables have no storage, so there is
@@ -3228,23 +3265,40 @@ heap_truncate_one_rel(Relation rel)
 	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 		return;
 
+	toastrelid = rel->rd_rel->reltoastrelid;
+
+	/*
+	 * Truncate global temp table only need RowExclusiveLock
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		lockmode = RowExclusiveLock;
+		if (OidIsValid(toastrelid) &&
+			gtt_storage_attached(toastrelid))
+			truncate_toastrel = true;
+	}
+	else if (OidIsValid(toastrelid))
+		truncate_toastrel = true;
+
 	/* Truncate the underlying relation */
 	table_relation_nontransactional_truncate(rel);
 
 	/* If the relation has indexes, truncate the indexes too */
-	RelationTruncateIndexes(rel);
+	RelationTruncateIndexes(rel, lockmode);
 
 	/* If there is a toast table, truncate that too */
-	toastrelid = rel->rd_rel->reltoastrelid;
-	if (OidIsValid(toastrelid))
+	if (truncate_toastrel)
 	{
-		Relation	toastrel = table_open(toastrelid, AccessExclusiveLock);
+		Relation	toastrel = table_open(toastrelid, lockmode);
 
 		table_relation_nontransactional_truncate(toastrel);
-		RelationTruncateIndexes(toastrel);
+		RelationTruncateIndexes(toastrel, lockmode);
 		/* keep the lock... */
 		table_close(toastrel, NoLock);
 	}
+
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		up_gtt_relstats(rel, 0, 0, 0, RecentXmin, InvalidMultiXactId);
 }
 
 /*
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 4f54631..3026309 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -52,6 +52,7 @@
 #include "catalog/pg_trigger.h"
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
+#include "catalog/storage_gtt.h"
 #include "commands/event_trigger.h"
 #include "commands/progress.h"
 #include "commands/tablecmds.h"
@@ -879,6 +880,26 @@ index_create(Relation heapRelation,
 						indexRelationName, RelationGetRelationName(heapRelation))));
 	}
 
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		if (accessMethodObjectId != BTREE_AM_OID)
+			elog(ERROR, "only support btree index on global temp table");
+
+		/* We allow to create index on global temp table only this session use it */
+		if (is_other_backend_use_gtt(heapRelation->rd_node) ||
+			gtt_storage_attached(heapRelation->rd_node.relNode))
+			elog(ERROR, "can not create index when have one or more backend attached this global temp table");
+
+		/* No support create index on global temp table use concurrent mode yet */
+		if (concurrent)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("cannot create indexes on global temporary tables using concurrent mode")));
+
+		/* if global temp table not init storage, then skip build index */
+		flags |= INDEX_CREATE_SKIP_BUILD;
+	}
+
 	/*
 	 * construct tuple descriptor for index tuples
 	 */
@@ -2040,6 +2061,13 @@ index_drop(Oid indexId, bool concurrent, bool concurrent_lock_mode)
 	 */
 	CheckTableNotInUse(userIndexRelation, "DROP INDEX");
 
+	/* We allow to drop index on global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(userHeapRelation))
+	{
+		if (is_other_backend_use_gtt(userHeapRelation->rd_node))
+			elog(ERROR, "can not drop index when other backend attached this global temp table");
+	}
+
 	/*
 	 * Drop Index Concurrently is more or less the reverse process of Create
 	 * Index Concurrently.
@@ -2699,20 +2727,29 @@ index_update_stats(Relation rel,
 		else					/* don't bother for indexes */
 			relallvisible = 0;
 
-		if (rd_rel->relpages != (int32) relpages)
+		/* update index stats into localhash for global temp table */
+		if (RELATION_IS_GLOBAL_TEMP(rel))
 		{
-			rd_rel->relpages = (int32) relpages;
-			dirty = true;
+			up_gtt_relstats(rel, relpages, reltuples, relallvisible,
+							InvalidTransactionId, InvalidMultiXactId);
 		}
-		if (rd_rel->reltuples != (float4) reltuples)
-		{
-			rd_rel->reltuples = (float4) reltuples;
-			dirty = true;
-		}
-		if (rd_rel->relallvisible != (int32) relallvisible)
+		else
 		{
-			rd_rel->relallvisible = (int32) relallvisible;
-			dirty = true;
+			if (rd_rel->relpages != (int32) relpages)
+			{
+				rd_rel->relpages = (int32) relpages;
+				dirty = true;
+			}
+			if (rd_rel->reltuples != (float4) reltuples)
+			{
+				rd_rel->reltuples = (float4) reltuples;
+				dirty = true;
+			}
+			if (rd_rel->relallvisible != (int32) relallvisible)
+			{
+				rd_rel->relallvisible = (int32) relallvisible;
+				dirty = true;
+			}
 		}
 	}
 
@@ -2827,6 +2864,13 @@ index_build(Relation heapRelation,
 		pgstat_progress_update_multi_param(6, index, val);
 	}
 
+	/* POALR */
+	if (RELATION_IS_GLOBAL_TEMP(indexRelation))
+	{
+		if (!gtt_storage_attached(indexRelation->rd_node.relNode))
+			RelationCreateStorage(indexRelation->rd_node, RELPERSISTENCE_GLOBAL_TEMP, indexRelation);
+	}
+
 	/*
 	 * Call the access method's build procedure
 	 */
@@ -3159,12 +3203,22 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	/*
 	 * Scan the index and gather up all the TIDs into a tuplesort object.
 	 */
+	memset(&ivinfo, 0, sizeof(IndexVacuumInfo));
 	ivinfo.index = indexRelation;
 	ivinfo.analyze_only = false;
 	ivinfo.report_progress = true;
 	ivinfo.estimated_count = true;
 	ivinfo.message_level = DEBUG2;
-	ivinfo.num_heap_tuples = heapRelation->rd_rel->reltuples;
+
+	/* get relstats abort global temp table from hashtable, not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		get_gtt_relstats(RelationGetRelid(heapRelation),
+						NULL, &ivinfo.num_heap_tuples, NULL,
+						NULL, NULL);
+	}
+	else
+		ivinfo.num_heap_tuples = heapRelation->rd_rel->reltuples;
 	ivinfo.strategy = NULL;
 
 	/*
@@ -3422,6 +3476,15 @@ reindex_index(Oid indexId, bool skip_constraint_checks, char persistence,
 				 errmsg("cannot reindex temporary tables of other sessions")));
 
 	/*
+	 * Because global temp table cannot change relfilenode
+	 * no support reindex on global temp table yet.
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(iRel))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot reindex global temporary tables")));
+
+	/*
 	 * Also check for active uses of the index in the current transaction; we
 	 * don't want to reindex underneath an open indexscan.
 	 */
diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index 8d0896c..4c04833 100644
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -647,6 +647,13 @@ RangeVarAdjustRelationPersistence(RangeVar *newRelation, Oid nspid)
 							 errmsg("cannot create temporary relation in non-temporary schema")));
 			}
 			break;
+		/* global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			if (isAnyTempNamespace(nspid))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+						 errmsg("cannot create global temp relations in temporary schemas")));
+			break;
 		case RELPERSISTENCE_PERMANENT:
 			if (isTempOrTempToastNamespace(nspid))
 				newRelation->relpersistence = RELPERSISTENCE_TEMP;
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index 3cc886f..6295f81 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -28,6 +28,7 @@
 #include "access/xlogutils.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "storage/freespace.h"
 #include "storage/smgr.h"
 #include "utils/memutils.h"
@@ -74,9 +75,10 @@ static PendingRelDelete *pendingDeletes = NULL; /* head of linked list */
  *
  * This function is transactional. The creation is WAL-logged, and if the
  * transaction aborts later on, the storage will be destroyed.
+ *
  */
 SMgrRelation
-RelationCreateStorage(RelFileNode rnode, char relpersistence)
+RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel)
 {
 	PendingRelDelete *pending;
 	SMgrRelation srel;
@@ -86,6 +88,8 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	switch (relpersistence)
 	{
 		case RELPERSISTENCE_TEMP:
+		/* global temp table use same storage strategy as local temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			needs_wal = false;
 			break;
@@ -118,6 +122,10 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	pending->next = pendingDeletes;
 	pendingDeletes = pending;
 
+	/* remember global temp table storage info to localhash */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP && rel)
+		remember_gtt_storage_info(rnode, rel);
+
 	return srel;
 }
 
@@ -455,8 +463,15 @@ smgrDoPendingDeletes(bool isCommit)
 		smgrdounlinkall(srels, nrels, false);
 
 		for (i = 0; i < nrels; i++)
+		{
 			smgrclose(srels[i]);
 
+			/* clean global temp table flags when transaction commit or rollback */
+			if (SmgrIsTemp(srels[i]) && 
+				gtt_storage_attached(srels[i]->smgr_rnode.node.relNode))
+				forget_gtt_storage_info(srels[i]->smgr_rnode.node.relNode);
+		}
+
 		pfree(srels);
 	}
 }
diff --git a/src/backend/catalog/storage_gtt.c b/src/backend/catalog/storage_gtt.c
new file mode 100644
index 0000000..37a8a97
--- /dev/null
+++ b/src/backend/catalog/storage_gtt.c
@@ -0,0 +1,814 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.c
+ *	  code to create and destroy physical storage for global temparary table
+ *
+ * IDENTIFICATION
+ *	  src/backend/catalog/storage_gtt.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/visibilitymap.h"
+#include "access/xact.h"
+#include "access/xlog.h"
+#include "access/xloginsert.h"
+#include "access/xlogutils.h"
+#include "access/htup_details.h"
+#include "access/multixact.h"
+#include "catalog/storage.h"
+#include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/heap.h"
+#include "commands/tablecmds.h"
+#include "nodes/primnodes.h"
+#include "nodes/pg_list.h"
+#include "miscadmin.h"
+#include "storage/freespace.h"
+#include "storage/smgr.h"
+#include "storage/ipc.h"
+#include "storage/proc.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "utils/memutils.h"
+#include "utils/rel.h"
+#include "utils/hsearch.h"
+#include "utils/catcache.h"
+#include <utils/relcache.h>
+#include "utils/inval.h"
+#include "utils/guc.h"
+#include "utils/guc.h"
+
+
+/* Copy from bitmapset.c, because gtt used the function in bitmapset.c */
+#define WORDNUM(x)	((x) / BITS_PER_BITMAPWORD)
+#define BITNUM(x)	((x) % BITS_PER_BITMAPWORD)
+
+#define BITMAPSET_SIZE(nwords)	\
+	(offsetof(Bitmapset, words) + (nwords) * sizeof(bitmapword))
+
+static bool gtt_cleaner_exit_registered = false;
+static HTAB *gtt_storage_local_hash = NULL;
+static HTAB *active_gtt_shared_hash = NULL;
+static MemoryContext gtt_relstats_context = NULL;
+
+/* relfrozenxid of all gtts in the current session */
+static List *gtt_session_relfrozenxid_list = NIL;
+static TransactionId gtt_session_frozenxid = InvalidTransactionId;
+
+typedef struct gtt_ctl_data
+{
+	LWLock			lock;
+	int			max_entry;
+	int			entry_size;
+}gtt_ctl_data;
+
+static gtt_ctl_data *gtt_shared_ctl = NULL;
+
+typedef struct
+{
+	RelFileNode	rnode;
+	Bitmapset	*map;
+	/* bitmap data */
+} gtt_shared_hash_entry;
+
+typedef struct
+{
+	Oid			relid;
+
+	Oid			spcnode;
+	/* pg_class stat */
+	int32		relpages;
+	float4		reltuples;
+	int32		relallvisible;
+	TransactionId relfrozenxid;
+	TransactionId relminmxid;
+	char		relkind;
+	bool		on_commit_delete;
+
+	/* pg_statistic */
+	int			natts;
+	int			*attnum;
+	HeapTuple	*att_stat_tups;
+} gtt_local_hash_entry;
+
+static Size action_gtt_shared_hash_entry_size(void);
+static void gtt_storage_checkin(RelFileNode rnode);
+static void gtt_storage_checkout(RelFileNode rnode, bool skiplock);
+static void gtt_storage_removeall(int code, Datum arg);
+static void insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid);
+static void remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid);
+static void set_gtt_session_relfrozenxid(void);
+
+static Size
+action_gtt_shared_hash_entry_size(void)
+{
+	int 	wordnum;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	wordnum = WORDNUM(MaxBackends + 1);
+	hash_entry_size += MAXALIGN(sizeof(gtt_shared_hash_entry));
+	hash_entry_size += MAXALIGN(BITMAPSET_SIZE(wordnum + 1));
+
+	return hash_entry_size;
+}
+
+Size
+active_gtt_shared_hash_size(void)
+{
+	Size	size = 0;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	size = MAXALIGN(sizeof(gtt_ctl_data));
+	hash_entry_size = action_gtt_shared_hash_entry_size();
+	size += hash_estimate_size(max_active_gtt, hash_entry_size);
+
+	return size;
+}
+
+void
+active_gtt_shared_hash_init(void)
+{
+	HASHCTL info;
+	bool	found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	gtt_shared_ctl =
+		ShmemInitStruct("gtt_shared_ctl",
+						sizeof(gtt_ctl_data),
+						&found);
+
+	if (!found)
+	{
+		LWLockRegisterTranche(LWTRANCHE_GTT_CTL, "gtt_shared_ctl");
+		LWLockInitialize(&gtt_shared_ctl->lock, LWTRANCHE_GTT_CTL);
+		gtt_shared_ctl->max_entry = max_active_gtt;
+		gtt_shared_ctl->entry_size = action_gtt_shared_hash_entry_size();
+	}
+
+	info.keysize = sizeof(RelFileNode);
+	info.entrysize = gtt_shared_ctl->entry_size;
+	active_gtt_shared_hash =
+		ShmemInitHash("active gtt shared hash",
+						gtt_shared_ctl->max_entry,
+						gtt_shared_ctl->max_entry,
+						&info, HASH_ELEM | HASH_BLOBS | HASH_FIXED_SIZE);
+}
+
+static void
+gtt_storage_checkin(RelFileNode rnode)
+{
+	gtt_shared_hash_entry	*entry;
+	bool			found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+	entry = (gtt_shared_hash_entry *) hash_search(active_gtt_shared_hash,
+												&rnode, HASH_ENTER_NULL, &found);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		ereport(ERROR,
+				(errcode(ERRCODE_OUT_OF_MEMORY),
+				 errmsg("out of shared memory"),
+				 errhint("You might need to increase max_active_gtt.")));
+	}
+
+	if (found == false)
+	{
+		int			wordnum;
+
+		entry->map = (Bitmapset *)((char *)entry + MAXALIGN(sizeof(gtt_shared_hash_entry)));
+		wordnum = WORDNUM(MaxBackends + 1);
+		memset(entry->map, 0, BITMAPSET_SIZE(wordnum + 1));
+		entry->map->nwords = wordnum + 1;
+	}
+
+	bms_add_member(entry->map, MyBackendId);
+	LWLockRelease(&gtt_shared_ctl->lock);
+}
+
+static void
+gtt_storage_checkout(RelFileNode rnode, bool skiplock)
+{
+	gtt_shared_hash_entry	*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (!skiplock)
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(rnode), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		if (!skiplock)
+			LWLockRelease(&gtt_shared_ctl->lock);
+
+		elog(WARNING, "relfilenode %u/%u/%u not exist in gtt shared hash when forget",
+						rnode.dbNode, rnode.spcNode, rnode.relNode);
+		return;
+	}
+
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+	bms_del_member(entry->map, MyBackendId);
+
+	if (bms_is_empty(entry->map))
+	{
+		if (!hash_search(active_gtt_shared_hash, &rnode, HASH_REMOVE, NULL))
+			elog(PANIC, "gtt shared hash table corrupted");
+	}
+
+	if (!skiplock)
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+	return;
+}
+
+Bitmapset *
+copy_active_gtt_bitmap(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	Bitmapset	*map_copy = NULL;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return NULL;
+	}
+
+	Assert(entry->map);
+	if (!bms_is_empty(entry->map))
+		map_copy = bms_copy(entry->map);
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return map_copy;
+}
+
+bool
+is_other_backend_use_gtt(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	bool		in_use = false;
+	int			num_use = 0;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return false;
+	}
+
+	Assert(entry->map);
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+
+	num_use = bms_num_members(entry->map);
+	if (num_use == 0)
+		in_use = false;
+	else if (num_use == 1)
+	{
+		if(bms_is_member(MyBackendId, entry->map))
+			in_use = false;
+		else
+			in_use = true;
+	}
+	else
+		in_use = true;
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return in_use;
+}
+
+void
+remember_gtt_storage_info(RelFileNode rnode, Relation rel)
+{
+	gtt_local_hash_entry	*entry;
+	MemoryContext			oldcontext;
+	Oid			relid = rnode.relNode;
+	bool		found;
+
+	if (max_active_gtt <= 0)
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("Global temporary table feature is disable"),
+			 errhint("You might need to increase max_active_gtt to enable this feature.")));
+
+	if (RecoveryInProgress())
+		elog(ERROR, "readonly mode not support access global temp table yet");
+
+	if (gtt_storage_local_hash == NULL)
+	{
+#define GTT_LOCAL_HASH_SIZE		1024
+		/* First time through: initialize the hash table */
+		HASHCTL		ctl;
+
+		MemSet(&ctl, 0, sizeof(ctl));
+		ctl.keysize = sizeof(Oid);
+		ctl.entrysize = sizeof(gtt_local_hash_entry);
+		gtt_storage_local_hash =
+			hash_create("global temp relation table",
+						GTT_LOCAL_HASH_SIZE,
+						&ctl, HASH_ELEM | HASH_BLOBS);
+
+		if (!CacheMemoryContext)
+			CreateCacheMemoryContext();
+
+		gtt_relstats_context =
+			AllocSetContextCreate(CacheMemoryContext,
+							"gtt relstats context",
+							ALLOCSET_DEFAULT_SIZES);
+	}
+
+	/* Look up or create an entry */
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_ENTER, &found);
+
+	if (found)
+	{
+		elog(ERROR, "backend %d relid %u already exists in global temp table local hash",
+					MyBackendId, relid);
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+
+	entry->spcnode = rnode.spcNode;
+	entry->relpages = 0;
+	entry->reltuples = 0;
+	entry->relallvisible = 0;
+	entry->relkind = rel->rd_rel->relkind;
+	/* only heap contain transaction information */
+	if (entry->relkind == RELKIND_RELATION)
+	{
+		int natts = RelationGetNumberOfAttributes(rel);
+		entry->natts = natts;
+		entry->attnum = palloc0(sizeof(int) * natts);
+		entry->att_stat_tups = palloc0(sizeof(HeapTuple) * natts);
+
+		if (RELATION_GTT_ON_COMMIT_DELETE(rel))
+		{
+			entry->on_commit_delete = true;
+			register_on_commit_action(rel->rd_node.relNode, ONCOMMIT_DELETE_ROWS);
+		}
+
+		entry->relfrozenxid = RecentXmin;
+		entry->relminmxid = GetOldestMultiXactId();
+		insert_gtt_relfrozenxid_to_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+		gtt_storage_checkin(rnode);
+	}
+	else
+	{
+		entry->natts = 0;
+		entry->attnum = 0;
+		entry->att_stat_tups = NULL;
+		entry->on_commit_delete = false;
+		entry->relfrozenxid = 0;
+		entry->relminmxid = 0;
+	}
+
+	MemoryContextSwitchTo(oldcontext);
+
+	if (!gtt_cleaner_exit_registered)
+	{
+		before_shmem_exit(gtt_storage_removeall, 0);
+		gtt_cleaner_exit_registered = true;
+	}
+
+	return;
+}
+
+void
+forget_gtt_storage_info(Oid relid)
+{
+	gtt_local_hash_entry		*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+				(void *) &(relid), HASH_FIND, NULL);
+
+	if (entry && entry->relkind == RELKIND_RELATION)
+	{
+		RelFileNode rnode;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		gtt_storage_checkout(rnode, false);
+
+		Assert(TransactionIdIsNormal(entry->relfrozenxid));
+		remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+	}
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_REMOVE, NULL);
+
+	return;
+}
+
+/* is the storage file was created in this backend */
+bool
+gtt_storage_attached(Oid relid)
+{
+	bool found;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	if (gtt_storage_local_hash == NULL)
+		return false;
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_FIND, &found);
+
+	return found;
+}
+
+static void
+gtt_storage_removeall(int code, Datum arg)
+{
+	HASH_SEQ_STATUS				status;
+	gtt_local_hash_entry		*entry;
+	int			nrels = 0,
+				maxrels = 0;
+	SMgrRelation	*srels = NULL;
+	RelFileNode		*rnodes = NULL;
+	char			*relkinds = NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	hash_seq_init(&status, gtt_storage_local_hash);
+	while ((entry = (gtt_local_hash_entry *) hash_seq_search(&status)) != NULL)
+	{
+		SMgrRelation srel;
+		RelFileNode rnode;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		srel = smgropen(rnode, MyBackendId);
+
+		/* allocate the initial array, or extend it, if needed */
+		if (maxrels == 0)
+		{
+			maxrels = 32;
+			srels = palloc(sizeof(SMgrRelation) * maxrels);
+			rnodes = palloc(sizeof(RelFileNode) * maxrels);
+			relkinds = palloc(sizeof(char) * maxrels);
+		}
+		else if (maxrels <= nrels)
+		{
+			maxrels *= 2;
+			srels = repalloc(srels, sizeof(SMgrRelation) * maxrels);
+			rnodes = repalloc(rnodes, sizeof(RelFileNode) * maxrels);
+			relkinds = repalloc(relkinds, sizeof(char) * maxrels);
+		}
+
+		srels[nrels] = srel;
+		rnodes[nrels] = rnode;
+		relkinds[nrels] = entry->relkind;
+		nrels++;
+	}
+
+	if (nrels > 0)
+	{
+		int i;
+
+		smgrdounlinkall(srels, nrels, false);
+
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+		for (i = 0; i < nrels; i++)
+		{
+			smgrclose(srels[i]);
+			if (relkinds[i] == RELKIND_RELATION)
+				gtt_storage_checkout(rnodes[i], true);
+		}
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+		pfree(srels);
+		pfree(rnodes);
+		pfree(relkinds);
+	}
+
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;
+
+	return;
+}
+
+/*
+ * Update global temp table relstats(relpage/reltuple/relallvisible) 
+ * to local hashtable
+ */
+void
+up_gtt_relstats(Relation relation,
+					BlockNumber num_pages,
+					double num_tuples,
+					BlockNumber num_all_visible_pages,
+					TransactionId relfrozenxid,
+					TransactionId relminmxid)
+{
+	Oid		relid = RelationGetRelid(relation);
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	Assert(entry->spcnode);
+
+	if (num_pages >= 0 &&
+		entry->relpages != (int32)num_pages)
+		entry->relpages = (int32)num_pages;
+
+	if (num_tuples >= 0 &&
+		num_tuples != (float4)entry->reltuples)
+		entry->reltuples = (float4)num_tuples;
+
+	/* only heap contain transaction information and relallvisible */
+	if (entry->relkind == RELKIND_RELATION)
+	{
+		if (entry->relallvisible >= 0 &&
+			entry->relallvisible != (int32)num_all_visible_pages)
+		{
+			entry->relallvisible = (int32)num_all_visible_pages;
+		}
+
+		if (TransactionIdIsNormal(relfrozenxid) &&
+			entry->relfrozenxid != relfrozenxid &&
+			(TransactionIdPrecedes(entry->relfrozenxid, relfrozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(), entry->relfrozenxid)))
+		{
+			remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+			entry->relfrozenxid = relfrozenxid;
+			insert_gtt_relfrozenxid_to_ordered_list(relfrozenxid);
+			set_gtt_session_relfrozenxid();
+		}
+
+		if (MultiXactIdIsValid(relminmxid) &&
+			entry->relminmxid != relminmxid &&
+			(MultiXactIdPrecedes(entry->relminmxid, relminmxid) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), entry->relminmxid)))
+		{
+			entry->relminmxid = relminmxid;
+		}
+	}
+
+	return;
+}
+
+/*
+ * Search global temp table relstats(relpage/reltuple/relallvisible) 
+ * from local hashtable.
+ */
+void
+get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+				BlockNumber *relallvisible, TransactionId *relfrozenxid,
+				TransactionId *relminmxid)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	Assert(entry->relid == relid);
+
+	if (relpages)
+		*relpages = entry->relpages;
+
+	if (reltuples)
+		*reltuples = entry->reltuples;
+
+	if (relallvisible)
+		*relallvisible = entry->relallvisible;
+
+	if (relfrozenxid)
+		*relfrozenxid = entry->relfrozenxid;
+
+	if (relminmxid)
+		*relminmxid = entry->relminmxid;
+
+	return;
+}
+
+/*
+ * Update global temp table statistic info(definition is same as pg_statistic)
+ * to local hashtable where ananyze global temp table
+ */
+void
+up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+					TupleDesc tupleDescriptor, Datum *values, bool *isnull)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	MemoryContext			oldcontext;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	if (entry->relkind != RELKIND_RELATION)
+	{
+		elog(WARNING, "oid %u not a relation", reloid);
+		return;
+	}
+
+	/* todo */
+	if (entry->natts < natts)
+	{
+		elog(WARNING, "reloid %u not support update attstat after add colunm", reloid);
+		return;
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	Assert(entry->relid == reloid);
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == 0)
+		{
+			entry->attnum[i] = attnum;
+			break;
+		}
+		else if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			heap_freetuple(entry->att_stat_tups[i]);
+			entry->att_stat_tups[i] = NULL;
+			break;
+		}
+	}
+
+	Assert(i < entry->natts);
+	Assert(entry->att_stat_tups[i] == NULL);
+	entry->att_stat_tups[i] = heap_form_tuple(tupleDescriptor, values, isnull);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+/*
+ * Search global temp table statistic info(definition is same as pg_statistic)
+ * from local hashtable.
+ */
+HeapTuple
+get_gtt_att_statistic(Oid reloid, int attnum, bool inh)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return NULL;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return NULL;
+
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			return entry->att_stat_tups[i];
+		}
+	}
+
+	return NULL;
+}
+
+void
+release_gtt_statistic_cache(HeapTuple tup)
+{
+	/* do nothing */
+	return;
+}
+
+static void
+insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid)
+{
+	MemoryContext	oldcontext;
+	ListCell	*prev;
+
+	Assert(TransactionIdIsNormal(relfrozenxid));
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	/* Does the datum belong at the front? */
+	if (gtt_session_relfrozenxid_list == NIL ||
+		TransactionIdFollowsOrEquals(relfrozenxid,
+			linitial_oid(gtt_session_relfrozenxid_list)))
+	{
+		gtt_session_relfrozenxid_list =
+			lcons_oid(relfrozenxid, gtt_session_relfrozenxid_list);
+		MemoryContextSwitchTo(oldcontext);
+
+		return;
+	}
+	/* No, so find the entry it belongs after */
+	prev = list_head(gtt_session_relfrozenxid_list);
+	for (;;)
+	{
+		ListCell   *curr = lnext(prev);
+
+		if (curr == NULL ||
+			TransactionIdFollowsOrEquals(relfrozenxid, lfirst_oid(curr)))
+			break;	/* it belongs after 'prev', before 'curr' */
+
+		prev = curr;
+	}
+	/* Insert datum into list after 'prev' */
+	lappend_cell_oid(gtt_session_relfrozenxid_list, prev, relfrozenxid);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+static void
+remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid)
+{
+	gtt_session_relfrozenxid_list =
+		list_delete_oid(gtt_session_relfrozenxid_list, relfrozenxid);
+}
+
+static void
+set_gtt_session_relfrozenxid(void)
+{
+	TransactionId gtt_frozenxid = InvalidTransactionId;
+
+	if (gtt_session_relfrozenxid_list)
+		gtt_frozenxid = llast_oid(gtt_session_relfrozenxid_list);
+
+	gtt_session_frozenxid = gtt_frozenxid;
+	if (MyProc->session_gtt_frozenxid != gtt_frozenxid)
+		MyProc->session_gtt_frozenxid = gtt_frozenxid;
+}
+
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index faabbeb..d79535d 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -65,6 +65,7 @@
 #include "utils/syscache.h"
 #include "utils/timestamp.h"
 
+#include "catalog/storage_gtt.h"
 
 /* Per-index data for ANALYZE */
 typedef struct AnlIndexData
@@ -102,7 +103,7 @@ static int	acquire_inherited_sample_rows(Relation onerel, int elevel,
 										  HeapTuple *rows, int targrows,
 										  double *totalrows, double *totaldeadrows);
 static void update_attstats(Oid relid, bool inh,
-							int natts, VacAttrStats **vacattrstats);
+							int natts, VacAttrStats **vacattrstats, char relpersistence);
 static Datum std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 static Datum ind_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 
@@ -563,14 +564,15 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 		 * pg_statistic for columns we didn't process, we leave them alone.)
 		 */
 		update_attstats(RelationGetRelid(onerel), inh,
-						attr_cnt, vacattrstats);
+						attr_cnt, vacattrstats, RelationGetRelPersistence(onerel));
 
 		for (ind = 0; ind < nindexes; ind++)
 		{
 			AnlIndexData *thisdata = &indexdata[ind];
 
 			update_attstats(RelationGetRelid(Irel[ind]), false,
-							thisdata->attr_cnt, thisdata->vacattrstats);
+							thisdata->attr_cnt, thisdata->vacattrstats,
+							RelationGetRelPersistence(Irel[ind]));
 		}
 
 		/*
@@ -647,11 +649,20 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 			IndexBulkDeleteResult *stats;
 			IndexVacuumInfo ivinfo;
 
+			memset(&ivinfo, 0, sizeof(IndexVacuumInfo));
 			ivinfo.index = Irel[ind];
 			ivinfo.analyze_only = true;
 			ivinfo.estimated_count = true;
 			ivinfo.message_level = elevel;
-			ivinfo.num_heap_tuples = onerel->rd_rel->reltuples;
+			/* get global temp relstats from localhash, not catalog */
+			if (RELATION_IS_GLOBAL_TEMP(onerel))
+			{
+				get_gtt_relstats(RelationGetRelid(onerel),
+								NULL, &ivinfo.num_heap_tuples, NULL,
+								NULL, NULL);
+			}
+			else
+				ivinfo.num_heap_tuples = onerel->rd_rel->reltuples;
 			ivinfo.strategy = vac_strategy;
 
 			stats = index_vacuum_cleanup(&ivinfo, NULL);
@@ -1414,7 +1425,7 @@ acquire_inherited_sample_rows(Relation onerel, int elevel,
  *		by taking a self-exclusive lock on the relation in analyze_rel().
  */
 static void
-update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
+update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats, char relpersistence)
 {
 	Relation	sd;
 	int			attno;
@@ -1516,31 +1527,45 @@ update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
 			}
 		}
 
-		/* Is there already a pg_statistic tuple for this attribute? */
-		oldtup = SearchSysCache3(STATRELATTINH,
-								 ObjectIdGetDatum(relid),
-								 Int16GetDatum(stats->attr->attnum),
-								 BoolGetDatum(inh));
-
-		if (HeapTupleIsValid(oldtup))
+		/* Update column statistic to localhash, not catalog */
+		if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		{
-			/* Yes, replace it */
-			stup = heap_modify_tuple(oldtup,
-									 RelationGetDescr(sd),
-									 values,
-									 nulls,
-									 replaces);
-			ReleaseSysCache(oldtup);
-			CatalogTupleUpdate(sd, &stup->t_self, stup);
+			up_gtt_att_statistic(relid,
+								stats->attr->attnum,
+								inh,
+								natts,
+								RelationGetDescr(sd),
+								values,
+								nulls);
 		}
 		else
 		{
-			/* No, insert new tuple */
-			stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
-			CatalogTupleInsert(sd, stup);
-		}
+			/* Is there already a pg_statistic tuple for this attribute? */
+			oldtup = SearchSysCache3(STATRELATTINH,
+									 ObjectIdGetDatum(relid),
+									 Int16GetDatum(stats->attr->attnum),
+									 BoolGetDatum(inh));
+
+			if (HeapTupleIsValid(oldtup))
+			{
+				/* Yes, replace it */
+				stup = heap_modify_tuple(oldtup,
+										 RelationGetDescr(sd),
+										 values,
+										 nulls,
+										 replaces);
+				ReleaseSysCache(oldtup);
+				CatalogTupleUpdate(sd, &stup->t_self, stup);
+			}
+			else
+			{
+				/* No, insert new tuple */
+				stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
+				CatalogTupleInsert(sd, stup);
+			}
 
-		heap_freetuple(stup);
+			heap_freetuple(stup);
+		}
 	}
 
 	table_close(sd, RowExclusiveLock);
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index ebaec4f..356df7c 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -392,6 +392,12 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 					 errmsg("cannot vacuum temporary tables of other sessions")));
 	}
 
+	/* not support cluster global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(OldHeap))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support cluster global temporary tables yet")));
+
 	/*
 	 * Also check for active uses of the relation in the current transaction,
 	 * including open scans and pending AFTER trigger events.
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index a528241..66f4b10 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -2584,6 +2584,16 @@ ReindexMultipleTables(const char *objectName, ReindexObjectType objectKind,
 			!isTempNamespace(classtuple->relnamespace))
 			continue;
 
+		/* not support reindex on global temp table, so skip it */
+		if (classtuple->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			ereport(WARNING,
+				(errmsg("global temp table \"%s.%s\" skip reindexed",
+					get_namespace_name(get_rel_namespace(relid)),
+					get_rel_name(relid))));
+			continue;
+		}
+
 		/* Check user/system classification, and optionally skip */
 		if (objectKind == REINDEX_OBJECT_SYSTEM &&
 			!IsSystemClass(relid, classtuple))
diff --git a/src/backend/commands/lockcmds.c b/src/backend/commands/lockcmds.c
index 417d595..b9c3a40 100644
--- a/src/backend/commands/lockcmds.c
+++ b/src/backend/commands/lockcmds.c
@@ -107,7 +107,8 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
 	 * transaction.
 	 */
 	relpersistence = get_rel_persistence(relid);
-	if (relpersistence == RELPERSISTENCE_TEMP)
+	if (relpersistence == RELPERSISTENCE_TEMP ||
+		relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		MyXactFlags |= XACT_FLAGS_ACCESSEDTEMPNAMESPACE;
 
 	/* Check permissions. */
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 792ba56..7a42efd 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -48,6 +48,7 @@
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
 #include "catalog/toasting.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/defrem.h"
@@ -530,6 +531,7 @@ static void refuseDupeIndexAttach(Relation parentIdx, Relation partIdx,
 								  Relation partitionTbl);
 static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
+static bool has_oncommit_option(List *options);
 
 
 /* ----------------------------------------------------------------
@@ -575,6 +577,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	LOCKMODE	parentLockmode;
 	const char *accessMethod = NULL;
 	Oid			accessMethodId = InvalidOid;
+	bool		has_oncommit_clause = false;
 
 	/*
 	 * Truncate relname to appropriate length (probably a waste of time, as
@@ -585,8 +588,10 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Check consistency of arguments
 	 */
+	/* global temp table same as local temp table */
 	if (stmt->oncommit != ONCOMMIT_NOOP
-		&& stmt->relation->relpersistence != RELPERSISTENCE_TEMP)
+		&& !(stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+			 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 				 errmsg("ON COMMIT can only be used on temporary tables")));
@@ -616,12 +621,28 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	 * code.  This is needed because calling code might not expect untrusted
 	 * tables to appear in pg_temp at the front of its search path.
 	 */
-	if (stmt->relation->relpersistence == RELPERSISTENCE_TEMP
+	/* global temp table same as local temp table */
+	if ((stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+		 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		&& InSecurityRestrictedOperation())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 errmsg("cannot create temporary table within security-restricted operation")));
 
+	/* Not support partitioned or inherited global temp table yet */
+	if (stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		if (relkind == RELKIND_PARTITIONED_TABLE)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support create global temporary partition table yet")));
+
+		if (stmt->inhRelations)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support create global temporary inheritance table yet")));
+	}
+
 	/*
 	 * Determine the lockmode to use when scanning parents.  A self-exclusive
 	 * lock is needed here.
@@ -717,6 +738,40 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Parse and validate reloptions, if any.
 	 */
+	/* global temp table */
+	has_oncommit_clause = has_oncommit_option(stmt->options);
+	if (stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		if (has_oncommit_clause)
+		{
+			if (stmt->oncommit != ONCOMMIT_NOOP)
+				elog(ERROR, "can not defeine global temp table with on commit and with clause at same time");
+		}
+		else
+		{
+			DefElem *opt = makeNode(DefElem);
+
+			opt->type = T_DefElem;
+			opt->defnamespace = NULL;
+			opt->defname = "on_commit_delete_rows";
+			opt->defaction = DEFELEM_UNSPEC;
+
+			/* use reloptions to remember on commit clause */
+			if (stmt->oncommit == ONCOMMIT_DELETE_ROWS)
+				opt->arg  = (Node *)makeString("true");
+			else if (stmt->oncommit == ONCOMMIT_PRESERVE_ROWS)
+				opt->arg  = (Node *)makeString("false");
+			else if (stmt->oncommit == ONCOMMIT_NOOP)
+				opt->arg  = (Node *)makeString("true");
+			else
+				elog(ERROR, "global temp table not support on commit drop clause");
+
+			stmt->options = lappend(stmt->options, opt);
+		}
+	}
+	else if (has_oncommit_clause)
+		elog(ERROR, "regular table cannot specifie on_commit_delete_rows");
+
 	reloptions = transformRelOptions((Datum) 0, stmt->options, NULL, validnsps,
 									 true, false);
 
@@ -1772,7 +1827,8 @@ ExecuteTruncateGuts(List *explicit_rels, List *relids, List *relids_logged,
 		 * table or the current physical file to be thrown away anyway.
 		 */
 		if (rel->rd_createSubid == mySubid ||
-			rel->rd_newRelfilenodeSubid == mySubid)
+			rel->rd_newRelfilenodeSubid == mySubid ||
+			RELATION_IS_GLOBAL_TEMP(rel))
 		{
 			/* Immediate, non-rollbackable truncation is OK */
 			heap_truncate_one_rel(rel);
@@ -3332,6 +3388,13 @@ RenameRelationInternal(Oid myrelid, const char *newrelname, bool is_internal, bo
 	 * specially.
 	 */
 	targetrelation = relation_open(myrelid, is_index ? ShareUpdateExclusiveLock : AccessExclusiveLock);
+
+	/* not support rename global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(targetrelation))
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("not support rename global temporary tables yet")));
+
 	namespaceId = RelationGetNamespace(targetrelation);
 
 	/*
@@ -3501,6 +3564,14 @@ AlterTable(Oid relid, LOCKMODE lockmode, AlterTableStmt *stmt)
 	/* Caller is required to provide an adequate lock. */
 	rel = relation_open(relid, NoLock);
 
+	/* not support alter global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("not support alter global temporary tables yet")));
+	}
+
 	CheckTableNotInUse(rel, "ALTER TABLE");
 
 	ATController(stmt, rel, stmt->cmds, stmt->relation->inh, lockmode);
@@ -7651,6 +7722,13 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 				 errmsg("referenced relation \"%s\" is not a table",
 						RelationGetRelationName(pkrel))));
 
+	/* global temp table not support foreign key constraint yet */
+	if (RELATION_IS_GLOBAL_TEMP(pkrel))
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("referenced relation \"%s\" is not a global temp table",
+						RelationGetRelationName(pkrel))));
+
 	if (!allowSystemTableMods && IsSystemRelation(pkrel))
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -7690,6 +7768,12 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 						 errmsg("constraints on temporary tables must involve temporary tables of this session")));
 			break;
+		/* global temp table not support foreign key constraint yet */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					 errmsg("not support foreign key constraints on global temp table yet")));
+			break;
 	}
 
 	/*
@@ -12702,7 +12786,7 @@ index_copy_data(Relation rel, RelFileNode newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
@@ -14109,7 +14193,9 @@ ATPrepChangePersistence(Relation rel, bool toLogged)
 	 */
 	switch (rel->rd_rel->relpersistence)
 	{
+		/* global temp table same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("cannot change logged status of table \"%s\" because it is temporary",
@@ -16716,3 +16802,20 @@ ATDetachCheckNoForeignKeyRefs(Relation partition)
 		table_close(rel, NoLock);
 	}
 }
+
+static bool
+has_oncommit_option(List *options)
+{
+	ListCell   *listptr;
+
+	foreach(listptr, options)
+	{
+		DefElem    *def = (DefElem *) lfirst(listptr);
+
+		if (pg_strcasecmp(def->defname, "on_commit_delete_rows") == 0)
+			return true;
+	}
+
+	return false;
+}
+
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index ef275c0..c44fad8 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -35,6 +35,7 @@
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
 #include "catalog/pg_namespace.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
 #include "commands/vacuum.h"
@@ -1068,12 +1069,25 @@ vac_estimate_reltuples(Relation relation,
 					   BlockNumber scanned_pages,
 					   double scanned_tuples)
 {
-	BlockNumber old_rel_pages = relation->rd_rel->relpages;
-	double		old_rel_tuples = relation->rd_rel->reltuples;
+	BlockNumber old_rel_pages = 0;
+	double		old_rel_tuples = 0;
 	double		old_density;
 	double		unscanned_pages;
 	double		total_tuples;
 
+	/* get relstat from gtt local hash */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+	{
+		get_gtt_relstats(RelationGetRelid(relation),
+						&old_rel_pages, &old_rel_tuples, NULL,
+						NULL, NULL);
+	}
+	else
+	{
+		old_rel_pages = relation->rd_rel->relpages;
+		old_rel_tuples = relation->rd_rel->reltuples;
+	}
+
 	/* If we did scan the whole table, just use the count as-is */
 	if (scanned_pages >= total_pages)
 		return scanned_tuples;
@@ -1173,24 +1187,8 @@ vac_update_relstats(Relation relation,
 	/* Apply statistical updates, if any, to copied tuple */
 
 	dirty = false;
-	if (pgcform->relpages != (int32) num_pages)
-	{
-		pgcform->relpages = (int32) num_pages;
-		dirty = true;
-	}
-	if (pgcform->reltuples != (float4) num_tuples)
-	{
-		pgcform->reltuples = (float4) num_tuples;
-		dirty = true;
-	}
-	if (pgcform->relallvisible != (int32) num_all_visible_pages)
-	{
-		pgcform->relallvisible = (int32) num_all_visible_pages;
-		dirty = true;
-	}
 
 	/* Apply DDL updates, but not inside an outer transaction (see above) */
-
 	if (!in_outer_xact)
 	{
 		/*
@@ -1215,37 +1213,64 @@ vac_update_relstats(Relation relation,
 		}
 	}
 
-	/*
-	 * Update relfrozenxid, unless caller passed InvalidTransactionId
-	 * indicating it has no new data.
-	 *
-	 * Ordinarily, we don't let relfrozenxid go backwards: if things are
-	 * working correctly, the only way the new frozenxid could be older would
-	 * be if a previous VACUUM was done with a tighter freeze_min_age, in
-	 * which case we don't want to forget the work it already did.  However,
-	 * if the stored relfrozenxid is "in the future", then it must be corrupt
-	 * and it seems best to overwrite it with the cutoff we used this time.
-	 * This should match vac_update_datfrozenxid() concerning what we consider
-	 * to be "in the future".
-	 */
-	if (TransactionIdIsNormal(frozenxid) &&
-		pgcform->relfrozenxid != frozenxid &&
-		(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
-		 TransactionIdPrecedes(ReadNewTransactionId(),
-							   pgcform->relfrozenxid)))
+	/* global temp table remember relstats to localhash not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
 	{
-		pgcform->relfrozenxid = frozenxid;
-		dirty = true;
+		up_gtt_relstats(relation,
+						num_pages, num_tuples,
+						num_all_visible_pages,
+						frozenxid, minmulti);
 	}
-
-	/* Similarly for relminmxid */
-	if (MultiXactIdIsValid(minmulti) &&
-		pgcform->relminmxid != minmulti &&
-		(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
-		 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
+	else
 	{
-		pgcform->relminmxid = minmulti;
-		dirty = true;
+		if (pgcform->relpages != (int32) num_pages)
+		{
+			pgcform->relpages = (int32) num_pages;
+			dirty = true;
+		}
+		if (pgcform->reltuples != (float4) num_tuples)
+		{
+			pgcform->reltuples = (float4) num_tuples;
+			dirty = true;
+		}
+		if (pgcform->relallvisible != (int32) num_all_visible_pages)
+		{
+			pgcform->relallvisible = (int32) num_all_visible_pages;
+			dirty = true;
+		}
+
+		/*
+		 * Update relfrozenxid, unless caller passed InvalidTransactionId
+		 * indicating it has no new data.
+		 *
+		 * Ordinarily, we don't let relfrozenxid go backwards: if things are
+		 * working correctly, the only way the new frozenxid could be older would
+		 * be if a previous VACUUM was done with a tighter freeze_min_age, in
+		 * which case we don't want to forget the work it already did.  However,
+		 * if the stored relfrozenxid is "in the future", then it must be corrupt
+		 * and it seems best to overwrite it with the cutoff we used this time.
+		 * This should match vac_update_datfrozenxid() concerning what we consider
+		 * to be "in the future".
+		 */
+		if (TransactionIdIsNormal(frozenxid) &&
+			pgcform->relfrozenxid != frozenxid &&
+			(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(),
+								   pgcform->relfrozenxid)))
+		{
+			pgcform->relfrozenxid = frozenxid;
+			dirty = true;
+		}
+
+		/* Similarly for relminmxid */
+		if (MultiXactIdIsValid(minmulti) &&
+			pgcform->relminmxid != minmulti &&
+			(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
+		{
+			pgcform->relminmxid = minmulti;
+			dirty = true;
+		}
 	}
 
 	/* If anything changed, write out the tuple. */
@@ -1337,6 +1362,10 @@ vac_update_datfrozenxid(void)
 			continue;
 		}
 
+		/* global temp table relstats not in pg_class */
+		if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			continue;
+
 		/*
 		 * Some table AMs might not need per-relation xid / multixid horizons.
 		 * It therefore seems reasonable to allow relfrozenxid and relminmxid
@@ -1394,6 +1423,25 @@ vac_update_datfrozenxid(void)
 	Assert(TransactionIdIsNormal(newFrozenXid));
 	Assert(MultiXactIdIsValid(newMinMulti));
 
+	/*
+	 * Global temp table get frozenxid from MyProc
+	 * to avoid the vacuum truncate clog that gtt need.
+	 */
+	if (max_active_gtt > 0)
+	{
+		TransactionId oldest_gtt_frozenxid =
+			list_all_session_gtt_frozenxids(0, NULL, NULL, NULL);
+
+		if (TransactionIdIsNormal(oldest_gtt_frozenxid) &&
+			TransactionIdPrecedes(oldest_gtt_frozenxid, newFrozenXid))
+		{
+			ereport(WARNING,
+				(errmsg("global temp table oldest FrozenXid is far in the past"),
+				 errhint("please truncate them or kill those sessions that use them.")));
+			newFrozenXid = oldest_gtt_frozenxid;
+		}
+	}
+
 	/* Now fetch the pg_database tuple we need to update. */
 	relation = table_open(DatabaseRelationId, RowExclusiveLock);
 
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index b772348..cf1c7e0 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -591,6 +591,8 @@ static void
 set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 						  RangeTblEntry *rte)
 {
+	char relpersistence;
+
 	/*
 	 * The flag has previously been initialized to false, so we can just
 	 * return if it becomes clear that we can't safely set it.
@@ -618,7 +620,11 @@ set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 			 * the rest of the necessary infrastructure right now anyway.  So
 			 * for now, bail out if we see a temporary table.
 			 */
-			if (get_rel_persistence(rte->relid) == RELPERSISTENCE_TEMP)
+			/* global temp table is same as local temp table */
+			relpersistence = get_rel_persistence(rte->relid);
+
+			if (relpersistence == RELPERSISTENCE_TEMP ||
+				relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 				return;
 
 			/*
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 401299e..7d63265 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -6306,7 +6306,9 @@ plan_create_index_workers(Oid tableOid, Oid indexOid)
 	 * Furthermore, any index predicate or index expressions must be parallel
 	 * safe.
 	 */
+	/* global temp table is same as local temp table */
 	if (heap->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		heap->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexExpressions(index)) ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexPredicate(index)))
 	{
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 40f4976..535cf80 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -53,6 +53,7 @@
 #include "utils/syscache.h"
 #include "utils/snapmgr.h"
 
+#include "catalog/storage_gtt.h"
 
 /* GUC parameter */
 int			constraint_exclusion = CONSTRAINT_EXCLUSION_PARTITION;
@@ -937,10 +938,10 @@ void
 estimate_rel_size(Relation rel, int32 *attr_widths,
 				  BlockNumber *pages, double *tuples, double *allvisfrac)
 {
-	BlockNumber curpages;
-	BlockNumber relpages;
-	double		reltuples;
-	BlockNumber relallvisible;
+	BlockNumber curpages = 0;
+	BlockNumber relpages = 0;
+	double		reltuples = 0;
+	BlockNumber relallvisible = 0;
 	double		density;
 
 	switch (rel->rd_rel->relkind)
@@ -954,6 +955,21 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 
 		case RELKIND_INDEX:
 
+			/* global temp table get relstats from localhash */
+			if (RELATION_IS_GLOBAL_TEMP(rel))
+			{
+				get_gtt_relstats(RelationGetRelid(rel),
+								&relpages, &reltuples, &relallvisible,
+								NULL, NULL);
+			}
+			else
+			{
+				/* coerce values in pg_class to more desirable types */
+				relpages = (BlockNumber) rel->rd_rel->relpages;
+				reltuples = (double) rel->rd_rel->reltuples;
+				relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
+			}
+
 			/*
 			 * XXX: It'd probably be good to move this into a callback,
 			 * individual index types e.g. know if they have a metapage.
@@ -962,11 +978,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 			/* it has storage, ok to call the smgr */
 			curpages = RelationGetNumberOfBlocks(rel);
 
-			/* coerce values in pg_class to more desirable types */
-			relpages = (BlockNumber) rel->rd_rel->relpages;
-			reltuples = (double) rel->rd_rel->reltuples;
-			relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
-
 			/* report estimated # pages */
 			*pages = curpages;
 			/* quick exit if rel is clearly empty */
@@ -976,10 +987,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 				*allvisfrac = 0;
 				break;
 			}
-			/* coerce values in pg_class to more desirable types */
-			relpages = (BlockNumber) rel->rd_rel->relpages;
-			reltuples = (double) rel->rd_rel->reltuples;
-			relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
 
 			/*
 			 * Discount the metapage while estimating the number of tuples.
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 345a8e6..076a210 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -2579,6 +2579,11 @@ transformCreateTableAsStmt(ParseState *pstate, CreateTableAsStmt *stmt)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("materialized views must not use temporary tables or views")));
 
+		if (is_query_using_gtt(query))
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("materialized views must not use global temporary tables or views")));
+
 		/*
 		 * A materialized view would either need to save parameters for use in
 		 * maintaining/loading the data or prohibit them entirely.  The latter
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 208b4a1..8cc52d9 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3267,17 +3267,11 @@ OptTemp:	TEMPORARY					{ $$ = RELPERSISTENCE_TEMP; }
 			| LOCAL TEMP				{ $$ = RELPERSISTENCE_TEMP; }
 			| GLOBAL TEMPORARY
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED					{ $$ = RELPERSISTENCE_UNLOGGED; }
 			| /*EMPTY*/					{ $$ = RELPERSISTENCE_PERMANENT; }
@@ -11476,19 +11470,13 @@ OptTempTableName:
 				}
 			| GLOBAL TEMPORARY opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED opt_table qualified_name
 				{
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 77a48b0..7f14d41 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -59,6 +59,7 @@ static void expandTupleDesc(TupleDesc tupdesc, Alias *eref,
 							List **colnames, List **colvars);
 static int	specialAttNum(const char *attname);
 static bool isQueryUsingTempRelation_walker(Node *node, void *context);
+static bool is_query_using_gtt_walker(Node *node, void *context);
 
 
 /*
@@ -3425,3 +3426,49 @@ isQueryUsingTempRelation_walker(Node *node, void *context)
 								  isQueryUsingTempRelation_walker,
 								  context);
 }
+
+/* check if the query uses global temp table */
+static bool
+is_query_using_gtt_walker(Node *node, void *context)
+{
+	if (node == NULL)
+		return false;
+
+	if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+		ListCell   *rtable;
+
+		foreach(rtable, query->rtable)
+		{
+			RangeTblEntry *rte = lfirst(rtable);
+
+			if (rte->rtekind == RTE_RELATION)
+			{
+				Relation	rel = heap_open(rte->relid, AccessShareLock);
+				char		relpersistence = rel->rd_rel->relpersistence;
+
+				heap_close(rel, AccessShareLock);
+				if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+					return true;
+			}
+		}
+
+		return query_tree_walker(query,
+								 is_query_using_gtt_walker,
+								 context,
+								 QTW_IGNORE_JOINALIASES);
+	}
+
+	return expression_tree_walker(node,
+								  is_query_using_gtt_walker,
+								  context);
+}
+
+/* check if the query uses global temp table */
+bool
+is_query_using_gtt(Query *query)
+{
+	return is_query_using_gtt_walker((Node *) query, NULL);
+}
+
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 2406ca7..ab6fc9a 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -359,6 +359,13 @@ generateSerialExtraStmts(CreateStmtContext *cxt, ColumnDef *column,
 	AlterSeqStmt *altseqstmt;
 	List	   *attnamelist;
 
+	if (cxt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("Global temp table does not yet support serial column")));
+	}
+
 	/*
 	 * Determine namespace and name to use for the sequence.
 	 *
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index fd85b9c..eb46e94 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -2088,6 +2088,11 @@ do_autovacuum(void)
 			}
 			continue;
 		}
+		else if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			/* autovacuum skip vacuum global temp table */
+			continue;
+		}
 
 		/* Fetch reloptions and the pgstat entry for this table */
 		relopts = extract_autovac_opts(tuple, pg_class_desc);
@@ -2154,7 +2159,9 @@ do_autovacuum(void)
 		/*
 		 * We cannot safely process other backends' temp tables, so skip 'em.
 		 */
-		if (classForm->relpersistence == RELPERSISTENCE_TEMP)
+		/* autovacuum skip vacuum global temp table */
+		if (classForm->relpersistence == RELPERSISTENCE_TEMP || 
+			classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 			continue;
 
 		relid = classForm->oid;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 7332e6b..f023aa3 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -53,6 +53,8 @@
 #include "utils/resowner_private.h"
 #include "utils/timestamp.h"
 
+#include "utils/guc.h"
+#include "catalog/storage_gtt.h"
 
 /* Note: these two macros only work on shared buffers, not local ones! */
 #define BufHdrGetBlock(bufHdr)	((Block) (BufferBlocks + ((Size) (bufHdr)->buf_id) * BLCKSZ))
@@ -432,7 +434,7 @@ ForgetPrivateRefCountEntry(PrivateRefCountEntry *ref)
 static Buffer ReadBuffer_common(SMgrRelation reln, char relpersistence,
 								ForkNumber forkNum, BlockNumber blockNum,
 								ReadBufferMode mode, BufferAccessStrategy strategy,
-								bool *hit);
+								bool *hit, Relation rel);
 static bool PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy);
 static void PinBuffer_Locked(BufferDesc *buf);
 static void UnpinBuffer(BufferDesc *buf, bool fixOwner);
@@ -663,7 +665,8 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
 	 */
 	pgstat_count_buffer_read(reln);
 	buf = ReadBuffer_common(reln->rd_smgr, reln->rd_rel->relpersistence,
-							forkNum, blockNum, mode, strategy, &hit);
+							forkNum, blockNum, mode, strategy, &hit,
+							reln);
 	if (hit)
 		pgstat_count_buffer_hit(reln);
 	return buf;
@@ -691,7 +694,7 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 	Assert(InRecovery);
 
 	return ReadBuffer_common(smgr, RELPERSISTENCE_PERMANENT, forkNum, blockNum,
-							 mode, strategy, &hit);
+							 mode, strategy, &hit, NULL);
 }
 
 
@@ -703,7 +706,8 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 static Buffer
 ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 				  BlockNumber blockNum, ReadBufferMode mode,
-				  BufferAccessStrategy strategy, bool *hit)
+				  BufferAccessStrategy strategy, bool *hit,
+				  Relation rel)
 {
 	BufferDesc *bufHdr;
 	Block		bufBlock;
@@ -718,6 +722,15 @@ ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 
 	isExtend = (blockNum == P_NEW);
 
+	/* create storage when first read data page for gtt */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP &&
+		(isExtend || blockNum == 0) &&
+		forkNum == MAIN_FORKNUM &&
+		!gtt_storage_attached(smgr->smgr_rnode.node.relNode))
+	{
+		RelationCreateStorage(smgr->smgr_rnode.node, relpersistence, rel);
+	}
+
 	TRACE_POSTGRESQL_BUFFER_READ_START(forkNum, blockNum,
 									   smgr->smgr_rnode.node.spcNode,
 									   smgr->smgr_rnode.node.dbNode,
@@ -2798,6 +2811,16 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln)
 BlockNumber
 RelationGetNumberOfBlocksInFork(Relation relation, ForkNumber forkNum)
 {
+	/*
+	 * When this backend not init gtt storage
+	 * return 0
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(relation) &&
+		!gtt_storage_attached(relation->rd_node.relNode))
+	{
+		return 0;
+	}
+
 	switch (relation->rd_rel->relkind)
 	{
 		case RELKIND_SEQUENCE:
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index d7d7335..3b2cc8b 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -21,6 +21,7 @@
 #include "access/nbtree.h"
 #include "access/subtrans.h"
 #include "access/twophase.h"
+#include "catalog/storage_gtt.h"
 #include "commands/async.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -147,6 +148,7 @@ CreateSharedMemoryAndSemaphores(int port)
 		size = add_size(size, BTreeShmemSize());
 		size = add_size(size, SyncScanShmemSize());
 		size = add_size(size, AsyncShmemSize());
+		size = add_size(size, active_gtt_shared_hash_size());
 #ifdef EXEC_BACKEND
 		size = add_size(size, ShmemBackendArraySize());
 #endif
@@ -217,6 +219,8 @@ CreateSharedMemoryAndSemaphores(int port)
 	SUBTRANSShmemInit();
 	MultiXactShmemInit();
 	InitBufferPool();
+	/* global temporary table */
+	active_gtt_shared_hash_init();
 
 	/*
 	 * Set up lock manager
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index 18a0f62..0d926bd 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -60,6 +60,7 @@
 #include "utils/builtins.h"
 #include "utils/rel.h"
 #include "utils/snapmgr.h"
+#include "utils/guc.h"
 
 #define UINT32_ACCESS_ONCE(var)		 ((uint32)(*((volatile uint32 *)&(var))))
 
@@ -3975,3 +3976,77 @@ KnownAssignedXidsReset(void)
 
 	LWLockRelease(ProcArrayLock);
 }
+
+/*
+ * search all active backend to get oldest frozenxid
+ * for global temp table.
+ */
+int
+list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n)
+{
+	ProcArrayStruct *arrayP = procArray;
+	TransactionId result = InvalidTransactionId;
+	int			index;
+	int			flags = 0;
+	int			i = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	if (max_size > 0)
+	{
+		Assert(pids);
+		Assert(xids);
+		Assert(n);
+		*n = 0;
+	}
+
+	if (max_active_gtt <= 0)
+		return InvalidTransactionId;
+
+	if (RecoveryInProgress())
+		return InvalidTransactionId;
+
+	flags |= PROC_IS_AUTOVACUUM;
+	flags |= PROC_IN_LOGICAL_DECODING;
+
+	LWLockAcquire(ProcArrayLock, LW_SHARED);
+	if (max_size > 0 && max_size < arrayP->numProcs)
+	{
+		LWLockRelease(ProcArrayLock);
+		elog(ERROR, "list_all_gtt_frozenxids require more array");
+	}
+
+	for (index = 0; index < arrayP->numProcs; index++)
+	{
+		int			pgprocno = arrayP->pgprocnos[index];
+		volatile PGPROC *proc = &allProcs[pgprocno];
+		volatile PGXACT *pgxact = &allPgXact[pgprocno];
+
+		if (pgxact->vacuumFlags & flags)
+			continue;
+
+		if (proc->databaseId == MyDatabaseId &&
+			TransactionIdIsNormal(proc->session_gtt_frozenxid))
+		{
+			if (result == InvalidTransactionId)
+				result = proc->session_gtt_frozenxid;
+			else if (TransactionIdPrecedes(proc->session_gtt_frozenxid, result))
+				result = proc->session_gtt_frozenxid;
+
+			if (max_size > 0)
+			{
+				pids[i] = proc->pid;
+				xids[i] = proc->session_gtt_frozenxid;
+				i++;
+			}
+		}
+	}
+	LWLockRelease(ProcArrayLock);
+
+	if (max_size > 0)
+		*n = i;
+
+	return result;
+}
+
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 498373f..542cc6b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -396,6 +396,7 @@ InitProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
@@ -578,6 +579,7 @@ InitAuxiliaryProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 64acc3f..fdbc95b 100644
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -629,6 +629,12 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 		 */
 		if (zero_damaged_pages || InRecovery)
 			MemSet(buffer, 0, BLCKSZ);
+		else if(SmgrIsTemp(reln) && blocknum == 0 && forknum == MAIN_FORKNUM)
+		{
+			/* global temp table init btree meta page */
+			MemSet(buffer, 0, BLCKSZ);
+			mdwrite(reln, forknum, blocknum, buffer, true);
+		}
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_DATA_CORRUPTED),
diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c
index a87e721..adce760 100644
--- a/src/backend/utils/adt/dbsize.c
+++ b/src/backend/utils/adt/dbsize.c
@@ -1008,6 +1008,10 @@ pg_relation_filepath(PG_FUNCTION_ARGS)
 				Assert(backend != InvalidBackendId);
 			}
 			break;
+		/* For global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			backend = BackendIdForTempRelations();
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relform->relpersistence);
 			backend = InvalidBackendId; /* placate compiler */
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index a314ecc..c957d12 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -141,6 +141,7 @@
 #include "utils/timestamp.h"
 #include "utils/typcache.h"
 
+#include "catalog/storage_gtt.h"
 
 /* Hooks for plugins to get control when we ask for stats */
 get_relation_stats_hook_type get_relation_stats_hook = NULL;
@@ -4586,12 +4587,25 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
 						}
 						else if (index->indpred == NIL)
 						{
-							vardata->statsTuple =
-								SearchSysCache3(STATRELATTINH,
-												ObjectIdGetDatum(index->indexoid),
-												Int16GetDatum(pos + 1),
-												BoolGetDatum(false));
-							vardata->freefunc = ReleaseSysCache;
+							char rel_persistence = get_rel_persistence(index->indexoid);
+
+							if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+							{
+								vardata->statsTuple =
+									get_gtt_att_statistic(index->indexoid,
+														Int16GetDatum(pos + 1),
+														false);
+								vardata->freefunc = release_gtt_statistic_cache;
+							}
+							else
+							{
+								vardata->statsTuple =
+									SearchSysCache3(STATRELATTINH,
+													ObjectIdGetDatum(index->indexoid),
+													Int16GetDatum(pos + 1),
+													BoolGetDatum(false));
+								vardata->freefunc = ReleaseSysCache;
+							}
 
 							if (HeapTupleIsValid(vardata->statsTuple))
 							{
@@ -4670,15 +4684,27 @@ examine_simple_variable(PlannerInfo *root, Var *var,
 	}
 	else if (rte->rtekind == RTE_RELATION)
 	{
-		/*
-		 * Plain table or parent of an inheritance appendrel, so look up the
-		 * column in pg_statistic
-		 */
-		vardata->statsTuple = SearchSysCache3(STATRELATTINH,
-											  ObjectIdGetDatum(rte->relid),
-											  Int16GetDatum(var->varattno),
-											  BoolGetDatum(rte->inh));
-		vardata->freefunc = ReleaseSysCache;
+		char rel_persistence = get_rel_persistence(rte->relid);
+
+		if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata->statsTuple = get_gtt_att_statistic(rte->relid,
+														var->varattno,
+														rte->inh);
+			vardata->freefunc = release_gtt_statistic_cache;
+		}
+		else
+		{
+			/*
+			 * Plain table or parent of an inheritance appendrel, so look up the
+			 * column in pg_statistic
+			 */
+			vardata->statsTuple = SearchSysCache3(STATRELATTINH,
+												  ObjectIdGetDatum(rte->relid),
+												  Int16GetDatum(var->varattno),
+												  BoolGetDatum(rte->inh));
+			vardata->freefunc = ReleaseSysCache;
+		}
 
 		if (HeapTupleIsValid(vardata->statsTuple))
 		{
@@ -5991,6 +6017,7 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	{
 		/* Simple variable --- look to stats for the underlying table */
 		RangeTblEntry *rte = planner_rt_fetch(index->rel->relid, root);
+		char	rel_persistence = get_rel_persistence(rte->relid);
 
 		Assert(rte->rtekind == RTE_RELATION);
 		relid = rte->relid;
@@ -6008,6 +6035,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													rte->inh);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -6019,6 +6053,8 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	}
 	else
 	{
+		char	rel_persistence = get_rel_persistence(index->indexoid);
+
 		/* Expression --- maybe there are stats for the index itself */
 		relid = index->indexoid;
 		colnum = 1;
@@ -6034,6 +6070,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													false);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -6900,6 +6943,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		/* attempt to lookup stats in relation for this index column */
 		if (attnum != 0)
 		{
+			char	rel_persistence = get_rel_persistence(rte->relid);
+
 			/* Simple variable -- look to stats for the underlying table */
 			if (get_relation_stats_hook &&
 				(*get_relation_stats_hook) (root, rte, attnum, &vardata))
@@ -6912,6 +6957,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					elog(ERROR,
 						 "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(rte->relid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple =
@@ -6924,6 +6977,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		}
 		else
 		{
+			char	rel_persistence = get_rel_persistence(index->indexoid);
+
 			/*
 			 * Looks like we've found an expression column in the index. Let's
 			 * see if there's any stats for it.
@@ -6943,6 +6998,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					!vardata.freefunc)
 					elog(ERROR, "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(index->indexoid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple = SearchSysCache3(STATRELATTINH,
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 27602fa..25a411a 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -34,6 +34,7 @@
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_transform.h"
 #include "catalog/pg_type.h"
+#include "catalog/storage_gtt.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "utils/array.h"
@@ -46,6 +47,7 @@
 #include "utils/syscache.h"
 #include "utils/typcache.h"
 
+
 /* Hook for plugins to get control in get_attavgwidth() */
 get_attavgwidth_hook_type get_attavgwidth_hook = NULL;
 
@@ -2878,6 +2880,18 @@ get_attavgwidth(Oid relid, AttrNumber attnum)
 		if (stawidth > 0)
 			return stawidth;
 	}
+	if (get_rel_persistence(relid) == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		tp = get_gtt_att_statistic(relid, attnum, false);
+		if (!HeapTupleIsValid(tp))
+			return 0;
+
+		stawidth = ((Form_pg_statistic) GETSTRUCT(tp))->stawidth;
+		if (stawidth > 0)
+			return stawidth;
+		else
+			return 0;
+	}
 	tp = SearchSysCache3(STATRELATTINH,
 						 ObjectIdGetDatum(relid),
 						 Int16GetDatum(attnum),
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index e8d11a1..0c7b455 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -1131,6 +1131,16 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
 				relation->rd_islocaltemp = false;
 			}
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			{
+				relation->rd_backend = BackendIdForTempRelations();
+				/*
+				 * For global temp table, all backend can use
+				 * this relation, so rd_islocaltemp always true.
+				 */
+				relation->rd_islocaltemp = true;
+			}
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c",
 				 relation->rd_rel->relpersistence);
@@ -3312,6 +3322,10 @@ RelationBuildLocalRelation(const char *relname,
 			rel->rd_backend = BackendIdForTempRelations();
 			rel->rd_islocaltemp = true;
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			rel->rd_backend = BackendIdForTempRelations();
+			rel->rd_islocaltemp = true;
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relpersistence);
 			break;
@@ -3426,6 +3440,9 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 	TransactionId freezeXid = InvalidTransactionId;
 	RelFileNode newrnode;
 
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+		elog(ERROR, "global temp table does not allow setting new relfilenode");
+
 	/* Allocate a new relfilenode */
 	newrelfilenode = GetNewRelFileNode(relation->rd_rel->reltablespace, NULL,
 									   persistence);
@@ -3466,7 +3483,7 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 				/* handle these directly, at least for now */
 				SMgrRelation srel;
 
-				srel = RelationCreateStorage(newrnode, persistence);
+				srel = RelationCreateStorage(newrnode, persistence, relation);
 				smgrclose(srel);
 			}
 			break;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index f0ed326..d4590a2 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -138,6 +138,18 @@ char	   *GUC_check_errmsg_string;
 char	   *GUC_check_errdetail_string;
 char	   *GUC_check_errhint_string;
 
+/*
+ * num = 0 means disable global temp table feature.
+ * global temp table define can still storage in catalog
+ * just can not use.
+ * num > 0 means database can management num active global temp table.
+ */
+#define	MIN_NUM_ACTIVE_GTT			0
+#define	DEFAULT_NUM_ACTIVE_GTT			1000
+#define	MAX_NUM_ACTIVE_GTT			1000000
+
+int		max_active_gtt = MIN_NUM_ACTIVE_GTT;
+
 static void do_serialize(char **destptr, Size *maxbytes, const char *fmt,...) pg_attribute_printf(3, 4);
 
 static void set_config_sourcefile(const char *name, char *sourcefile,
@@ -1962,6 +1974,15 @@ static struct config_bool ConfigureNamesBool[] =
 static struct config_int ConfigureNamesInt[] =
 {
 	{
+		{"max_active_global_temporary_table", PGC_POSTMASTER, UNGROUPED,
+			gettext_noop("max active global temporary table."),
+			NULL
+		},
+		&max_active_gtt,
+		DEFAULT_NUM_ACTIVE_GTT, MIN_NUM_ACTIVE_GTT, MAX_NUM_ACTIVE_GTT,
+		NULL, NULL, NULL
+	},
+	{
 		{"archive_timeout", PGC_SIGHUP, WAL_ARCHIVING,
 			gettext_noop("Forces a switch to the next WAL file if a "
 						 "new file has not been started within N seconds."),
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index a9c868b..3831341 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15535,6 +15535,7 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 	{
 		char	   *ftoptions = NULL;
 		char	   *srvname = NULL;
+		char		*table_type = NULL;
 
 		switch (tbinfo->relkind)
 		{
@@ -15586,9 +15587,15 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 			binary_upgrade_set_pg_class_oids(fout, q,
 											 tbinfo->dobj.catId.oid, false);
 
+		if (tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED)
+			table_type = "UNLOGGED ";
+		else if (tbinfo->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			table_type = "GLOBAL TEMPORARY ";
+		else
+			table_type = "";
+
 		appendPQExpBuffer(q, "CREATE %s%s %s",
-						  tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED ?
-						  "UNLOGGED " : "",
+						  table_type,
 						  reltypename,
 						  qualrelname);
 
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index 090b6ba..34b4683 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -165,6 +165,7 @@ typedef FormData_pg_class *Form_pg_class;
 #define		  RELPERSISTENCE_PERMANENT	'p' /* regular table */
 #define		  RELPERSISTENCE_UNLOGGED	'u' /* unlogged permanent table */
 #define		  RELPERSISTENCE_TEMP		't' /* temporary table */
+#define		  RELPERSISTENCE_GLOBAL_TEMP	'g' /* global temporary table */
 
 /* default selection for replica identity (primary key or nothing) */
 #define		  REPLICA_IDENTITY_DEFAULT	'd'
diff --git a/src/include/catalog/storage.h b/src/include/catalog/storage.h
index 3579d3f..2bde386 100644
--- a/src/include/catalog/storage.h
+++ b/src/include/catalog/storage.h
@@ -19,7 +19,7 @@
 #include "storage/smgr.h"
 #include "utils/relcache.h"
 
-extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence);
+extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel);
 extern void RelationDropStorage(Relation rel);
 extern void RelationPreserveStorage(RelFileNode rnode, bool atCommit);
 extern void RelationTruncate(Relation rel, BlockNumber nblocks);
diff --git a/src/include/catalog/storage_gtt.h b/src/include/catalog/storage_gtt.h
new file mode 100644
index 0000000..ea41e66
--- /dev/null
+++ b/src/include/catalog/storage_gtt.h
@@ -0,0 +1,39 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.h
+ *	  prototypes for functions in backend/catalog/storage_gtt.c
+ *
+ * src/include/catalog/storage_gtt.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef STORAGE_GTT_H
+#define STORAGE_GTT_H
+
+#include "access/htup.h"
+#include "storage/block.h"
+#include "storage/relfilenode.h"
+#include "utils/relcache.h"
+
+extern Size active_gtt_shared_hash_size(void);
+extern void active_gtt_shared_hash_init(void);
+extern void remember_gtt_storage_info(RelFileNode rnode, Relation rel);
+extern void forget_gtt_storage_info(Oid relid);
+extern bool is_other_backend_use_gtt(RelFileNode node);
+extern bool gtt_storage_attached(Oid relid);
+extern Bitmapset *copy_active_gtt_bitmap(RelFileNode node);
+extern void up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+								TupleDesc tupleDescriptor, Datum *values, bool *isnull);
+extern HeapTuple get_gtt_att_statistic(Oid reloid, int attnum, bool inh);
+extern void release_gtt_statistic_cache(HeapTuple tup);
+extern void up_gtt_relstats(Relation relation,
+							BlockNumber num_pages,
+							double num_tuples,
+							BlockNumber num_all_visible_pages,
+							TransactionId relfrozenxid,
+							TransactionId relminmxid);
+extern void get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+							BlockNumber *relallvisible, TransactionId *relfrozenxid,
+							TransactionId *relminmxid);
+
+#endif							/* STORAGE_H */
diff --git a/src/include/parser/parse_relation.h b/src/include/parser/parse_relation.h
index f7e0781..4f5a353 100644
--- a/src/include/parser/parse_relation.h
+++ b/src/include/parser/parse_relation.h
@@ -130,4 +130,7 @@ extern Oid	attnumTypeId(Relation rd, int attid);
 extern Oid	attnumCollationId(Relation rd, int attid);
 extern bool isQueryUsingTempRelation(Query *query);
 
+/* global temp table check */
+extern bool is_query_using_gtt(Query *query);
+
 #endif							/* PARSE_RELATION_H */
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 08e0dc8..297e20c 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -220,6 +220,7 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_TBM,
 	LWTRANCHE_PARALLEL_APPEND,
 	LWTRANCHE_SXACT,
+	LWTRANCHE_GTT_CTL,
 	LWTRANCHE_FIRST_USER_DEFINED
 }			BuiltinTrancheIds;
 
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index ac7ee72..74a074a 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -117,6 +117,8 @@ struct PGPROC
 	Oid			tempNamespaceId;	/* OID of temp schema this backend is
 									 * using */
 
+	TransactionId session_gtt_frozenxid;	/* session level global temp table relfrozenxid */
+
 	bool		isBackgroundWorker; /* true if background worker. */
 
 	/*
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index da8b672..8e7d4c7 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -124,4 +124,6 @@ extern void ProcArraySetReplicationSlotXmin(TransactionId xmin,
 extern void ProcArrayGetReplicationSlotXmin(TransactionId *xmin,
 											TransactionId *catalog_xmin);
 
+extern int list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n);
+
 #endif							/* PROCARRAY_H */
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index a93ed77..a782eee 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -276,6 +276,10 @@ extern int	tcp_user_timeout;
 extern bool trace_sort;
 #endif
 
+/* global temporary table */
+extern int	max_active_gtt;
+/* end */
+
 /*
  * Functions exported by guc.c
  */
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 1385ff3..a5a991d 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -273,6 +273,7 @@ typedef struct StdRdOptions
 	int			parallel_workers;	/* max number of parallel workers */
 	bool		vacuum_index_cleanup;	/* enables index vacuuming and cleanup */
 	bool		vacuum_truncate;	/* enables vacuum to truncate a relation */
+	bool		on_commit_delete_rows;	/* global temp table */
 } StdRdOptions;
 
 #define HEAP_MIN_FILLFACTOR			10
@@ -524,7 +525,8 @@ typedef struct ViewOptions
  *		True if relation's pages are stored in local buffers.
  */
 #define RelationUsesLocalBuffers(relation) \
-	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP || \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 
 /*
  * RELATION_IS_LOCAL
@@ -603,6 +605,17 @@ typedef struct ViewOptions
  */
 #define RelationGetPartitionDesc(relation) ((relation)->rd_partdesc)
 
+/* global temp table implementations */
+#define RELATION_IS_GLOBAL_TEMP(relation)	((relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+
+#define RELATION_GTT_ON_COMMIT_DELETE(relation)	\
+	((relation)->rd_options && \
+	 (relation)->rd_rel->relkind == RELKIND_RELATION && \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ? \
+	 ((StdRdOptions *) (relation)->rd_options)->on_commit_delete_rows : false)
+
+#define RelationGetRelPersistence(relation) ((relation)->rd_rel->relpersistence)
+
 /* routines in utils/cache/relcache.c */
 extern void RelationIncrementReferenceCount(Relation rel);
 extern void RelationDecrementReferenceCount(Relation rel);
diff --git a/src/test/regress/expected/gtt_clean.out b/src/test/regress/expected/gtt_clean.out
new file mode 100644
index 0000000..50ca9ac
--- /dev/null
+++ b/src/test/regress/expected/gtt_clean.out
@@ -0,0 +1,7 @@
+reset search_path;
+drop schema gtt cascade;
+NOTICE:  drop cascades to 4 other objects
+DETAIL:  drop cascades to table gtt.gtt1
+drop cascades to table gtt.gtt2
+drop cascades to table gtt.gtt3
+drop cascades to table gtt.gtt_t_kenyon
diff --git a/src/test/regress/expected/gtt_error.out b/src/test/regress/expected/gtt_error.out
new file mode 100644
index 0000000..80c16dc
--- /dev/null
+++ b/src/test/regress/expected/gtt_error.out
@@ -0,0 +1,106 @@
+CREATE SCHEMA IF NOT EXISTS gtt_error;
+set search_path=gtt_error,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+ERROR:  cannot create indexes on global temporary tables using concurrent mode
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+ERROR:  not support cluster global temporary tables yet
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+ERROR:  ON COMMIT can only be used on temporary tables
+-- ERROR
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+ERROR:  regular table cannot specifie on_commit_delete_rows
+-- ERROR
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+ERROR:  not support create global temporary partition table yet
+-- ERROR
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+ERROR:  not support create global temporary inheritance table yet
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+ERROR:  global temp table not support on commit drop clause
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+ERROR:  can not defeine global temp table with on commit and with clause at same time
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+--ERROR
+alter table gtt1 rename to gttx;
+ERROR:  not support rename global temporary tables yet
+-- ERROR
+ALTER TABLE gtt1 ADD COLUMN address varchar(30);
+ERROR:  not support alter global temporary tables yet
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  referenced relation "products" is not a global temp table
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  not support alter global temporary tables yet
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+ERROR:  Global temp table does not yet support serial column
+-- ERROR
+create global temp table gttx(id int GENERATED ALWAYS AS IDENTITY (START WITH 2));
+ERROR:  Global temp table does not yet support serial column
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+ERROR:  materialized views must not use global temporary tables or views
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+ERROR:  only support btree index on global temp table
+create index idx_err on gtt1 using gist (a);
+ERROR:  data type integer has no default operator class for access method "gist"
+HINT:  You must specify an operator class for the index or define a default operator class for the data type.
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+ERROR:  only support btree index on global temp table
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+ERROR:  only support btree index on global temp table
+reset search_path;
+drop schema gtt_error cascade;
+NOTICE:  drop cascades to 8 other objects
+DETAIL:  drop cascades to table gtt_error.gtt1
+drop cascades to table gtt_error.gtt2
+drop cascades to table gtt_error.gtt3
+drop cascades to table gtt_error.tmp_t0
+drop cascades to table gtt_error.tbl_inherits_parent
+drop cascades to table gtt_error.tbl_inherits_parent_global_temp
+drop cascades to table gtt_error.products
+drop cascades to table gtt_error.gtt5
diff --git a/src/test/regress/expected/gtt_parallel_1.out b/src/test/regress/expected/gtt_parallel_1.out
new file mode 100644
index 0000000..30d8a7b
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_1.out
@@ -0,0 +1,84 @@
+set search_path=gtt,sys;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_parallel_2.out b/src/test/regress/expected/gtt_parallel_2.out
new file mode 100644
index 0000000..70bf4a6
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_2.out
@@ -0,0 +1,142 @@
+set search_path=gtt,sys;
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+ 3 | test1
+(3 rows)
+
+rollback;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test2
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 3 | test3
+(1 row)
+
+rollback;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 5 | test5
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 6 | test6
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+ count  
+--------
+ 100000
+(1 row)
+
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+             QUERY PLAN             
+------------------------------------
+ Index Scan using gtt3_pkey on gtt3
+   Index Cond: (a = 300)
+(2 rows)
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',10000);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid) from pg_class where relname = 'gtt_t_kenyon';
+   relname    | pg_relation_size | pg_relation_size 
+--------------+------------------+------------------
+ gtt_t_kenyon |           450560 |            16384
+(1 row)
+
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+   relname    
+--------------
+ gtt_t_kenyon
+(1 row)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_prepare.out b/src/test/regress/expected/gtt_prepare.out
new file mode 100644
index 0000000..9e8f5f0
--- /dev/null
+++ b/src/test/regress/expected/gtt_prepare.out
@@ -0,0 +1,7 @@
+CREATE SCHEMA IF NOT EXISTS gtt;
+set search_path=gtt,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+reset search_path;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 8fb55f0..588f4e5 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -120,3 +120,9 @@ test: fast_default
 
 # run stats by itself because its delay may be insufficient under heavy load
 test: stats
+
+# global temp table test
+test: gtt_error
+test: gtt_prepare
+test: gtt_parallel_1 gtt_parallel_2
+test: gtt_clean
diff --git a/src/test/regress/sql/gtt_clean.sql b/src/test/regress/sql/gtt_clean.sql
new file mode 100644
index 0000000..f3cf710
--- /dev/null
+++ b/src/test/regress/sql/gtt_clean.sql
@@ -0,0 +1,6 @@
+
+
+reset search_path;
+
+drop schema gtt cascade;
+
diff --git a/src/test/regress/sql/gtt_error.sql b/src/test/regress/sql/gtt_error.sql
new file mode 100644
index 0000000..e895574
--- /dev/null
+++ b/src/test/regress/sql/gtt_error.sql
@@ -0,0 +1,106 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt_error;
+
+set search_path=gtt_error,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+
+-- ERROR
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+
+-- ERROR
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+
+-- ERROR
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+
+--ERROR
+alter table gtt1 rename to gttx;
+
+-- ERROR
+ALTER TABLE gtt1 ADD COLUMN address varchar(30);
+
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+
+-- ERROR
+create global temp table gttx(id int GENERATED ALWAYS AS IDENTITY (START WITH 2));
+
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+create index idx_err on gtt1 using gist (a);
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+
+reset search_path;
+
+drop schema gtt_error cascade;
+
diff --git a/src/test/regress/sql/gtt_parallel_1.sql b/src/test/regress/sql/gtt_parallel_1.sql
new file mode 100644
index 0000000..d7d81de
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_1.sql
@@ -0,0 +1,42 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+commit;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+rollback;
+select * from gtt1 order by a;
+
+truncate gtt1;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+select * from gtt1 order by a;
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+
+begin;
+select * from gtt1 order by a;
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_parallel_2.sql b/src/test/regress/sql/gtt_parallel_2.sql
new file mode 100644
index 0000000..cb2f7a6
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_2.sql
@@ -0,0 +1,62 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+commit;
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+truncate gtt3;
+select * from gtt3 order by a;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+truncate gtt3;
+select * from gtt3 order by a;
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+begin;
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',10000);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid) from pg_class where relname = 'gtt_t_kenyon';
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_prepare.sql b/src/test/regress/sql/gtt_prepare.sql
new file mode 100644
index 0000000..042d9e6
--- /dev/null
+++ b/src/test/regress/sql/gtt_prepare.sql
@@ -0,0 +1,15 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt;
+
+set search_path=gtt,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+
+reset search_path;
+
--
libgit2 0.23.3

diff --git a/contrib/Makefile b/contrib/Makefile
index 92184ed..4b1a596 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -48,7 +48,8 @@ SUBDIRS = \
 		tsm_system_rows \
 		tsm_system_time \
 		unaccent	\
-		vacuumlo
+		vacuumlo	\
+		pg_gtt
 
 ifeq ($(with_openssl),yes)
 SUBDIRS += sslinfo
diff --git a/contrib/pg_gtt/Makefile b/contrib/pg_gtt/Makefile
new file mode 100644
index 0000000..1d2ef64
--- /dev/null
+++ b/contrib/pg_gtt/Makefile
@@ -0,0 +1,22 @@
+# contrib/pg_gtt/Makefile
+
+MODULE_big = pg_gtt
+OBJS = pg_gtt.o
+
+EXTENSION = pg_gtt
+DATA = pg_gtt--1.0.sql
+
+LDFLAGS_SL += $(filter -lm, $(LIBS))
+
+NO_INSTALLCHECK = 1
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/pg_pfs
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/contrib/pg_gtt/pg_gtt--1.0.sql b/contrib/pg_gtt/pg_gtt--1.0.sql
new file mode 100644
index 0000000..3f794d7
--- /dev/null
+++ b/contrib/pg_gtt/pg_gtt--1.0.sql
@@ -0,0 +1,28 @@
+/* contrib/pg_gtt/pg_gtt--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION pg_gtt" to load this file. \quit
+
+
+CREATE FUNCTION pg_gtt_att_statistic(text, text, int)
+RETURNS setof pg_statistic
+AS 'MODULE_PATHNAME','pg_gtt_att_statistic'
+LANGUAGE C STRICT;
+
+CREATE TYPE relstats_type AS (relpages int4, reltuples float4, relallvisible int4, relfrozenxid xid, relminmxid xid);
+CREATE TYPE rel_vac_type AS (pid int4, relfrozenxid xid, relminmxid xid);
+
+CREATE FUNCTION pg_gtt_relstats(text, text)
+RETURNS relstats_type
+AS 'MODULE_PATHNAME','pg_gtt_relstats'
+LANGUAGE C STRICT;
+
+CREATE FUNCTION pg_gtt_attached_pid(text, text)
+RETURNS setof int4
+AS 'MODULE_PATHNAME','pg_gtt_attached_pid'
+LANGUAGE C STRICT;
+
+CREATE FUNCTION pg_list_gtt_relfrozenxids()
+RETURNS setof rel_vac_type
+AS 'MODULE_PATHNAME','pg_list_gtt_relfrozenxids'
+LANGUAGE C STRICT;
diff --git a/contrib/pg_gtt/pg_gtt.c b/contrib/pg_gtt/pg_gtt.c
new file mode 100644
index 0000000..19e1ec0
--- /dev/null
+++ b/contrib/pg_gtt/pg_gtt.c
@@ -0,0 +1,474 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_gtt.c
+ *	code to management function for global temparary table
+ *
+ * IDENTIFICATION
+ *	  contrib/pg_gtt/pg_gtt.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <unistd.h>
+#include <sys/time.h>
+#include "port.h"
+#include "access/htup_details.h"
+#include "access/table.h"
+#include "access/xlog.h"
+#include "catalog/pg_type.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/namespace.h"
+#include "catalog/pg_class.h"
+#include "funcapi.h"
+#include "storage/ipc.h"
+#include "storage/shmem.h"
+#include "storage/lwlock.h"
+#include "storage/procarray.h"
+#include "storage/proc.h"
+#include "tcop/utility.h"
+#include "utils/builtins.h"
+#include "utils/memutils.h"
+#include "utils/timeout.h"
+#include "utils/guc.h"
+#include "utils/lsyscache.h"
+#include "utils/rel.h"
+#include <nodes/makefuncs.h>
+#include "storage/sinvaladt.h"
+#include "miscadmin.h"
+
+PG_MODULE_MAGIC;
+
+static Oid pg_get_relid(const char *relname, char *schema);
+
+Datum pg_gtt_att_statistic(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(pg_gtt_att_statistic);
+
+Datum pg_gtt_relstats(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(pg_gtt_relstats);
+
+Datum pg_gtt_attached_pid(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(pg_gtt_attached_pid);
+
+Datum pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(pg_list_gtt_relfrozenxids);
+
+void		_PG_init(void);
+void		_PG_fini(void);
+
+void
+_PG_init(void)
+{
+	return;
+}
+
+void
+_PG_fini(void)
+{
+	return;
+}
+
+static Oid
+pg_get_relid(const char *relname, char *schema)
+{
+	Oid			relid;
+	RangeVar   *rv = makeRangeVar(schema, (char *)relname, -1);
+
+	relid = RangeVarGetRelid(rv, NoLock, true);
+
+	pfree(rv);
+	return relid;
+}
+
+Datum
+pg_gtt_att_statistic(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc		tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple		tuple;
+	Relation	rel = NULL;
+	char	*relname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	char	*schema = text_to_cstring(PG_GETARG_TEXT_PP(1));
+	int		attnum = PG_GETARG_INT32(2);
+	Oid		reloid;
+	char	rel_persistence;
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = NULL;
+	rsinfo->setDesc = NULL;
+
+	tupdesc = CreateTemplateTupleDesc(31);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "starelid",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "staattnum",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 3, "stainherit",
+						BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 4, "stanullfrac",
+						FLOAT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "stawidth",
+						INT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "stadistinct",
+						FLOAT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 7, "stakind1",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 8, "stakind2",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 9, "stakind3",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 10, "stakind4",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 11, "stakind5",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 12, "staop1",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 13, "staop2",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 14, "staop3",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 15, "staop4",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 16, "staop5",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 17, "stacoll1",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 18, "stacoll2",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 19, "stacoll3",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 20, "stacoll4",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 21, "stacoll5",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 22, "stanumbers1",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 23, "stanumbers2",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 24, "stanumbers3",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 25, "stanumbers4",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 26, "stanumbers5",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 27, "stavalues1",
+						ANYARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 28, "stavalues2",
+						ANYARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 29, "stavalues3",
+						ANYARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 30, "stavalues4",
+						ANYARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 31, "stavalues5",
+						ANYARRAYOID, -1, 0);
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (schema == NULL)
+		schema = "public";
+
+	reloid = pg_get_relid(relname, schema);
+	if (reloid == InvalidOid)
+	{
+		elog(WARNING, "relation %s.%s does not exist", schema, relname);
+		return (Datum) 0;
+	}
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation %s.%s not global temp table", schema, relname);
+		return (Datum) 0;
+	}
+
+	tuple = get_gtt_att_statistic(reloid, attnum, false);
+	if (tuple)
+	{
+		HeapTuple tp = heap_copytuple(tuple);
+		tuplestore_puttuple(tupstore, tp);
+	}
+	tuplestore_donestoring(tupstore);
+
+	table_close(rel, NoLock);
+	return (Datum) 0;
+}
+
+Datum
+pg_gtt_relstats(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	char	*relname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	char	*schema = text_to_cstring(PG_GETARG_TEXT_PP(1));
+	Oid	reloid;
+	char	rel_persistence;
+	Datum	values[5];
+	bool	isnull[5];
+	BlockNumber	relpages = 0;
+	double		reltuples = 0;
+	BlockNumber	relallvisible = 0;
+	uint32		relfrozenxid = 0;
+	uint32		relminmxid = 0;
+	Relation	rel = NULL;
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = NULL;
+	rsinfo->setDesc = NULL;
+
+	tupdesc = CreateTemplateTupleDesc(5);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "relpages",
+						INT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "reltuples",
+						FLOAT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 3, "relallvisible",
+						INT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 4, "relfrozenxid",
+						XIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "relminmxid",
+						XIDOID, -1, 0);
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (schema == NULL)
+		schema = "public";
+
+	reloid = pg_get_relid(relname, schema);
+	if (reloid == InvalidOid)
+	{
+		elog(WARNING, "relation %s.%s does not exist", schema, relname);
+		return (Datum) 0;
+	}
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation %s.%s not global temp table", schema, relname);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	get_gtt_relstats(reloid,
+					&relpages, &reltuples, &relallvisible,
+					&relfrozenxid, &relminmxid);
+
+	memset(isnull, false, sizeof(isnull));
+	memset(values, 0, sizeof(values));
+	values[0] = Int32GetDatum(relpages);
+	values[1] = Float4GetDatum((float4)reltuples);
+	values[2] = Int32GetDatum(relallvisible);
+	values[3] = UInt32GetDatum(relfrozenxid);
+	values[4] = UInt32GetDatum(relminmxid);
+	tuple = heap_form_tuple(tupdesc, values, isnull);
+	tuplestore_puttuple(tupstore, tuple);
+	tuplestore_donestoring(tupstore);
+
+	table_close(rel, NoLock);
+	return (Datum) 0;
+}
+
+Datum
+pg_gtt_attached_pid(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	char	*relname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	char	*schema = text_to_cstring(PG_GETARG_TEXT_PP(1));
+	Oid	reloid;
+	char	rel_persistence;
+	Datum	values[1];
+	bool	isnull[1];
+	Relation	rel = NULL;
+	PGPROC		*proc = NULL;
+	Bitmapset	*map = NULL;
+	pid_t		pid = 0;
+	int			backendid = 0;
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = NULL;
+	rsinfo->setDesc = NULL;
+
+	tupdesc = CreateTemplateTupleDesc(1);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "pid",
+						INT4OID, -1, 0);
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (schema == NULL)
+		schema = "public";
+
+	reloid = pg_get_relid(relname, schema);
+	if (reloid == InvalidOid)
+	{
+		elog(WARNING, "relation %s.%s does not exist", schema, relname);
+		return (Datum) 0;
+	}
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation %s.%s not global temp table", schema, relname);
+		return (Datum) 0;
+	}
+
+	map = copy_active_gtt_bitmap(rel->rd_node);
+	if (map)
+	{
+		backendid = bms_first_member(map);
+
+		do
+		{
+			proc = BackendIdGetProc(backendid);
+			pid = proc->pid;
+			if (pid > 0)
+			{
+				memset(isnull, false, sizeof(isnull));
+				memset(values, 0, sizeof(values));
+				values[0] = Int32GetDatum(pid);
+				tuple = heap_form_tuple(tupdesc, values, isnull);
+				tuplestore_puttuple(tupstore, tuple);
+			}
+			backendid = bms_next_member(map, backendid);
+		} while (backendid > 0);
+
+		pfree(map);
+	}
+
+	tuplestore_donestoring(tupstore);
+	table_close(rel, NoLock);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	Datum	values[3];
+	bool	isnull[3];
+	int			num_xid = MaxBackends + 1;
+	int			*pids = NULL;
+	uint32		*xids = NULL;
+	int			i = 0;
+	int			j = 0;
+	uint32		oldest = 0;
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = NULL;
+	rsinfo->setDesc = NULL;
+
+	tupdesc = CreateTemplateTupleDesc(3);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "pid",
+						INT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "relfrozenxid",
+						XIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 3, "relminmxid",
+						XIDOID, -1, 0);
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (max_active_gtt <= 0)
+		return (Datum) 0;
+
+	if (RecoveryInProgress())
+		return (Datum) 0;
+
+	pids = palloc0(sizeof(int) * num_xid);
+	xids = palloc0(sizeof(int) * num_xid);
+	oldest = list_all_session_gtt_frozenxids(num_xid, pids, xids, &i);
+	if (i > 0)
+	{
+		if (i > 0)
+		{
+			pids[i] = 0;
+			xids[i] = oldest;
+			i++;
+		}
+
+		for(j = 0; j < i; j++)
+		{
+			memset(isnull, false, sizeof(isnull));
+			memset(values, 0, sizeof(values));
+			values[0] = Int32GetDatum(pids[j]);
+			values[1] = UInt32GetDatum(xids[j]);
+			values[2] = UInt32GetDatum(0);
+			tuple = heap_form_tuple(tupdesc, values, isnull);
+			tuplestore_puttuple(tupstore, tuple);
+		}
+	}
+	tuplestore_donestoring(tupstore);
+	pfree(pids);
+	pfree(xids);
+
+	return (Datum) 0;
+}
+
diff --git a/contrib/pg_gtt/pg_gtt.control b/contrib/pg_gtt/pg_gtt.control
new file mode 100644
index 0000000..342af1d
--- /dev/null
+++ b/contrib/pg_gtt/pg_gtt.control
@@ -0,0 +1,4 @@
+comment = 'pg_gtt'
+default_version = '1.0'
+module_pathname = '$libdir/pg_gtt'
+relocatable = true
diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c
index d8790ad..7e30039 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -158,6 +158,19 @@ static relopt_bool boolRelOpts[] =
 		},
 		true
 	},
+	/*
+	 * For global temp table only
+	 * use AccessExclusiveLock for ensure safety
+	 */
+	{
+		{
+			"on_commit_delete_rows",
+			"global temp table on commit options",
+			RELOPT_KIND_HEAP,
+			ShareUpdateExclusiveLock
+		},
+		true
+	},	
 	/* list terminator */
 	{{NULL}}
 };
@@ -1475,6 +1488,8 @@ bytea *
 default_reloptions(Datum reloptions, bool validate, relopt_kind kind)
 {
 	static const relopt_parse_elt tab[] = {
+		{"on_commit_delete_rows", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, on_commit_delete_rows)},
 		{"fillfactor", RELOPT_TYPE_INT, offsetof(StdRdOptions, fillfactor)},
 		{"autovacuum_enabled", RELOPT_TYPE_BOOL,
 		offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, enabled)},
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index a23dec7..79bdb26 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -1014,7 +1014,9 @@ gistGetFakeLSN(Relation rel)
 {
 	static XLogRecPtr counter = FirstNormalUnloggedLSN;
 
-	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	/* global temp is same as local temp table */
+	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		rel->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 	{
 		/*
 		 * Temporary relations are only accessible in our session, so a simple
diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index 5cc30da..49b7d2e 100644
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -148,7 +148,9 @@ hashbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	 * metapage, nor the first bitmap page.
 	 */
 	sort_threshold = (maintenance_work_mem * 1024L) / BLCKSZ;
-	if (index->rd_rel->relpersistence != RELPERSISTENCE_TEMP)
+	/* global temp table is same as local temp table */
+	if (!(index->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		index->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		sort_threshold = Min(sort_threshold, NBuffers);
 	else
 		sort_threshold = Min(sort_threshold, NLocBuffer);
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 2dd8821..24c56b9 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -601,7 +601,7 @@ heapam_relation_set_new_filenode(Relation rel,
 	 */
 	*minmulti = GetOldestMultiXactId();
 
-	srel = RelationCreateStorage(*newrnode, persistence);
+	srel = RelationCreateStorage(*newrnode, persistence, rel);
 
 	/*
 	 * If required, set up an init fork for an unlogged table so that it can
@@ -654,7 +654,7 @@ heapam_relation_copy_data(Relation rel, const RelFileNode *newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index a3c4a1d..03fac55 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -60,6 +60,7 @@
 #include "utils/pg_rusage.h"
 #include "utils/timestamp.h"
 
+#include "catalog/storage_gtt.h"
 
 /*
  * Space/time tradeoff parameters: do these need to be user-tunable?
@@ -214,8 +215,10 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 	Assert(params->truncate != VACOPT_TERNARY_DEFAULT);
 
 	/* not every AM requires these to be valid, but heap does */
-	Assert(TransactionIdIsNormal(onerel->rd_rel->relfrozenxid));
-	Assert(MultiXactIdIsValid(onerel->rd_rel->relminmxid));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relfrozenxid == InvalidTransactionId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && TransactionIdIsNormal(onerel->rd_rel->relfrozenxid)));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relminmxid == InvalidMultiXactId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && MultiXactIdIsValid(onerel->rd_rel->relminmxid)));
 
 	/* measure elapsed time iff autovacuum logging requires it */
 	if (IsAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
@@ -274,8 +277,19 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 
 	vacrelstats = (LVRelStats *) palloc0(sizeof(LVRelStats));
 
-	vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
-	vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
+	/* get relstat from gtt localhash */
+	if (RELATION_IS_GLOBAL_TEMP(onerel))
+	{
+		get_gtt_relstats(RelationGetRelid(onerel),
+						&vacrelstats->old_rel_pages,
+						&vacrelstats->old_live_tuples,
+						NULL, NULL, NULL);
+	}
+	else
+	{
+		vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
+		vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
+	}
 	vacrelstats->num_index_scans = 0;
 	vacrelstats->pages_removed = 0;
 	vacrelstats->lock_waiter_detected = false;
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index 268f869..8b2e610 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -763,7 +763,14 @@ _bt_getbuf(Relation rel, BlockNumber blkno, int access)
 		/* Read an existing block of the relation */
 		buf = ReadBuffer(rel, blkno);
 		LockBuffer(buf, access);
-		_bt_checkpage(rel, buf);
+
+		/* global temp table may be not yet initialized for this backend. */
+		if (RELATION_IS_GLOBAL_TEMP(rel) &&
+			blkno == BTREE_METAPAGE &&
+			PageIsNew(BufferGetPage(buf)))
+			_bt_initmetapage(BufferGetPage(buf), P_NONE, 0);
+		else
+			_bt_checkpage(rel, buf);
 	}
 	else
 	{
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 2e3cc51..b8a57b6 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6314,6 +6314,10 @@ StartupXLOG(void)
 	else
 		recoveryTargetTLI = ControlFile->checkPointCopy.ThisTimeLineID;
 
+	/* clean temp relation files */
+	if (max_active_gtt > 0)
+		RemovePgTempFiles();
+
 	/*
 	 * Check for signal files, and if so set up state for offline recovery
 	 */
diff --git a/src/backend/catalog/Makefile b/src/backend/catalog/Makefile
index a511532..665b7fb 100644
--- a/src/backend/catalog/Makefile
+++ b/src/backend/catalog/Makefile
@@ -44,6 +44,8 @@ OBJS = \
 	storage.o \
 	toasting.o
 
+OBJS += storage_gtt.o
+
 BKIFILES = postgres.bki postgres.description postgres.shdescription
 
 include $(top_srcdir)/src/backend/common.mk
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index 1af31c2..ecb516e 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -399,7 +399,9 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class, char relpersistence)
 
 	switch (relpersistence)
 	{
+		/* global temp table is same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			break;
 		case RELPERSISTENCE_UNLOGGED:
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index b7bcdd9..6e089dd 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -61,6 +61,7 @@
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "commands/tablecmds.h"
 #include "commands/typecmds.h"
 #include "executor/executor.h"
@@ -100,6 +101,7 @@ static void AddNewRelationTuple(Relation pg_class_desc,
 								Oid reloftype,
 								Oid relowner,
 								char relkind,
+								char relpersistence,
 								TransactionId relfrozenxid,
 								TransactionId relminmxid,
 								Datum relacl,
@@ -405,6 +407,10 @@ heap_create(const char *relname,
 									 relpersistence,
 									 relkind);
 
+	/* global temp table not create storage file when catalog create */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		create_storage = false;
+
 	/*
 	 * Have the storage manager create the relation's disk file, if needed.
 	 *
@@ -428,7 +434,7 @@ heap_create(const char *relname,
 
 			case RELKIND_INDEX:
 			case RELKIND_SEQUENCE:
-				RelationCreateStorage(rel->rd_node, relpersistence);
+				RelationCreateStorage(rel->rd_node, relpersistence, rel);
 				break;
 
 			case RELKIND_RELATION:
@@ -925,6 +931,7 @@ AddNewRelationTuple(Relation pg_class_desc,
 					Oid reloftype,
 					Oid relowner,
 					char relkind,
+					char relpersistence,
 					TransactionId relfrozenxid,
 					TransactionId relminmxid,
 					Datum relacl,
@@ -963,8 +970,18 @@ AddNewRelationTuple(Relation pg_class_desc,
 			break;
 	}
 
-	new_rel_reltup->relfrozenxid = relfrozenxid;
-	new_rel_reltup->relminmxid = relminmxid;
+	/* global temp table not remember transaction info in catalog */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		new_rel_reltup->relfrozenxid = InvalidTransactionId;
+		new_rel_reltup->relminmxid = InvalidMultiXactId;
+	}
+	else
+	{
+		new_rel_reltup->relfrozenxid = relfrozenxid;
+		new_rel_reltup->relminmxid = relminmxid;
+	}
+
 	new_rel_reltup->relowner = relowner;
 	new_rel_reltup->reltype = new_type_oid;
 	new_rel_reltup->reloftype = reloftype;
@@ -1326,6 +1343,7 @@ heap_create_with_catalog(const char *relname,
 						reloftypeid,
 						ownerid,
 						relkind,
+						relpersistence,
 						relfrozenxid,
 						relminmxid,
 						PointerGetDatum(relacl),
@@ -1410,11 +1428,15 @@ heap_create_with_catalog(const char *relname,
 	 */
 	StoreConstraints(new_rel_desc, cooked_constraints, is_internal);
 
-	/*
-	 * If there's a special on-commit action, remember it
-	 */
-	if (oncommit != ONCOMMIT_NOOP)
-		register_on_commit_action(relid, oncommit);
+	/* global temp table register action when storage init */
+	if (relpersistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		/*
+		 * If there's a special on-commit action, remember it
+		 */
+		if (oncommit != ONCOMMIT_NOOP)
+			register_on_commit_action(relid, oncommit);
+	}
 
 	/*
 	 * ok, the relation has been cataloged, so close our relations and return
@@ -1906,6 +1928,13 @@ heap_drop_with_catalog(Oid relid)
 	if (relid == defaultPartOid)
 		update_default_partition_oid(parentOid, InvalidOid);
 
+	/* We allow to drop global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (is_other_backend_use_gtt(rel->rd_node))
+			elog(ERROR, "can not drop relation when other backend attached this global temp table");
+	}
+
 	/*
 	 * Schedule unlinking of the relation's physical files at commit.
 	 */
@@ -3132,9 +3161,10 @@ RemoveStatistics(Oid relid, AttrNumber attnum)
  *
  * The routine will truncate and then reconstruct the indexes on
  * the specified relation.  Caller must hold exclusive lock on rel.
+ *
  */
 static void
-RelationTruncateIndexes(Relation heapRelation)
+RelationTruncateIndexes(Relation heapRelation, LOCKMODE lockmode)
 {
 	ListCell   *indlist;
 
@@ -3146,7 +3176,7 @@ RelationTruncateIndexes(Relation heapRelation)
 		IndexInfo  *indexInfo;
 
 		/* Open the index relation; use exclusive lock, just to be sure */
-		currentIndex = index_open(indexId, AccessExclusiveLock);
+		currentIndex = index_open(indexId, lockmode);
 
 		/* Fetch info needed for index_build */
 		indexInfo = BuildIndexInfo(currentIndex);
@@ -3185,8 +3215,13 @@ heap_truncate(List *relids)
 	{
 		Oid			rid = lfirst_oid(cell);
 		Relation	rel;
+		LOCKMODE	lockmode = AccessExclusiveLock;
 
-		rel = table_open(rid, AccessExclusiveLock);
+		/* truncate global temp table only need RowExclusiveLock */
+		if (get_rel_persistence(rid) == RELPERSISTENCE_GLOBAL_TEMP)
+			lockmode = RowExclusiveLock;
+
+		rel = table_open(rid, lockmode);
 		relations = lappend(relations, rel);
 	}
 
@@ -3219,6 +3254,8 @@ void
 heap_truncate_one_rel(Relation rel)
 {
 	Oid			toastrelid;
+	LOCKMODE	lockmode = AccessExclusiveLock;
+	bool		truncate_toastrel = false;
 
 	/*
 	 * Truncate the relation.  Partitioned tables have no storage, so there is
@@ -3227,23 +3264,40 @@ heap_truncate_one_rel(Relation rel)
 	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 		return;
 
+	toastrelid = rel->rd_rel->reltoastrelid;
+
+	/*
+	 * Truncate global temp table only need RowExclusiveLock
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		lockmode = RowExclusiveLock;
+		if (OidIsValid(toastrelid) &&
+			gtt_storage_attached(toastrelid))
+			truncate_toastrel = true;
+	}
+	else if (OidIsValid(toastrelid))
+		truncate_toastrel = true;
+
 	/* Truncate the underlying relation */
 	table_relation_nontransactional_truncate(rel);
 
 	/* If the relation has indexes, truncate the indexes too */
-	RelationTruncateIndexes(rel);
+	RelationTruncateIndexes(rel, lockmode);
 
 	/* If there is a toast table, truncate that too */
-	toastrelid = rel->rd_rel->reltoastrelid;
-	if (OidIsValid(toastrelid))
+	if (truncate_toastrel)
 	{
-		Relation	toastrel = table_open(toastrelid, AccessExclusiveLock);
+		Relation	toastrel = table_open(toastrelid, lockmode);
 
 		table_relation_nontransactional_truncate(toastrel);
-		RelationTruncateIndexes(toastrel);
+		RelationTruncateIndexes(toastrel, lockmode);
 		/* keep the lock... */
 		table_close(toastrel, NoLock);
 	}
+
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		up_gtt_relstats(rel, 0, 0, 0, RecentXmin, InvalidMultiXactId);
 }
 
 /*
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 7c34509..f623626 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -52,6 +52,7 @@
 #include "catalog/pg_trigger.h"
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
+#include "catalog/storage_gtt.h"
 #include "commands/event_trigger.h"
 #include "commands/progress.h"
 #include "commands/tablecmds.h"
@@ -879,6 +880,26 @@ index_create(Relation heapRelation,
 						indexRelationName, RelationGetRelationName(heapRelation))));
 	}
 
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		if (accessMethodObjectId != BTREE_AM_OID)
+			elog(ERROR, "only support btree index on global temp table");
+
+		/* We allow to create index on global temp table only this session use it */
+		if (is_other_backend_use_gtt(heapRelation->rd_node) ||
+			gtt_storage_attached(heapRelation->rd_node.relNode))
+			elog(ERROR, "can not create index when have one or more backend attached this global temp table");
+
+		/* No support create index on global temp table use concurrent mode yet */
+		if (concurrent)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("cannot create indexes on global temporary tables using concurrent mode")));
+
+		/* if global temp table not init storage, then skip build index */
+		flags |= INDEX_CREATE_SKIP_BUILD;
+	}
+
 	/*
 	 * construct tuple descriptor for index tuples
 	 */
@@ -2047,6 +2068,13 @@ index_drop(Oid indexId, bool concurrent, bool concurrent_lock_mode)
 	 */
 	CheckTableNotInUse(userIndexRelation, "DROP INDEX");
 
+	/* We allow to drop index on global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(userHeapRelation))
+	{
+		if (is_other_backend_use_gtt(userHeapRelation->rd_node))
+			elog(ERROR, "can not drop index when other backend attached this global temp table");
+	}
+
 	/*
 	 * Drop Index Concurrently is more or less the reverse process of Create
 	 * Index Concurrently.
@@ -2688,20 +2716,29 @@ index_update_stats(Relation rel,
 		else					/* don't bother for indexes */
 			relallvisible = 0;
 
-		if (rd_rel->relpages != (int32) relpages)
+		/* update index stats into localhash for global temp table */
+		if (RELATION_IS_GLOBAL_TEMP(rel))
 		{
-			rd_rel->relpages = (int32) relpages;
-			dirty = true;
+			up_gtt_relstats(rel, relpages, reltuples, relallvisible,
+							InvalidTransactionId, InvalidMultiXactId);
 		}
-		if (rd_rel->reltuples != (float4) reltuples)
-		{
-			rd_rel->reltuples = (float4) reltuples;
-			dirty = true;
-		}
-		if (rd_rel->relallvisible != (int32) relallvisible)
+		else
 		{
-			rd_rel->relallvisible = (int32) relallvisible;
-			dirty = true;
+			if (rd_rel->relpages != (int32) relpages)
+			{
+				rd_rel->relpages = (int32) relpages;
+				dirty = true;
+			}
+			if (rd_rel->reltuples != (float4) reltuples)
+			{
+				rd_rel->reltuples = (float4) reltuples;
+				dirty = true;
+			}
+			if (rd_rel->relallvisible != (int32) relallvisible)
+			{
+				rd_rel->relallvisible = (int32) relallvisible;
+				dirty = true;
+			}
 		}
 	}
 
@@ -2816,6 +2853,13 @@ index_build(Relation heapRelation,
 		pgstat_progress_update_multi_param(6, index, val);
 	}
 
+	/* POALR */
+	if (RELATION_IS_GLOBAL_TEMP(indexRelation))
+	{
+		if (!gtt_storage_attached(indexRelation->rd_node.relNode))
+			RelationCreateStorage(indexRelation->rd_node, RELPERSISTENCE_GLOBAL_TEMP, indexRelation);
+	}
+
 	/*
 	 * Call the access method's build procedure
 	 */
@@ -3148,12 +3192,22 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	/*
 	 * Scan the index and gather up all the TIDs into a tuplesort object.
 	 */
+	memset(&ivinfo, 0, sizeof(IndexVacuumInfo));
 	ivinfo.index = indexRelation;
 	ivinfo.analyze_only = false;
 	ivinfo.report_progress = true;
 	ivinfo.estimated_count = true;
 	ivinfo.message_level = DEBUG2;
-	ivinfo.num_heap_tuples = heapRelation->rd_rel->reltuples;
+
+	/* get relstats abort global temp table from hashtable, not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		get_gtt_relstats(RelationGetRelid(heapRelation),
+						NULL, &ivinfo.num_heap_tuples, NULL,
+						NULL, NULL);
+	}
+	else
+		ivinfo.num_heap_tuples = heapRelation->rd_rel->reltuples;
 	ivinfo.strategy = NULL;
 
 	/*
@@ -3411,6 +3465,15 @@ reindex_index(Oid indexId, bool skip_constraint_checks, char persistence,
 				 errmsg("cannot reindex temporary tables of other sessions")));
 
 	/*
+	 * Because global temp table cannot change relfilenode
+	 * no support reindex on global temp table yet.
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(iRel))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot reindex global temporary tables")));
+
+	/*
 	 * Also check for active uses of the index in the current transaction; we
 	 * don't want to reindex underneath an open indexscan.
 	 */
diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index e251f5a..97bf247 100644
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -647,6 +647,13 @@ RangeVarAdjustRelationPersistence(RangeVar *newRelation, Oid nspid)
 							 errmsg("cannot create temporary relation in non-temporary schema")));
 			}
 			break;
+		/* global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			if (isAnyTempNamespace(nspid))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+						 errmsg("cannot create global temp relations in temporary schemas")));
+			break;
 		case RELPERSISTENCE_PERMANENT:
 			if (isTempOrTempToastNamespace(nspid))
 				newRelation->relpersistence = RELPERSISTENCE_TEMP;
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index 625af8d..baf7d61 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -28,6 +28,7 @@
 #include "access/xlogutils.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "storage/freespace.h"
 #include "storage/smgr.h"
 #include "utils/memutils.h"
@@ -74,9 +75,10 @@ static PendingRelDelete *pendingDeletes = NULL; /* head of linked list */
  *
  * This function is transactional. The creation is WAL-logged, and if the
  * transaction aborts later on, the storage will be destroyed.
+ *
  */
 SMgrRelation
-RelationCreateStorage(RelFileNode rnode, char relpersistence)
+RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel)
 {
 	PendingRelDelete *pending;
 	SMgrRelation srel;
@@ -86,6 +88,8 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	switch (relpersistence)
 	{
 		case RELPERSISTENCE_TEMP:
+		/* global temp table use same storage strategy as local temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			needs_wal = false;
 			break;
@@ -118,6 +122,10 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	pending->next = pendingDeletes;
 	pendingDeletes = pending;
 
+	/* remember global temp table storage info to localhash */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP && rel)
+		remember_gtt_storage_info(rnode, rel);
+
 	return srel;
 }
 
@@ -487,8 +495,15 @@ smgrDoPendingDeletes(bool isCommit)
 		smgrdounlinkall(srels, nrels, false);
 
 		for (i = 0; i < nrels; i++)
+		{
 			smgrclose(srels[i]);
 
+			/* clean global temp table flags when transaction commit or rollback */
+			if (SmgrIsTemp(srels[i]) && 
+				gtt_storage_attached(srels[i]->smgr_rnode.node.relNode))
+				forget_gtt_storage_info(srels[i]->smgr_rnode.node.relNode);
+		}
+
 		pfree(srels);
 	}
 }
diff --git a/src/backend/catalog/storage_gtt.c b/src/backend/catalog/storage_gtt.c
new file mode 100644
index 0000000..c7b9a48
--- /dev/null
+++ b/src/backend/catalog/storage_gtt.c
@@ -0,0 +1,810 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.c
+ *	  code to create and destroy physical storage for global temparary table
+ *
+ * IDENTIFICATION
+ *	  src/backend/catalog/storage_gtt.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/visibilitymap.h"
+#include "access/xact.h"
+#include "access/xlog.h"
+#include "access/xloginsert.h"
+#include "access/xlogutils.h"
+#include "access/htup_details.h"
+#include "access/multixact.h"
+#include "catalog/storage.h"
+#include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/heap.h"
+#include "commands/tablecmds.h"
+#include "nodes/primnodes.h"
+#include "nodes/pg_list.h"
+#include "miscadmin.h"
+#include "storage/freespace.h"
+#include "storage/smgr.h"
+#include "storage/ipc.h"
+#include "storage/proc.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "utils/memutils.h"
+#include "utils/rel.h"
+#include "utils/hsearch.h"
+#include "utils/catcache.h"
+#include <utils/relcache.h>
+#include "utils/inval.h"
+#include "utils/guc.h"
+#include "utils/guc.h"
+
+
+/* Copy from bitmapset.c, because gtt used the function in bitmapset.c */
+#define WORDNUM(x)	((x) / BITS_PER_BITMAPWORD)
+#define BITNUM(x)	((x) % BITS_PER_BITMAPWORD)
+
+#define BITMAPSET_SIZE(nwords)	\
+	(offsetof(Bitmapset, words) + (nwords) * sizeof(bitmapword))
+
+static bool gtt_cleaner_exit_registered = false;
+static HTAB *gtt_storage_local_hash = NULL;
+static HTAB *active_gtt_shared_hash = NULL;
+static MemoryContext gtt_relstats_context = NULL;
+
+/* relfrozenxid of all gtts in the current session */
+static List *gtt_session_relfrozenxid_list = NIL;
+static TransactionId gtt_session_frozenxid = InvalidTransactionId;
+
+typedef struct gtt_ctl_data
+{
+	LWLock			lock;
+	int			max_entry;
+	int			entry_size;
+}gtt_ctl_data;
+
+static gtt_ctl_data *gtt_shared_ctl = NULL;
+
+typedef struct
+{
+	RelFileNode	rnode;
+	Bitmapset	*map;
+	/* bitmap data */
+} gtt_shared_hash_entry;
+
+typedef struct
+{
+	Oid			relid;
+
+	Oid			spcnode;
+	/* pg_class stat */
+	int32		relpages;
+	float4		reltuples;
+	int32		relallvisible;
+	TransactionId relfrozenxid;
+	TransactionId relminmxid;
+	char		relkind;
+	bool		on_commit_delete;
+
+	/* pg_statistic */
+	int			natts;
+	int			*attnum;
+	HeapTuple	*att_stat_tups;
+} gtt_local_hash_entry;
+
+static Size action_gtt_shared_hash_entry_size(void);
+static void gtt_storage_checkin(RelFileNode rnode);
+static void gtt_storage_checkout(RelFileNode rnode, bool skiplock);
+static void gtt_storage_removeall(int code, Datum arg);
+static void insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid);
+static void remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid);
+static void set_gtt_session_relfrozenxid(void);
+
+static Size
+action_gtt_shared_hash_entry_size(void)
+{
+	int 	wordnum;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	wordnum = WORDNUM(MaxBackends + 1);
+	hash_entry_size += MAXALIGN(sizeof(gtt_shared_hash_entry));
+	hash_entry_size += MAXALIGN(BITMAPSET_SIZE(wordnum + 1));
+
+	return hash_entry_size;
+}
+
+Size
+active_gtt_shared_hash_size(void)
+{
+	Size	size = 0;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	size = MAXALIGN(sizeof(gtt_ctl_data));
+	hash_entry_size = action_gtt_shared_hash_entry_size();
+	size += hash_estimate_size(max_active_gtt, hash_entry_size);
+
+	return size;
+}
+
+void
+active_gtt_shared_hash_init(void)
+{
+	HASHCTL info;
+	bool	found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	gtt_shared_ctl =
+		ShmemInitStruct("gtt_shared_ctl",
+						sizeof(gtt_ctl_data),
+						&found);
+
+	if (!found)
+	{
+		LWLockRegisterTranche(LWTRANCHE_GTT_CTL, "gtt_shared_ctl");
+		LWLockInitialize(&gtt_shared_ctl->lock, LWTRANCHE_GTT_CTL);
+		gtt_shared_ctl->max_entry = max_active_gtt;
+		gtt_shared_ctl->entry_size = action_gtt_shared_hash_entry_size();
+	}
+
+	info.keysize = sizeof(RelFileNode);
+	info.entrysize = gtt_shared_ctl->entry_size;
+	active_gtt_shared_hash =
+		ShmemInitHash("active gtt shared hash",
+						gtt_shared_ctl->max_entry,
+						gtt_shared_ctl->max_entry,
+						&info, HASH_ELEM | HASH_BLOBS | HASH_FIXED_SIZE);
+}
+
+static void
+gtt_storage_checkin(RelFileNode rnode)
+{
+	gtt_shared_hash_entry	*entry;
+	bool			found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+	entry = (gtt_shared_hash_entry *) hash_search(active_gtt_shared_hash,
+												&rnode, HASH_ENTER_NULL, &found);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		ereport(ERROR,
+				(errcode(ERRCODE_OUT_OF_MEMORY),
+				 errmsg("out of shared memory"),
+				 errhint("You might need to increase max_active_gtt.")));
+	}
+
+	if (found == false)
+	{
+		int			wordnum;
+
+		entry->map = (Bitmapset *)((char *)entry + MAXALIGN(sizeof(gtt_shared_hash_entry)));
+		wordnum = WORDNUM(MaxBackends + 1);
+		memset(entry->map, 0, BITMAPSET_SIZE(wordnum + 1));
+		entry->map->nwords = wordnum + 1;
+	}
+
+	bms_add_member(entry->map, MyBackendId);
+	LWLockRelease(&gtt_shared_ctl->lock);
+}
+
+static void
+gtt_storage_checkout(RelFileNode rnode, bool skiplock)
+{
+	gtt_shared_hash_entry	*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (!skiplock)
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(rnode), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		if (!skiplock)
+			LWLockRelease(&gtt_shared_ctl->lock);
+
+		elog(WARNING, "relfilenode %u/%u/%u not exist in gtt shared hash when forget",
+						rnode.dbNode, rnode.spcNode, rnode.relNode);
+		return;
+	}
+
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+	bms_del_member(entry->map, MyBackendId);
+
+	if (bms_is_empty(entry->map))
+	{
+		if (!hash_search(active_gtt_shared_hash, &rnode, HASH_REMOVE, NULL))
+			elog(PANIC, "gtt shared hash table corrupted");
+	}
+
+	if (!skiplock)
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+	return;
+}
+
+Bitmapset *
+copy_active_gtt_bitmap(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	Bitmapset	*map_copy = NULL;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return NULL;
+	}
+
+	Assert(entry->map);
+	if (!bms_is_empty(entry->map))
+		map_copy = bms_copy(entry->map);
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return map_copy;
+}
+
+bool
+is_other_backend_use_gtt(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	bool		in_use = false;
+	int			num_use = 0;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return false;
+	}
+
+	Assert(entry->map);
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+
+	num_use = bms_num_members(entry->map);
+	if (num_use == 0)
+		in_use = false;
+	else if (num_use == 1)
+	{
+		if(bms_is_member(MyBackendId, entry->map))
+			in_use = false;
+		else
+			in_use = true;
+	}
+	else
+		in_use = true;
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return in_use;
+}
+
+void
+remember_gtt_storage_info(RelFileNode rnode, Relation rel)
+{
+	gtt_local_hash_entry	*entry;
+	MemoryContext			oldcontext;
+	Oid			relid = rnode.relNode;
+	bool		found;
+
+	if (max_active_gtt <= 0)
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("Global temporary table feature is disable"),
+			 errhint("You might need to increase max_active_gtt to enable this feature.")));
+
+	if (RecoveryInProgress())
+		elog(ERROR, "readonly mode not support access global temp table yet");
+
+	if (gtt_storage_local_hash == NULL)
+	{
+#define GTT_LOCAL_HASH_SIZE		1024
+		/* First time through: initialize the hash table */
+		HASHCTL		ctl;
+
+		MemSet(&ctl, 0, sizeof(ctl));
+		ctl.keysize = sizeof(Oid);
+		ctl.entrysize = sizeof(gtt_local_hash_entry);
+		gtt_storage_local_hash =
+			hash_create("global temp relation table",
+						GTT_LOCAL_HASH_SIZE,
+						&ctl, HASH_ELEM | HASH_BLOBS);
+
+		if (!CacheMemoryContext)
+			CreateCacheMemoryContext();
+
+		gtt_relstats_context =
+			AllocSetContextCreate(CacheMemoryContext,
+							"gtt relstats context",
+							ALLOCSET_DEFAULT_SIZES);
+	}
+
+	/* Look up or create an entry */
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_ENTER, &found);
+
+	if (found)
+	{
+		elog(ERROR, "backend %d relid %u already exists in global temp table local hash",
+					MyBackendId, relid);
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+
+	entry->spcnode = rnode.spcNode;
+	entry->relpages = 0;
+	entry->reltuples = 0;
+	entry->relallvisible = 0;
+	entry->relkind = rel->rd_rel->relkind;
+	/* only heap contain transaction information */
+	if (entry->relkind == RELKIND_RELATION)
+	{
+		int natts = RelationGetNumberOfAttributes(rel);
+		entry->natts = natts;
+		entry->attnum = palloc0(sizeof(int) * natts);
+		entry->att_stat_tups = palloc0(sizeof(HeapTuple) * natts);
+
+		if (RELATION_GTT_ON_COMMIT_DELETE(rel))
+		{
+			entry->on_commit_delete = true;
+			register_on_commit_action(rel->rd_node.relNode, ONCOMMIT_DELETE_ROWS);
+		}
+
+		entry->relfrozenxid = RecentXmin;
+		entry->relminmxid = GetOldestMultiXactId();
+		insert_gtt_relfrozenxid_to_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+		gtt_storage_checkin(rnode);
+	}
+	else
+	{
+		entry->natts = 0;
+		entry->attnum = 0;
+		entry->att_stat_tups = NULL;
+		entry->on_commit_delete = false;
+		entry->relfrozenxid = 0;
+		entry->relminmxid = 0;
+	}
+
+	MemoryContextSwitchTo(oldcontext);
+
+	if (!gtt_cleaner_exit_registered)
+	{
+		before_shmem_exit(gtt_storage_removeall, 0);
+		gtt_cleaner_exit_registered = true;
+	}
+
+	return;
+}
+
+void
+forget_gtt_storage_info(Oid relid)
+{
+	gtt_local_hash_entry		*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+				(void *) &(relid), HASH_FIND, NULL);
+
+	if (entry && entry->relkind == RELKIND_RELATION)
+	{
+		RelFileNode rnode;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		gtt_storage_checkout(rnode, false);
+
+		Assert(TransactionIdIsNormal(entry->relfrozenxid));
+		remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+	}
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_REMOVE, NULL);
+
+	return;
+}
+
+/* is the storage file was created in this backend */
+bool
+gtt_storage_attached(Oid relid)
+{
+	bool found;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	if (gtt_storage_local_hash == NULL)
+		return false;
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_FIND, &found);
+
+	return found;
+}
+
+static void
+gtt_storage_removeall(int code, Datum arg)
+{
+	HASH_SEQ_STATUS				status;
+	gtt_local_hash_entry		*entry;
+	int			nrels = 0,
+				maxrels = 0;
+	SMgrRelation	*srels = NULL;
+	RelFileNode		*rnodes = NULL;
+	char			*relkinds = NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	hash_seq_init(&status, gtt_storage_local_hash);
+	while ((entry = (gtt_local_hash_entry *) hash_seq_search(&status)) != NULL)
+	{
+		SMgrRelation srel;
+		RelFileNode rnode;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		srel = smgropen(rnode, MyBackendId);
+
+		/* allocate the initial array, or extend it, if needed */
+		if (maxrels == 0)
+		{
+			maxrels = 32;
+			srels = palloc(sizeof(SMgrRelation) * maxrels);
+			rnodes = palloc(sizeof(RelFileNode) * maxrels);
+			relkinds = palloc(sizeof(char) * maxrels);
+		}
+		else if (maxrels <= nrels)
+		{
+			maxrels *= 2;
+			srels = repalloc(srels, sizeof(SMgrRelation) * maxrels);
+			rnodes = repalloc(rnodes, sizeof(RelFileNode) * maxrels);
+			relkinds = repalloc(relkinds, sizeof(char) * maxrels);
+		}
+
+		srels[nrels] = srel;
+		rnodes[nrels] = rnode;
+		relkinds[nrels] = entry->relkind;
+		nrels++;
+	}
+
+	if (nrels > 0)
+	{
+		int i;
+
+		smgrdounlinkall(srels, nrels, false);
+
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+		for (i = 0; i < nrels; i++)
+		{
+			smgrclose(srels[i]);
+			if (relkinds[i] == RELKIND_RELATION)
+				gtt_storage_checkout(rnodes[i], true);
+		}
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+		pfree(srels);
+		pfree(rnodes);
+		pfree(relkinds);
+	}
+
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;
+
+	return;
+}
+
+/*
+ * Update global temp table relstats(relpage/reltuple/relallvisible) 
+ * to local hashtable
+ */
+void
+up_gtt_relstats(Relation relation,
+					BlockNumber num_pages,
+					double num_tuples,
+					BlockNumber num_all_visible_pages,
+					TransactionId relfrozenxid,
+					TransactionId relminmxid)
+{
+	Oid		relid = RelationGetRelid(relation);
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	Assert(entry->spcnode);
+
+	if (num_pages >= 0 &&
+		entry->relpages != (int32)num_pages)
+		entry->relpages = (int32)num_pages;
+
+	if (num_tuples >= 0 &&
+		num_tuples != (float4)entry->reltuples)
+		entry->reltuples = (float4)num_tuples;
+
+	/* only heap contain transaction information and relallvisible */
+	if (entry->relkind == RELKIND_RELATION)
+	{
+		if (entry->relallvisible >= 0 &&
+			entry->relallvisible != (int32)num_all_visible_pages)
+		{
+			entry->relallvisible = (int32)num_all_visible_pages;
+		}
+
+		if (TransactionIdIsNormal(relfrozenxid) &&
+			entry->relfrozenxid != relfrozenxid &&
+			(TransactionIdPrecedes(entry->relfrozenxid, relfrozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(), entry->relfrozenxid)))
+		{
+			remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+			entry->relfrozenxid = relfrozenxid;
+			insert_gtt_relfrozenxid_to_ordered_list(relfrozenxid);
+			set_gtt_session_relfrozenxid();
+		}
+
+		if (MultiXactIdIsValid(relminmxid) &&
+			entry->relminmxid != relminmxid &&
+			(MultiXactIdPrecedes(entry->relminmxid, relminmxid) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), entry->relminmxid)))
+		{
+			entry->relminmxid = relminmxid;
+		}
+	}
+
+	return;
+}
+
+/*
+ * Search global temp table relstats(relpage/reltuple/relallvisible) 
+ * from local hashtable.
+ */
+void
+get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+				BlockNumber *relallvisible, TransactionId *relfrozenxid,
+				TransactionId *relminmxid)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	Assert(entry->relid == relid);
+
+	if (relpages)
+		*relpages = entry->relpages;
+
+	if (reltuples)
+		*reltuples = entry->reltuples;
+
+	if (relallvisible)
+		*relallvisible = entry->relallvisible;
+
+	if (relfrozenxid)
+		*relfrozenxid = entry->relfrozenxid;
+
+	if (relminmxid)
+		*relminmxid = entry->relminmxid;
+
+	return;
+}
+
+/*
+ * Update global temp table statistic info(definition is same as pg_statistic)
+ * to local hashtable where ananyze global temp table
+ */
+void
+up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+					TupleDesc tupleDescriptor, Datum *values, bool *isnull)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	MemoryContext			oldcontext;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	if (entry->relkind != RELKIND_RELATION)
+	{
+		elog(WARNING, "oid %u not a relation", reloid);
+		return;
+	}
+
+	/* todo */
+	if (entry->natts < natts)
+	{
+		elog(WARNING, "reloid %u not support update attstat after add colunm", reloid);
+		return;
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	Assert(entry->relid == reloid);
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == 0)
+		{
+			entry->attnum[i] = attnum;
+			break;
+		}
+		else if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			heap_freetuple(entry->att_stat_tups[i]);
+			entry->att_stat_tups[i] = NULL;
+			break;
+		}
+	}
+
+	Assert(i < entry->natts);
+	Assert(entry->att_stat_tups[i] == NULL);
+	entry->att_stat_tups[i] = heap_form_tuple(tupleDescriptor, values, isnull);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+/*
+ * Search global temp table statistic info(definition is same as pg_statistic)
+ * from local hashtable.
+ */
+HeapTuple
+get_gtt_att_statistic(Oid reloid, int attnum, bool inh)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return NULL;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return NULL;
+
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			return entry->att_stat_tups[i];
+		}
+	}
+
+	return NULL;
+}
+
+void
+release_gtt_statistic_cache(HeapTuple tup)
+{
+	/* do nothing */
+	return;
+}
+
+static void
+insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid)
+{
+	MemoryContext	oldcontext;
+	ListCell	*cell;
+	int i;
+	Assert(TransactionIdIsNormal(relfrozenxid));
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	/* Does the datum belong at the front? */
+	if (gtt_session_relfrozenxid_list == NIL ||
+		TransactionIdFollowsOrEquals(relfrozenxid,
+			linitial_oid(gtt_session_relfrozenxid_list)))
+	{
+		gtt_session_relfrozenxid_list =
+			lcons_oid(relfrozenxid, gtt_session_relfrozenxid_list);
+		MemoryContextSwitchTo(oldcontext);
+
+		return;
+	}
+	/* No, so find the entry it belongs after */
+
+	i = 0;
+	foreach (cell, gtt_session_relfrozenxid_list)
+	{
+		if (TransactionIdFollowsOrEquals(relfrozenxid, lfirst_oid(cell)))
+			break;	/* it belongs after 'prev', before 'curr' */
+
+		i += 1;
+	}
+	/* Insert datum into list after 'prev' */
+	list_insert_nth_oid(gtt_session_relfrozenxid_list, i, relfrozenxid);
+	MemoryContextSwitchTo(oldcontext);
+}
+
+static void
+remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid)
+{
+	gtt_session_relfrozenxid_list =
+		list_delete_oid(gtt_session_relfrozenxid_list, relfrozenxid);
+}
+
+static void
+set_gtt_session_relfrozenxid(void)
+{
+	TransactionId gtt_frozenxid = InvalidTransactionId;
+
+	if (gtt_session_relfrozenxid_list)
+		gtt_frozenxid = llast_oid(gtt_session_relfrozenxid_list);
+
+	gtt_session_frozenxid = gtt_frozenxid;
+	if (MyProc->session_gtt_frozenxid != gtt_frozenxid)
+		MyProc->session_gtt_frozenxid = gtt_frozenxid;
+}
+
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 7accb95..e0dc376 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -65,6 +65,7 @@
 #include "utils/syscache.h"
 #include "utils/timestamp.h"
 
+#include "catalog/storage_gtt.h"
 
 /* Per-index data for ANALYZE */
 typedef struct AnlIndexData
@@ -102,7 +103,7 @@ static int	acquire_inherited_sample_rows(Relation onerel, int elevel,
 										  HeapTuple *rows, int targrows,
 										  double *totalrows, double *totaldeadrows);
 static void update_attstats(Oid relid, bool inh,
-							int natts, VacAttrStats **vacattrstats);
+							int natts, VacAttrStats **vacattrstats, char relpersistence);
 static Datum std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 static Datum ind_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 
@@ -575,14 +576,15 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 		 * pg_statistic for columns we didn't process, we leave them alone.)
 		 */
 		update_attstats(RelationGetRelid(onerel), inh,
-						attr_cnt, vacattrstats);
+						attr_cnt, vacattrstats, RelationGetRelPersistence(onerel));
 
 		for (ind = 0; ind < nindexes; ind++)
 		{
 			AnlIndexData *thisdata = &indexdata[ind];
 
 			update_attstats(RelationGetRelid(Irel[ind]), false,
-							thisdata->attr_cnt, thisdata->vacattrstats);
+							thisdata->attr_cnt, thisdata->vacattrstats,
+							RelationGetRelPersistence(Irel[ind]));
 		}
 
 		/*
@@ -659,11 +661,20 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 			IndexBulkDeleteResult *stats;
 			IndexVacuumInfo ivinfo;
 
+			memset(&ivinfo, 0, sizeof(IndexVacuumInfo));
 			ivinfo.index = Irel[ind];
 			ivinfo.analyze_only = true;
 			ivinfo.estimated_count = true;
 			ivinfo.message_level = elevel;
-			ivinfo.num_heap_tuples = onerel->rd_rel->reltuples;
+			/* get global temp relstats from localhash, not catalog */
+			if (RELATION_IS_GLOBAL_TEMP(onerel))
+			{
+				get_gtt_relstats(RelationGetRelid(onerel),
+								NULL, &ivinfo.num_heap_tuples, NULL,
+								NULL, NULL);
+			}
+			else
+				ivinfo.num_heap_tuples = onerel->rd_rel->reltuples;
 			ivinfo.strategy = vac_strategy;
 
 			stats = index_vacuum_cleanup(&ivinfo, NULL);
@@ -1425,7 +1436,7 @@ acquire_inherited_sample_rows(Relation onerel, int elevel,
  *		by taking a self-exclusive lock on the relation in analyze_rel().
  */
 static void
-update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
+update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats, char relpersistence)
 {
 	Relation	sd;
 	int			attno;
@@ -1527,31 +1538,45 @@ update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
 			}
 		}
 
-		/* Is there already a pg_statistic tuple for this attribute? */
-		oldtup = SearchSysCache3(STATRELATTINH,
-								 ObjectIdGetDatum(relid),
-								 Int16GetDatum(stats->attr->attnum),
-								 BoolGetDatum(inh));
-
-		if (HeapTupleIsValid(oldtup))
+		/* Update column statistic to localhash, not catalog */
+		if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		{
-			/* Yes, replace it */
-			stup = heap_modify_tuple(oldtup,
-									 RelationGetDescr(sd),
-									 values,
-									 nulls,
-									 replaces);
-			ReleaseSysCache(oldtup);
-			CatalogTupleUpdate(sd, &stup->t_self, stup);
+			up_gtt_att_statistic(relid,
+								stats->attr->attnum,
+								inh,
+								natts,
+								RelationGetDescr(sd),
+								values,
+								nulls);
 		}
 		else
 		{
-			/* No, insert new tuple */
-			stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
-			CatalogTupleInsert(sd, stup);
-		}
+			/* Is there already a pg_statistic tuple for this attribute? */
+			oldtup = SearchSysCache3(STATRELATTINH,
+									 ObjectIdGetDatum(relid),
+									 Int16GetDatum(stats->attr->attnum),
+									 BoolGetDatum(inh));
+
+			if (HeapTupleIsValid(oldtup))
+			{
+				/* Yes, replace it */
+				stup = heap_modify_tuple(oldtup,
+										 RelationGetDescr(sd),
+										 values,
+										 nulls,
+										 replaces);
+				ReleaseSysCache(oldtup);
+				CatalogTupleUpdate(sd, &stup->t_self, stup);
+			}
+			else
+			{
+				/* No, insert new tuple */
+				stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
+				CatalogTupleInsert(sd, stup);
+			}
 
-		heap_freetuple(stup);
+			heap_freetuple(stup);
+		}
 	}
 
 	table_close(sd, RowExclusiveLock);
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index a23128d..0d38988 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -392,6 +392,12 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 					 errmsg("cannot vacuum temporary tables of other sessions")));
 	}
 
+	/* not support cluster global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(OldHeap))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support cluster global temporary tables yet")));
+
 	/*
 	 * Also check for active uses of the relation in the current transaction,
 	 * including open scans and pending AFTER trigger events.
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 374e2d0..8e88a59 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -2585,6 +2585,16 @@ ReindexMultipleTables(const char *objectName, ReindexObjectType objectKind,
 			!isTempNamespace(classtuple->relnamespace))
 			continue;
 
+		/* not support reindex on global temp table, so skip it */
+		if (classtuple->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			ereport(WARNING,
+				(errmsg("global temp table \"%s.%s\" skip reindexed",
+					get_namespace_name(get_rel_namespace(relid)),
+					get_rel_name(relid))));
+			continue;
+		}
+
 		/* Check user/system classification, and optionally skip */
 		if (objectKind == REINDEX_OBJECT_SYSTEM &&
 			!IsSystemClass(relid, classtuple))
diff --git a/src/backend/commands/lockcmds.c b/src/backend/commands/lockcmds.c
index bae3b38..ff9d5cb 100644
--- a/src/backend/commands/lockcmds.c
+++ b/src/backend/commands/lockcmds.c
@@ -107,7 +107,8 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
 	 * transaction.
 	 */
 	relpersistence = get_rel_persistence(relid);
-	if (relpersistence == RELPERSISTENCE_TEMP)
+	if (relpersistence == RELPERSISTENCE_TEMP ||
+		relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		MyXactFlags |= XACT_FLAGS_ACCESSEDTEMPNAMESPACE;
 
 	/* Check permissions. */
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 5597be6..4bf4b9a 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -48,6 +48,7 @@
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
 #include "catalog/toasting.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/defrem.h"
@@ -531,6 +532,7 @@ static void refuseDupeIndexAttach(Relation parentIdx, Relation partIdx,
 								  Relation partitionTbl);
 static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
+static bool has_oncommit_option(List *options);
 
 
 /* ----------------------------------------------------------------
@@ -576,6 +578,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	LOCKMODE	parentLockmode;
 	const char *accessMethod = NULL;
 	Oid			accessMethodId = InvalidOid;
+	bool		has_oncommit_clause = false;
 
 	/*
 	 * Truncate relname to appropriate length (probably a waste of time, as
@@ -586,8 +589,10 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Check consistency of arguments
 	 */
+	/* global temp table same as local temp table */
 	if (stmt->oncommit != ONCOMMIT_NOOP
-		&& stmt->relation->relpersistence != RELPERSISTENCE_TEMP)
+		&& !(stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+			 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 				 errmsg("ON COMMIT can only be used on temporary tables")));
@@ -617,12 +622,28 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	 * code.  This is needed because calling code might not expect untrusted
 	 * tables to appear in pg_temp at the front of its search path.
 	 */
-	if (stmt->relation->relpersistence == RELPERSISTENCE_TEMP
+	/* global temp table same as local temp table */
+	if ((stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+		 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		&& InSecurityRestrictedOperation())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 errmsg("cannot create temporary table within security-restricted operation")));
 
+	/* Not support partitioned or inherited global temp table yet */
+	if (stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		if (relkind == RELKIND_PARTITIONED_TABLE)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support create global temporary partition table yet")));
+
+		if (stmt->inhRelations)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support create global temporary inheritance table yet")));
+	}
+
 	/*
 	 * Determine the lockmode to use when scanning parents.  A self-exclusive
 	 * lock is needed here.
@@ -718,6 +739,40 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Parse and validate reloptions, if any.
 	 */
+	/* global temp table */
+	has_oncommit_clause = has_oncommit_option(stmt->options);
+	if (stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		if (has_oncommit_clause)
+		{
+			if (stmt->oncommit != ONCOMMIT_NOOP)
+				elog(ERROR, "can not defeine global temp table with on commit and with clause at same time");
+		}
+		else
+		{
+			DefElem *opt = makeNode(DefElem);
+
+			opt->type = T_DefElem;
+			opt->defnamespace = NULL;
+			opt->defname = "on_commit_delete_rows";
+			opt->defaction = DEFELEM_UNSPEC;
+
+			/* use reloptions to remember on commit clause */
+			if (stmt->oncommit == ONCOMMIT_DELETE_ROWS)
+				opt->arg  = (Node *)makeString("true");
+			else if (stmt->oncommit == ONCOMMIT_PRESERVE_ROWS)
+				opt->arg  = (Node *)makeString("false");
+			else if (stmt->oncommit == ONCOMMIT_NOOP)
+				opt->arg  = (Node *)makeString("true");
+			else
+				elog(ERROR, "global temp table not support on commit drop clause");
+
+			stmt->options = lappend(stmt->options, opt);
+		}
+	}
+	else if (has_oncommit_clause)
+		elog(ERROR, "regular table cannot specifie on_commit_delete_rows");
+
 	reloptions = transformRelOptions((Datum) 0, stmt->options, NULL, validnsps,
 									 true, false);
 
@@ -1772,7 +1827,8 @@ ExecuteTruncateGuts(List *explicit_rels, List *relids, List *relids_logged,
 		 * table or the current physical file to be thrown away anyway.
 		 */
 		if (rel->rd_createSubid == mySubid ||
-			rel->rd_newRelfilenodeSubid == mySubid)
+			rel->rd_newRelfilenodeSubid == mySubid ||
+			RELATION_IS_GLOBAL_TEMP(rel))
 		{
 			/* Immediate, non-rollbackable truncation is OK */
 			heap_truncate_one_rel(rel);
@@ -3330,6 +3386,13 @@ RenameRelationInternal(Oid myrelid, const char *newrelname, bool is_internal, bo
 	 * specially.
 	 */
 	targetrelation = relation_open(myrelid, is_index ? ShareUpdateExclusiveLock : AccessExclusiveLock);
+
+	/* not support rename global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(targetrelation))
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("not support rename global temporary tables yet")));
+
 	namespaceId = RelationGetNamespace(targetrelation);
 
 	/*
@@ -3499,6 +3562,14 @@ AlterTable(Oid relid, LOCKMODE lockmode, AlterTableStmt *stmt)
 	/* Caller is required to provide an adequate lock. */
 	rel = relation_open(relid, NoLock);
 
+	/* not support alter global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("not support alter global temporary tables yet")));
+	}
+
 	CheckTableNotInUse(rel, "ALTER TABLE");
 
 	ATController(stmt, rel, stmt->cmds, stmt->relation->inh, lockmode);
@@ -7679,6 +7750,13 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 				 errmsg("referenced relation \"%s\" is not a table",
 						RelationGetRelationName(pkrel))));
 
+	/* global temp table not support foreign key constraint yet */
+	if (RELATION_IS_GLOBAL_TEMP(pkrel))
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("referenced relation \"%s\" is not a global temp table",
+						RelationGetRelationName(pkrel))));
+
 	if (!allowSystemTableMods && IsSystemRelation(pkrel))
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -7718,6 +7796,12 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 						 errmsg("constraints on temporary tables must involve temporary tables of this session")));
 			break;
+		/* global temp table not support foreign key constraint yet */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					 errmsg("not support foreign key constraints on global temp table yet")));
+			break;
 	}
 
 	/*
@@ -12726,7 +12810,7 @@ index_copy_data(Relation rel, RelFileNode newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
@@ -14133,7 +14217,9 @@ ATPrepChangePersistence(Relation rel, bool toLogged)
 	 */
 	switch (rel->rd_rel->relpersistence)
 	{
+		/* global temp table same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("cannot change logged status of table \"%s\" because it is temporary",
@@ -16723,3 +16809,20 @@ ATDetachCheckNoForeignKeyRefs(Relation partition)
 		table_close(rel, NoLock);
 	}
 }
+
+static bool
+has_oncommit_option(List *options)
+{
+	ListCell   *listptr;
+
+	foreach(listptr, options)
+	{
+		DefElem    *def = (DefElem *) lfirst(listptr);
+
+		if (pg_strcasecmp(def->defname, "on_commit_delete_rows") == 0)
+			return true;
+	}
+
+	return false;
+}
+
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index da1da23..70278a6 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -35,6 +35,7 @@
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
 #include "catalog/pg_namespace.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
 #include "commands/vacuum.h"
@@ -1070,12 +1071,25 @@ vac_estimate_reltuples(Relation relation,
 					   BlockNumber scanned_pages,
 					   double scanned_tuples)
 {
-	BlockNumber old_rel_pages = relation->rd_rel->relpages;
-	double		old_rel_tuples = relation->rd_rel->reltuples;
+	BlockNumber old_rel_pages = 0;
+	double		old_rel_tuples = 0;
 	double		old_density;
 	double		unscanned_pages;
 	double		total_tuples;
 
+	/* get relstat from gtt local hash */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+	{
+		get_gtt_relstats(RelationGetRelid(relation),
+						&old_rel_pages, &old_rel_tuples, NULL,
+						NULL, NULL);
+	}
+	else
+	{
+		old_rel_pages = relation->rd_rel->relpages;
+		old_rel_tuples = relation->rd_rel->reltuples;
+	}
+
 	/* If we did scan the whole table, just use the count as-is */
 	if (scanned_pages >= total_pages)
 		return scanned_tuples;
@@ -1175,24 +1189,8 @@ vac_update_relstats(Relation relation,
 	/* Apply statistical updates, if any, to copied tuple */
 
 	dirty = false;
-	if (pgcform->relpages != (int32) num_pages)
-	{
-		pgcform->relpages = (int32) num_pages;
-		dirty = true;
-	}
-	if (pgcform->reltuples != (float4) num_tuples)
-	{
-		pgcform->reltuples = (float4) num_tuples;
-		dirty = true;
-	}
-	if (pgcform->relallvisible != (int32) num_all_visible_pages)
-	{
-		pgcform->relallvisible = (int32) num_all_visible_pages;
-		dirty = true;
-	}
 
 	/* Apply DDL updates, but not inside an outer transaction (see above) */
-
 	if (!in_outer_xact)
 	{
 		/*
@@ -1217,37 +1215,64 @@ vac_update_relstats(Relation relation,
 		}
 	}
 
-	/*
-	 * Update relfrozenxid, unless caller passed InvalidTransactionId
-	 * indicating it has no new data.
-	 *
-	 * Ordinarily, we don't let relfrozenxid go backwards: if things are
-	 * working correctly, the only way the new frozenxid could be older would
-	 * be if a previous VACUUM was done with a tighter freeze_min_age, in
-	 * which case we don't want to forget the work it already did.  However,
-	 * if the stored relfrozenxid is "in the future", then it must be corrupt
-	 * and it seems best to overwrite it with the cutoff we used this time.
-	 * This should match vac_update_datfrozenxid() concerning what we consider
-	 * to be "in the future".
-	 */
-	if (TransactionIdIsNormal(frozenxid) &&
-		pgcform->relfrozenxid != frozenxid &&
-		(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
-		 TransactionIdPrecedes(ReadNewTransactionId(),
-							   pgcform->relfrozenxid)))
+	/* global temp table remember relstats to localhash not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
 	{
-		pgcform->relfrozenxid = frozenxid;
-		dirty = true;
+		up_gtt_relstats(relation,
+						num_pages, num_tuples,
+						num_all_visible_pages,
+						frozenxid, minmulti);
 	}
-
-	/* Similarly for relminmxid */
-	if (MultiXactIdIsValid(minmulti) &&
-		pgcform->relminmxid != minmulti &&
-		(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
-		 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
+	else
 	{
-		pgcform->relminmxid = minmulti;
-		dirty = true;
+		if (pgcform->relpages != (int32) num_pages)
+		{
+			pgcform->relpages = (int32) num_pages;
+			dirty = true;
+		}
+		if (pgcform->reltuples != (float4) num_tuples)
+		{
+			pgcform->reltuples = (float4) num_tuples;
+			dirty = true;
+		}
+		if (pgcform->relallvisible != (int32) num_all_visible_pages)
+		{
+			pgcform->relallvisible = (int32) num_all_visible_pages;
+			dirty = true;
+		}
+
+		/*
+		 * Update relfrozenxid, unless caller passed InvalidTransactionId
+		 * indicating it has no new data.
+		 *
+		 * Ordinarily, we don't let relfrozenxid go backwards: if things are
+		 * working correctly, the only way the new frozenxid could be older would
+		 * be if a previous VACUUM was done with a tighter freeze_min_age, in
+		 * which case we don't want to forget the work it already did.  However,
+		 * if the stored relfrozenxid is "in the future", then it must be corrupt
+		 * and it seems best to overwrite it with the cutoff we used this time.
+		 * This should match vac_update_datfrozenxid() concerning what we consider
+		 * to be "in the future".
+		 */
+		if (TransactionIdIsNormal(frozenxid) &&
+			pgcform->relfrozenxid != frozenxid &&
+			(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(),
+								   pgcform->relfrozenxid)))
+		{
+			pgcform->relfrozenxid = frozenxid;
+			dirty = true;
+		}
+
+		/* Similarly for relminmxid */
+		if (MultiXactIdIsValid(minmulti) &&
+			pgcform->relminmxid != minmulti &&
+			(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
+		{
+			pgcform->relminmxid = minmulti;
+			dirty = true;
+		}
 	}
 
 	/* If anything changed, write out the tuple. */
@@ -1339,6 +1364,10 @@ vac_update_datfrozenxid(void)
 			continue;
 		}
 
+		/* global temp table relstats not in pg_class */
+		if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			continue;
+
 		/*
 		 * Some table AMs might not need per-relation xid / multixid horizons.
 		 * It therefore seems reasonable to allow relfrozenxid and relminmxid
@@ -1396,6 +1425,25 @@ vac_update_datfrozenxid(void)
 	Assert(TransactionIdIsNormal(newFrozenXid));
 	Assert(MultiXactIdIsValid(newMinMulti));
 
+	/*
+	 * Global temp table get frozenxid from MyProc
+	 * to avoid the vacuum truncate clog that gtt need.
+	 */
+	if (max_active_gtt > 0)
+	{
+		TransactionId oldest_gtt_frozenxid =
+			list_all_session_gtt_frozenxids(0, NULL, NULL, NULL);
+
+		if (TransactionIdIsNormal(oldest_gtt_frozenxid) &&
+			TransactionIdPrecedes(oldest_gtt_frozenxid, newFrozenXid))
+		{
+			ereport(WARNING,
+				(errmsg("global temp table oldest FrozenXid is far in the past"),
+				 errhint("please truncate them or kill those sessions that use them.")));
+			newFrozenXid = oldest_gtt_frozenxid;
+		}
+	}
+
 	/* Now fetch the pg_database tuple we need to update. */
 	relation = table_open(DatabaseRelationId, RowExclusiveLock);
 
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index db3a68a..b41a920 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -591,6 +591,8 @@ static void
 set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 						  RangeTblEntry *rte)
 {
+	char relpersistence;
+
 	/*
 	 * The flag has previously been initialized to false, so we can just
 	 * return if it becomes clear that we can't safely set it.
@@ -618,7 +620,11 @@ set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 			 * the rest of the necessary infrastructure right now anyway.  So
 			 * for now, bail out if we see a temporary table.
 			 */
-			if (get_rel_persistence(rte->relid) == RELPERSISTENCE_TEMP)
+			/* global temp table is same as local temp table */
+			relpersistence = get_rel_persistence(rte->relid);
+
+			if (relpersistence == RELPERSISTENCE_TEMP ||
+				relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 				return;
 
 			/*
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 17c5f08..fa6aee5 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -6307,7 +6307,9 @@ plan_create_index_workers(Oid tableOid, Oid indexOid)
 	 * Furthermore, any index predicate or index expressions must be parallel
 	 * safe.
 	 */
+	/* global temp table is same as local temp table */
 	if (heap->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		heap->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexExpressions(index)) ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexPredicate(index)))
 	{
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index e5f9e04..ecc4543 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -53,6 +53,7 @@
 #include "utils/syscache.h"
 #include "utils/snapmgr.h"
 
+#include "catalog/storage_gtt.h"
 
 /* GUC parameter */
 int			constraint_exclusion = CONSTRAINT_EXCLUSION_PARTITION;
@@ -947,10 +948,10 @@ void
 estimate_rel_size(Relation rel, int32 *attr_widths,
 				  BlockNumber *pages, double *tuples, double *allvisfrac)
 {
-	BlockNumber curpages;
-	BlockNumber relpages;
-	double		reltuples;
-	BlockNumber relallvisible;
+	BlockNumber curpages = 0;
+	BlockNumber relpages = 0;
+	double		reltuples = 0;
+	BlockNumber relallvisible = 0;
 	double		density;
 
 	switch (rel->rd_rel->relkind)
@@ -964,6 +965,21 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 
 		case RELKIND_INDEX:
 
+			/* global temp table get relstats from localhash */
+			if (RELATION_IS_GLOBAL_TEMP(rel))
+			{
+				get_gtt_relstats(RelationGetRelid(rel),
+								&relpages, &reltuples, &relallvisible,
+								NULL, NULL);
+			}
+			else
+			{
+				/* coerce values in pg_class to more desirable types */
+				relpages = (BlockNumber) rel->rd_rel->relpages;
+				reltuples = (double) rel->rd_rel->reltuples;
+				relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
+			}
+
 			/*
 			 * XXX: It'd probably be good to move this into a callback,
 			 * individual index types e.g. know if they have a metapage.
@@ -972,11 +988,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 			/* it has storage, ok to call the smgr */
 			curpages = RelationGetNumberOfBlocks(rel);
 
-			/* coerce values in pg_class to more desirable types */
-			relpages = (BlockNumber) rel->rd_rel->relpages;
-			reltuples = (double) rel->rd_rel->reltuples;
-			relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
-
 			/* report estimated # pages */
 			*pages = curpages;
 			/* quick exit if rel is clearly empty */
@@ -986,10 +997,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 				*allvisfrac = 0;
 				break;
 			}
-			/* coerce values in pg_class to more desirable types */
-			relpages = (BlockNumber) rel->rd_rel->relpages;
-			reltuples = (double) rel->rd_rel->reltuples;
-			relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
 
 			/*
 			 * Discount the metapage while estimating the number of tuples.
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 85d7a96..67b200d 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -2579,6 +2579,11 @@ transformCreateTableAsStmt(ParseState *pstate, CreateTableAsStmt *stmt)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("materialized views must not use temporary tables or views")));
 
+		if (is_query_using_gtt(query))
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("materialized views must not use global temporary tables or views")));
+
 		/*
 		 * A materialized view would either need to save parameters for use in
 		 * maintaining/loading the data or prohibit them entirely.  The latter
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 3f67aaf..333e54f 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3268,17 +3268,11 @@ OptTemp:	TEMPORARY					{ $$ = RELPERSISTENCE_TEMP; }
 			| LOCAL TEMP				{ $$ = RELPERSISTENCE_TEMP; }
 			| GLOBAL TEMPORARY
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED					{ $$ = RELPERSISTENCE_UNLOGGED; }
 			| /*EMPTY*/					{ $$ = RELPERSISTENCE_PERMANENT; }
@@ -11505,19 +11499,13 @@ OptTempTableName:
 				}
 			| GLOBAL TEMPORARY opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED opt_table qualified_name
 				{
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 4dd8150..637a15c 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -59,6 +59,7 @@ static void expandTupleDesc(TupleDesc tupdesc, Alias *eref,
 							List **colnames, List **colvars);
 static int	specialAttNum(const char *attname);
 static bool isQueryUsingTempRelation_walker(Node *node, void *context);
+static bool is_query_using_gtt_walker(Node *node, void *context);
 
 
 /*
@@ -3420,3 +3421,49 @@ isQueryUsingTempRelation_walker(Node *node, void *context)
 								  isQueryUsingTempRelation_walker,
 								  context);
 }
+
+/* check if the query uses global temp table */
+static bool
+is_query_using_gtt_walker(Node *node, void *context)
+{
+	if (node == NULL)
+		return false;
+
+	if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+		ListCell   *rtable;
+
+		foreach(rtable, query->rtable)
+		{
+			RangeTblEntry *rte = lfirst(rtable);
+
+			if (rte->rtekind == RTE_RELATION)
+			{
+				Relation	rel = relation_open(rte->relid, AccessShareLock);
+				char		relpersistence = rel->rd_rel->relpersistence;
+
+				relation_close(rel, AccessShareLock);
+				if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+					return true;
+			}
+		}
+
+		return query_tree_walker(query,
+								 is_query_using_gtt_walker,
+								 context,
+								 QTW_IGNORE_JOINALIASES);
+	}
+
+	return expression_tree_walker(node,
+								  is_query_using_gtt_walker,
+								  context);
+}
+
+/* check if the query uses global temp table */
+bool
+is_query_using_gtt(Query *query)
+{
+	return is_query_using_gtt_walker((Node *) query, NULL);
+}
+
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index ee47547..d13e253 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -359,6 +359,13 @@ generateSerialExtraStmts(CreateStmtContext *cxt, ColumnDef *column,
 	AlterSeqStmt *altseqstmt;
 	List	   *attnamelist;
 
+	if (cxt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("Global temp table does not yet support serial column")));
+	}
+
 	/*
 	 * Determine namespace and name to use for the sequence.
 	 *
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index c1dd816..f2d3df9 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -2091,6 +2091,11 @@ do_autovacuum(void)
 			}
 			continue;
 		}
+		else if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			/* autovacuum skip vacuum global temp table */
+			continue;
+		}
 
 		/* Fetch reloptions and the pgstat entry for this table */
 		relopts = extract_autovac_opts(tuple, pg_class_desc);
@@ -2157,7 +2162,9 @@ do_autovacuum(void)
 		/*
 		 * We cannot safely process other backends' temp tables, so skip 'em.
 		 */
-		if (classForm->relpersistence == RELPERSISTENCE_TEMP)
+		/* autovacuum skip vacuum global temp table */
+		if (classForm->relpersistence == RELPERSISTENCE_TEMP || 
+			classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 			continue;
 
 		relid = classForm->oid;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 7ad1073..8e81701 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -53,6 +53,8 @@
 #include "utils/resowner_private.h"
 #include "utils/timestamp.h"
 
+#include "utils/guc.h"
+#include "catalog/storage_gtt.h"
 
 /* Note: these two macros only work on shared buffers, not local ones! */
 #define BufHdrGetBlock(bufHdr)	((Block) (BufferBlocks + ((Size) (bufHdr)->buf_id) * BLCKSZ))
@@ -432,7 +434,7 @@ ForgetPrivateRefCountEntry(PrivateRefCountEntry *ref)
 static Buffer ReadBuffer_common(SMgrRelation reln, char relpersistence,
 								ForkNumber forkNum, BlockNumber blockNum,
 								ReadBufferMode mode, BufferAccessStrategy strategy,
-								bool *hit);
+								bool *hit, Relation rel);
 static bool PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy);
 static void PinBuffer_Locked(BufferDesc *buf);
 static void UnpinBuffer(BufferDesc *buf, bool fixOwner);
@@ -664,7 +666,8 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
 	 */
 	pgstat_count_buffer_read(reln);
 	buf = ReadBuffer_common(reln->rd_smgr, reln->rd_rel->relpersistence,
-							forkNum, blockNum, mode, strategy, &hit);
+							forkNum, blockNum, mode, strategy, &hit,
+							reln);
 	if (hit)
 		pgstat_count_buffer_hit(reln);
 	return buf;
@@ -692,7 +695,7 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 	Assert(InRecovery);
 
 	return ReadBuffer_common(smgr, RELPERSISTENCE_PERMANENT, forkNum, blockNum,
-							 mode, strategy, &hit);
+							 mode, strategy, &hit, NULL);
 }
 
 
@@ -704,7 +707,8 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 static Buffer
 ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 				  BlockNumber blockNum, ReadBufferMode mode,
-				  BufferAccessStrategy strategy, bool *hit)
+				  BufferAccessStrategy strategy, bool *hit,
+				  Relation rel)
 {
 	BufferDesc *bufHdr;
 	Block		bufBlock;
@@ -719,6 +723,15 @@ ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 
 	isExtend = (blockNum == P_NEW);
 
+	/* create storage when first read data page for gtt */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP &&
+		(isExtend || blockNum == 0) &&
+		forkNum == MAIN_FORKNUM &&
+		!gtt_storage_attached(smgr->smgr_rnode.node.relNode))
+	{
+		RelationCreateStorage(smgr->smgr_rnode.node, relpersistence, rel);
+	}
+
 	TRACE_POSTGRESQL_BUFFER_READ_START(forkNum, blockNum,
 									   smgr->smgr_rnode.node.spcNode,
 									   smgr->smgr_rnode.node.dbNode,
@@ -2799,6 +2812,16 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln)
 BlockNumber
 RelationGetNumberOfBlocksInFork(Relation relation, ForkNumber forkNum)
 {
+	/*
+	 * When this backend not init gtt storage
+	 * return 0
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(relation) &&
+		!gtt_storage_attached(relation->rd_node.relNode))
+	{
+		return 0;
+	}
+
 	switch (relation->rd_rel->relkind)
 	{
 		case RELKIND_SEQUENCE:
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 8853706..b3544dd 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -21,6 +21,7 @@
 #include "access/nbtree.h"
 #include "access/subtrans.h"
 #include "access/twophase.h"
+#include "catalog/storage_gtt.h"
 #include "commands/async.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -147,6 +148,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, BTreeShmemSize());
 		size = add_size(size, SyncScanShmemSize());
 		size = add_size(size, AsyncShmemSize());
+		size = add_size(size, active_gtt_shared_hash_size());
 #ifdef EXEC_BACKEND
 		size = add_size(size, ShmemBackendArraySize());
 #endif
@@ -217,6 +219,8 @@ CreateSharedMemoryAndSemaphores(void)
 	SUBTRANSShmemInit();
 	MultiXactShmemInit();
 	InitBufferPool();
+	/* global temporary table */
+	active_gtt_shared_hash_init();
 
 	/*
 	 * Set up lock manager
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index 3da5307..21bd1f2 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -60,6 +60,7 @@
 #include "utils/builtins.h"
 #include "utils/rel.h"
 #include "utils/snapmgr.h"
+#include "utils/guc.h"
 
 #define UINT32_ACCESS_ONCE(var)		 ((uint32)(*((volatile uint32 *)&(var))))
 
@@ -3973,3 +3974,77 @@ KnownAssignedXidsReset(void)
 
 	LWLockRelease(ProcArrayLock);
 }
+
+/*
+ * search all active backend to get oldest frozenxid
+ * for global temp table.
+ */
+int
+list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n)
+{
+	ProcArrayStruct *arrayP = procArray;
+	TransactionId result = InvalidTransactionId;
+	int			index;
+	int			flags = 0;
+	int			i = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	if (max_size > 0)
+	{
+		Assert(pids);
+		Assert(xids);
+		Assert(n);
+		*n = 0;
+	}
+
+	if (max_active_gtt <= 0)
+		return InvalidTransactionId;
+
+	if (RecoveryInProgress())
+		return InvalidTransactionId;
+
+	flags |= PROC_IS_AUTOVACUUM;
+	flags |= PROC_IN_LOGICAL_DECODING;
+
+	LWLockAcquire(ProcArrayLock, LW_SHARED);
+	if (max_size > 0 && max_size < arrayP->numProcs)
+	{
+		LWLockRelease(ProcArrayLock);
+		elog(ERROR, "list_all_gtt_frozenxids require more array");
+	}
+
+	for (index = 0; index < arrayP->numProcs; index++)
+	{
+		int			pgprocno = arrayP->pgprocnos[index];
+		volatile PGPROC *proc = &allProcs[pgprocno];
+		volatile PGXACT *pgxact = &allPgXact[pgprocno];
+
+		if (pgxact->vacuumFlags & flags)
+			continue;
+
+		if (proc->databaseId == MyDatabaseId &&
+			TransactionIdIsNormal(proc->session_gtt_frozenxid))
+		{
+			if (result == InvalidTransactionId)
+				result = proc->session_gtt_frozenxid;
+			else if (TransactionIdPrecedes(proc->session_gtt_frozenxid, result))
+				result = proc->session_gtt_frozenxid;
+
+			if (max_size > 0)
+			{
+				pids[i] = proc->pid;
+				xids[i] = proc->session_gtt_frozenxid;
+				i++;
+			}
+		}
+	}
+	LWLockRelease(ProcArrayLock);
+
+	if (max_size > 0)
+		*n = i;
+
+	return result;
+}
+
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index b3c54a6..645456c 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -396,6 +396,7 @@ InitProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
@@ -578,6 +579,7 @@ InitAuxiliaryProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 07f3c93..cee8f9e 100644
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -654,6 +654,12 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 		 */
 		if (zero_damaged_pages || InRecovery)
 			MemSet(buffer, 0, BLCKSZ);
+		else if(SmgrIsTemp(reln) && blocknum == 0 && forknum == MAIN_FORKNUM)
+		{
+			/* global temp table init btree meta page */
+			MemSet(buffer, 0, BLCKSZ);
+			mdwrite(reln, forknum, blocknum, buffer, true);
+		}
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_DATA_CORRUPTED),
diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c
index a87e721..adce760 100644
--- a/src/backend/utils/adt/dbsize.c
+++ b/src/backend/utils/adt/dbsize.c
@@ -1008,6 +1008,10 @@ pg_relation_filepath(PG_FUNCTION_ARGS)
 				Assert(backend != InvalidBackendId);
 			}
 			break;
+		/* For global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			backend = BackendIdForTempRelations();
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relform->relpersistence);
 			backend = InvalidBackendId; /* placate compiler */
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 35a8995..42dc3a5 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -141,6 +141,7 @@
 #include "utils/timestamp.h"
 #include "utils/typcache.h"
 
+#include "catalog/storage_gtt.h"
 
 /* Hooks for plugins to get control when we ask for stats */
 get_relation_stats_hook_type get_relation_stats_hook = NULL;
@@ -4568,12 +4569,25 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
 						}
 						else if (index->indpred == NIL)
 						{
-							vardata->statsTuple =
-								SearchSysCache3(STATRELATTINH,
-												ObjectIdGetDatum(index->indexoid),
-												Int16GetDatum(pos + 1),
-												BoolGetDatum(false));
-							vardata->freefunc = ReleaseSysCache;
+							char rel_persistence = get_rel_persistence(index->indexoid);
+
+							if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+							{
+								vardata->statsTuple =
+									get_gtt_att_statistic(index->indexoid,
+														Int16GetDatum(pos + 1),
+														false);
+								vardata->freefunc = release_gtt_statistic_cache;
+							}
+							else
+							{
+								vardata->statsTuple =
+									SearchSysCache3(STATRELATTINH,
+													ObjectIdGetDatum(index->indexoid),
+													Int16GetDatum(pos + 1),
+													BoolGetDatum(false));
+								vardata->freefunc = ReleaseSysCache;
+							}
 
 							if (HeapTupleIsValid(vardata->statsTuple))
 							{
@@ -4652,15 +4666,27 @@ examine_simple_variable(PlannerInfo *root, Var *var,
 	}
 	else if (rte->rtekind == RTE_RELATION)
 	{
-		/*
-		 * Plain table or parent of an inheritance appendrel, so look up the
-		 * column in pg_statistic
-		 */
-		vardata->statsTuple = SearchSysCache3(STATRELATTINH,
-											  ObjectIdGetDatum(rte->relid),
-											  Int16GetDatum(var->varattno),
-											  BoolGetDatum(rte->inh));
-		vardata->freefunc = ReleaseSysCache;
+		char rel_persistence = get_rel_persistence(rte->relid);
+
+		if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata->statsTuple = get_gtt_att_statistic(rte->relid,
+														var->varattno,
+														rte->inh);
+			vardata->freefunc = release_gtt_statistic_cache;
+		}
+		else
+		{
+			/*
+			 * Plain table or parent of an inheritance appendrel, so look up the
+			 * column in pg_statistic
+			 */
+			vardata->statsTuple = SearchSysCache3(STATRELATTINH,
+												  ObjectIdGetDatum(rte->relid),
+												  Int16GetDatum(var->varattno),
+												  BoolGetDatum(rte->inh));
+			vardata->freefunc = ReleaseSysCache;
+		}
 
 		if (HeapTupleIsValid(vardata->statsTuple))
 		{
@@ -5972,6 +5998,7 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	{
 		/* Simple variable --- look to stats for the underlying table */
 		RangeTblEntry *rte = planner_rt_fetch(index->rel->relid, root);
+		char	rel_persistence = get_rel_persistence(rte->relid);
 
 		Assert(rte->rtekind == RTE_RELATION);
 		relid = rte->relid;
@@ -5989,6 +6016,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													rte->inh);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -6000,6 +6034,8 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	}
 	else
 	{
+		char	rel_persistence = get_rel_persistence(index->indexoid);
+
 		/* Expression --- maybe there are stats for the index itself */
 		relid = index->indexoid;
 		colnum = 1;
@@ -6015,6 +6051,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													false);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -6881,6 +6924,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		/* attempt to lookup stats in relation for this index column */
 		if (attnum != 0)
 		{
+			char	rel_persistence = get_rel_persistence(rte->relid);
+
 			/* Simple variable -- look to stats for the underlying table */
 			if (get_relation_stats_hook &&
 				(*get_relation_stats_hook) (root, rte, attnum, &vardata))
@@ -6893,6 +6938,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					elog(ERROR,
 						 "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(rte->relid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple =
@@ -6905,6 +6958,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		}
 		else
 		{
+			char	rel_persistence = get_rel_persistence(index->indexoid);
+
 			/*
 			 * Looks like we've found an expression column in the index. Let's
 			 * see if there's any stats for it.
@@ -6924,6 +6979,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					!vardata.freefunc)
 					elog(ERROR, "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(index->indexoid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple = SearchSysCache3(STATRELATTINH,
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 27602fa..25a411a 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -34,6 +34,7 @@
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_transform.h"
 #include "catalog/pg_type.h"
+#include "catalog/storage_gtt.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "utils/array.h"
@@ -46,6 +47,7 @@
 #include "utils/syscache.h"
 #include "utils/typcache.h"
 
+
 /* Hook for plugins to get control in get_attavgwidth() */
 get_attavgwidth_hook_type get_attavgwidth_hook = NULL;
 
@@ -2878,6 +2880,18 @@ get_attavgwidth(Oid relid, AttrNumber attnum)
 		if (stawidth > 0)
 			return stawidth;
 	}
+	if (get_rel_persistence(relid) == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		tp = get_gtt_att_statistic(relid, attnum, false);
+		if (!HeapTupleIsValid(tp))
+			return 0;
+
+		stawidth = ((Form_pg_statistic) GETSTRUCT(tp))->stawidth;
+		if (stawidth > 0)
+			return stawidth;
+		else
+			return 0;
+	}
 	tp = SearchSysCache3(STATRELATTINH,
 						 ObjectIdGetDatum(relid),
 						 Int16GetDatum(attnum),
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 585dcee..b8f2a41 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -1130,6 +1130,16 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
 				relation->rd_islocaltemp = false;
 			}
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			{
+				relation->rd_backend = BackendIdForTempRelations();
+				/*
+				 * For global temp table, all backend can use
+				 * this relation, so rd_islocaltemp always true.
+				 */
+				relation->rd_islocaltemp = true;
+			}
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c",
 				 relation->rd_rel->relpersistence);
@@ -3311,6 +3321,10 @@ RelationBuildLocalRelation(const char *relname,
 			rel->rd_backend = BackendIdForTempRelations();
 			rel->rd_islocaltemp = true;
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			rel->rd_backend = BackendIdForTempRelations();
+			rel->rd_islocaltemp = true;
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relpersistence);
 			break;
@@ -3425,6 +3439,9 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 	TransactionId freezeXid = InvalidTransactionId;
 	RelFileNode newrnode;
 
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+		elog(ERROR, "global temp table does not allow setting new relfilenode");
+
 	/* Allocate a new relfilenode */
 	newrelfilenode = GetNewRelFileNode(relation->rd_rel->reltablespace, NULL,
 									   persistence);
@@ -3465,7 +3482,7 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 				/* handle these directly, at least for now */
 				SMgrRelation srel;
 
-				srel = RelationCreateStorage(newrnode, persistence);
+				srel = RelationCreateStorage(newrnode, persistence, relation);
 				smgrclose(srel);
 			}
 			break;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 31a5ef0..518d0fa 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -138,6 +138,18 @@ char	   *GUC_check_errmsg_string;
 char	   *GUC_check_errdetail_string;
 char	   *GUC_check_errhint_string;
 
+/*
+ * num = 0 means disable global temp table feature.
+ * global temp table define can still storage in catalog
+ * just can not use.
+ * num > 0 means database can management num active global temp table.
+ */
+#define	MIN_NUM_ACTIVE_GTT			0
+#define	DEFAULT_NUM_ACTIVE_GTT			1000
+#define	MAX_NUM_ACTIVE_GTT			1000000
+
+int		max_active_gtt = MIN_NUM_ACTIVE_GTT;
+
 static void do_serialize(char **destptr, Size *maxbytes, const char *fmt,...) pg_attribute_printf(3, 4);
 
 static void set_config_sourcefile(const char *name, char *sourcefile,
@@ -1962,6 +1974,15 @@ static struct config_bool ConfigureNamesBool[] =
 static struct config_int ConfigureNamesInt[] =
 {
 	{
+		{"max_active_global_temporary_table", PGC_POSTMASTER, UNGROUPED,
+			gettext_noop("max active global temporary table."),
+			NULL
+		},
+		&max_active_gtt,
+		DEFAULT_NUM_ACTIVE_GTT, MIN_NUM_ACTIVE_GTT, MAX_NUM_ACTIVE_GTT,
+		NULL, NULL, NULL
+	},
+	{
 		{"archive_timeout", PGC_SIGHUP, WAL_ARCHIVING,
 			gettext_noop("Forces a switch to the next WAL file if a "
 						 "new file has not been started within N seconds."),
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index bf69adc..72e291b 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15585,6 +15585,7 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 	{
 		char	   *ftoptions = NULL;
 		char	   *srvname = NULL;
+		char		*table_type = NULL;
 
 		switch (tbinfo->relkind)
 		{
@@ -15636,9 +15637,15 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 			binary_upgrade_set_pg_class_oids(fout, q,
 											 tbinfo->dobj.catId.oid, false);
 
+		if (tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED)
+			table_type = "UNLOGGED ";
+		else if (tbinfo->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			table_type = "GLOBAL TEMPORARY ";
+		else
+			table_type = "";
+
 		appendPQExpBuffer(q, "CREATE %s%s %s",
-						  tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED ?
-						  "UNLOGGED " : "",
+						  table_type,
 						  reltypename,
 						  qualrelname);
 
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index 090b6ba..34b4683 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -165,6 +165,7 @@ typedef FormData_pg_class *Form_pg_class;
 #define		  RELPERSISTENCE_PERMANENT	'p' /* regular table */
 #define		  RELPERSISTENCE_UNLOGGED	'u' /* unlogged permanent table */
 #define		  RELPERSISTENCE_TEMP		't' /* temporary table */
+#define		  RELPERSISTENCE_GLOBAL_TEMP	'g' /* global temporary table */
 
 /* default selection for replica identity (primary key or nothing) */
 #define		  REPLICA_IDENTITY_DEFAULT	'd'
diff --git a/src/include/catalog/storage.h b/src/include/catalog/storage.h
index 3579d3f..2bde386 100644
--- a/src/include/catalog/storage.h
+++ b/src/include/catalog/storage.h
@@ -19,7 +19,7 @@
 #include "storage/smgr.h"
 #include "utils/relcache.h"
 
-extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence);
+extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel);
 extern void RelationDropStorage(Relation rel);
 extern void RelationPreserveStorage(RelFileNode rnode, bool atCommit);
 extern void RelationTruncate(Relation rel, BlockNumber nblocks);
diff --git a/src/include/catalog/storage_gtt.h b/src/include/catalog/storage_gtt.h
new file mode 100644
index 0000000..ea41e66
--- /dev/null
+++ b/src/include/catalog/storage_gtt.h
@@ -0,0 +1,39 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.h
+ *	  prototypes for functions in backend/catalog/storage_gtt.c
+ *
+ * src/include/catalog/storage_gtt.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef STORAGE_GTT_H
+#define STORAGE_GTT_H
+
+#include "access/htup.h"
+#include "storage/block.h"
+#include "storage/relfilenode.h"
+#include "utils/relcache.h"
+
+extern Size active_gtt_shared_hash_size(void);
+extern void active_gtt_shared_hash_init(void);
+extern void remember_gtt_storage_info(RelFileNode rnode, Relation rel);
+extern void forget_gtt_storage_info(Oid relid);
+extern bool is_other_backend_use_gtt(RelFileNode node);
+extern bool gtt_storage_attached(Oid relid);
+extern Bitmapset *copy_active_gtt_bitmap(RelFileNode node);
+extern void up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+								TupleDesc tupleDescriptor, Datum *values, bool *isnull);
+extern HeapTuple get_gtt_att_statistic(Oid reloid, int attnum, bool inh);
+extern void release_gtt_statistic_cache(HeapTuple tup);
+extern void up_gtt_relstats(Relation relation,
+							BlockNumber num_pages,
+							double num_tuples,
+							BlockNumber num_all_visible_pages,
+							TransactionId relfrozenxid,
+							TransactionId relminmxid);
+extern void get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+							BlockNumber *relallvisible, TransactionId *relfrozenxid,
+							TransactionId *relminmxid);
+
+#endif							/* STORAGE_H */
diff --git a/src/include/parser/parse_relation.h b/src/include/parser/parse_relation.h
index f7e0781..4f5a353 100644
--- a/src/include/parser/parse_relation.h
+++ b/src/include/parser/parse_relation.h
@@ -130,4 +130,7 @@ extern Oid	attnumTypeId(Relation rd, int attid);
 extern Oid	attnumCollationId(Relation rd, int attid);
 extern bool isQueryUsingTempRelation(Query *query);
 
+/* global temp table check */
+extern bool is_query_using_gtt(Query *query);
+
 #endif							/* PARSE_RELATION_H */
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index f627dfe..cfc6c78 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -220,6 +220,7 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_TBM,
 	LWTRANCHE_PARALLEL_APPEND,
 	LWTRANCHE_SXACT,
+	LWTRANCHE_GTT_CTL,
 	LWTRANCHE_FIRST_USER_DEFINED
 }			BuiltinTrancheIds;
 
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 281e1db..2ab8e91 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -117,6 +117,8 @@ struct PGPROC
 	Oid			tempNamespaceId;	/* OID of temp schema this backend is
 									 * using */
 
+	TransactionId session_gtt_frozenxid;	/* session level global temp table relfrozenxid */
+
 	bool		isBackgroundWorker; /* true if background worker. */
 
 	/*
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index da8b672..8e7d4c7 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -124,4 +124,6 @@ extern void ProcArraySetReplicationSlotXmin(TransactionId xmin,
 extern void ProcArrayGetReplicationSlotXmin(TransactionId *xmin,
 											TransactionId *catalog_xmin);
 
+extern int list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n);
+
 #endif							/* PROCARRAY_H */
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index 6791e0c..82b672f 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -276,6 +276,10 @@ extern int	tcp_user_timeout;
 extern bool trace_sort;
 #endif
 
+/* global temporary table */
+extern int	max_active_gtt;
+/* end */
+
 /*
  * Functions exported by guc.c
  */
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 8b8b237..c1962b7 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -272,6 +272,7 @@ typedef struct StdRdOptions
 	int			parallel_workers;	/* max number of parallel workers */
 	bool		vacuum_index_cleanup;	/* enables index vacuuming and cleanup */
 	bool		vacuum_truncate;	/* enables vacuum to truncate a relation */
+	bool		on_commit_delete_rows;	/* global temp table */
 } StdRdOptions;
 
 #define HEAP_MIN_FILLFACTOR			10
@@ -530,7 +531,8 @@ typedef struct ViewOptions
  *		True if relation's pages are stored in local buffers.
  */
 #define RelationUsesLocalBuffers(relation) \
-	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP || \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 
 /*
  * RELATION_IS_LOCAL
@@ -609,6 +611,17 @@ typedef struct ViewOptions
  */
 #define RelationGetPartitionDesc(relation) ((relation)->rd_partdesc)
 
+/* global temp table implementations */
+#define RELATION_IS_GLOBAL_TEMP(relation)	((relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+
+#define RELATION_GTT_ON_COMMIT_DELETE(relation)	\
+	((relation)->rd_options && \
+	 (relation)->rd_rel->relkind == RELKIND_RELATION && \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ? \
+	 ((StdRdOptions *) (relation)->rd_options)->on_commit_delete_rows : false)
+
+#define RelationGetRelPersistence(relation) ((relation)->rd_rel->relpersistence)
+
 /* routines in utils/cache/relcache.c */
 extern void RelationIncrementReferenceCount(Relation rel);
 extern void RelationDecrementReferenceCount(Relation rel);
diff --git a/src/test/regress/expected/gtt_clean.out b/src/test/regress/expected/gtt_clean.out
new file mode 100644
index 0000000..50ca9ac
--- /dev/null
+++ b/src/test/regress/expected/gtt_clean.out
@@ -0,0 +1,7 @@
+reset search_path;
+drop schema gtt cascade;
+NOTICE:  drop cascades to 4 other objects
+DETAIL:  drop cascades to table gtt.gtt1
+drop cascades to table gtt.gtt2
+drop cascades to table gtt.gtt3
+drop cascades to table gtt.gtt_t_kenyon
diff --git a/src/test/regress/expected/gtt_error.out b/src/test/regress/expected/gtt_error.out
new file mode 100644
index 0000000..80c16dc
--- /dev/null
+++ b/src/test/regress/expected/gtt_error.out
@@ -0,0 +1,106 @@
+CREATE SCHEMA IF NOT EXISTS gtt_error;
+set search_path=gtt_error,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+ERROR:  cannot create indexes on global temporary tables using concurrent mode
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+ERROR:  not support cluster global temporary tables yet
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+ERROR:  ON COMMIT can only be used on temporary tables
+-- ERROR
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+ERROR:  regular table cannot specifie on_commit_delete_rows
+-- ERROR
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+ERROR:  not support create global temporary partition table yet
+-- ERROR
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+ERROR:  not support create global temporary inheritance table yet
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+ERROR:  global temp table not support on commit drop clause
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+ERROR:  can not defeine global temp table with on commit and with clause at same time
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+--ERROR
+alter table gtt1 rename to gttx;
+ERROR:  not support rename global temporary tables yet
+-- ERROR
+ALTER TABLE gtt1 ADD COLUMN address varchar(30);
+ERROR:  not support alter global temporary tables yet
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  referenced relation "products" is not a global temp table
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  not support alter global temporary tables yet
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+ERROR:  Global temp table does not yet support serial column
+-- ERROR
+create global temp table gttx(id int GENERATED ALWAYS AS IDENTITY (START WITH 2));
+ERROR:  Global temp table does not yet support serial column
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+ERROR:  materialized views must not use global temporary tables or views
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+ERROR:  only support btree index on global temp table
+create index idx_err on gtt1 using gist (a);
+ERROR:  data type integer has no default operator class for access method "gist"
+HINT:  You must specify an operator class for the index or define a default operator class for the data type.
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+ERROR:  only support btree index on global temp table
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+ERROR:  only support btree index on global temp table
+reset search_path;
+drop schema gtt_error cascade;
+NOTICE:  drop cascades to 8 other objects
+DETAIL:  drop cascades to table gtt_error.gtt1
+drop cascades to table gtt_error.gtt2
+drop cascades to table gtt_error.gtt3
+drop cascades to table gtt_error.tmp_t0
+drop cascades to table gtt_error.tbl_inherits_parent
+drop cascades to table gtt_error.tbl_inherits_parent_global_temp
+drop cascades to table gtt_error.products
+drop cascades to table gtt_error.gtt5
diff --git a/src/test/regress/expected/gtt_parallel_1.out b/src/test/regress/expected/gtt_parallel_1.out
new file mode 100644
index 0000000..30d8a7b
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_1.out
@@ -0,0 +1,84 @@
+set search_path=gtt,sys;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_parallel_2.out b/src/test/regress/expected/gtt_parallel_2.out
new file mode 100644
index 0000000..70bf4a6
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_2.out
@@ -0,0 +1,142 @@
+set search_path=gtt,sys;
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+ 3 | test1
+(3 rows)
+
+rollback;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test2
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 3 | test3
+(1 row)
+
+rollback;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 5 | test5
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 6 | test6
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+ count  
+--------
+ 100000
+(1 row)
+
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+             QUERY PLAN             
+------------------------------------
+ Index Scan using gtt3_pkey on gtt3
+   Index Cond: (a = 300)
+(2 rows)
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',10000);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid) from pg_class where relname = 'gtt_t_kenyon';
+   relname    | pg_relation_size | pg_relation_size 
+--------------+------------------+------------------
+ gtt_t_kenyon |           450560 |            16384
+(1 row)
+
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+   relname    
+--------------
+ gtt_t_kenyon
+(1 row)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_prepare.out b/src/test/regress/expected/gtt_prepare.out
new file mode 100644
index 0000000..9e8f5f0
--- /dev/null
+++ b/src/test/regress/expected/gtt_prepare.out
@@ -0,0 +1,7 @@
+CREATE SCHEMA IF NOT EXISTS gtt;
+set search_path=gtt,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+reset search_path;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index fc0f141..6836eeb 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -121,3 +121,9 @@ test: fast_default
 
 # run stats by itself because its delay may be insufficient under heavy load
 test: stats
+
+# global temp table test
+test: gtt_error
+test: gtt_prepare
+test: gtt_parallel_1 gtt_parallel_2
+test: gtt_clean
diff --git a/src/test/regress/sql/gtt_error.sql b/src/test/regress/sql/gtt_error.sql
new file mode 100644
index 0000000..e895574
--- /dev/null
+++ b/src/test/regress/sql/gtt_error.sql
@@ -0,0 +1,106 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt_error;
+
+set search_path=gtt_error,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+
+-- ERROR
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+
+-- ERROR
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+
+-- ERROR
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+
+--ERROR
+alter table gtt1 rename to gttx;
+
+-- ERROR
+ALTER TABLE gtt1 ADD COLUMN address varchar(30);
+
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+
+-- ERROR
+create global temp table gttx(id int GENERATED ALWAYS AS IDENTITY (START WITH 2));
+
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+create index idx_err on gtt1 using gist (a);
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+
+reset search_path;
+
+drop schema gtt_error cascade;
+
diff --git a/src/test/regress/sql/gtt_parallel_1.sql b/src/test/regress/sql/gtt_parallel_1.sql
new file mode 100644
index 0000000..d7d81de
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_1.sql
@@ -0,0 +1,42 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+commit;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+rollback;
+select * from gtt1 order by a;
+
+truncate gtt1;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+select * from gtt1 order by a;
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+
+begin;
+select * from gtt1 order by a;
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_parallel_2.sql b/src/test/regress/sql/gtt_parallel_2.sql
new file mode 100644
index 0000000..cb2f7a6
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_2.sql
@@ -0,0 +1,62 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+commit;
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+truncate gtt3;
+select * from gtt3 order by a;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+truncate gtt3;
+select * from gtt3 order by a;
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+begin;
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',10000);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid) from pg_class where relname = 'gtt_t_kenyon';
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_prepare.sql b/src/test/regress/sql/gtt_prepare.sql
new file mode 100644
index 0000000..042d9e6
--- /dev/null
+++ b/src/test/regress/sql/gtt_prepare.sql
@@ -0,0 +1,15 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt;
+
+set search_path=gtt,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+
+reset search_path;
+

From 94c807315d12a8c30a1654947d289775a6b7682b Mon Sep 17 00:00:00 2001
From: wenjing.zwj <wenjing.zwj@alibaba-inc.com>
Date: Tue, 25 Jun 2019 17:44:26 +0800
Subject: [PATCH] support global temp table

---
 contrib/Makefile                             |   3 ++-
 contrib/pg_gtt/Makefile                      |  22 ++++++++++++++++++++++
 contrib/pg_gtt/pg_gtt--1.0.sql               |  28 ++++++++++++++++++++++++++++
 contrib/pg_gtt/pg_gtt.c                      | 474 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 contrib/pg_gtt/pg_gtt.control                |   4 ++++
 src/backend/access/common/reloptions.c       |  17 +++++++++++++++++
 src/backend/access/gist/gistutil.c           |   4 +++-
 src/backend/access/hash/hash.c               |   4 +++-
 src/backend/access/heap/heapam_handler.c     |   4 ++--
 src/backend/access/heap/vacuumlazy.c         |  22 ++++++++++++++++++----
 src/backend/access/nbtree/nbtpage.c          |   9 ++++++++-
 src/backend/access/transam/xlog.c            |   4 ++++
 src/backend/catalog/Makefile                 |   2 ++
 src/backend/catalog/catalog.c                |   2 ++
 src/backend/catalog/heap.c                   |  86 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------
 src/backend/catalog/index.c                  |  87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------------
 src/backend/catalog/namespace.c              |   7 +++++++
 src/backend/catalog/storage.c                |  17 ++++++++++++++++-
 src/backend/catalog/storage_gtt.c            | 814 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/backend/commands/analyze.c               |  75 ++++++++++++++++++++++++++++++++++++++++++++++++++-------------------------
 src/backend/commands/cluster.c               |   6 ++++++
 src/backend/commands/indexcmds.c             |  10 ++++++++++
 src/backend/commands/lockcmds.c              |   3 ++-
 src/backend/commands/tablecmds.c             | 111 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 src/backend/commands/vacuum.c                | 140 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------------------------------------
 src/backend/optimizer/path/allpaths.c        |   8 +++++++-
 src/backend/optimizer/plan/planner.c         |   2 ++
 src/backend/optimizer/util/plancat.c         |  33 ++++++++++++++++++++-------------
 src/backend/parser/analyze.c                 |   5 +++++
 src/backend/parser/gram.y                    |  20 ++++----------------
 src/backend/parser/parse_relation.c          |  47 +++++++++++++++++++++++++++++++++++++++++++++++
 src/backend/parser/parse_utilcmd.c           |   7 +++++++
 src/backend/postmaster/autovacuum.c          |   9 ++++++++-
 src/backend/storage/buffer/bufmgr.c          |  31 +++++++++++++++++++++++++++----
 src/backend/storage/ipc/ipci.c               |   4 ++++
 src/backend/storage/ipc/procarray.c          |  75 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/backend/storage/lmgr/proc.c              |   2 ++
 src/backend/storage/smgr/md.c                |   6 ++++++
 src/backend/utils/adt/dbsize.c               |   4 ++++
 src/backend/utils/adt/selfuncs.c             |  93 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---------------
 src/backend/utils/cache/lsyscache.c          |  14 ++++++++++++++
 src/backend/utils/cache/relcache.c           |  19 ++++++++++++++++++-
 src/backend/utils/misc/guc.c                 |  21 +++++++++++++++++++++
 src/bin/pg_dump/pg_dump.c                    |  11 +++++++++--
 src/include/catalog/pg_class.h               |   1 +
 src/include/catalog/storage.h                |   2 +-
 src/include/catalog/storage_gtt.h            |  39 +++++++++++++++++++++++++++++++++++++++
 src/include/parser/parse_relation.h          |   3 +++
 src/include/storage/lwlock.h                 |   1 +
 src/include/storage/proc.h                   |   2 ++
 src/include/storage/procarray.h              |   2 ++
 src/include/utils/guc.h                      |   4 ++++
 src/include/utils/rel.h                      |  15 ++++++++++++++-
 src/test/regress/expected/gtt_clean.out      |   7 +++++++
 src/test/regress/expected/gtt_error.out      | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/expected/gtt_parallel_1.out |  84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/expected/gtt_parallel_2.out | 142 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/expected/gtt_prepare.out    |   7 +++++++
 src/test/regress/parallel_schedule           |   6 ++++++
 src/test/regress/sql/gtt_clean.sql           |   6 ++++++
 src/test/regress/sql/gtt_error.sql           | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/sql/gtt_parallel_1.sql      |  42 ++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/sql/gtt_parallel_2.sql      |  62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/sql/gtt_prepare.sql         |  15 +++++++++++++++
 64 files changed, 2848 insertions(+), 170 deletions(-)
 create mode 100644 contrib/pg_gtt/Makefile
 create mode 100644 contrib/pg_gtt/pg_gtt--1.0.sql
 create mode 100644 contrib/pg_gtt/pg_gtt.c
 create mode 100644 contrib/pg_gtt/pg_gtt.control
 create mode 100644 src/backend/catalog/storage_gtt.c
 create mode 100644 src/include/catalog/storage_gtt.h
 create mode 100644 src/test/regress/expected/gtt_clean.out
 create mode 100644 src/test/regress/expected/gtt_error.out
 create mode 100644 src/test/regress/expected/gtt_parallel_1.out
 create mode 100644 src/test/regress/expected/gtt_parallel_2.out
 create mode 100644 src/test/regress/expected/gtt_prepare.out
 create mode 100644 src/test/regress/sql/gtt_clean.sql
 create mode 100644 src/test/regress/sql/gtt_error.sql
 create mode 100644 src/test/regress/sql/gtt_parallel_1.sql
 create mode 100644 src/test/regress/sql/gtt_parallel_2.sql
 create mode 100644 src/test/regress/sql/gtt_prepare.sql

diff --git a/contrib/Makefile b/contrib/Makefile
index 92184ed..4b1a596 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -48,7 +48,8 @@ SUBDIRS = \
 		tsm_system_rows \
 		tsm_system_time \
 		unaccent	\
-		vacuumlo
+		vacuumlo	\
+		pg_gtt
 
 ifeq ($(with_openssl),yes)
 SUBDIRS += sslinfo
diff --git a/contrib/pg_gtt/Makefile b/contrib/pg_gtt/Makefile
new file mode 100644
index 0000000..1d2ef64
--- /dev/null
+++ b/contrib/pg_gtt/Makefile
@@ -0,0 +1,22 @@
+# contrib/pg_gtt/Makefile
+
+MODULE_big = pg_gtt
+OBJS = pg_gtt.o
+
+EXTENSION = pg_gtt
+DATA = pg_gtt--1.0.sql
+
+LDFLAGS_SL += $(filter -lm, $(LIBS))
+
+NO_INSTALLCHECK = 1
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/pg_pfs
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/contrib/pg_gtt/pg_gtt--1.0.sql b/contrib/pg_gtt/pg_gtt--1.0.sql
new file mode 100644
index 0000000..3f794d7
--- /dev/null
+++ b/contrib/pg_gtt/pg_gtt--1.0.sql
@@ -0,0 +1,28 @@
+/* contrib/pg_gtt/pg_gtt--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION pg_gtt" to load this file. \quit
+
+
+CREATE FUNCTION pg_gtt_att_statistic(text, text, int)
+RETURNS setof pg_statistic
+AS 'MODULE_PATHNAME','pg_gtt_att_statistic'
+LANGUAGE C STRICT;
+
+CREATE TYPE relstats_type AS (relpages int4, reltuples float4, relallvisible int4, relfrozenxid xid, relminmxid xid);
+CREATE TYPE rel_vac_type AS (pid int4, relfrozenxid xid, relminmxid xid);
+
+CREATE FUNCTION pg_gtt_relstats(text, text)
+RETURNS relstats_type
+AS 'MODULE_PATHNAME','pg_gtt_relstats'
+LANGUAGE C STRICT;
+
+CREATE FUNCTION pg_gtt_attached_pid(text, text)
+RETURNS setof int4
+AS 'MODULE_PATHNAME','pg_gtt_attached_pid'
+LANGUAGE C STRICT;
+
+CREATE FUNCTION pg_list_gtt_relfrozenxids()
+RETURNS setof rel_vac_type
+AS 'MODULE_PATHNAME','pg_list_gtt_relfrozenxids'
+LANGUAGE C STRICT;
diff --git a/contrib/pg_gtt/pg_gtt.c b/contrib/pg_gtt/pg_gtt.c
new file mode 100644
index 0000000..19e1ec0
--- /dev/null
+++ b/contrib/pg_gtt/pg_gtt.c
@@ -0,0 +1,474 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_gtt.c
+ *	code to management function for global temparary table
+ *
+ * IDENTIFICATION
+ *	  contrib/pg_gtt/pg_gtt.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <unistd.h>
+#include <sys/time.h>
+#include "port.h"
+#include "access/htup_details.h"
+#include "access/table.h"
+#include "access/xlog.h"
+#include "catalog/pg_type.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/namespace.h"
+#include "catalog/pg_class.h"
+#include "funcapi.h"
+#include "storage/ipc.h"
+#include "storage/shmem.h"
+#include "storage/lwlock.h"
+#include "storage/procarray.h"
+#include "storage/proc.h"
+#include "tcop/utility.h"
+#include "utils/builtins.h"
+#include "utils/memutils.h"
+#include "utils/timeout.h"
+#include "utils/guc.h"
+#include "utils/lsyscache.h"
+#include "utils/rel.h"
+#include <nodes/makefuncs.h>
+#include "storage/sinvaladt.h"
+#include "miscadmin.h"
+
+PG_MODULE_MAGIC;
+
+static Oid pg_get_relid(const char *relname, char *schema);
+
+Datum pg_gtt_att_statistic(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(pg_gtt_att_statistic);
+
+Datum pg_gtt_relstats(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(pg_gtt_relstats);
+
+Datum pg_gtt_attached_pid(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(pg_gtt_attached_pid);
+
+Datum pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(pg_list_gtt_relfrozenxids);
+
+void		_PG_init(void);
+void		_PG_fini(void);
+
+void
+_PG_init(void)
+{
+	return;
+}
+
+void
+_PG_fini(void)
+{
+	return;
+}
+
+static Oid
+pg_get_relid(const char *relname, char *schema)
+{
+	Oid			relid;
+	RangeVar   *rv = makeRangeVar(schema, (char *)relname, -1);
+
+	relid = RangeVarGetRelid(rv, NoLock, true);
+
+	pfree(rv);
+	return relid;
+}
+
+Datum
+pg_gtt_att_statistic(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc		tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple		tuple;
+	Relation	rel = NULL;
+	char	*relname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	char	*schema = text_to_cstring(PG_GETARG_TEXT_PP(1));
+	int		attnum = PG_GETARG_INT32(2);
+	Oid		reloid;
+	char	rel_persistence;
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = NULL;
+	rsinfo->setDesc = NULL;
+
+	tupdesc = CreateTemplateTupleDesc(31);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "starelid",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "staattnum",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 3, "stainherit",
+						BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 4, "stanullfrac",
+						FLOAT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "stawidth",
+						INT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "stadistinct",
+						FLOAT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 7, "stakind1",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 8, "stakind2",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 9, "stakind3",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 10, "stakind4",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 11, "stakind5",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 12, "staop1",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 13, "staop2",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 14, "staop3",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 15, "staop4",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 16, "staop5",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 17, "stacoll1",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 18, "stacoll2",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 19, "stacoll3",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 20, "stacoll4",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 21, "stacoll5",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 22, "stanumbers1",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 23, "stanumbers2",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 24, "stanumbers3",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 25, "stanumbers4",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 26, "stanumbers5",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 27, "stavalues1",
+						ANYARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 28, "stavalues2",
+						ANYARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 29, "stavalues3",
+						ANYARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 30, "stavalues4",
+						ANYARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 31, "stavalues5",
+						ANYARRAYOID, -1, 0);
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (schema == NULL)
+		schema = "public";
+
+	reloid = pg_get_relid(relname, schema);
+	if (reloid == InvalidOid)
+	{
+		elog(WARNING, "relation %s.%s does not exist", schema, relname);
+		return (Datum) 0;
+	}
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation %s.%s not global temp table", schema, relname);
+		return (Datum) 0;
+	}
+
+	tuple = get_gtt_att_statistic(reloid, attnum, false);
+	if (tuple)
+	{
+		HeapTuple tp = heap_copytuple(tuple);
+		tuplestore_puttuple(tupstore, tp);
+	}
+	tuplestore_donestoring(tupstore);
+
+	table_close(rel, NoLock);
+	return (Datum) 0;
+}
+
+Datum
+pg_gtt_relstats(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	char	*relname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	char	*schema = text_to_cstring(PG_GETARG_TEXT_PP(1));
+	Oid	reloid;
+	char	rel_persistence;
+	Datum	values[5];
+	bool	isnull[5];
+	BlockNumber	relpages = 0;
+	double		reltuples = 0;
+	BlockNumber	relallvisible = 0;
+	uint32		relfrozenxid = 0;
+	uint32		relminmxid = 0;
+	Relation	rel = NULL;
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = NULL;
+	rsinfo->setDesc = NULL;
+
+	tupdesc = CreateTemplateTupleDesc(5);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "relpages",
+						INT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "reltuples",
+						FLOAT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 3, "relallvisible",
+						INT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 4, "relfrozenxid",
+						XIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "relminmxid",
+						XIDOID, -1, 0);
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (schema == NULL)
+		schema = "public";
+
+	reloid = pg_get_relid(relname, schema);
+	if (reloid == InvalidOid)
+	{
+		elog(WARNING, "relation %s.%s does not exist", schema, relname);
+		return (Datum) 0;
+	}
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation %s.%s not global temp table", schema, relname);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	get_gtt_relstats(reloid,
+					&relpages, &reltuples, &relallvisible,
+					&relfrozenxid, &relminmxid);
+
+	memset(isnull, false, sizeof(isnull));
+	memset(values, 0, sizeof(values));
+	values[0] = Int32GetDatum(relpages);
+	values[1] = Float4GetDatum((float4)reltuples);
+	values[2] = Int32GetDatum(relallvisible);
+	values[3] = UInt32GetDatum(relfrozenxid);
+	values[4] = UInt32GetDatum(relminmxid);
+	tuple = heap_form_tuple(tupdesc, values, isnull);
+	tuplestore_puttuple(tupstore, tuple);
+	tuplestore_donestoring(tupstore);
+
+	table_close(rel, NoLock);
+	return (Datum) 0;
+}
+
+Datum
+pg_gtt_attached_pid(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	char	*relname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	char	*schema = text_to_cstring(PG_GETARG_TEXT_PP(1));
+	Oid	reloid;
+	char	rel_persistence;
+	Datum	values[1];
+	bool	isnull[1];
+	Relation	rel = NULL;
+	PGPROC		*proc = NULL;
+	Bitmapset	*map = NULL;
+	pid_t		pid = 0;
+	int			backendid = 0;
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = NULL;
+	rsinfo->setDesc = NULL;
+
+	tupdesc = CreateTemplateTupleDesc(1);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "pid",
+						INT4OID, -1, 0);
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (schema == NULL)
+		schema = "public";
+
+	reloid = pg_get_relid(relname, schema);
+	if (reloid == InvalidOid)
+	{
+		elog(WARNING, "relation %s.%s does not exist", schema, relname);
+		return (Datum) 0;
+	}
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation %s.%s not global temp table", schema, relname);
+		return (Datum) 0;
+	}
+
+	map = copy_active_gtt_bitmap(rel->rd_node);
+	if (map)
+	{
+		backendid = bms_first_member(map);
+
+		do
+		{
+			proc = BackendIdGetProc(backendid);
+			pid = proc->pid;
+			if (pid > 0)
+			{
+				memset(isnull, false, sizeof(isnull));
+				memset(values, 0, sizeof(values));
+				values[0] = Int32GetDatum(pid);
+				tuple = heap_form_tuple(tupdesc, values, isnull);
+				tuplestore_puttuple(tupstore, tuple);
+			}
+			backendid = bms_next_member(map, backendid);
+		} while (backendid > 0);
+
+		pfree(map);
+	}
+
+	tuplestore_donestoring(tupstore);
+	table_close(rel, NoLock);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	Datum	values[3];
+	bool	isnull[3];
+	int			num_xid = MaxBackends + 1;
+	int			*pids = NULL;
+	uint32		*xids = NULL;
+	int			i = 0;
+	int			j = 0;
+	uint32		oldest = 0;
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = NULL;
+	rsinfo->setDesc = NULL;
+
+	tupdesc = CreateTemplateTupleDesc(3);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "pid",
+						INT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "relfrozenxid",
+						XIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 3, "relminmxid",
+						XIDOID, -1, 0);
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (max_active_gtt <= 0)
+		return (Datum) 0;
+
+	if (RecoveryInProgress())
+		return (Datum) 0;
+
+	pids = palloc0(sizeof(int) * num_xid);
+	xids = palloc0(sizeof(int) * num_xid);
+	oldest = list_all_session_gtt_frozenxids(num_xid, pids, xids, &i);
+	if (i > 0)
+	{
+		if (i > 0)
+		{
+			pids[i] = 0;
+			xids[i] = oldest;
+			i++;
+		}
+
+		for(j = 0; j < i; j++)
+		{
+			memset(isnull, false, sizeof(isnull));
+			memset(values, 0, sizeof(values));
+			values[0] = Int32GetDatum(pids[j]);
+			values[1] = UInt32GetDatum(xids[j]);
+			values[2] = UInt32GetDatum(0);
+			tuple = heap_form_tuple(tupdesc, values, isnull);
+			tuplestore_puttuple(tupstore, tuple);
+		}
+	}
+	tuplestore_donestoring(tupstore);
+	pfree(pids);
+	pfree(xids);
+
+	return (Datum) 0;
+}
+
diff --git a/contrib/pg_gtt/pg_gtt.control b/contrib/pg_gtt/pg_gtt.control
new file mode 100644
index 0000000..342af1d
--- /dev/null
+++ b/contrib/pg_gtt/pg_gtt.control
@@ -0,0 +1,4 @@
+comment = 'pg_gtt'
+default_version = '1.0'
+module_pathname = '$libdir/pg_gtt'
+relocatable = true
diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c
index 2e1dcb9..3eb57df 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -158,6 +158,19 @@ static relopt_bool boolRelOpts[] =
 		},
 		true
 	},
+	/*
+	 * For global temp table only
+	 * use AccessExclusiveLock for ensure safety
+	 */
+	{
+		{
+			"on_commit_delete_rows",
+			"global temp table on commit options",
+			RELOPT_KIND_HEAP,
+			ShareUpdateExclusiveLock
+		},
+		true
+	},	
 	/* list terminator */
 	{{NULL}}
 };
@@ -1378,7 +1391,11 @@ default_reloptions(Datum reloptions, bool validate, relopt_kind kind)
 	relopt_value *options;
 	StdRdOptions *rdopts;
 	int			numoptions;
+
+	/* add on_commit_delete_rows for global temp table */
 	static const relopt_parse_elt tab[] = {
+		{"on_commit_delete_rows", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, on_commit_delete_rows)},
 		{"fillfactor", RELOPT_TYPE_INT, offsetof(StdRdOptions, fillfactor)},
 		{"autovacuum_enabled", RELOPT_TYPE_BOOL,
 		offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, enabled)},
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index f428729..6c9b052 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -1028,7 +1028,9 @@ gistGetFakeLSN(Relation rel)
 {
 	static XLogRecPtr counter = FirstNormalUnloggedLSN;
 
-	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	/* global temp is same as local temp table */
+	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		rel->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 	{
 		/*
 		 * Temporary relations are only accessible in our session, so a simple
diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index 5cc30da..49b7d2e 100644
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -148,7 +148,9 @@ hashbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	 * metapage, nor the first bitmap page.
 	 */
 	sort_threshold = (maintenance_work_mem * 1024L) / BLCKSZ;
-	if (index->rd_rel->relpersistence != RELPERSISTENCE_TEMP)
+	/* global temp table is same as local temp table */
+	if (!(index->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		index->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		sort_threshold = Min(sort_threshold, NBuffers);
 	else
 		sort_threshold = Min(sort_threshold, NLocBuffer);
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index fc19f40..681521a 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -602,7 +602,7 @@ heapam_relation_set_new_filenode(Relation rel,
 	 */
 	*minmulti = GetOldestMultiXactId();
 
-	srel = RelationCreateStorage(*newrnode, persistence);
+	srel = RelationCreateStorage(*newrnode, persistence, rel);
 
 	/*
 	 * If required, set up an init fork for an unlogged table so that it can
@@ -655,7 +655,7 @@ heapam_relation_copy_data(Relation rel, const RelFileNode *newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index a3c4a1d..03fac55 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -60,6 +60,7 @@
 #include "utils/pg_rusage.h"
 #include "utils/timestamp.h"
 
+#include "catalog/storage_gtt.h"
 
 /*
  * Space/time tradeoff parameters: do these need to be user-tunable?
@@ -214,8 +215,10 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 	Assert(params->truncate != VACOPT_TERNARY_DEFAULT);
 
 	/* not every AM requires these to be valid, but heap does */
-	Assert(TransactionIdIsNormal(onerel->rd_rel->relfrozenxid));
-	Assert(MultiXactIdIsValid(onerel->rd_rel->relminmxid));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relfrozenxid == InvalidTransactionId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && TransactionIdIsNormal(onerel->rd_rel->relfrozenxid)));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relminmxid == InvalidMultiXactId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && MultiXactIdIsValid(onerel->rd_rel->relminmxid)));
 
 	/* measure elapsed time iff autovacuum logging requires it */
 	if (IsAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
@@ -274,8 +277,19 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 
 	vacrelstats = (LVRelStats *) palloc0(sizeof(LVRelStats));
 
-	vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
-	vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
+	/* get relstat from gtt localhash */
+	if (RELATION_IS_GLOBAL_TEMP(onerel))
+	{
+		get_gtt_relstats(RelationGetRelid(onerel),
+						&vacrelstats->old_rel_pages,
+						&vacrelstats->old_live_tuples,
+						NULL, NULL, NULL);
+	}
+	else
+	{
+		vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
+		vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
+	}
 	vacrelstats->num_index_scans = 0;
 	vacrelstats->pages_removed = 0;
 	vacrelstats->lock_waiter_detected = false;
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index 6b2655c..dcb5acb 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -765,7 +765,14 @@ _bt_getbuf(Relation rel, BlockNumber blkno, int access)
 		/* Read an existing block of the relation */
 		buf = ReadBuffer(rel, blkno);
 		LockBuffer(buf, access);
-		_bt_checkpage(rel, buf);
+
+		/* global temp table may be not yet initialized for this backend. */
+		if (RELATION_IS_GLOBAL_TEMP(rel) &&
+			blkno == BTREE_METAPAGE &&
+			PageIsNew(BufferGetPage(buf)))
+			_bt_initmetapage(BufferGetPage(buf), P_NONE, 0);
+		else
+			_bt_checkpage(rel, buf);
 	}
 	else
 	{
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 77ad765..9ff98ff 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6319,6 +6319,10 @@ StartupXLOG(void)
 	else
 		recoveryTargetTLI = ControlFile->checkPointCopy.ThisTimeLineID;
 
+	/* clean temp relation files */
+	if (max_active_gtt > 0)
+		RemovePgTempFiles();
+
 	/*
 	 * Check for signal files, and if so set up state for offline recovery
 	 */
diff --git a/src/backend/catalog/Makefile b/src/backend/catalog/Makefile
index 8bece07..470683b 100644
--- a/src/backend/catalog/Makefile
+++ b/src/backend/catalog/Makefile
@@ -21,6 +21,8 @@ OBJS = catalog.o dependency.o heap.o index.o indexing.o namespace.o aclchk.o \
 	   pg_db_role_setting.o pg_shdepend.o pg_subscription.o pg_type.o \
 	   storage.o toasting.o
 
+OBJS += storage_gtt.o
+
 BKIFILES = postgres.bki postgres.description postgres.shdescription
 
 include $(top_srcdir)/src/backend/common.mk
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index a065419..db86aa6 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -406,7 +406,9 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class, char relpersistence)
 
 	switch (relpersistence)
 	{
+		/* global temp table is same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			break;
 		case RELPERSISTENCE_UNLOGGED:
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index b8b4768..832a3f1 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -61,6 +61,7 @@
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "commands/tablecmds.h"
 #include "commands/typecmds.h"
 #include "executor/executor.h"
@@ -100,6 +101,7 @@ static void AddNewRelationTuple(Relation pg_class_desc,
 								Oid reloftype,
 								Oid relowner,
 								char relkind,
+								char relpersistence,
 								TransactionId relfrozenxid,
 								TransactionId relminmxid,
 								Datum relacl,
@@ -406,6 +408,10 @@ heap_create(const char *relname,
 									 relpersistence,
 									 relkind);
 
+	/* global temp table not create storage file when catalog create */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		create_storage = false;
+
 	/*
 	 * Have the storage manager create the relation's disk file, if needed.
 	 *
@@ -429,7 +435,7 @@ heap_create(const char *relname,
 
 			case RELKIND_INDEX:
 			case RELKIND_SEQUENCE:
-				RelationCreateStorage(rel->rd_node, relpersistence);
+				RelationCreateStorage(rel->rd_node, relpersistence, rel);
 				break;
 
 			case RELKIND_RELATION:
@@ -926,6 +932,7 @@ AddNewRelationTuple(Relation pg_class_desc,
 					Oid reloftype,
 					Oid relowner,
 					char relkind,
+					char relpersistence,
 					TransactionId relfrozenxid,
 					TransactionId relminmxid,
 					Datum relacl,
@@ -964,8 +971,18 @@ AddNewRelationTuple(Relation pg_class_desc,
 			break;
 	}
 
-	new_rel_reltup->relfrozenxid = relfrozenxid;
-	new_rel_reltup->relminmxid = relminmxid;
+	/* global temp table not remember transaction info in catalog */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		new_rel_reltup->relfrozenxid = InvalidTransactionId;
+		new_rel_reltup->relminmxid = InvalidMultiXactId;
+	}
+	else
+	{
+		new_rel_reltup->relfrozenxid = relfrozenxid;
+		new_rel_reltup->relminmxid = relminmxid;
+	}
+
 	new_rel_reltup->relowner = relowner;
 	new_rel_reltup->reltype = new_type_oid;
 	new_rel_reltup->reloftype = reloftype;
@@ -1327,6 +1344,7 @@ heap_create_with_catalog(const char *relname,
 						reloftypeid,
 						ownerid,
 						relkind,
+						relpersistence,
 						relfrozenxid,
 						relminmxid,
 						PointerGetDatum(relacl),
@@ -1411,11 +1429,15 @@ heap_create_with_catalog(const char *relname,
 	 */
 	StoreConstraints(new_rel_desc, cooked_constraints, is_internal);
 
-	/*
-	 * If there's a special on-commit action, remember it
-	 */
-	if (oncommit != ONCOMMIT_NOOP)
-		register_on_commit_action(relid, oncommit);
+	/* global temp table register action when storage init */
+	if (relpersistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		/*
+		 * If there's a special on-commit action, remember it
+		 */
+		if (oncommit != ONCOMMIT_NOOP)
+			register_on_commit_action(relid, oncommit);
+	}
 
 	/*
 	 * ok, the relation has been cataloged, so close our relations and return
@@ -1907,6 +1929,13 @@ heap_drop_with_catalog(Oid relid)
 	if (relid == defaultPartOid)
 		update_default_partition_oid(parentOid, InvalidOid);
 
+	/* We allow to drop global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (is_other_backend_use_gtt(rel->rd_node))
+			elog(ERROR, "can not drop relation when other backend attached this global temp table");
+	}
+
 	/*
 	 * Schedule unlinking of the relation's physical files at commit.
 	 */
@@ -3133,9 +3162,10 @@ RemoveStatistics(Oid relid, AttrNumber attnum)
  *
  * The routine will truncate and then reconstruct the indexes on
  * the specified relation.  Caller must hold exclusive lock on rel.
+ *
  */
 static void
-RelationTruncateIndexes(Relation heapRelation)
+RelationTruncateIndexes(Relation heapRelation, LOCKMODE lockmode)
 {
 	ListCell   *indlist;
 
@@ -3147,7 +3177,7 @@ RelationTruncateIndexes(Relation heapRelation)
 		IndexInfo  *indexInfo;
 
 		/* Open the index relation; use exclusive lock, just to be sure */
-		currentIndex = index_open(indexId, AccessExclusiveLock);
+		currentIndex = index_open(indexId, lockmode);
 
 		/* Fetch info needed for index_build */
 		indexInfo = BuildIndexInfo(currentIndex);
@@ -3186,8 +3216,13 @@ heap_truncate(List *relids)
 	{
 		Oid			rid = lfirst_oid(cell);
 		Relation	rel;
+		LOCKMODE	lockmode = AccessExclusiveLock;
 
-		rel = table_open(rid, AccessExclusiveLock);
+		/* truncate global temp table only need RowExclusiveLock */
+		if (get_rel_persistence(rid) == RELPERSISTENCE_GLOBAL_TEMP)
+			lockmode = RowExclusiveLock;
+
+		rel = table_open(rid, lockmode);
 		relations = lappend(relations, rel);
 	}
 
@@ -3220,6 +3255,8 @@ void
 heap_truncate_one_rel(Relation rel)
 {
 	Oid			toastrelid;
+	LOCKMODE	lockmode = AccessExclusiveLock;
+	bool		truncate_toastrel = false;
 
 	/*
 	 * Truncate the relation.  Partitioned tables have no storage, so there is
@@ -3228,23 +3265,40 @@ heap_truncate_one_rel(Relation rel)
 	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 		return;
 
+	toastrelid = rel->rd_rel->reltoastrelid;
+
+	/*
+	 * Truncate global temp table only need RowExclusiveLock
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		lockmode = RowExclusiveLock;
+		if (OidIsValid(toastrelid) &&
+			gtt_storage_attached(toastrelid))
+			truncate_toastrel = true;
+	}
+	else if (OidIsValid(toastrelid))
+		truncate_toastrel = true;
+
 	/* Truncate the underlying relation */
 	table_relation_nontransactional_truncate(rel);
 
 	/* If the relation has indexes, truncate the indexes too */
-	RelationTruncateIndexes(rel);
+	RelationTruncateIndexes(rel, lockmode);
 
 	/* If there is a toast table, truncate that too */
-	toastrelid = rel->rd_rel->reltoastrelid;
-	if (OidIsValid(toastrelid))
+	if (truncate_toastrel)
 	{
-		Relation	toastrel = table_open(toastrelid, AccessExclusiveLock);
+		Relation	toastrel = table_open(toastrelid, lockmode);
 
 		table_relation_nontransactional_truncate(toastrel);
-		RelationTruncateIndexes(toastrel);
+		RelationTruncateIndexes(toastrel, lockmode);
 		/* keep the lock... */
 		table_close(toastrel, NoLock);
 	}
+
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		up_gtt_relstats(rel, 0, 0, 0, RecentXmin, InvalidMultiXactId);
 }
 
 /*
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 4f54631..163128d 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -52,6 +52,7 @@
 #include "catalog/pg_trigger.h"
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
+#include "catalog/storage_gtt.h"
 #include "commands/event_trigger.h"
 #include "commands/progress.h"
 #include "commands/tablecmds.h"
@@ -879,6 +880,26 @@ index_create(Relation heapRelation,
 						indexRelationName, RelationGetRelationName(heapRelation))));
 	}
 
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		if (accessMethodObjectId != BTREE_AM_OID)
+			elog(ERROR, "only support btree index on global temp table");
+
+		/* We allow to create index on global temp table only this session use it */
+		if (is_other_backend_use_gtt(heapRelation->rd_node))
+			elog(ERROR, "can not create index when have other backend attached this global temp table");
+
+		/* No support create index on global temp table use concurrent mode yet */
+		if (concurrent)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("cannot create indexes on global temporary tables using concurrent mode")));
+
+		/* if global temp table not init storage, then skip build index */
+		if (!gtt_storage_attached(heapRelation->rd_node.relNode))
+			flags |= INDEX_CREATE_SKIP_BUILD;
+	}
+
 	/*
 	 * construct tuple descriptor for index tuples
 	 */
@@ -2040,6 +2061,13 @@ index_drop(Oid indexId, bool concurrent, bool concurrent_lock_mode)
 	 */
 	CheckTableNotInUse(userIndexRelation, "DROP INDEX");
 
+	/* We allow to drop index on global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(userHeapRelation))
+	{
+		if (is_other_backend_use_gtt(userHeapRelation->rd_node))
+			elog(ERROR, "can not drop index when other backend attached this global temp table");
+	}
+
 	/*
 	 * Drop Index Concurrently is more or less the reverse process of Create
 	 * Index Concurrently.
@@ -2699,20 +2727,29 @@ index_update_stats(Relation rel,
 		else					/* don't bother for indexes */
 			relallvisible = 0;
 
-		if (rd_rel->relpages != (int32) relpages)
+		/* update index stats into localhash for global temp table */
+		if (RELATION_IS_GLOBAL_TEMP(rel))
 		{
-			rd_rel->relpages = (int32) relpages;
-			dirty = true;
+			up_gtt_relstats(rel, relpages, reltuples, relallvisible,
+							InvalidTransactionId, InvalidMultiXactId);
 		}
-		if (rd_rel->reltuples != (float4) reltuples)
-		{
-			rd_rel->reltuples = (float4) reltuples;
-			dirty = true;
-		}
-		if (rd_rel->relallvisible != (int32) relallvisible)
+		else
 		{
-			rd_rel->relallvisible = (int32) relallvisible;
-			dirty = true;
+			if (rd_rel->relpages != (int32) relpages)
+			{
+				rd_rel->relpages = (int32) relpages;
+				dirty = true;
+			}
+			if (rd_rel->reltuples != (float4) reltuples)
+			{
+				rd_rel->reltuples = (float4) reltuples;
+				dirty = true;
+			}
+			if (rd_rel->relallvisible != (int32) relallvisible)
+			{
+				rd_rel->relallvisible = (int32) relallvisible;
+				dirty = true;
+			}
 		}
 	}
 
@@ -2827,6 +2864,13 @@ index_build(Relation heapRelation,
 		pgstat_progress_update_multi_param(6, index, val);
 	}
 
+	/* POALR */
+	if (RELATION_IS_GLOBAL_TEMP(indexRelation))
+	{
+		if (!gtt_storage_attached(indexRelation->rd_node.relNode))
+			RelationCreateStorage(indexRelation->rd_node, RELPERSISTENCE_GLOBAL_TEMP, indexRelation);
+	}
+
 	/*
 	 * Call the access method's build procedure
 	 */
@@ -3159,12 +3203,22 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	/*
 	 * Scan the index and gather up all the TIDs into a tuplesort object.
 	 */
+	memset(&ivinfo, 0, sizeof(IndexVacuumInfo));
 	ivinfo.index = indexRelation;
 	ivinfo.analyze_only = false;
 	ivinfo.report_progress = true;
 	ivinfo.estimated_count = true;
 	ivinfo.message_level = DEBUG2;
-	ivinfo.num_heap_tuples = heapRelation->rd_rel->reltuples;
+
+	/* get relstats abort global temp table from hashtable, not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		get_gtt_relstats(RelationGetRelid(heapRelation),
+						NULL, &ivinfo.num_heap_tuples, NULL,
+						NULL, NULL);
+	}
+	else
+		ivinfo.num_heap_tuples = heapRelation->rd_rel->reltuples;
 	ivinfo.strategy = NULL;
 
 	/*
@@ -3422,6 +3476,15 @@ reindex_index(Oid indexId, bool skip_constraint_checks, char persistence,
 				 errmsg("cannot reindex temporary tables of other sessions")));
 
 	/*
+	 * Because global temp table cannot change relfilenode
+	 * no support reindex on global temp table yet.
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(iRel))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot reindex global temporary tables")));
+
+	/*
 	 * Also check for active uses of the index in the current transaction; we
 	 * don't want to reindex underneath an open indexscan.
 	 */
diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index 8d0896c..4c04833 100644
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -647,6 +647,13 @@ RangeVarAdjustRelationPersistence(RangeVar *newRelation, Oid nspid)
 							 errmsg("cannot create temporary relation in non-temporary schema")));
 			}
 			break;
+		/* global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			if (isAnyTempNamespace(nspid))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+						 errmsg("cannot create global temp relations in temporary schemas")));
+			break;
 		case RELPERSISTENCE_PERMANENT:
 			if (isTempOrTempToastNamespace(nspid))
 				newRelation->relpersistence = RELPERSISTENCE_TEMP;
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index 3cc886f..6295f81 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -28,6 +28,7 @@
 #include "access/xlogutils.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "storage/freespace.h"
 #include "storage/smgr.h"
 #include "utils/memutils.h"
@@ -74,9 +75,10 @@ static PendingRelDelete *pendingDeletes = NULL; /* head of linked list */
  *
  * This function is transactional. The creation is WAL-logged, and if the
  * transaction aborts later on, the storage will be destroyed.
+ *
  */
 SMgrRelation
-RelationCreateStorage(RelFileNode rnode, char relpersistence)
+RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel)
 {
 	PendingRelDelete *pending;
 	SMgrRelation srel;
@@ -86,6 +88,8 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	switch (relpersistence)
 	{
 		case RELPERSISTENCE_TEMP:
+		/* global temp table use same storage strategy as local temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			needs_wal = false;
 			break;
@@ -118,6 +122,10 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	pending->next = pendingDeletes;
 	pendingDeletes = pending;
 
+	/* remember global temp table storage info to localhash */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP && rel)
+		remember_gtt_storage_info(rnode, rel);
+
 	return srel;
 }
 
@@ -455,8 +463,15 @@ smgrDoPendingDeletes(bool isCommit)
 		smgrdounlinkall(srels, nrels, false);
 
 		for (i = 0; i < nrels; i++)
+		{
 			smgrclose(srels[i]);
 
+			/* clean global temp table flags when transaction commit or rollback */
+			if (SmgrIsTemp(srels[i]) && 
+				gtt_storage_attached(srels[i]->smgr_rnode.node.relNode))
+				forget_gtt_storage_info(srels[i]->smgr_rnode.node.relNode);
+		}
+
 		pfree(srels);
 	}
 }
diff --git a/src/backend/catalog/storage_gtt.c b/src/backend/catalog/storage_gtt.c
new file mode 100644
index 0000000..37a8a97
--- /dev/null
+++ b/src/backend/catalog/storage_gtt.c
@@ -0,0 +1,814 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.c
+ *	  code to create and destroy physical storage for global temparary table
+ *
+ * IDENTIFICATION
+ *	  src/backend/catalog/storage_gtt.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/visibilitymap.h"
+#include "access/xact.h"
+#include "access/xlog.h"
+#include "access/xloginsert.h"
+#include "access/xlogutils.h"
+#include "access/htup_details.h"
+#include "access/multixact.h"
+#include "catalog/storage.h"
+#include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/heap.h"
+#include "commands/tablecmds.h"
+#include "nodes/primnodes.h"
+#include "nodes/pg_list.h"
+#include "miscadmin.h"
+#include "storage/freespace.h"
+#include "storage/smgr.h"
+#include "storage/ipc.h"
+#include "storage/proc.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "utils/memutils.h"
+#include "utils/rel.h"
+#include "utils/hsearch.h"
+#include "utils/catcache.h"
+#include <utils/relcache.h>
+#include "utils/inval.h"
+#include "utils/guc.h"
+#include "utils/guc.h"
+
+
+/* Copy from bitmapset.c, because gtt used the function in bitmapset.c */
+#define WORDNUM(x)	((x) / BITS_PER_BITMAPWORD)
+#define BITNUM(x)	((x) % BITS_PER_BITMAPWORD)
+
+#define BITMAPSET_SIZE(nwords)	\
+	(offsetof(Bitmapset, words) + (nwords) * sizeof(bitmapword))
+
+static bool gtt_cleaner_exit_registered = false;
+static HTAB *gtt_storage_local_hash = NULL;
+static HTAB *active_gtt_shared_hash = NULL;
+static MemoryContext gtt_relstats_context = NULL;
+
+/* relfrozenxid of all gtts in the current session */
+static List *gtt_session_relfrozenxid_list = NIL;
+static TransactionId gtt_session_frozenxid = InvalidTransactionId;
+
+typedef struct gtt_ctl_data
+{
+	LWLock			lock;
+	int			max_entry;
+	int			entry_size;
+}gtt_ctl_data;
+
+static gtt_ctl_data *gtt_shared_ctl = NULL;
+
+typedef struct
+{
+	RelFileNode	rnode;
+	Bitmapset	*map;
+	/* bitmap data */
+} gtt_shared_hash_entry;
+
+typedef struct
+{
+	Oid			relid;
+
+	Oid			spcnode;
+	/* pg_class stat */
+	int32		relpages;
+	float4		reltuples;
+	int32		relallvisible;
+	TransactionId relfrozenxid;
+	TransactionId relminmxid;
+	char		relkind;
+	bool		on_commit_delete;
+
+	/* pg_statistic */
+	int			natts;
+	int			*attnum;
+	HeapTuple	*att_stat_tups;
+} gtt_local_hash_entry;
+
+static Size action_gtt_shared_hash_entry_size(void);
+static void gtt_storage_checkin(RelFileNode rnode);
+static void gtt_storage_checkout(RelFileNode rnode, bool skiplock);
+static void gtt_storage_removeall(int code, Datum arg);
+static void insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid);
+static void remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid);
+static void set_gtt_session_relfrozenxid(void);
+
+static Size
+action_gtt_shared_hash_entry_size(void)
+{
+	int 	wordnum;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	wordnum = WORDNUM(MaxBackends + 1);
+	hash_entry_size += MAXALIGN(sizeof(gtt_shared_hash_entry));
+	hash_entry_size += MAXALIGN(BITMAPSET_SIZE(wordnum + 1));
+
+	return hash_entry_size;
+}
+
+Size
+active_gtt_shared_hash_size(void)
+{
+	Size	size = 0;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	size = MAXALIGN(sizeof(gtt_ctl_data));
+	hash_entry_size = action_gtt_shared_hash_entry_size();
+	size += hash_estimate_size(max_active_gtt, hash_entry_size);
+
+	return size;
+}
+
+void
+active_gtt_shared_hash_init(void)
+{
+	HASHCTL info;
+	bool	found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	gtt_shared_ctl =
+		ShmemInitStruct("gtt_shared_ctl",
+						sizeof(gtt_ctl_data),
+						&found);
+
+	if (!found)
+	{
+		LWLockRegisterTranche(LWTRANCHE_GTT_CTL, "gtt_shared_ctl");
+		LWLockInitialize(&gtt_shared_ctl->lock, LWTRANCHE_GTT_CTL);
+		gtt_shared_ctl->max_entry = max_active_gtt;
+		gtt_shared_ctl->entry_size = action_gtt_shared_hash_entry_size();
+	}
+
+	info.keysize = sizeof(RelFileNode);
+	info.entrysize = gtt_shared_ctl->entry_size;
+	active_gtt_shared_hash =
+		ShmemInitHash("active gtt shared hash",
+						gtt_shared_ctl->max_entry,
+						gtt_shared_ctl->max_entry,
+						&info, HASH_ELEM | HASH_BLOBS | HASH_FIXED_SIZE);
+}
+
+static void
+gtt_storage_checkin(RelFileNode rnode)
+{
+	gtt_shared_hash_entry	*entry;
+	bool			found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+	entry = (gtt_shared_hash_entry *) hash_search(active_gtt_shared_hash,
+												&rnode, HASH_ENTER_NULL, &found);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		ereport(ERROR,
+				(errcode(ERRCODE_OUT_OF_MEMORY),
+				 errmsg("out of shared memory"),
+				 errhint("You might need to increase max_active_gtt.")));
+	}
+
+	if (found == false)
+	{
+		int			wordnum;
+
+		entry->map = (Bitmapset *)((char *)entry + MAXALIGN(sizeof(gtt_shared_hash_entry)));
+		wordnum = WORDNUM(MaxBackends + 1);
+		memset(entry->map, 0, BITMAPSET_SIZE(wordnum + 1));
+		entry->map->nwords = wordnum + 1;
+	}
+
+	bms_add_member(entry->map, MyBackendId);
+	LWLockRelease(&gtt_shared_ctl->lock);
+}
+
+static void
+gtt_storage_checkout(RelFileNode rnode, bool skiplock)
+{
+	gtt_shared_hash_entry	*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (!skiplock)
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(rnode), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		if (!skiplock)
+			LWLockRelease(&gtt_shared_ctl->lock);
+
+		elog(WARNING, "relfilenode %u/%u/%u not exist in gtt shared hash when forget",
+						rnode.dbNode, rnode.spcNode, rnode.relNode);
+		return;
+	}
+
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+	bms_del_member(entry->map, MyBackendId);
+
+	if (bms_is_empty(entry->map))
+	{
+		if (!hash_search(active_gtt_shared_hash, &rnode, HASH_REMOVE, NULL))
+			elog(PANIC, "gtt shared hash table corrupted");
+	}
+
+	if (!skiplock)
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+	return;
+}
+
+Bitmapset *
+copy_active_gtt_bitmap(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	Bitmapset	*map_copy = NULL;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return NULL;
+	}
+
+	Assert(entry->map);
+	if (!bms_is_empty(entry->map))
+		map_copy = bms_copy(entry->map);
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return map_copy;
+}
+
+bool
+is_other_backend_use_gtt(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	bool		in_use = false;
+	int			num_use = 0;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return false;
+	}
+
+	Assert(entry->map);
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+
+	num_use = bms_num_members(entry->map);
+	if (num_use == 0)
+		in_use = false;
+	else if (num_use == 1)
+	{
+		if(bms_is_member(MyBackendId, entry->map))
+			in_use = false;
+		else
+			in_use = true;
+	}
+	else
+		in_use = true;
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return in_use;
+}
+
+void
+remember_gtt_storage_info(RelFileNode rnode, Relation rel)
+{
+	gtt_local_hash_entry	*entry;
+	MemoryContext			oldcontext;
+	Oid			relid = rnode.relNode;
+	bool		found;
+
+	if (max_active_gtt <= 0)
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("Global temporary table feature is disable"),
+			 errhint("You might need to increase max_active_gtt to enable this feature.")));
+
+	if (RecoveryInProgress())
+		elog(ERROR, "readonly mode not support access global temp table yet");
+
+	if (gtt_storage_local_hash == NULL)
+	{
+#define GTT_LOCAL_HASH_SIZE		1024
+		/* First time through: initialize the hash table */
+		HASHCTL		ctl;
+
+		MemSet(&ctl, 0, sizeof(ctl));
+		ctl.keysize = sizeof(Oid);
+		ctl.entrysize = sizeof(gtt_local_hash_entry);
+		gtt_storage_local_hash =
+			hash_create("global temp relation table",
+						GTT_LOCAL_HASH_SIZE,
+						&ctl, HASH_ELEM | HASH_BLOBS);
+
+		if (!CacheMemoryContext)
+			CreateCacheMemoryContext();
+
+		gtt_relstats_context =
+			AllocSetContextCreate(CacheMemoryContext,
+							"gtt relstats context",
+							ALLOCSET_DEFAULT_SIZES);
+	}
+
+	/* Look up or create an entry */
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_ENTER, &found);
+
+	if (found)
+	{
+		elog(ERROR, "backend %d relid %u already exists in global temp table local hash",
+					MyBackendId, relid);
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+
+	entry->spcnode = rnode.spcNode;
+	entry->relpages = 0;
+	entry->reltuples = 0;
+	entry->relallvisible = 0;
+	entry->relkind = rel->rd_rel->relkind;
+	/* only heap contain transaction information */
+	if (entry->relkind == RELKIND_RELATION)
+	{
+		int natts = RelationGetNumberOfAttributes(rel);
+		entry->natts = natts;
+		entry->attnum = palloc0(sizeof(int) * natts);
+		entry->att_stat_tups = palloc0(sizeof(HeapTuple) * natts);
+
+		if (RELATION_GTT_ON_COMMIT_DELETE(rel))
+		{
+			entry->on_commit_delete = true;
+			register_on_commit_action(rel->rd_node.relNode, ONCOMMIT_DELETE_ROWS);
+		}
+
+		entry->relfrozenxid = RecentXmin;
+		entry->relminmxid = GetOldestMultiXactId();
+		insert_gtt_relfrozenxid_to_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+		gtt_storage_checkin(rnode);
+	}
+	else
+	{
+		entry->natts = 0;
+		entry->attnum = 0;
+		entry->att_stat_tups = NULL;
+		entry->on_commit_delete = false;
+		entry->relfrozenxid = 0;
+		entry->relminmxid = 0;
+	}
+
+	MemoryContextSwitchTo(oldcontext);
+
+	if (!gtt_cleaner_exit_registered)
+	{
+		before_shmem_exit(gtt_storage_removeall, 0);
+		gtt_cleaner_exit_registered = true;
+	}
+
+	return;
+}
+
+void
+forget_gtt_storage_info(Oid relid)
+{
+	gtt_local_hash_entry		*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+				(void *) &(relid), HASH_FIND, NULL);
+
+	if (entry && entry->relkind == RELKIND_RELATION)
+	{
+		RelFileNode rnode;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		gtt_storage_checkout(rnode, false);
+
+		Assert(TransactionIdIsNormal(entry->relfrozenxid));
+		remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+	}
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_REMOVE, NULL);
+
+	return;
+}
+
+/* is the storage file was created in this backend */
+bool
+gtt_storage_attached(Oid relid)
+{
+	bool found;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	if (gtt_storage_local_hash == NULL)
+		return false;
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_FIND, &found);
+
+	return found;
+}
+
+static void
+gtt_storage_removeall(int code, Datum arg)
+{
+	HASH_SEQ_STATUS				status;
+	gtt_local_hash_entry		*entry;
+	int			nrels = 0,
+				maxrels = 0;
+	SMgrRelation	*srels = NULL;
+	RelFileNode		*rnodes = NULL;
+	char			*relkinds = NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	hash_seq_init(&status, gtt_storage_local_hash);
+	while ((entry = (gtt_local_hash_entry *) hash_seq_search(&status)) != NULL)
+	{
+		SMgrRelation srel;
+		RelFileNode rnode;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		srel = smgropen(rnode, MyBackendId);
+
+		/* allocate the initial array, or extend it, if needed */
+		if (maxrels == 0)
+		{
+			maxrels = 32;
+			srels = palloc(sizeof(SMgrRelation) * maxrels);
+			rnodes = palloc(sizeof(RelFileNode) * maxrels);
+			relkinds = palloc(sizeof(char) * maxrels);
+		}
+		else if (maxrels <= nrels)
+		{
+			maxrels *= 2;
+			srels = repalloc(srels, sizeof(SMgrRelation) * maxrels);
+			rnodes = repalloc(rnodes, sizeof(RelFileNode) * maxrels);
+			relkinds = repalloc(relkinds, sizeof(char) * maxrels);
+		}
+
+		srels[nrels] = srel;
+		rnodes[nrels] = rnode;
+		relkinds[nrels] = entry->relkind;
+		nrels++;
+	}
+
+	if (nrels > 0)
+	{
+		int i;
+
+		smgrdounlinkall(srels, nrels, false);
+
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+		for (i = 0; i < nrels; i++)
+		{
+			smgrclose(srels[i]);
+			if (relkinds[i] == RELKIND_RELATION)
+				gtt_storage_checkout(rnodes[i], true);
+		}
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+		pfree(srels);
+		pfree(rnodes);
+		pfree(relkinds);
+	}
+
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;
+
+	return;
+}
+
+/*
+ * Update global temp table relstats(relpage/reltuple/relallvisible) 
+ * to local hashtable
+ */
+void
+up_gtt_relstats(Relation relation,
+					BlockNumber num_pages,
+					double num_tuples,
+					BlockNumber num_all_visible_pages,
+					TransactionId relfrozenxid,
+					TransactionId relminmxid)
+{
+	Oid		relid = RelationGetRelid(relation);
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	Assert(entry->spcnode);
+
+	if (num_pages >= 0 &&
+		entry->relpages != (int32)num_pages)
+		entry->relpages = (int32)num_pages;
+
+	if (num_tuples >= 0 &&
+		num_tuples != (float4)entry->reltuples)
+		entry->reltuples = (float4)num_tuples;
+
+	/* only heap contain transaction information and relallvisible */
+	if (entry->relkind == RELKIND_RELATION)
+	{
+		if (entry->relallvisible >= 0 &&
+			entry->relallvisible != (int32)num_all_visible_pages)
+		{
+			entry->relallvisible = (int32)num_all_visible_pages;
+		}
+
+		if (TransactionIdIsNormal(relfrozenxid) &&
+			entry->relfrozenxid != relfrozenxid &&
+			(TransactionIdPrecedes(entry->relfrozenxid, relfrozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(), entry->relfrozenxid)))
+		{
+			remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+			entry->relfrozenxid = relfrozenxid;
+			insert_gtt_relfrozenxid_to_ordered_list(relfrozenxid);
+			set_gtt_session_relfrozenxid();
+		}
+
+		if (MultiXactIdIsValid(relminmxid) &&
+			entry->relminmxid != relminmxid &&
+			(MultiXactIdPrecedes(entry->relminmxid, relminmxid) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), entry->relminmxid)))
+		{
+			entry->relminmxid = relminmxid;
+		}
+	}
+
+	return;
+}
+
+/*
+ * Search global temp table relstats(relpage/reltuple/relallvisible) 
+ * from local hashtable.
+ */
+void
+get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+				BlockNumber *relallvisible, TransactionId *relfrozenxid,
+				TransactionId *relminmxid)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	Assert(entry->relid == relid);
+
+	if (relpages)
+		*relpages = entry->relpages;
+
+	if (reltuples)
+		*reltuples = entry->reltuples;
+
+	if (relallvisible)
+		*relallvisible = entry->relallvisible;
+
+	if (relfrozenxid)
+		*relfrozenxid = entry->relfrozenxid;
+
+	if (relminmxid)
+		*relminmxid = entry->relminmxid;
+
+	return;
+}
+
+/*
+ * Update global temp table statistic info(definition is same as pg_statistic)
+ * to local hashtable where ananyze global temp table
+ */
+void
+up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+					TupleDesc tupleDescriptor, Datum *values, bool *isnull)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	MemoryContext			oldcontext;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	if (entry->relkind != RELKIND_RELATION)
+	{
+		elog(WARNING, "oid %u not a relation", reloid);
+		return;
+	}
+
+	/* todo */
+	if (entry->natts < natts)
+	{
+		elog(WARNING, "reloid %u not support update attstat after add colunm", reloid);
+		return;
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	Assert(entry->relid == reloid);
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == 0)
+		{
+			entry->attnum[i] = attnum;
+			break;
+		}
+		else if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			heap_freetuple(entry->att_stat_tups[i]);
+			entry->att_stat_tups[i] = NULL;
+			break;
+		}
+	}
+
+	Assert(i < entry->natts);
+	Assert(entry->att_stat_tups[i] == NULL);
+	entry->att_stat_tups[i] = heap_form_tuple(tupleDescriptor, values, isnull);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+/*
+ * Search global temp table statistic info(definition is same as pg_statistic)
+ * from local hashtable.
+ */
+HeapTuple
+get_gtt_att_statistic(Oid reloid, int attnum, bool inh)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return NULL;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return NULL;
+
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			return entry->att_stat_tups[i];
+		}
+	}
+
+	return NULL;
+}
+
+void
+release_gtt_statistic_cache(HeapTuple tup)
+{
+	/* do nothing */
+	return;
+}
+
+static void
+insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid)
+{
+	MemoryContext	oldcontext;
+	ListCell	*prev;
+
+	Assert(TransactionIdIsNormal(relfrozenxid));
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	/* Does the datum belong at the front? */
+	if (gtt_session_relfrozenxid_list == NIL ||
+		TransactionIdFollowsOrEquals(relfrozenxid,
+			linitial_oid(gtt_session_relfrozenxid_list)))
+	{
+		gtt_session_relfrozenxid_list =
+			lcons_oid(relfrozenxid, gtt_session_relfrozenxid_list);
+		MemoryContextSwitchTo(oldcontext);
+
+		return;
+	}
+	/* No, so find the entry it belongs after */
+	prev = list_head(gtt_session_relfrozenxid_list);
+	for (;;)
+	{
+		ListCell   *curr = lnext(prev);
+
+		if (curr == NULL ||
+			TransactionIdFollowsOrEquals(relfrozenxid, lfirst_oid(curr)))
+			break;	/* it belongs after 'prev', before 'curr' */
+
+		prev = curr;
+	}
+	/* Insert datum into list after 'prev' */
+	lappend_cell_oid(gtt_session_relfrozenxid_list, prev, relfrozenxid);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+static void
+remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid)
+{
+	gtt_session_relfrozenxid_list =
+		list_delete_oid(gtt_session_relfrozenxid_list, relfrozenxid);
+}
+
+static void
+set_gtt_session_relfrozenxid(void)
+{
+	TransactionId gtt_frozenxid = InvalidTransactionId;
+
+	if (gtt_session_relfrozenxid_list)
+		gtt_frozenxid = llast_oid(gtt_session_relfrozenxid_list);
+
+	gtt_session_frozenxid = gtt_frozenxid;
+	if (MyProc->session_gtt_frozenxid != gtt_frozenxid)
+		MyProc->session_gtt_frozenxid = gtt_frozenxid;
+}
+
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index faabbeb..d79535d 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -65,6 +65,7 @@
 #include "utils/syscache.h"
 #include "utils/timestamp.h"
 
+#include "catalog/storage_gtt.h"
 
 /* Per-index data for ANALYZE */
 typedef struct AnlIndexData
@@ -102,7 +103,7 @@ static int	acquire_inherited_sample_rows(Relation onerel, int elevel,
 										  HeapTuple *rows, int targrows,
 										  double *totalrows, double *totaldeadrows);
 static void update_attstats(Oid relid, bool inh,
-							int natts, VacAttrStats **vacattrstats);
+							int natts, VacAttrStats **vacattrstats, char relpersistence);
 static Datum std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 static Datum ind_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 
@@ -563,14 +564,15 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 		 * pg_statistic for columns we didn't process, we leave them alone.)
 		 */
 		update_attstats(RelationGetRelid(onerel), inh,
-						attr_cnt, vacattrstats);
+						attr_cnt, vacattrstats, RelationGetRelPersistence(onerel));
 
 		for (ind = 0; ind < nindexes; ind++)
 		{
 			AnlIndexData *thisdata = &indexdata[ind];
 
 			update_attstats(RelationGetRelid(Irel[ind]), false,
-							thisdata->attr_cnt, thisdata->vacattrstats);
+							thisdata->attr_cnt, thisdata->vacattrstats,
+							RelationGetRelPersistence(Irel[ind]));
 		}
 
 		/*
@@ -647,11 +649,20 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 			IndexBulkDeleteResult *stats;
 			IndexVacuumInfo ivinfo;
 
+			memset(&ivinfo, 0, sizeof(IndexVacuumInfo));
 			ivinfo.index = Irel[ind];
 			ivinfo.analyze_only = true;
 			ivinfo.estimated_count = true;
 			ivinfo.message_level = elevel;
-			ivinfo.num_heap_tuples = onerel->rd_rel->reltuples;
+			/* get global temp relstats from localhash, not catalog */
+			if (RELATION_IS_GLOBAL_TEMP(onerel))
+			{
+				get_gtt_relstats(RelationGetRelid(onerel),
+								NULL, &ivinfo.num_heap_tuples, NULL,
+								NULL, NULL);
+			}
+			else
+				ivinfo.num_heap_tuples = onerel->rd_rel->reltuples;
 			ivinfo.strategy = vac_strategy;
 
 			stats = index_vacuum_cleanup(&ivinfo, NULL);
@@ -1414,7 +1425,7 @@ acquire_inherited_sample_rows(Relation onerel, int elevel,
  *		by taking a self-exclusive lock on the relation in analyze_rel().
  */
 static void
-update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
+update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats, char relpersistence)
 {
 	Relation	sd;
 	int			attno;
@@ -1516,31 +1527,45 @@ update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
 			}
 		}
 
-		/* Is there already a pg_statistic tuple for this attribute? */
-		oldtup = SearchSysCache3(STATRELATTINH,
-								 ObjectIdGetDatum(relid),
-								 Int16GetDatum(stats->attr->attnum),
-								 BoolGetDatum(inh));
-
-		if (HeapTupleIsValid(oldtup))
+		/* Update column statistic to localhash, not catalog */
+		if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		{
-			/* Yes, replace it */
-			stup = heap_modify_tuple(oldtup,
-									 RelationGetDescr(sd),
-									 values,
-									 nulls,
-									 replaces);
-			ReleaseSysCache(oldtup);
-			CatalogTupleUpdate(sd, &stup->t_self, stup);
+			up_gtt_att_statistic(relid,
+								stats->attr->attnum,
+								inh,
+								natts,
+								RelationGetDescr(sd),
+								values,
+								nulls);
 		}
 		else
 		{
-			/* No, insert new tuple */
-			stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
-			CatalogTupleInsert(sd, stup);
-		}
+			/* Is there already a pg_statistic tuple for this attribute? */
+			oldtup = SearchSysCache3(STATRELATTINH,
+									 ObjectIdGetDatum(relid),
+									 Int16GetDatum(stats->attr->attnum),
+									 BoolGetDatum(inh));
+
+			if (HeapTupleIsValid(oldtup))
+			{
+				/* Yes, replace it */
+				stup = heap_modify_tuple(oldtup,
+										 RelationGetDescr(sd),
+										 values,
+										 nulls,
+										 replaces);
+				ReleaseSysCache(oldtup);
+				CatalogTupleUpdate(sd, &stup->t_self, stup);
+			}
+			else
+			{
+				/* No, insert new tuple */
+				stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
+				CatalogTupleInsert(sd, stup);
+			}
 
-		heap_freetuple(stup);
+			heap_freetuple(stup);
+		}
 	}
 
 	table_close(sd, RowExclusiveLock);
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index ebaec4f..356df7c 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -392,6 +392,12 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 					 errmsg("cannot vacuum temporary tables of other sessions")));
 	}
 
+	/* not support cluster global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(OldHeap))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support cluster global temporary tables yet")));
+
 	/*
 	 * Also check for active uses of the relation in the current transaction,
 	 * including open scans and pending AFTER trigger events.
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index a528241..66f4b10 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -2584,6 +2584,16 @@ ReindexMultipleTables(const char *objectName, ReindexObjectType objectKind,
 			!isTempNamespace(classtuple->relnamespace))
 			continue;
 
+		/* not support reindex on global temp table, so skip it */
+		if (classtuple->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			ereport(WARNING,
+				(errmsg("global temp table \"%s.%s\" skip reindexed",
+					get_namespace_name(get_rel_namespace(relid)),
+					get_rel_name(relid))));
+			continue;
+		}
+
 		/* Check user/system classification, and optionally skip */
 		if (objectKind == REINDEX_OBJECT_SYSTEM &&
 			!IsSystemClass(relid, classtuple))
diff --git a/src/backend/commands/lockcmds.c b/src/backend/commands/lockcmds.c
index 417d595..b9c3a40 100644
--- a/src/backend/commands/lockcmds.c
+++ b/src/backend/commands/lockcmds.c
@@ -107,7 +107,8 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
 	 * transaction.
 	 */
 	relpersistence = get_rel_persistence(relid);
-	if (relpersistence == RELPERSISTENCE_TEMP)
+	if (relpersistence == RELPERSISTENCE_TEMP ||
+		relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		MyXactFlags |= XACT_FLAGS_ACCESSEDTEMPNAMESPACE;
 
 	/* Check permissions. */
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 792ba56..7a42efd 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -48,6 +48,7 @@
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
 #include "catalog/toasting.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/defrem.h"
@@ -530,6 +531,7 @@ static void refuseDupeIndexAttach(Relation parentIdx, Relation partIdx,
 								  Relation partitionTbl);
 static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
+static bool has_oncommit_option(List *options);
 
 
 /* ----------------------------------------------------------------
@@ -575,6 +577,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	LOCKMODE	parentLockmode;
 	const char *accessMethod = NULL;
 	Oid			accessMethodId = InvalidOid;
+	bool		has_oncommit_clause = false;
 
 	/*
 	 * Truncate relname to appropriate length (probably a waste of time, as
@@ -585,8 +588,10 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Check consistency of arguments
 	 */
+	/* global temp table same as local temp table */
 	if (stmt->oncommit != ONCOMMIT_NOOP
-		&& stmt->relation->relpersistence != RELPERSISTENCE_TEMP)
+		&& !(stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+			 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 				 errmsg("ON COMMIT can only be used on temporary tables")));
@@ -616,12 +621,28 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	 * code.  This is needed because calling code might not expect untrusted
 	 * tables to appear in pg_temp at the front of its search path.
 	 */
-	if (stmt->relation->relpersistence == RELPERSISTENCE_TEMP
+	/* global temp table same as local temp table */
+	if ((stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+		 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		&& InSecurityRestrictedOperation())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 errmsg("cannot create temporary table within security-restricted operation")));
 
+	/* Not support partitioned or inherited global temp table yet */
+	if (stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		if (relkind == RELKIND_PARTITIONED_TABLE)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support create global temporary partition table yet")));
+
+		if (stmt->inhRelations)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support create global temporary inheritance table yet")));
+	}
+
 	/*
 	 * Determine the lockmode to use when scanning parents.  A self-exclusive
 	 * lock is needed here.
@@ -717,6 +738,40 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Parse and validate reloptions, if any.
 	 */
+	/* global temp table */
+	has_oncommit_clause = has_oncommit_option(stmt->options);
+	if (stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		if (has_oncommit_clause)
+		{
+			if (stmt->oncommit != ONCOMMIT_NOOP)
+				elog(ERROR, "can not defeine global temp table with on commit and with clause at same time");
+		}
+		else
+		{
+			DefElem *opt = makeNode(DefElem);
+
+			opt->type = T_DefElem;
+			opt->defnamespace = NULL;
+			opt->defname = "on_commit_delete_rows";
+			opt->defaction = DEFELEM_UNSPEC;
+
+			/* use reloptions to remember on commit clause */
+			if (stmt->oncommit == ONCOMMIT_DELETE_ROWS)
+				opt->arg  = (Node *)makeString("true");
+			else if (stmt->oncommit == ONCOMMIT_PRESERVE_ROWS)
+				opt->arg  = (Node *)makeString("false");
+			else if (stmt->oncommit == ONCOMMIT_NOOP)
+				opt->arg  = (Node *)makeString("true");
+			else
+				elog(ERROR, "global temp table not support on commit drop clause");
+
+			stmt->options = lappend(stmt->options, opt);
+		}
+	}
+	else if (has_oncommit_clause)
+		elog(ERROR, "regular table cannot specifie on_commit_delete_rows");
+
 	reloptions = transformRelOptions((Datum) 0, stmt->options, NULL, validnsps,
 									 true, false);
 
@@ -1772,7 +1827,8 @@ ExecuteTruncateGuts(List *explicit_rels, List *relids, List *relids_logged,
 		 * table or the current physical file to be thrown away anyway.
 		 */
 		if (rel->rd_createSubid == mySubid ||
-			rel->rd_newRelfilenodeSubid == mySubid)
+			rel->rd_newRelfilenodeSubid == mySubid ||
+			RELATION_IS_GLOBAL_TEMP(rel))
 		{
 			/* Immediate, non-rollbackable truncation is OK */
 			heap_truncate_one_rel(rel);
@@ -3332,6 +3388,13 @@ RenameRelationInternal(Oid myrelid, const char *newrelname, bool is_internal, bo
 	 * specially.
 	 */
 	targetrelation = relation_open(myrelid, is_index ? ShareUpdateExclusiveLock : AccessExclusiveLock);
+
+	/* not support rename global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(targetrelation))
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("not support rename global temporary tables yet")));
+
 	namespaceId = RelationGetNamespace(targetrelation);
 
 	/*
@@ -3501,6 +3564,14 @@ AlterTable(Oid relid, LOCKMODE lockmode, AlterTableStmt *stmt)
 	/* Caller is required to provide an adequate lock. */
 	rel = relation_open(relid, NoLock);
 
+	/* not support alter global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("not support alter global temporary tables yet")));
+	}
+
 	CheckTableNotInUse(rel, "ALTER TABLE");
 
 	ATController(stmt, rel, stmt->cmds, stmt->relation->inh, lockmode);
@@ -7651,6 +7722,13 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 				 errmsg("referenced relation \"%s\" is not a table",
 						RelationGetRelationName(pkrel))));
 
+	/* global temp table not support foreign key constraint yet */
+	if (RELATION_IS_GLOBAL_TEMP(pkrel))
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("referenced relation \"%s\" is not a global temp table",
+						RelationGetRelationName(pkrel))));
+
 	if (!allowSystemTableMods && IsSystemRelation(pkrel))
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -7690,6 +7768,12 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 						 errmsg("constraints on temporary tables must involve temporary tables of this session")));
 			break;
+		/* global temp table not support foreign key constraint yet */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					 errmsg("not support foreign key constraints on global temp table yet")));
+			break;
 	}
 
 	/*
@@ -12702,7 +12786,7 @@ index_copy_data(Relation rel, RelFileNode newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
@@ -14109,7 +14193,9 @@ ATPrepChangePersistence(Relation rel, bool toLogged)
 	 */
 	switch (rel->rd_rel->relpersistence)
 	{
+		/* global temp table same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("cannot change logged status of table \"%s\" because it is temporary",
@@ -16716,3 +16802,20 @@ ATDetachCheckNoForeignKeyRefs(Relation partition)
 		table_close(rel, NoLock);
 	}
 }
+
+static bool
+has_oncommit_option(List *options)
+{
+	ListCell   *listptr;
+
+	foreach(listptr, options)
+	{
+		DefElem    *def = (DefElem *) lfirst(listptr);
+
+		if (pg_strcasecmp(def->defname, "on_commit_delete_rows") == 0)
+			return true;
+	}
+
+	return false;
+}
+
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index ef275c0..c44fad8 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -35,6 +35,7 @@
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
 #include "catalog/pg_namespace.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
 #include "commands/vacuum.h"
@@ -1068,12 +1069,25 @@ vac_estimate_reltuples(Relation relation,
 					   BlockNumber scanned_pages,
 					   double scanned_tuples)
 {
-	BlockNumber old_rel_pages = relation->rd_rel->relpages;
-	double		old_rel_tuples = relation->rd_rel->reltuples;
+	BlockNumber old_rel_pages = 0;
+	double		old_rel_tuples = 0;
 	double		old_density;
 	double		unscanned_pages;
 	double		total_tuples;
 
+	/* get relstat from gtt local hash */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+	{
+		get_gtt_relstats(RelationGetRelid(relation),
+						&old_rel_pages, &old_rel_tuples, NULL,
+						NULL, NULL);
+	}
+	else
+	{
+		old_rel_pages = relation->rd_rel->relpages;
+		old_rel_tuples = relation->rd_rel->reltuples;
+	}
+
 	/* If we did scan the whole table, just use the count as-is */
 	if (scanned_pages >= total_pages)
 		return scanned_tuples;
@@ -1173,24 +1187,8 @@ vac_update_relstats(Relation relation,
 	/* Apply statistical updates, if any, to copied tuple */
 
 	dirty = false;
-	if (pgcform->relpages != (int32) num_pages)
-	{
-		pgcform->relpages = (int32) num_pages;
-		dirty = true;
-	}
-	if (pgcform->reltuples != (float4) num_tuples)
-	{
-		pgcform->reltuples = (float4) num_tuples;
-		dirty = true;
-	}
-	if (pgcform->relallvisible != (int32) num_all_visible_pages)
-	{
-		pgcform->relallvisible = (int32) num_all_visible_pages;
-		dirty = true;
-	}
 
 	/* Apply DDL updates, but not inside an outer transaction (see above) */
-
 	if (!in_outer_xact)
 	{
 		/*
@@ -1215,37 +1213,64 @@ vac_update_relstats(Relation relation,
 		}
 	}
 
-	/*
-	 * Update relfrozenxid, unless caller passed InvalidTransactionId
-	 * indicating it has no new data.
-	 *
-	 * Ordinarily, we don't let relfrozenxid go backwards: if things are
-	 * working correctly, the only way the new frozenxid could be older would
-	 * be if a previous VACUUM was done with a tighter freeze_min_age, in
-	 * which case we don't want to forget the work it already did.  However,
-	 * if the stored relfrozenxid is "in the future", then it must be corrupt
-	 * and it seems best to overwrite it with the cutoff we used this time.
-	 * This should match vac_update_datfrozenxid() concerning what we consider
-	 * to be "in the future".
-	 */
-	if (TransactionIdIsNormal(frozenxid) &&
-		pgcform->relfrozenxid != frozenxid &&
-		(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
-		 TransactionIdPrecedes(ReadNewTransactionId(),
-							   pgcform->relfrozenxid)))
+	/* global temp table remember relstats to localhash not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
 	{
-		pgcform->relfrozenxid = frozenxid;
-		dirty = true;
+		up_gtt_relstats(relation,
+						num_pages, num_tuples,
+						num_all_visible_pages,
+						frozenxid, minmulti);
 	}
-
-	/* Similarly for relminmxid */
-	if (MultiXactIdIsValid(minmulti) &&
-		pgcform->relminmxid != minmulti &&
-		(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
-		 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
+	else
 	{
-		pgcform->relminmxid = minmulti;
-		dirty = true;
+		if (pgcform->relpages != (int32) num_pages)
+		{
+			pgcform->relpages = (int32) num_pages;
+			dirty = true;
+		}
+		if (pgcform->reltuples != (float4) num_tuples)
+		{
+			pgcform->reltuples = (float4) num_tuples;
+			dirty = true;
+		}
+		if (pgcform->relallvisible != (int32) num_all_visible_pages)
+		{
+			pgcform->relallvisible = (int32) num_all_visible_pages;
+			dirty = true;
+		}
+
+		/*
+		 * Update relfrozenxid, unless caller passed InvalidTransactionId
+		 * indicating it has no new data.
+		 *
+		 * Ordinarily, we don't let relfrozenxid go backwards: if things are
+		 * working correctly, the only way the new frozenxid could be older would
+		 * be if a previous VACUUM was done with a tighter freeze_min_age, in
+		 * which case we don't want to forget the work it already did.  However,
+		 * if the stored relfrozenxid is "in the future", then it must be corrupt
+		 * and it seems best to overwrite it with the cutoff we used this time.
+		 * This should match vac_update_datfrozenxid() concerning what we consider
+		 * to be "in the future".
+		 */
+		if (TransactionIdIsNormal(frozenxid) &&
+			pgcform->relfrozenxid != frozenxid &&
+			(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(),
+								   pgcform->relfrozenxid)))
+		{
+			pgcform->relfrozenxid = frozenxid;
+			dirty = true;
+		}
+
+		/* Similarly for relminmxid */
+		if (MultiXactIdIsValid(minmulti) &&
+			pgcform->relminmxid != minmulti &&
+			(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
+		{
+			pgcform->relminmxid = minmulti;
+			dirty = true;
+		}
 	}
 
 	/* If anything changed, write out the tuple. */
@@ -1337,6 +1362,10 @@ vac_update_datfrozenxid(void)
 			continue;
 		}
 
+		/* global temp table relstats not in pg_class */
+		if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			continue;
+
 		/*
 		 * Some table AMs might not need per-relation xid / multixid horizons.
 		 * It therefore seems reasonable to allow relfrozenxid and relminmxid
@@ -1394,6 +1423,25 @@ vac_update_datfrozenxid(void)
 	Assert(TransactionIdIsNormal(newFrozenXid));
 	Assert(MultiXactIdIsValid(newMinMulti));
 
+	/*
+	 * Global temp table get frozenxid from MyProc
+	 * to avoid the vacuum truncate clog that gtt need.
+	 */
+	if (max_active_gtt > 0)
+	{
+		TransactionId oldest_gtt_frozenxid =
+			list_all_session_gtt_frozenxids(0, NULL, NULL, NULL);
+
+		if (TransactionIdIsNormal(oldest_gtt_frozenxid) &&
+			TransactionIdPrecedes(oldest_gtt_frozenxid, newFrozenXid))
+		{
+			ereport(WARNING,
+				(errmsg("global temp table oldest FrozenXid is far in the past"),
+				 errhint("please truncate them or kill those sessions that use them.")));
+			newFrozenXid = oldest_gtt_frozenxid;
+		}
+	}
+
 	/* Now fetch the pg_database tuple we need to update. */
 	relation = table_open(DatabaseRelationId, RowExclusiveLock);
 
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index b772348..cf1c7e0 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -591,6 +591,8 @@ static void
 set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 						  RangeTblEntry *rte)
 {
+	char relpersistence;
+
 	/*
 	 * The flag has previously been initialized to false, so we can just
 	 * return if it becomes clear that we can't safely set it.
@@ -618,7 +620,11 @@ set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 			 * the rest of the necessary infrastructure right now anyway.  So
 			 * for now, bail out if we see a temporary table.
 			 */
-			if (get_rel_persistence(rte->relid) == RELPERSISTENCE_TEMP)
+			/* global temp table is same as local temp table */
+			relpersistence = get_rel_persistence(rte->relid);
+
+			if (relpersistence == RELPERSISTENCE_TEMP ||
+				relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 				return;
 
 			/*
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 401299e..7d63265 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -6306,7 +6306,9 @@ plan_create_index_workers(Oid tableOid, Oid indexOid)
 	 * Furthermore, any index predicate or index expressions must be parallel
 	 * safe.
 	 */
+	/* global temp table is same as local temp table */
 	if (heap->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		heap->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexExpressions(index)) ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexPredicate(index)))
 	{
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 40f4976..535cf80 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -53,6 +53,7 @@
 #include "utils/syscache.h"
 #include "utils/snapmgr.h"
 
+#include "catalog/storage_gtt.h"
 
 /* GUC parameter */
 int			constraint_exclusion = CONSTRAINT_EXCLUSION_PARTITION;
@@ -937,10 +938,10 @@ void
 estimate_rel_size(Relation rel, int32 *attr_widths,
 				  BlockNumber *pages, double *tuples, double *allvisfrac)
 {
-	BlockNumber curpages;
-	BlockNumber relpages;
-	double		reltuples;
-	BlockNumber relallvisible;
+	BlockNumber curpages = 0;
+	BlockNumber relpages = 0;
+	double		reltuples = 0;
+	BlockNumber relallvisible = 0;
 	double		density;
 
 	switch (rel->rd_rel->relkind)
@@ -954,6 +955,21 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 
 		case RELKIND_INDEX:
 
+			/* global temp table get relstats from localhash */
+			if (RELATION_IS_GLOBAL_TEMP(rel))
+			{
+				get_gtt_relstats(RelationGetRelid(rel),
+								&relpages, &reltuples, &relallvisible,
+								NULL, NULL);
+			}
+			else
+			{
+				/* coerce values in pg_class to more desirable types */
+				relpages = (BlockNumber) rel->rd_rel->relpages;
+				reltuples = (double) rel->rd_rel->reltuples;
+				relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
+			}
+
 			/*
 			 * XXX: It'd probably be good to move this into a callback,
 			 * individual index types e.g. know if they have a metapage.
@@ -962,11 +978,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 			/* it has storage, ok to call the smgr */
 			curpages = RelationGetNumberOfBlocks(rel);
 
-			/* coerce values in pg_class to more desirable types */
-			relpages = (BlockNumber) rel->rd_rel->relpages;
-			reltuples = (double) rel->rd_rel->reltuples;
-			relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
-
 			/* report estimated # pages */
 			*pages = curpages;
 			/* quick exit if rel is clearly empty */
@@ -976,10 +987,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 				*allvisfrac = 0;
 				break;
 			}
-			/* coerce values in pg_class to more desirable types */
-			relpages = (BlockNumber) rel->rd_rel->relpages;
-			reltuples = (double) rel->rd_rel->reltuples;
-			relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
 
 			/*
 			 * Discount the metapage while estimating the number of tuples.
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 345a8e6..076a210 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -2579,6 +2579,11 @@ transformCreateTableAsStmt(ParseState *pstate, CreateTableAsStmt *stmt)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("materialized views must not use temporary tables or views")));
 
+		if (is_query_using_gtt(query))
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("materialized views must not use global temporary tables or views")));
+
 		/*
 		 * A materialized view would either need to save parameters for use in
 		 * maintaining/loading the data or prohibit them entirely.  The latter
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 208b4a1..8cc52d9 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3267,17 +3267,11 @@ OptTemp:	TEMPORARY					{ $$ = RELPERSISTENCE_TEMP; }
 			| LOCAL TEMP				{ $$ = RELPERSISTENCE_TEMP; }
 			| GLOBAL TEMPORARY
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED					{ $$ = RELPERSISTENCE_UNLOGGED; }
 			| /*EMPTY*/					{ $$ = RELPERSISTENCE_PERMANENT; }
@@ -11476,19 +11470,13 @@ OptTempTableName:
 				}
 			| GLOBAL TEMPORARY opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED opt_table qualified_name
 				{
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 77a48b0..7f14d41 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -59,6 +59,7 @@ static void expandTupleDesc(TupleDesc tupdesc, Alias *eref,
 							List **colnames, List **colvars);
 static int	specialAttNum(const char *attname);
 static bool isQueryUsingTempRelation_walker(Node *node, void *context);
+static bool is_query_using_gtt_walker(Node *node, void *context);
 
 
 /*
@@ -3425,3 +3426,49 @@ isQueryUsingTempRelation_walker(Node *node, void *context)
 								  isQueryUsingTempRelation_walker,
 								  context);
 }
+
+/* check if the query uses global temp table */
+static bool
+is_query_using_gtt_walker(Node *node, void *context)
+{
+	if (node == NULL)
+		return false;
+
+	if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+		ListCell   *rtable;
+
+		foreach(rtable, query->rtable)
+		{
+			RangeTblEntry *rte = lfirst(rtable);
+
+			if (rte->rtekind == RTE_RELATION)
+			{
+				Relation	rel = heap_open(rte->relid, AccessShareLock);
+				char		relpersistence = rel->rd_rel->relpersistence;
+
+				heap_close(rel, AccessShareLock);
+				if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+					return true;
+			}
+		}
+
+		return query_tree_walker(query,
+								 is_query_using_gtt_walker,
+								 context,
+								 QTW_IGNORE_JOINALIASES);
+	}
+
+	return expression_tree_walker(node,
+								  is_query_using_gtt_walker,
+								  context);
+}
+
+/* check if the query uses global temp table */
+bool
+is_query_using_gtt(Query *query)
+{
+	return is_query_using_gtt_walker((Node *) query, NULL);
+}
+
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 2406ca7..ab6fc9a 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -359,6 +359,13 @@ generateSerialExtraStmts(CreateStmtContext *cxt, ColumnDef *column,
 	AlterSeqStmt *altseqstmt;
 	List	   *attnamelist;
 
+	if (cxt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("Global temp table does not yet support serial column")));
+	}
+
 	/*
 	 * Determine namespace and name to use for the sequence.
 	 *
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index fd85b9c..eb46e94 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -2088,6 +2088,11 @@ do_autovacuum(void)
 			}
 			continue;
 		}
+		else if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			/* autovacuum skip vacuum global temp table */
+			continue;
+		}
 
 		/* Fetch reloptions and the pgstat entry for this table */
 		relopts = extract_autovac_opts(tuple, pg_class_desc);
@@ -2154,7 +2159,9 @@ do_autovacuum(void)
 		/*
 		 * We cannot safely process other backends' temp tables, so skip 'em.
 		 */
-		if (classForm->relpersistence == RELPERSISTENCE_TEMP)
+		/* autovacuum skip vacuum global temp table */
+		if (classForm->relpersistence == RELPERSISTENCE_TEMP || 
+			classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 			continue;
 
 		relid = classForm->oid;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 7332e6b..f023aa3 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -53,6 +53,8 @@
 #include "utils/resowner_private.h"
 #include "utils/timestamp.h"
 
+#include "utils/guc.h"
+#include "catalog/storage_gtt.h"
 
 /* Note: these two macros only work on shared buffers, not local ones! */
 #define BufHdrGetBlock(bufHdr)	((Block) (BufferBlocks + ((Size) (bufHdr)->buf_id) * BLCKSZ))
@@ -432,7 +434,7 @@ ForgetPrivateRefCountEntry(PrivateRefCountEntry *ref)
 static Buffer ReadBuffer_common(SMgrRelation reln, char relpersistence,
 								ForkNumber forkNum, BlockNumber blockNum,
 								ReadBufferMode mode, BufferAccessStrategy strategy,
-								bool *hit);
+								bool *hit, Relation rel);
 static bool PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy);
 static void PinBuffer_Locked(BufferDesc *buf);
 static void UnpinBuffer(BufferDesc *buf, bool fixOwner);
@@ -663,7 +665,8 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
 	 */
 	pgstat_count_buffer_read(reln);
 	buf = ReadBuffer_common(reln->rd_smgr, reln->rd_rel->relpersistence,
-							forkNum, blockNum, mode, strategy, &hit);
+							forkNum, blockNum, mode, strategy, &hit,
+							reln);
 	if (hit)
 		pgstat_count_buffer_hit(reln);
 	return buf;
@@ -691,7 +694,7 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 	Assert(InRecovery);
 
 	return ReadBuffer_common(smgr, RELPERSISTENCE_PERMANENT, forkNum, blockNum,
-							 mode, strategy, &hit);
+							 mode, strategy, &hit, NULL);
 }
 
 
@@ -703,7 +706,8 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 static Buffer
 ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 				  BlockNumber blockNum, ReadBufferMode mode,
-				  BufferAccessStrategy strategy, bool *hit)
+				  BufferAccessStrategy strategy, bool *hit,
+				  Relation rel)
 {
 	BufferDesc *bufHdr;
 	Block		bufBlock;
@@ -718,6 +722,15 @@ ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 
 	isExtend = (blockNum == P_NEW);
 
+	/* create storage when first read data page for gtt */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP &&
+		(isExtend || blockNum == 0) &&
+		forkNum == MAIN_FORKNUM &&
+		!gtt_storage_attached(smgr->smgr_rnode.node.relNode))
+	{
+		RelationCreateStorage(smgr->smgr_rnode.node, relpersistence, rel);
+	}
+
 	TRACE_POSTGRESQL_BUFFER_READ_START(forkNum, blockNum,
 									   smgr->smgr_rnode.node.spcNode,
 									   smgr->smgr_rnode.node.dbNode,
@@ -2798,6 +2811,16 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln)
 BlockNumber
 RelationGetNumberOfBlocksInFork(Relation relation, ForkNumber forkNum)
 {
+	/*
+	 * When this backend not init gtt storage
+	 * return 0
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(relation) &&
+		!gtt_storage_attached(relation->rd_node.relNode))
+	{
+		return 0;
+	}
+
 	switch (relation->rd_rel->relkind)
 	{
 		case RELKIND_SEQUENCE:
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index d7d7335..3b2cc8b 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -21,6 +21,7 @@
 #include "access/nbtree.h"
 #include "access/subtrans.h"
 #include "access/twophase.h"
+#include "catalog/storage_gtt.h"
 #include "commands/async.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -147,6 +148,7 @@ CreateSharedMemoryAndSemaphores(int port)
 		size = add_size(size, BTreeShmemSize());
 		size = add_size(size, SyncScanShmemSize());
 		size = add_size(size, AsyncShmemSize());
+		size = add_size(size, active_gtt_shared_hash_size());
 #ifdef EXEC_BACKEND
 		size = add_size(size, ShmemBackendArraySize());
 #endif
@@ -217,6 +219,8 @@ CreateSharedMemoryAndSemaphores(int port)
 	SUBTRANSShmemInit();
 	MultiXactShmemInit();
 	InitBufferPool();
+	/* global temporary table */
+	active_gtt_shared_hash_init();
 
 	/*
 	 * Set up lock manager
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index 18a0f62..0d926bd 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -60,6 +60,7 @@
 #include "utils/builtins.h"
 #include "utils/rel.h"
 #include "utils/snapmgr.h"
+#include "utils/guc.h"
 
 #define UINT32_ACCESS_ONCE(var)		 ((uint32)(*((volatile uint32 *)&(var))))
 
@@ -3975,3 +3976,77 @@ KnownAssignedXidsReset(void)
 
 	LWLockRelease(ProcArrayLock);
 }
+
+/*
+ * search all active backend to get oldest frozenxid
+ * for global temp table.
+ */
+int
+list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n)
+{
+	ProcArrayStruct *arrayP = procArray;
+	TransactionId result = InvalidTransactionId;
+	int			index;
+	int			flags = 0;
+	int			i = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	if (max_size > 0)
+	{
+		Assert(pids);
+		Assert(xids);
+		Assert(n);
+		*n = 0;
+	}
+
+	if (max_active_gtt <= 0)
+		return InvalidTransactionId;
+
+	if (RecoveryInProgress())
+		return InvalidTransactionId;
+
+	flags |= PROC_IS_AUTOVACUUM;
+	flags |= PROC_IN_LOGICAL_DECODING;
+
+	LWLockAcquire(ProcArrayLock, LW_SHARED);
+	if (max_size > 0 && max_size < arrayP->numProcs)
+	{
+		LWLockRelease(ProcArrayLock);
+		elog(ERROR, "list_all_gtt_frozenxids require more array");
+	}
+
+	for (index = 0; index < arrayP->numProcs; index++)
+	{
+		int			pgprocno = arrayP->pgprocnos[index];
+		volatile PGPROC *proc = &allProcs[pgprocno];
+		volatile PGXACT *pgxact = &allPgXact[pgprocno];
+
+		if (pgxact->vacuumFlags & flags)
+			continue;
+
+		if (proc->databaseId == MyDatabaseId &&
+			TransactionIdIsNormal(proc->session_gtt_frozenxid))
+		{
+			if (result == InvalidTransactionId)
+				result = proc->session_gtt_frozenxid;
+			else if (TransactionIdPrecedes(proc->session_gtt_frozenxid, result))
+				result = proc->session_gtt_frozenxid;
+
+			if (max_size > 0)
+			{
+				pids[i] = proc->pid;
+				xids[i] = proc->session_gtt_frozenxid;
+				i++;
+			}
+		}
+	}
+	LWLockRelease(ProcArrayLock);
+
+	if (max_size > 0)
+		*n = i;
+
+	return result;
+}
+
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 498373f..542cc6b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -396,6 +396,7 @@ InitProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
@@ -578,6 +579,7 @@ InitAuxiliaryProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 64acc3f..fdbc95b 100644
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -629,6 +629,12 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 		 */
 		if (zero_damaged_pages || InRecovery)
 			MemSet(buffer, 0, BLCKSZ);
+		else if(SmgrIsTemp(reln) && blocknum == 0 && forknum == MAIN_FORKNUM)
+		{
+			/* global temp table init btree meta page */
+			MemSet(buffer, 0, BLCKSZ);
+			mdwrite(reln, forknum, blocknum, buffer, true);
+		}
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_DATA_CORRUPTED),
diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c
index a87e721..adce760 100644
--- a/src/backend/utils/adt/dbsize.c
+++ b/src/backend/utils/adt/dbsize.c
@@ -1008,6 +1008,10 @@ pg_relation_filepath(PG_FUNCTION_ARGS)
 				Assert(backend != InvalidBackendId);
 			}
 			break;
+		/* For global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			backend = BackendIdForTempRelations();
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relform->relpersistence);
 			backend = InvalidBackendId; /* placate compiler */
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index a314ecc..c957d12 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -141,6 +141,7 @@
 #include "utils/timestamp.h"
 #include "utils/typcache.h"
 
+#include "catalog/storage_gtt.h"
 
 /* Hooks for plugins to get control when we ask for stats */
 get_relation_stats_hook_type get_relation_stats_hook = NULL;
@@ -4586,12 +4587,25 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
 						}
 						else if (index->indpred == NIL)
 						{
-							vardata->statsTuple =
-								SearchSysCache3(STATRELATTINH,
-												ObjectIdGetDatum(index->indexoid),
-												Int16GetDatum(pos + 1),
-												BoolGetDatum(false));
-							vardata->freefunc = ReleaseSysCache;
+							char rel_persistence = get_rel_persistence(index->indexoid);
+
+							if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+							{
+								vardata->statsTuple =
+									get_gtt_att_statistic(index->indexoid,
+														Int16GetDatum(pos + 1),
+														false);
+								vardata->freefunc = release_gtt_statistic_cache;
+							}
+							else
+							{
+								vardata->statsTuple =
+									SearchSysCache3(STATRELATTINH,
+													ObjectIdGetDatum(index->indexoid),
+													Int16GetDatum(pos + 1),
+													BoolGetDatum(false));
+								vardata->freefunc = ReleaseSysCache;
+							}
 
 							if (HeapTupleIsValid(vardata->statsTuple))
 							{
@@ -4670,15 +4684,27 @@ examine_simple_variable(PlannerInfo *root, Var *var,
 	}
 	else if (rte->rtekind == RTE_RELATION)
 	{
-		/*
-		 * Plain table or parent of an inheritance appendrel, so look up the
-		 * column in pg_statistic
-		 */
-		vardata->statsTuple = SearchSysCache3(STATRELATTINH,
-											  ObjectIdGetDatum(rte->relid),
-											  Int16GetDatum(var->varattno),
-											  BoolGetDatum(rte->inh));
-		vardata->freefunc = ReleaseSysCache;
+		char rel_persistence = get_rel_persistence(rte->relid);
+
+		if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata->statsTuple = get_gtt_att_statistic(rte->relid,
+														var->varattno,
+														rte->inh);
+			vardata->freefunc = release_gtt_statistic_cache;
+		}
+		else
+		{
+			/*
+			 * Plain table or parent of an inheritance appendrel, so look up the
+			 * column in pg_statistic
+			 */
+			vardata->statsTuple = SearchSysCache3(STATRELATTINH,
+												  ObjectIdGetDatum(rte->relid),
+												  Int16GetDatum(var->varattno),
+												  BoolGetDatum(rte->inh));
+			vardata->freefunc = ReleaseSysCache;
+		}
 
 		if (HeapTupleIsValid(vardata->statsTuple))
 		{
@@ -5991,6 +6017,7 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	{
 		/* Simple variable --- look to stats for the underlying table */
 		RangeTblEntry *rte = planner_rt_fetch(index->rel->relid, root);
+		char	rel_persistence = get_rel_persistence(rte->relid);
 
 		Assert(rte->rtekind == RTE_RELATION);
 		relid = rte->relid;
@@ -6008,6 +6035,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													rte->inh);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -6019,6 +6053,8 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	}
 	else
 	{
+		char	rel_persistence = get_rel_persistence(index->indexoid);
+
 		/* Expression --- maybe there are stats for the index itself */
 		relid = index->indexoid;
 		colnum = 1;
@@ -6034,6 +6070,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													false);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -6900,6 +6943,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		/* attempt to lookup stats in relation for this index column */
 		if (attnum != 0)
 		{
+			char	rel_persistence = get_rel_persistence(rte->relid);
+
 			/* Simple variable -- look to stats for the underlying table */
 			if (get_relation_stats_hook &&
 				(*get_relation_stats_hook) (root, rte, attnum, &vardata))
@@ -6912,6 +6957,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					elog(ERROR,
 						 "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(rte->relid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple =
@@ -6924,6 +6977,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		}
 		else
 		{
+			char	rel_persistence = get_rel_persistence(index->indexoid);
+
 			/*
 			 * Looks like we've found an expression column in the index. Let's
 			 * see if there's any stats for it.
@@ -6943,6 +6998,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					!vardata.freefunc)
 					elog(ERROR, "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(index->indexoid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple = SearchSysCache3(STATRELATTINH,
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 27602fa..25a411a 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -34,6 +34,7 @@
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_transform.h"
 #include "catalog/pg_type.h"
+#include "catalog/storage_gtt.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "utils/array.h"
@@ -46,6 +47,7 @@
 #include "utils/syscache.h"
 #include "utils/typcache.h"
 
+
 /* Hook for plugins to get control in get_attavgwidth() */
 get_attavgwidth_hook_type get_attavgwidth_hook = NULL;
 
@@ -2878,6 +2880,18 @@ get_attavgwidth(Oid relid, AttrNumber attnum)
 		if (stawidth > 0)
 			return stawidth;
 	}
+	if (get_rel_persistence(relid) == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		tp = get_gtt_att_statistic(relid, attnum, false);
+		if (!HeapTupleIsValid(tp))
+			return 0;
+
+		stawidth = ((Form_pg_statistic) GETSTRUCT(tp))->stawidth;
+		if (stawidth > 0)
+			return stawidth;
+		else
+			return 0;
+	}
 	tp = SearchSysCache3(STATRELATTINH,
 						 ObjectIdGetDatum(relid),
 						 Int16GetDatum(attnum),
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index e8d11a1..0c7b455 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -1131,6 +1131,16 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
 				relation->rd_islocaltemp = false;
 			}
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			{
+				relation->rd_backend = BackendIdForTempRelations();
+				/*
+				 * For global temp table, all backend can use
+				 * this relation, so rd_islocaltemp always true.
+				 */
+				relation->rd_islocaltemp = true;
+			}
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c",
 				 relation->rd_rel->relpersistence);
@@ -3312,6 +3322,10 @@ RelationBuildLocalRelation(const char *relname,
 			rel->rd_backend = BackendIdForTempRelations();
 			rel->rd_islocaltemp = true;
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			rel->rd_backend = BackendIdForTempRelations();
+			rel->rd_islocaltemp = true;
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relpersistence);
 			break;
@@ -3426,6 +3440,9 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 	TransactionId freezeXid = InvalidTransactionId;
 	RelFileNode newrnode;
 
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+		elog(ERROR, "global temp table does not allow setting new relfilenode");
+
 	/* Allocate a new relfilenode */
 	newrelfilenode = GetNewRelFileNode(relation->rd_rel->reltablespace, NULL,
 									   persistence);
@@ -3466,7 +3483,7 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 				/* handle these directly, at least for now */
 				SMgrRelation srel;
 
-				srel = RelationCreateStorage(newrnode, persistence);
+				srel = RelationCreateStorage(newrnode, persistence, relation);
 				smgrclose(srel);
 			}
 			break;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index f0ed326..d4590a2 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -138,6 +138,18 @@ char	   *GUC_check_errmsg_string;
 char	   *GUC_check_errdetail_string;
 char	   *GUC_check_errhint_string;
 
+/*
+ * num = 0 means disable global temp table feature.
+ * global temp table define can still storage in catalog
+ * just can not use.
+ * num > 0 means database can management num active global temp table.
+ */
+#define	MIN_NUM_ACTIVE_GTT			0
+#define	DEFAULT_NUM_ACTIVE_GTT			1000
+#define	MAX_NUM_ACTIVE_GTT			1000000
+
+int		max_active_gtt = MIN_NUM_ACTIVE_GTT;
+
 static void do_serialize(char **destptr, Size *maxbytes, const char *fmt,...) pg_attribute_printf(3, 4);
 
 static void set_config_sourcefile(const char *name, char *sourcefile,
@@ -1962,6 +1974,15 @@ static struct config_bool ConfigureNamesBool[] =
 static struct config_int ConfigureNamesInt[] =
 {
 	{
+		{"max_active_global_temporary_table", PGC_POSTMASTER, UNGROUPED,
+			gettext_noop("max active global temporary table."),
+			NULL
+		},
+		&max_active_gtt,
+		DEFAULT_NUM_ACTIVE_GTT, MIN_NUM_ACTIVE_GTT, MAX_NUM_ACTIVE_GTT,
+		NULL, NULL, NULL
+	},
+	{
 		{"archive_timeout", PGC_SIGHUP, WAL_ARCHIVING,
 			gettext_noop("Forces a switch to the next WAL file if a "
 						 "new file has not been started within N seconds."),
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index a9c868b..3831341 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15535,6 +15535,7 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 	{
 		char	   *ftoptions = NULL;
 		char	   *srvname = NULL;
+		char		*table_type = NULL;
 
 		switch (tbinfo->relkind)
 		{
@@ -15586,9 +15587,15 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 			binary_upgrade_set_pg_class_oids(fout, q,
 											 tbinfo->dobj.catId.oid, false);
 
+		if (tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED)
+			table_type = "UNLOGGED ";
+		else if (tbinfo->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			table_type = "GLOBAL TEMPORARY ";
+		else
+			table_type = "";
+
 		appendPQExpBuffer(q, "CREATE %s%s %s",
-						  tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED ?
-						  "UNLOGGED " : "",
+						  table_type,
 						  reltypename,
 						  qualrelname);
 
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index 090b6ba..34b4683 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -165,6 +165,7 @@ typedef FormData_pg_class *Form_pg_class;
 #define		  RELPERSISTENCE_PERMANENT	'p' /* regular table */
 #define		  RELPERSISTENCE_UNLOGGED	'u' /* unlogged permanent table */
 #define		  RELPERSISTENCE_TEMP		't' /* temporary table */
+#define		  RELPERSISTENCE_GLOBAL_TEMP	'g' /* global temporary table */
 
 /* default selection for replica identity (primary key or nothing) */
 #define		  REPLICA_IDENTITY_DEFAULT	'd'
diff --git a/src/include/catalog/storage.h b/src/include/catalog/storage.h
index 3579d3f..2bde386 100644
--- a/src/include/catalog/storage.h
+++ b/src/include/catalog/storage.h
@@ -19,7 +19,7 @@
 #include "storage/smgr.h"
 #include "utils/relcache.h"
 
-extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence);
+extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel);
 extern void RelationDropStorage(Relation rel);
 extern void RelationPreserveStorage(RelFileNode rnode, bool atCommit);
 extern void RelationTruncate(Relation rel, BlockNumber nblocks);
diff --git a/src/include/catalog/storage_gtt.h b/src/include/catalog/storage_gtt.h
new file mode 100644
index 0000000..ea41e66
--- /dev/null
+++ b/src/include/catalog/storage_gtt.h
@@ -0,0 +1,39 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.h
+ *	  prototypes for functions in backend/catalog/storage_gtt.c
+ *
+ * src/include/catalog/storage_gtt.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef STORAGE_GTT_H
+#define STORAGE_GTT_H
+
+#include "access/htup.h"
+#include "storage/block.h"
+#include "storage/relfilenode.h"
+#include "utils/relcache.h"
+
+extern Size active_gtt_shared_hash_size(void);
+extern void active_gtt_shared_hash_init(void);
+extern void remember_gtt_storage_info(RelFileNode rnode, Relation rel);
+extern void forget_gtt_storage_info(Oid relid);
+extern bool is_other_backend_use_gtt(RelFileNode node);
+extern bool gtt_storage_attached(Oid relid);
+extern Bitmapset *copy_active_gtt_bitmap(RelFileNode node);
+extern void up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+								TupleDesc tupleDescriptor, Datum *values, bool *isnull);
+extern HeapTuple get_gtt_att_statistic(Oid reloid, int attnum, bool inh);
+extern void release_gtt_statistic_cache(HeapTuple tup);
+extern void up_gtt_relstats(Relation relation,
+							BlockNumber num_pages,
+							double num_tuples,
+							BlockNumber num_all_visible_pages,
+							TransactionId relfrozenxid,
+							TransactionId relminmxid);
+extern void get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+							BlockNumber *relallvisible, TransactionId *relfrozenxid,
+							TransactionId *relminmxid);
+
+#endif							/* STORAGE_H */
diff --git a/src/include/parser/parse_relation.h b/src/include/parser/parse_relation.h
index f7e0781..4f5a353 100644
--- a/src/include/parser/parse_relation.h
+++ b/src/include/parser/parse_relation.h
@@ -130,4 +130,7 @@ extern Oid	attnumTypeId(Relation rd, int attid);
 extern Oid	attnumCollationId(Relation rd, int attid);
 extern bool isQueryUsingTempRelation(Query *query);
 
+/* global temp table check */
+extern bool is_query_using_gtt(Query *query);
+
 #endif							/* PARSE_RELATION_H */
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 08e0dc8..297e20c 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -220,6 +220,7 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_TBM,
 	LWTRANCHE_PARALLEL_APPEND,
 	LWTRANCHE_SXACT,
+	LWTRANCHE_GTT_CTL,
 	LWTRANCHE_FIRST_USER_DEFINED
 }			BuiltinTrancheIds;
 
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index ac7ee72..74a074a 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -117,6 +117,8 @@ struct PGPROC
 	Oid			tempNamespaceId;	/* OID of temp schema this backend is
 									 * using */
 
+	TransactionId session_gtt_frozenxid;	/* session level global temp table relfrozenxid */
+
 	bool		isBackgroundWorker; /* true if background worker. */
 
 	/*
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index da8b672..8e7d4c7 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -124,4 +124,6 @@ extern void ProcArraySetReplicationSlotXmin(TransactionId xmin,
 extern void ProcArrayGetReplicationSlotXmin(TransactionId *xmin,
 											TransactionId *catalog_xmin);
 
+extern int list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n);
+
 #endif							/* PROCARRAY_H */
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index a93ed77..a782eee 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -276,6 +276,10 @@ extern int	tcp_user_timeout;
 extern bool trace_sort;
 #endif
 
+/* global temporary table */
+extern int	max_active_gtt;
+/* end */
+
 /*
  * Functions exported by guc.c
  */
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 1385ff3..a5a991d 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -273,6 +273,7 @@ typedef struct StdRdOptions
 	int			parallel_workers;	/* max number of parallel workers */
 	bool		vacuum_index_cleanup;	/* enables index vacuuming and cleanup */
 	bool		vacuum_truncate;	/* enables vacuum to truncate a relation */
+	bool		on_commit_delete_rows;	/* global temp table */
 } StdRdOptions;
 
 #define HEAP_MIN_FILLFACTOR			10
@@ -524,7 +525,8 @@ typedef struct ViewOptions
  *		True if relation's pages are stored in local buffers.
  */
 #define RelationUsesLocalBuffers(relation) \
-	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP || \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 
 /*
  * RELATION_IS_LOCAL
@@ -603,6 +605,17 @@ typedef struct ViewOptions
  */
 #define RelationGetPartitionDesc(relation) ((relation)->rd_partdesc)
 
+/* global temp table implementations */
+#define RELATION_IS_GLOBAL_TEMP(relation)	((relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+
+#define RELATION_GTT_ON_COMMIT_DELETE(relation)	\
+	((relation)->rd_options && \
+	 (relation)->rd_rel->relkind == RELKIND_RELATION && \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ? \
+	 ((StdRdOptions *) (relation)->rd_options)->on_commit_delete_rows : false)
+
+#define RelationGetRelPersistence(relation) ((relation)->rd_rel->relpersistence)
+
 /* routines in utils/cache/relcache.c */
 extern void RelationIncrementReferenceCount(Relation rel);
 extern void RelationDecrementReferenceCount(Relation rel);
diff --git a/src/test/regress/expected/gtt_clean.out b/src/test/regress/expected/gtt_clean.out
new file mode 100644
index 0000000..50ca9ac
--- /dev/null
+++ b/src/test/regress/expected/gtt_clean.out
@@ -0,0 +1,7 @@
+reset search_path;
+drop schema gtt cascade;
+NOTICE:  drop cascades to 4 other objects
+DETAIL:  drop cascades to table gtt.gtt1
+drop cascades to table gtt.gtt2
+drop cascades to table gtt.gtt3
+drop cascades to table gtt.gtt_t_kenyon
diff --git a/src/test/regress/expected/gtt_error.out b/src/test/regress/expected/gtt_error.out
new file mode 100644
index 0000000..80c16dc
--- /dev/null
+++ b/src/test/regress/expected/gtt_error.out
@@ -0,0 +1,106 @@
+CREATE SCHEMA IF NOT EXISTS gtt_error;
+set search_path=gtt_error,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+ERROR:  cannot create indexes on global temporary tables using concurrent mode
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+ERROR:  not support cluster global temporary tables yet
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+ERROR:  ON COMMIT can only be used on temporary tables
+-- ERROR
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+ERROR:  regular table cannot specifie on_commit_delete_rows
+-- ERROR
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+ERROR:  not support create global temporary partition table yet
+-- ERROR
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+ERROR:  not support create global temporary inheritance table yet
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+ERROR:  global temp table not support on commit drop clause
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+ERROR:  can not defeine global temp table with on commit and with clause at same time
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+--ERROR
+alter table gtt1 rename to gttx;
+ERROR:  not support rename global temporary tables yet
+-- ERROR
+ALTER TABLE gtt1 ADD COLUMN address varchar(30);
+ERROR:  not support alter global temporary tables yet
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  referenced relation "products" is not a global temp table
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  not support alter global temporary tables yet
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+ERROR:  Global temp table does not yet support serial column
+-- ERROR
+create global temp table gttx(id int GENERATED ALWAYS AS IDENTITY (START WITH 2));
+ERROR:  Global temp table does not yet support serial column
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+ERROR:  materialized views must not use global temporary tables or views
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+ERROR:  only support btree index on global temp table
+create index idx_err on gtt1 using gist (a);
+ERROR:  data type integer has no default operator class for access method "gist"
+HINT:  You must specify an operator class for the index or define a default operator class for the data type.
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+ERROR:  only support btree index on global temp table
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+ERROR:  only support btree index on global temp table
+reset search_path;
+drop schema gtt_error cascade;
+NOTICE:  drop cascades to 8 other objects
+DETAIL:  drop cascades to table gtt_error.gtt1
+drop cascades to table gtt_error.gtt2
+drop cascades to table gtt_error.gtt3
+drop cascades to table gtt_error.tmp_t0
+drop cascades to table gtt_error.tbl_inherits_parent
+drop cascades to table gtt_error.tbl_inherits_parent_global_temp
+drop cascades to table gtt_error.products
+drop cascades to table gtt_error.gtt5
diff --git a/src/test/regress/expected/gtt_parallel_1.out b/src/test/regress/expected/gtt_parallel_1.out
new file mode 100644
index 0000000..30d8a7b
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_1.out
@@ -0,0 +1,84 @@
+set search_path=gtt,sys;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_parallel_2.out b/src/test/regress/expected/gtt_parallel_2.out
new file mode 100644
index 0000000..70bf4a6
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_2.out
@@ -0,0 +1,142 @@
+set search_path=gtt,sys;
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+ 3 | test1
+(3 rows)
+
+rollback;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test2
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 3 | test3
+(1 row)
+
+rollback;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 5 | test5
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 6 | test6
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+ count  
+--------
+ 100000
+(1 row)
+
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+             QUERY PLAN             
+------------------------------------
+ Index Scan using gtt3_pkey on gtt3
+   Index Cond: (a = 300)
+(2 rows)
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',10000);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid) from pg_class where relname = 'gtt_t_kenyon';
+   relname    | pg_relation_size | pg_relation_size 
+--------------+------------------+------------------
+ gtt_t_kenyon |           450560 |            16384
+(1 row)
+
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+   relname    
+--------------
+ gtt_t_kenyon
+(1 row)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_prepare.out b/src/test/regress/expected/gtt_prepare.out
new file mode 100644
index 0000000..9e8f5f0
--- /dev/null
+++ b/src/test/regress/expected/gtt_prepare.out
@@ -0,0 +1,7 @@
+CREATE SCHEMA IF NOT EXISTS gtt;
+set search_path=gtt,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+reset search_path;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 8fb55f0..588f4e5 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -120,3 +120,9 @@ test: fast_default
 
 # run stats by itself because its delay may be insufficient under heavy load
 test: stats
+
+# global temp table test
+test: gtt_error
+test: gtt_prepare
+test: gtt_parallel_1 gtt_parallel_2
+test: gtt_clean
diff --git a/src/test/regress/sql/gtt_clean.sql b/src/test/regress/sql/gtt_clean.sql
new file mode 100644
index 0000000..f3cf710
--- /dev/null
+++ b/src/test/regress/sql/gtt_clean.sql
@@ -0,0 +1,6 @@
+
+
+reset search_path;
+
+drop schema gtt cascade;
+
diff --git a/src/test/regress/sql/gtt_error.sql b/src/test/regress/sql/gtt_error.sql
new file mode 100644
index 0000000..e895574
--- /dev/null
+++ b/src/test/regress/sql/gtt_error.sql
@@ -0,0 +1,106 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt_error;
+
+set search_path=gtt_error,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+
+-- ERROR
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+
+-- ERROR
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+
+-- ERROR
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+
+--ERROR
+alter table gtt1 rename to gttx;
+
+-- ERROR
+ALTER TABLE gtt1 ADD COLUMN address varchar(30);
+
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+
+-- ERROR
+create global temp table gttx(id int GENERATED ALWAYS AS IDENTITY (START WITH 2));
+
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+create index idx_err on gtt1 using gist (a);
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+
+reset search_path;
+
+drop schema gtt_error cascade;
+
diff --git a/src/test/regress/sql/gtt_parallel_1.sql b/src/test/regress/sql/gtt_parallel_1.sql
new file mode 100644
index 0000000..d7d81de
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_1.sql
@@ -0,0 +1,42 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+commit;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+rollback;
+select * from gtt1 order by a;
+
+truncate gtt1;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+select * from gtt1 order by a;
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+
+begin;
+select * from gtt1 order by a;
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_parallel_2.sql b/src/test/regress/sql/gtt_parallel_2.sql
new file mode 100644
index 0000000..cb2f7a6
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_2.sql
@@ -0,0 +1,62 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+commit;
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+truncate gtt3;
+select * from gtt3 order by a;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+truncate gtt3;
+select * from gtt3 order by a;
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+begin;
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',10000);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid) from pg_class where relname = 'gtt_t_kenyon';
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_prepare.sql b/src/test/regress/sql/gtt_prepare.sql
new file mode 100644
index 0000000..042d9e6
--- /dev/null
+++ b/src/test/regress/sql/gtt_prepare.sql
@@ -0,0 +1,15 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt;
+
+set search_path=gtt,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+
+reset search_path;
+
--
libgit2 0.23.3

From 979b6f9dda32d0f4735a6a2eb43076c3d822b1d4 Mon Sep 17 00:00:00 2001
From: 义从 <wenjing.zwj@alibaba-inc.com>
Date: Fri, 8 Nov 2019 11:35:02 +0800
Subject: [PATCH] global_temporary_table_v2-pg13

---
 contrib/Makefile                             |   3 ++-
 contrib/pg_gtt/Makefile                      |  22 ++++++++++++++++++++++
 contrib/pg_gtt/pg_gtt--1.0.sql               |  28 ++++++++++++++++++++++++++++
 contrib/pg_gtt/pg_gtt.c                      | 474 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 contrib/pg_gtt/pg_gtt.control                |   4 ++++
 src/backend/access/common/reloptions.c       |  15 +++++++++++++++
 src/backend/access/gist/gistutil.c           |   4 +++-
 src/backend/access/hash/hash.c               |   4 +++-
 src/backend/access/heap/heapam_handler.c     |   4 ++--
 src/backend/access/heap/vacuumlazy.c         |  22 ++++++++++++++++++----
 src/backend/access/nbtree/nbtpage.c          |   9 ++++++++-
 src/backend/access/transam/xlog.c            |   4 ++++
 src/backend/catalog/Makefile                 |   2 ++
 src/backend/catalog/catalog.c                |   2 ++
 src/backend/catalog/heap.c                   |  86 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------
 src/backend/catalog/index.c                  |  87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------------
 src/backend/catalog/namespace.c              |   7 +++++++
 src/backend/catalog/storage.c                |  17 ++++++++++++++++-
 src/backend/catalog/storage_gtt.c            | 813 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/backend/commands/analyze.c               |  75 ++++++++++++++++++++++++++++++++++++++++++++++++++-------------------------
 src/backend/commands/cluster.c               |   6 ++++++
 src/backend/commands/indexcmds.c             |  10 ++++++++++
 src/backend/commands/lockcmds.c              |   3 ++-
 src/backend/commands/tablecmds.c             | 111 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 src/backend/commands/vacuum.c                | 140 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------------------------------------
 src/backend/optimizer/path/allpaths.c        |   8 +++++++-
 src/backend/optimizer/plan/planner.c         |   2 ++
 src/backend/optimizer/util/plancat.c         |  33 ++++++++++++++++++++-------------
 src/backend/parser/analyze.c                 |   5 +++++
 src/backend/parser/gram.y                    |  20 ++++----------------
 src/backend/parser/parse_relation.c          |  47 +++++++++++++++++++++++++++++++++++++++++++++++
 src/backend/parser/parse_utilcmd.c           |   7 +++++++
 src/backend/postmaster/autovacuum.c          |   9 ++++++++-
 src/backend/storage/buffer/bufmgr.c          |  31 +++++++++++++++++++++++++++----
 src/backend/storage/ipc/ipci.c               |   4 ++++
 src/backend/storage/ipc/procarray.c          |  75 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/backend/storage/lmgr/proc.c              |   2 ++
 src/backend/storage/smgr/md.c                |   6 ++++++
 src/backend/utils/adt/dbsize.c               |   4 ++++
 src/backend/utils/adt/selfuncs.c             |  93 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---------------
 src/backend/utils/cache/lsyscache.c          |  14 ++++++++++++++
 src/backend/utils/cache/relcache.c           |  19 ++++++++++++++++++-
 src/backend/utils/misc/guc.c                 |  21 +++++++++++++++++++++
 src/bin/pg_dump/pg_dump.c                    |  11 +++++++++--
 src/include/catalog/pg_class.h               |   1 +
 src/include/catalog/storage.h                |   2 +-
 src/include/catalog/storage_gtt.h            |  39 +++++++++++++++++++++++++++++++++++++++
 src/include/parser/parse_relation.h          |   3 +++
 src/include/storage/lwlock.h                 |   1 +
 src/include/storage/proc.h                   |   2 ++
 src/include/storage/procarray.h              |   2 ++
 src/include/utils/guc.h                      |   4 ++++
 src/include/utils/rel.h                      |  15 ++++++++++++++-
 src/test/regress/expected/gtt_clean.out      |   7 +++++++
 src/test/regress/expected/gtt_error.out      | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/expected/gtt_parallel_1.out |  84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/expected/gtt_parallel_2.out | 142 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/expected/gtt_prepare.out    |   7 +++++++
 src/test/regress/parallel_schedule           |   6 ++++++
 src/test/regress/sql/gtt_clean.sql           |   6 ++++++
 src/test/regress/sql/gtt_error.sql           | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/sql/gtt_parallel_1.sql      |  42 ++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/sql/gtt_parallel_2.sql      |  62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/test/regress/sql/gtt_prepare.sql         |  15 +++++++++++++++
 64 files changed, 2845 insertions(+), 170 deletions(-)
 create mode 100644 contrib/pg_gtt/Makefile
 create mode 100644 contrib/pg_gtt/pg_gtt--1.0.sql
 create mode 100644 contrib/pg_gtt/pg_gtt.c
 create mode 100644 contrib/pg_gtt/pg_gtt.control
 create mode 100644 src/backend/catalog/storage_gtt.c
 create mode 100644 src/include/catalog/storage_gtt.h
 create mode 100644 src/test/regress/expected/gtt_clean.out
 create mode 100644 src/test/regress/expected/gtt_error.out
 create mode 100644 src/test/regress/expected/gtt_parallel_1.out
 create mode 100644 src/test/regress/expected/gtt_parallel_2.out
 create mode 100644 src/test/regress/expected/gtt_prepare.out
 create mode 100644 src/test/regress/sql/gtt_clean.sql
 create mode 100644 src/test/regress/sql/gtt_error.sql
 create mode 100644 src/test/regress/sql/gtt_parallel_1.sql
 create mode 100644 src/test/regress/sql/gtt_parallel_2.sql
 create mode 100644 src/test/regress/sql/gtt_prepare.sql

diff --git a/contrib/Makefile b/contrib/Makefile
index 92184ed..4b1a596 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -48,7 +48,8 @@ SUBDIRS = \
 		tsm_system_rows \
 		tsm_system_time \
 		unaccent	\
-		vacuumlo
+		vacuumlo	\
+		pg_gtt
 
 ifeq ($(with_openssl),yes)
 SUBDIRS += sslinfo
diff --git a/contrib/pg_gtt/Makefile b/contrib/pg_gtt/Makefile
new file mode 100644
index 0000000..1d2ef64
--- /dev/null
+++ b/contrib/pg_gtt/Makefile
@@ -0,0 +1,22 @@
+# contrib/pg_gtt/Makefile
+
+MODULE_big = pg_gtt
+OBJS = pg_gtt.o
+
+EXTENSION = pg_gtt
+DATA = pg_gtt--1.0.sql
+
+LDFLAGS_SL += $(filter -lm, $(LIBS))
+
+NO_INSTALLCHECK = 1
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/pg_pfs
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/contrib/pg_gtt/pg_gtt--1.0.sql b/contrib/pg_gtt/pg_gtt--1.0.sql
new file mode 100644
index 0000000..3f794d7
--- /dev/null
+++ b/contrib/pg_gtt/pg_gtt--1.0.sql
@@ -0,0 +1,28 @@
+/* contrib/pg_gtt/pg_gtt--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION pg_gtt" to load this file. \quit
+
+
+CREATE FUNCTION pg_gtt_att_statistic(text, text, int)
+RETURNS setof pg_statistic
+AS 'MODULE_PATHNAME','pg_gtt_att_statistic'
+LANGUAGE C STRICT;
+
+CREATE TYPE relstats_type AS (relpages int4, reltuples float4, relallvisible int4, relfrozenxid xid, relminmxid xid);
+CREATE TYPE rel_vac_type AS (pid int4, relfrozenxid xid, relminmxid xid);
+
+CREATE FUNCTION pg_gtt_relstats(text, text)
+RETURNS relstats_type
+AS 'MODULE_PATHNAME','pg_gtt_relstats'
+LANGUAGE C STRICT;
+
+CREATE FUNCTION pg_gtt_attached_pid(text, text)
+RETURNS setof int4
+AS 'MODULE_PATHNAME','pg_gtt_attached_pid'
+LANGUAGE C STRICT;
+
+CREATE FUNCTION pg_list_gtt_relfrozenxids()
+RETURNS setof rel_vac_type
+AS 'MODULE_PATHNAME','pg_list_gtt_relfrozenxids'
+LANGUAGE C STRICT;
diff --git a/contrib/pg_gtt/pg_gtt.c b/contrib/pg_gtt/pg_gtt.c
new file mode 100644
index 0000000..19e1ec0
--- /dev/null
+++ b/contrib/pg_gtt/pg_gtt.c
@@ -0,0 +1,474 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_gtt.c
+ *	code to management function for global temparary table
+ *
+ * IDENTIFICATION
+ *	  contrib/pg_gtt/pg_gtt.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <unistd.h>
+#include <sys/time.h>
+#include "port.h"
+#include "access/htup_details.h"
+#include "access/table.h"
+#include "access/xlog.h"
+#include "catalog/pg_type.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/namespace.h"
+#include "catalog/pg_class.h"
+#include "funcapi.h"
+#include "storage/ipc.h"
+#include "storage/shmem.h"
+#include "storage/lwlock.h"
+#include "storage/procarray.h"
+#include "storage/proc.h"
+#include "tcop/utility.h"
+#include "utils/builtins.h"
+#include "utils/memutils.h"
+#include "utils/timeout.h"
+#include "utils/guc.h"
+#include "utils/lsyscache.h"
+#include "utils/rel.h"
+#include <nodes/makefuncs.h>
+#include "storage/sinvaladt.h"
+#include "miscadmin.h"
+
+PG_MODULE_MAGIC;
+
+static Oid pg_get_relid(const char *relname, char *schema);
+
+Datum pg_gtt_att_statistic(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(pg_gtt_att_statistic);
+
+Datum pg_gtt_relstats(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(pg_gtt_relstats);
+
+Datum pg_gtt_attached_pid(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(pg_gtt_attached_pid);
+
+Datum pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS);
+PG_FUNCTION_INFO_V1(pg_list_gtt_relfrozenxids);
+
+void		_PG_init(void);
+void		_PG_fini(void);
+
+void
+_PG_init(void)
+{
+	return;
+}
+
+void
+_PG_fini(void)
+{
+	return;
+}
+
+static Oid
+pg_get_relid(const char *relname, char *schema)
+{
+	Oid			relid;
+	RangeVar   *rv = makeRangeVar(schema, (char *)relname, -1);
+
+	relid = RangeVarGetRelid(rv, NoLock, true);
+
+	pfree(rv);
+	return relid;
+}
+
+Datum
+pg_gtt_att_statistic(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc		tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple		tuple;
+	Relation	rel = NULL;
+	char	*relname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	char	*schema = text_to_cstring(PG_GETARG_TEXT_PP(1));
+	int		attnum = PG_GETARG_INT32(2);
+	Oid		reloid;
+	char	rel_persistence;
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = NULL;
+	rsinfo->setDesc = NULL;
+
+	tupdesc = CreateTemplateTupleDesc(31);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "starelid",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "staattnum",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 3, "stainherit",
+						BOOLOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 4, "stanullfrac",
+						FLOAT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "stawidth",
+						INT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "stadistinct",
+						FLOAT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 7, "stakind1",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 8, "stakind2",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 9, "stakind3",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 10, "stakind4",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 11, "stakind5",
+						INT2OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 12, "staop1",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 13, "staop2",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 14, "staop3",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 15, "staop4",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 16, "staop5",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 17, "stacoll1",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 18, "stacoll2",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 19, "stacoll3",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 20, "stacoll4",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 21, "stacoll5",
+						OIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 22, "stanumbers1",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 23, "stanumbers2",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 24, "stanumbers3",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 25, "stanumbers4",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 26, "stanumbers5",
+						FLOAT4ARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 27, "stavalues1",
+						ANYARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 28, "stavalues2",
+						ANYARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 29, "stavalues3",
+						ANYARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 30, "stavalues4",
+						ANYARRAYOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 31, "stavalues5",
+						ANYARRAYOID, -1, 0);
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (schema == NULL)
+		schema = "public";
+
+	reloid = pg_get_relid(relname, schema);
+	if (reloid == InvalidOid)
+	{
+		elog(WARNING, "relation %s.%s does not exist", schema, relname);
+		return (Datum) 0;
+	}
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation %s.%s not global temp table", schema, relname);
+		return (Datum) 0;
+	}
+
+	tuple = get_gtt_att_statistic(reloid, attnum, false);
+	if (tuple)
+	{
+		HeapTuple tp = heap_copytuple(tuple);
+		tuplestore_puttuple(tupstore, tp);
+	}
+	tuplestore_donestoring(tupstore);
+
+	table_close(rel, NoLock);
+	return (Datum) 0;
+}
+
+Datum
+pg_gtt_relstats(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	char	*relname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	char	*schema = text_to_cstring(PG_GETARG_TEXT_PP(1));
+	Oid	reloid;
+	char	rel_persistence;
+	Datum	values[5];
+	bool	isnull[5];
+	BlockNumber	relpages = 0;
+	double		reltuples = 0;
+	BlockNumber	relallvisible = 0;
+	uint32		relfrozenxid = 0;
+	uint32		relminmxid = 0;
+	Relation	rel = NULL;
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = NULL;
+	rsinfo->setDesc = NULL;
+
+	tupdesc = CreateTemplateTupleDesc(5);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "relpages",
+						INT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "reltuples",
+						FLOAT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 3, "relallvisible",
+						INT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 4, "relfrozenxid",
+						XIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "relminmxid",
+						XIDOID, -1, 0);
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (schema == NULL)
+		schema = "public";
+
+	reloid = pg_get_relid(relname, schema);
+	if (reloid == InvalidOid)
+	{
+		elog(WARNING, "relation %s.%s does not exist", schema, relname);
+		return (Datum) 0;
+	}
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation %s.%s not global temp table", schema, relname);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	get_gtt_relstats(reloid,
+					&relpages, &reltuples, &relallvisible,
+					&relfrozenxid, &relminmxid);
+
+	memset(isnull, false, sizeof(isnull));
+	memset(values, 0, sizeof(values));
+	values[0] = Int32GetDatum(relpages);
+	values[1] = Float4GetDatum((float4)reltuples);
+	values[2] = Int32GetDatum(relallvisible);
+	values[3] = UInt32GetDatum(relfrozenxid);
+	values[4] = UInt32GetDatum(relminmxid);
+	tuple = heap_form_tuple(tupdesc, values, isnull);
+	tuplestore_puttuple(tupstore, tuple);
+	tuplestore_donestoring(tupstore);
+
+	table_close(rel, NoLock);
+	return (Datum) 0;
+}
+
+Datum
+pg_gtt_attached_pid(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	char	*relname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	char	*schema = text_to_cstring(PG_GETARG_TEXT_PP(1));
+	Oid	reloid;
+	char	rel_persistence;
+	Datum	values[1];
+	bool	isnull[1];
+	Relation	rel = NULL;
+	PGPROC		*proc = NULL;
+	Bitmapset	*map = NULL;
+	pid_t		pid = 0;
+	int			backendid = 0;
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = NULL;
+	rsinfo->setDesc = NULL;
+
+	tupdesc = CreateTemplateTupleDesc(1);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "pid",
+						INT4OID, -1, 0);
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (schema == NULL)
+		schema = "public";
+
+	reloid = pg_get_relid(relname, schema);
+	if (reloid == InvalidOid)
+	{
+		elog(WARNING, "relation %s.%s does not exist", schema, relname);
+		return (Datum) 0;
+	}
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation %s.%s not global temp table", schema, relname);
+		return (Datum) 0;
+	}
+
+	map = copy_active_gtt_bitmap(rel->rd_node);
+	if (map)
+	{
+		backendid = bms_first_member(map);
+
+		do
+		{
+			proc = BackendIdGetProc(backendid);
+			pid = proc->pid;
+			if (pid > 0)
+			{
+				memset(isnull, false, sizeof(isnull));
+				memset(values, 0, sizeof(values));
+				values[0] = Int32GetDatum(pid);
+				tuple = heap_form_tuple(tupdesc, values, isnull);
+				tuplestore_puttuple(tupstore, tuple);
+			}
+			backendid = bms_next_member(map, backendid);
+		} while (backendid > 0);
+
+		pfree(map);
+	}
+
+	tuplestore_donestoring(tupstore);
+	table_close(rel, NoLock);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	Datum	values[3];
+	bool	isnull[3];
+	int			num_xid = MaxBackends + 1;
+	int			*pids = NULL;
+	uint32		*xids = NULL;
+	int			i = 0;
+	int			j = 0;
+	uint32		oldest = 0;
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = NULL;
+	rsinfo->setDesc = NULL;
+
+	tupdesc = CreateTemplateTupleDesc(3);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "pid",
+						INT4OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "relfrozenxid",
+						XIDOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 3, "relminmxid",
+						XIDOID, -1, 0);
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (max_active_gtt <= 0)
+		return (Datum) 0;
+
+	if (RecoveryInProgress())
+		return (Datum) 0;
+
+	pids = palloc0(sizeof(int) * num_xid);
+	xids = palloc0(sizeof(int) * num_xid);
+	oldest = list_all_session_gtt_frozenxids(num_xid, pids, xids, &i);
+	if (i > 0)
+	{
+		if (i > 0)
+		{
+			pids[i] = 0;
+			xids[i] = oldest;
+			i++;
+		}
+
+		for(j = 0; j < i; j++)
+		{
+			memset(isnull, false, sizeof(isnull));
+			memset(values, 0, sizeof(values));
+			values[0] = Int32GetDatum(pids[j]);
+			values[1] = UInt32GetDatum(xids[j]);
+			values[2] = UInt32GetDatum(0);
+			tuple = heap_form_tuple(tupdesc, values, isnull);
+			tuplestore_puttuple(tupstore, tuple);
+		}
+	}
+	tuplestore_donestoring(tupstore);
+	pfree(pids);
+	pfree(xids);
+
+	return (Datum) 0;
+}
+
diff --git a/contrib/pg_gtt/pg_gtt.control b/contrib/pg_gtt/pg_gtt.control
new file mode 100644
index 0000000..342af1d
--- /dev/null
+++ b/contrib/pg_gtt/pg_gtt.control
@@ -0,0 +1,4 @@
+comment = 'pg_gtt'
+default_version = '1.0'
+module_pathname = '$libdir/pg_gtt'
+relocatable = true
diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c
index d8790ad..7e30039 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -158,6 +158,19 @@ static relopt_bool boolRelOpts[] =
 		},
 		true
 	},
+	/*
+	 * For global temp table only
+	 * use AccessExclusiveLock for ensure safety
+	 */
+	{
+		{
+			"on_commit_delete_rows",
+			"global temp table on commit options",
+			RELOPT_KIND_HEAP,
+			ShareUpdateExclusiveLock
+		},
+		true
+	},	
 	/* list terminator */
 	{{NULL}}
 };
@@ -1475,6 +1488,8 @@ bytea *
 default_reloptions(Datum reloptions, bool validate, relopt_kind kind)
 {
 	static const relopt_parse_elt tab[] = {
+		{"on_commit_delete_rows", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, on_commit_delete_rows)},
 		{"fillfactor", RELOPT_TYPE_INT, offsetof(StdRdOptions, fillfactor)},
 		{"autovacuum_enabled", RELOPT_TYPE_BOOL,
 		offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, enabled)},
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index a23dec7..79bdb26 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -1014,7 +1014,9 @@ gistGetFakeLSN(Relation rel)
 {
 	static XLogRecPtr counter = FirstNormalUnloggedLSN;
 
-	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	/* global temp is same as local temp table */
+	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		rel->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 	{
 		/*
 		 * Temporary relations are only accessible in our session, so a simple
diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index 5cc30da..49b7d2e 100644
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -148,7 +148,9 @@ hashbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	 * metapage, nor the first bitmap page.
 	 */
 	sort_threshold = (maintenance_work_mem * 1024L) / BLCKSZ;
-	if (index->rd_rel->relpersistence != RELPERSISTENCE_TEMP)
+	/* global temp table is same as local temp table */
+	if (!(index->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		index->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		sort_threshold = Min(sort_threshold, NBuffers);
 	else
 		sort_threshold = Min(sort_threshold, NLocBuffer);
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 2dd8821..24c56b9 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -601,7 +601,7 @@ heapam_relation_set_new_filenode(Relation rel,
 	 */
 	*minmulti = GetOldestMultiXactId();
 
-	srel = RelationCreateStorage(*newrnode, persistence);
+	srel = RelationCreateStorage(*newrnode, persistence, rel);
 
 	/*
 	 * If required, set up an init fork for an unlogged table so that it can
@@ -654,7 +654,7 @@ heapam_relation_copy_data(Relation rel, const RelFileNode *newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index a3c4a1d..03fac55 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -60,6 +60,7 @@
 #include "utils/pg_rusage.h"
 #include "utils/timestamp.h"
 
+#include "catalog/storage_gtt.h"
 
 /*
  * Space/time tradeoff parameters: do these need to be user-tunable?
@@ -214,8 +215,10 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 	Assert(params->truncate != VACOPT_TERNARY_DEFAULT);
 
 	/* not every AM requires these to be valid, but heap does */
-	Assert(TransactionIdIsNormal(onerel->rd_rel->relfrozenxid));
-	Assert(MultiXactIdIsValid(onerel->rd_rel->relminmxid));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relfrozenxid == InvalidTransactionId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && TransactionIdIsNormal(onerel->rd_rel->relfrozenxid)));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relminmxid == InvalidMultiXactId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && MultiXactIdIsValid(onerel->rd_rel->relminmxid)));
 
 	/* measure elapsed time iff autovacuum logging requires it */
 	if (IsAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
@@ -274,8 +277,19 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 
 	vacrelstats = (LVRelStats *) palloc0(sizeof(LVRelStats));
 
-	vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
-	vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
+	/* get relstat from gtt localhash */
+	if (RELATION_IS_GLOBAL_TEMP(onerel))
+	{
+		get_gtt_relstats(RelationGetRelid(onerel),
+						&vacrelstats->old_rel_pages,
+						&vacrelstats->old_live_tuples,
+						NULL, NULL, NULL);
+	}
+	else
+	{
+		vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
+		vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
+	}
 	vacrelstats->num_index_scans = 0;
 	vacrelstats->pages_removed = 0;
 	vacrelstats->lock_waiter_detected = false;
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index 268f869..8b2e610 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -763,7 +763,14 @@ _bt_getbuf(Relation rel, BlockNumber blkno, int access)
 		/* Read an existing block of the relation */
 		buf = ReadBuffer(rel, blkno);
 		LockBuffer(buf, access);
-		_bt_checkpage(rel, buf);
+
+		/* global temp table may be not yet initialized for this backend. */
+		if (RELATION_IS_GLOBAL_TEMP(rel) &&
+			blkno == BTREE_METAPAGE &&
+			PageIsNew(BufferGetPage(buf)))
+			_bt_initmetapage(BufferGetPage(buf), P_NONE, 0);
+		else
+			_bt_checkpage(rel, buf);
 	}
 	else
 	{
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 2e3cc51..b8a57b6 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6314,6 +6314,10 @@ StartupXLOG(void)
 	else
 		recoveryTargetTLI = ControlFile->checkPointCopy.ThisTimeLineID;
 
+	/* clean temp relation files */
+	if (max_active_gtt > 0)
+		RemovePgTempFiles();
+
 	/*
 	 * Check for signal files, and if so set up state for offline recovery
 	 */
diff --git a/src/backend/catalog/Makefile b/src/backend/catalog/Makefile
index a511532..665b7fb 100644
--- a/src/backend/catalog/Makefile
+++ b/src/backend/catalog/Makefile
@@ -44,6 +44,8 @@ OBJS = \
 	storage.o \
 	toasting.o
 
+OBJS += storage_gtt.o
+
 BKIFILES = postgres.bki postgres.description postgres.shdescription
 
 include $(top_srcdir)/src/backend/common.mk
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index 1af31c2..ecb516e 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -399,7 +399,9 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class, char relpersistence)
 
 	switch (relpersistence)
 	{
+		/* global temp table is same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			break;
 		case RELPERSISTENCE_UNLOGGED:
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index b7bcdd9..6e089dd 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -61,6 +61,7 @@
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "commands/tablecmds.h"
 #include "commands/typecmds.h"
 #include "executor/executor.h"
@@ -100,6 +101,7 @@ static void AddNewRelationTuple(Relation pg_class_desc,
 								Oid reloftype,
 								Oid relowner,
 								char relkind,
+								char relpersistence,
 								TransactionId relfrozenxid,
 								TransactionId relminmxid,
 								Datum relacl,
@@ -405,6 +407,10 @@ heap_create(const char *relname,
 									 relpersistence,
 									 relkind);
 
+	/* global temp table not create storage file when catalog create */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		create_storage = false;
+
 	/*
 	 * Have the storage manager create the relation's disk file, if needed.
 	 *
@@ -428,7 +434,7 @@ heap_create(const char *relname,
 
 			case RELKIND_INDEX:
 			case RELKIND_SEQUENCE:
-				RelationCreateStorage(rel->rd_node, relpersistence);
+				RelationCreateStorage(rel->rd_node, relpersistence, rel);
 				break;
 
 			case RELKIND_RELATION:
@@ -925,6 +931,7 @@ AddNewRelationTuple(Relation pg_class_desc,
 					Oid reloftype,
 					Oid relowner,
 					char relkind,
+					char relpersistence,
 					TransactionId relfrozenxid,
 					TransactionId relminmxid,
 					Datum relacl,
@@ -963,8 +970,18 @@ AddNewRelationTuple(Relation pg_class_desc,
 			break;
 	}
 
-	new_rel_reltup->relfrozenxid = relfrozenxid;
-	new_rel_reltup->relminmxid = relminmxid;
+	/* global temp table not remember transaction info in catalog */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		new_rel_reltup->relfrozenxid = InvalidTransactionId;
+		new_rel_reltup->relminmxid = InvalidMultiXactId;
+	}
+	else
+	{
+		new_rel_reltup->relfrozenxid = relfrozenxid;
+		new_rel_reltup->relminmxid = relminmxid;
+	}
+
 	new_rel_reltup->relowner = relowner;
 	new_rel_reltup->reltype = new_type_oid;
 	new_rel_reltup->reloftype = reloftype;
@@ -1326,6 +1343,7 @@ heap_create_with_catalog(const char *relname,
 						reloftypeid,
 						ownerid,
 						relkind,
+						relpersistence,
 						relfrozenxid,
 						relminmxid,
 						PointerGetDatum(relacl),
@@ -1410,11 +1428,15 @@ heap_create_with_catalog(const char *relname,
 	 */
 	StoreConstraints(new_rel_desc, cooked_constraints, is_internal);
 
-	/*
-	 * If there's a special on-commit action, remember it
-	 */
-	if (oncommit != ONCOMMIT_NOOP)
-		register_on_commit_action(relid, oncommit);
+	/* global temp table register action when storage init */
+	if (relpersistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		/*
+		 * If there's a special on-commit action, remember it
+		 */
+		if (oncommit != ONCOMMIT_NOOP)
+			register_on_commit_action(relid, oncommit);
+	}
 
 	/*
 	 * ok, the relation has been cataloged, so close our relations and return
@@ -1906,6 +1928,13 @@ heap_drop_with_catalog(Oid relid)
 	if (relid == defaultPartOid)
 		update_default_partition_oid(parentOid, InvalidOid);
 
+	/* We allow to drop global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (is_other_backend_use_gtt(rel->rd_node))
+			elog(ERROR, "can not drop relation when other backend attached this global temp table");
+	}
+
 	/*
 	 * Schedule unlinking of the relation's physical files at commit.
 	 */
@@ -3132,9 +3161,10 @@ RemoveStatistics(Oid relid, AttrNumber attnum)
  *
  * The routine will truncate and then reconstruct the indexes on
  * the specified relation.  Caller must hold exclusive lock on rel.
+ *
  */
 static void
-RelationTruncateIndexes(Relation heapRelation)
+RelationTruncateIndexes(Relation heapRelation, LOCKMODE lockmode)
 {
 	ListCell   *indlist;
 
@@ -3146,7 +3176,7 @@ RelationTruncateIndexes(Relation heapRelation)
 		IndexInfo  *indexInfo;
 
 		/* Open the index relation; use exclusive lock, just to be sure */
-		currentIndex = index_open(indexId, AccessExclusiveLock);
+		currentIndex = index_open(indexId, lockmode);
 
 		/* Fetch info needed for index_build */
 		indexInfo = BuildIndexInfo(currentIndex);
@@ -3185,8 +3215,13 @@ heap_truncate(List *relids)
 	{
 		Oid			rid = lfirst_oid(cell);
 		Relation	rel;
+		LOCKMODE	lockmode = AccessExclusiveLock;
 
-		rel = table_open(rid, AccessExclusiveLock);
+		/* truncate global temp table only need RowExclusiveLock */
+		if (get_rel_persistence(rid) == RELPERSISTENCE_GLOBAL_TEMP)
+			lockmode = RowExclusiveLock;
+
+		rel = table_open(rid, lockmode);
 		relations = lappend(relations, rel);
 	}
 
@@ -3219,6 +3254,8 @@ void
 heap_truncate_one_rel(Relation rel)
 {
 	Oid			toastrelid;
+	LOCKMODE	lockmode = AccessExclusiveLock;
+	bool		truncate_toastrel = false;
 
 	/*
 	 * Truncate the relation.  Partitioned tables have no storage, so there is
@@ -3227,23 +3264,40 @@ heap_truncate_one_rel(Relation rel)
 	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 		return;
 
+	toastrelid = rel->rd_rel->reltoastrelid;
+
+	/*
+	 * Truncate global temp table only need RowExclusiveLock
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		lockmode = RowExclusiveLock;
+		if (OidIsValid(toastrelid) &&
+			gtt_storage_attached(toastrelid))
+			truncate_toastrel = true;
+	}
+	else if (OidIsValid(toastrelid))
+		truncate_toastrel = true;
+
 	/* Truncate the underlying relation */
 	table_relation_nontransactional_truncate(rel);
 
 	/* If the relation has indexes, truncate the indexes too */
-	RelationTruncateIndexes(rel);
+	RelationTruncateIndexes(rel, lockmode);
 
 	/* If there is a toast table, truncate that too */
-	toastrelid = rel->rd_rel->reltoastrelid;
-	if (OidIsValid(toastrelid))
+	if (truncate_toastrel)
 	{
-		Relation	toastrel = table_open(toastrelid, AccessExclusiveLock);
+		Relation	toastrel = table_open(toastrelid, lockmode);
 
 		table_relation_nontransactional_truncate(toastrel);
-		RelationTruncateIndexes(toastrel);
+		RelationTruncateIndexes(toastrel, lockmode);
 		/* keep the lock... */
 		table_close(toastrel, NoLock);
 	}
+
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		up_gtt_relstats(rel, 0, 0, 0, RecentXmin, InvalidMultiXactId);
 }
 
 /*
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 7c34509..a9ed190 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -52,6 +52,7 @@
 #include "catalog/pg_trigger.h"
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
+#include "catalog/storage_gtt.h"
 #include "commands/event_trigger.h"
 #include "commands/progress.h"
 #include "commands/tablecmds.h"
@@ -879,6 +880,26 @@ index_create(Relation heapRelation,
 						indexRelationName, RelationGetRelationName(heapRelation))));
 	}
 
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		if (accessMethodObjectId != BTREE_AM_OID)
+			elog(ERROR, "only support btree index on global temp table");
+
+		/* We allow to create index on global temp table only this session use it */
+		if (is_other_backend_use_gtt(heapRelation->rd_node))
+			elog(ERROR, "can not create index when have other backend attached this global temp table");
+
+		/* No support create index on global temp table use concurrent mode yet */
+		if (concurrent)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("cannot create indexes on global temporary tables using concurrent mode")));
+
+		/* if global temp table not init storage, then skip build index */
+		if (!gtt_storage_attached(heapRelation->rd_node.relNode))
+			flags |= INDEX_CREATE_SKIP_BUILD;
+	}
+
 	/*
 	 * construct tuple descriptor for index tuples
 	 */
@@ -2047,6 +2068,13 @@ index_drop(Oid indexId, bool concurrent, bool concurrent_lock_mode)
 	 */
 	CheckTableNotInUse(userIndexRelation, "DROP INDEX");
 
+	/* We allow to drop index on global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(userHeapRelation))
+	{
+		if (is_other_backend_use_gtt(userHeapRelation->rd_node))
+			elog(ERROR, "can not drop index when other backend attached this global temp table");
+	}
+
 	/*
 	 * Drop Index Concurrently is more or less the reverse process of Create
 	 * Index Concurrently.
@@ -2688,20 +2716,29 @@ index_update_stats(Relation rel,
 		else					/* don't bother for indexes */
 			relallvisible = 0;
 
-		if (rd_rel->relpages != (int32) relpages)
+		/* update index stats into localhash for global temp table */
+		if (RELATION_IS_GLOBAL_TEMP(rel))
 		{
-			rd_rel->relpages = (int32) relpages;
-			dirty = true;
+			up_gtt_relstats(rel, relpages, reltuples, relallvisible,
+							InvalidTransactionId, InvalidMultiXactId);
 		}
-		if (rd_rel->reltuples != (float4) reltuples)
-		{
-			rd_rel->reltuples = (float4) reltuples;
-			dirty = true;
-		}
-		if (rd_rel->relallvisible != (int32) relallvisible)
+		else
 		{
-			rd_rel->relallvisible = (int32) relallvisible;
-			dirty = true;
+			if (rd_rel->relpages != (int32) relpages)
+			{
+				rd_rel->relpages = (int32) relpages;
+				dirty = true;
+			}
+			if (rd_rel->reltuples != (float4) reltuples)
+			{
+				rd_rel->reltuples = (float4) reltuples;
+				dirty = true;
+			}
+			if (rd_rel->relallvisible != (int32) relallvisible)
+			{
+				rd_rel->relallvisible = (int32) relallvisible;
+				dirty = true;
+			}
 		}
 	}
 
@@ -2816,6 +2853,13 @@ index_build(Relation heapRelation,
 		pgstat_progress_update_multi_param(6, index, val);
 	}
 
+	/* POALR */
+	if (RELATION_IS_GLOBAL_TEMP(indexRelation))
+	{
+		if (!gtt_storage_attached(indexRelation->rd_node.relNode))
+			RelationCreateStorage(indexRelation->rd_node, RELPERSISTENCE_GLOBAL_TEMP, indexRelation);
+	}
+
 	/*
 	 * Call the access method's build procedure
 	 */
@@ -3148,12 +3192,22 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	/*
 	 * Scan the index and gather up all the TIDs into a tuplesort object.
 	 */
+	memset(&ivinfo, 0, sizeof(IndexVacuumInfo));
 	ivinfo.index = indexRelation;
 	ivinfo.analyze_only = false;
 	ivinfo.report_progress = true;
 	ivinfo.estimated_count = true;
 	ivinfo.message_level = DEBUG2;
-	ivinfo.num_heap_tuples = heapRelation->rd_rel->reltuples;
+
+	/* get relstats abort global temp table from hashtable, not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		get_gtt_relstats(RelationGetRelid(heapRelation),
+						NULL, &ivinfo.num_heap_tuples, NULL,
+						NULL, NULL);
+	}
+	else
+		ivinfo.num_heap_tuples = heapRelation->rd_rel->reltuples;
 	ivinfo.strategy = NULL;
 
 	/*
@@ -3411,6 +3465,15 @@ reindex_index(Oid indexId, bool skip_constraint_checks, char persistence,
 				 errmsg("cannot reindex temporary tables of other sessions")));
 
 	/*
+	 * Because global temp table cannot change relfilenode
+	 * no support reindex on global temp table yet.
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(iRel))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot reindex global temporary tables")));
+
+	/*
 	 * Also check for active uses of the index in the current transaction; we
 	 * don't want to reindex underneath an open indexscan.
 	 */
diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index e251f5a..97bf247 100644
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -647,6 +647,13 @@ RangeVarAdjustRelationPersistence(RangeVar *newRelation, Oid nspid)
 							 errmsg("cannot create temporary relation in non-temporary schema")));
 			}
 			break;
+		/* global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			if (isAnyTempNamespace(nspid))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+						 errmsg("cannot create global temp relations in temporary schemas")));
+			break;
 		case RELPERSISTENCE_PERMANENT:
 			if (isTempOrTempToastNamespace(nspid))
 				newRelation->relpersistence = RELPERSISTENCE_TEMP;
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index 625af8d..baf7d61 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -28,6 +28,7 @@
 #include "access/xlogutils.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "storage/freespace.h"
 #include "storage/smgr.h"
 #include "utils/memutils.h"
@@ -74,9 +75,10 @@ static PendingRelDelete *pendingDeletes = NULL; /* head of linked list */
  *
  * This function is transactional. The creation is WAL-logged, and if the
  * transaction aborts later on, the storage will be destroyed.
+ *
  */
 SMgrRelation
-RelationCreateStorage(RelFileNode rnode, char relpersistence)
+RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel)
 {
 	PendingRelDelete *pending;
 	SMgrRelation srel;
@@ -86,6 +88,8 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	switch (relpersistence)
 	{
 		case RELPERSISTENCE_TEMP:
+		/* global temp table use same storage strategy as local temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			needs_wal = false;
 			break;
@@ -118,6 +122,10 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	pending->next = pendingDeletes;
 	pendingDeletes = pending;
 
+	/* remember global temp table storage info to localhash */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP && rel)
+		remember_gtt_storage_info(rnode, rel);
+
 	return srel;
 }
 
@@ -487,8 +495,15 @@ smgrDoPendingDeletes(bool isCommit)
 		smgrdounlinkall(srels, nrels, false);
 
 		for (i = 0; i < nrels; i++)
+		{
 			smgrclose(srels[i]);
 
+			/* clean global temp table flags when transaction commit or rollback */
+			if (SmgrIsTemp(srels[i]) && 
+				gtt_storage_attached(srels[i]->smgr_rnode.node.relNode))
+				forget_gtt_storage_info(srels[i]->smgr_rnode.node.relNode);
+		}
+
 		pfree(srels);
 	}
 }
diff --git a/src/backend/catalog/storage_gtt.c b/src/backend/catalog/storage_gtt.c
new file mode 100644
index 0000000..0749afc
--- /dev/null
+++ b/src/backend/catalog/storage_gtt.c
@@ -0,0 +1,813 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.c
+ *	  code to create and destroy physical storage for global temparary table
+ *
+ * IDENTIFICATION
+ *	  src/backend/catalog/storage_gtt.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/visibilitymap.h"
+#include "access/xact.h"
+#include "access/xlog.h"
+#include "access/xloginsert.h"
+#include "access/xlogutils.h"
+#include "access/htup_details.h"
+#include "access/multixact.h"
+#include "catalog/storage.h"
+#include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/heap.h"
+#include "commands/tablecmds.h"
+#include "nodes/primnodes.h"
+#include "nodes/pg_list.h"
+#include "miscadmin.h"
+#include "storage/freespace.h"
+#include "storage/smgr.h"
+#include "storage/ipc.h"
+#include "storage/proc.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "utils/memutils.h"
+#include "utils/rel.h"
+#include "utils/hsearch.h"
+#include "utils/catcache.h"
+#include <utils/relcache.h>
+#include "utils/inval.h"
+#include "utils/guc.h"
+#include "utils/guc.h"
+
+
+/* Copy from bitmapset.c, because gtt used the function in bitmapset.c */
+#define WORDNUM(x)	((x) / BITS_PER_BITMAPWORD)
+#define BITNUM(x)	((x) % BITS_PER_BITMAPWORD)
+
+#define BITMAPSET_SIZE(nwords)	\
+	(offsetof(Bitmapset, words) + (nwords) * sizeof(bitmapword))
+
+static bool gtt_cleaner_exit_registered = false;
+static HTAB *gtt_storage_local_hash = NULL;
+static HTAB *active_gtt_shared_hash = NULL;
+static MemoryContext gtt_relstats_context = NULL;
+
+/* relfrozenxid of all gtts in the current session */
+static List *gtt_session_relfrozenxid_list = NIL;
+static TransactionId gtt_session_frozenxid = InvalidTransactionId;
+
+typedef struct gtt_ctl_data
+{
+	LWLock			lock;
+	int			max_entry;
+	int			entry_size;
+}gtt_ctl_data;
+
+static gtt_ctl_data *gtt_shared_ctl = NULL;
+
+typedef struct
+{
+	RelFileNode	rnode;
+	Bitmapset	*map;
+	/* bitmap data */
+} gtt_shared_hash_entry;
+
+typedef struct
+{
+	Oid			relid;
+
+	Oid			spcnode;
+	/* pg_class stat */
+	int32		relpages;
+	float4		reltuples;
+	int32		relallvisible;
+	TransactionId relfrozenxid;
+	TransactionId relminmxid;
+	char		relkind;
+	bool		on_commit_delete;
+
+	/* pg_statistic */
+	int			natts;
+	int			*attnum;
+	HeapTuple	*att_stat_tups;
+} gtt_local_hash_entry;
+
+static Size action_gtt_shared_hash_entry_size(void);
+static void gtt_storage_checkin(RelFileNode rnode);
+static void gtt_storage_checkout(RelFileNode rnode, bool skiplock);
+static void gtt_storage_removeall(int code, Datum arg);
+static void insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid);
+static void remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid);
+static void set_gtt_session_relfrozenxid(void);
+
+static Size
+action_gtt_shared_hash_entry_size(void)
+{
+	int 	wordnum;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	wordnum = WORDNUM(MaxBackends + 1);
+	hash_entry_size += MAXALIGN(sizeof(gtt_shared_hash_entry));
+	hash_entry_size += MAXALIGN(BITMAPSET_SIZE(wordnum + 1));
+
+	return hash_entry_size;
+}
+
+Size
+active_gtt_shared_hash_size(void)
+{
+	Size	size = 0;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	size = MAXALIGN(sizeof(gtt_ctl_data));
+	hash_entry_size = action_gtt_shared_hash_entry_size();
+	size += hash_estimate_size(max_active_gtt, hash_entry_size);
+
+	return size;
+}
+
+void
+active_gtt_shared_hash_init(void)
+{
+	HASHCTL info;
+	bool	found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	gtt_shared_ctl =
+		ShmemInitStruct("gtt_shared_ctl",
+						sizeof(gtt_ctl_data),
+						&found);
+
+	if (!found)
+	{
+		LWLockRegisterTranche(LWTRANCHE_GTT_CTL, "gtt_shared_ctl");
+		LWLockInitialize(&gtt_shared_ctl->lock, LWTRANCHE_GTT_CTL);
+		gtt_shared_ctl->max_entry = max_active_gtt;
+		gtt_shared_ctl->entry_size = action_gtt_shared_hash_entry_size();
+	}
+
+	info.keysize = sizeof(RelFileNode);
+	info.entrysize = gtt_shared_ctl->entry_size;
+	active_gtt_shared_hash =
+		ShmemInitHash("active gtt shared hash",
+						gtt_shared_ctl->max_entry,
+						gtt_shared_ctl->max_entry,
+						&info, HASH_ELEM | HASH_BLOBS | HASH_FIXED_SIZE);
+}
+
+static void
+gtt_storage_checkin(RelFileNode rnode)
+{
+	gtt_shared_hash_entry	*entry;
+	bool			found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+	entry = (gtt_shared_hash_entry *) hash_search(active_gtt_shared_hash,
+												&rnode, HASH_ENTER_NULL, &found);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		ereport(ERROR,
+				(errcode(ERRCODE_OUT_OF_MEMORY),
+				 errmsg("out of shared memory"),
+				 errhint("You might need to increase max_active_gtt.")));
+	}
+
+	if (found == false)
+	{
+		int			wordnum;
+
+		entry->map = (Bitmapset *)((char *)entry + MAXALIGN(sizeof(gtt_shared_hash_entry)));
+		wordnum = WORDNUM(MaxBackends + 1);
+		memset(entry->map, 0, BITMAPSET_SIZE(wordnum + 1));
+		entry->map->nwords = wordnum + 1;
+	}
+
+	bms_add_member(entry->map, MyBackendId);
+	LWLockRelease(&gtt_shared_ctl->lock);
+}
+
+static void
+gtt_storage_checkout(RelFileNode rnode, bool skiplock)
+{
+	gtt_shared_hash_entry	*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (!skiplock)
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(rnode), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		if (!skiplock)
+			LWLockRelease(&gtt_shared_ctl->lock);
+
+		elog(WARNING, "relfilenode %u/%u/%u not exist in gtt shared hash when forget",
+						rnode.dbNode, rnode.spcNode, rnode.relNode);
+		return;
+	}
+
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+	bms_del_member(entry->map, MyBackendId);
+
+	if (bms_is_empty(entry->map))
+	{
+		if (!hash_search(active_gtt_shared_hash, &rnode, HASH_REMOVE, NULL))
+			elog(PANIC, "gtt shared hash table corrupted");
+	}
+
+	if (!skiplock)
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+	return;
+}
+
+Bitmapset *
+copy_active_gtt_bitmap(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	Bitmapset	*map_copy = NULL;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return NULL;
+	}
+
+	Assert(entry->map);
+	if (!bms_is_empty(entry->map))
+		map_copy = bms_copy(entry->map);
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return map_copy;
+}
+
+bool
+is_other_backend_use_gtt(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	bool		in_use = false;
+	int			num_use = 0;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return false;
+	}
+
+	Assert(entry->map);
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+
+	num_use = bms_num_members(entry->map);
+	if (num_use == 0)
+		in_use = false;
+	else if (num_use == 1)
+	{
+		if(bms_is_member(MyBackendId, entry->map))
+			in_use = false;
+		else
+			in_use = true;
+	}
+	else
+		in_use = true;
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return in_use;
+}
+
+void
+remember_gtt_storage_info(RelFileNode rnode, Relation rel)
+{
+	gtt_local_hash_entry	*entry;
+	MemoryContext			oldcontext;
+	Oid			relid = rnode.relNode;
+	bool		found;
+
+	if (max_active_gtt <= 0)
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("Global temporary table feature is disable"),
+			 errhint("You might need to increase max_active_gtt to enable this feature.")));
+
+	if (RecoveryInProgress())
+		elog(ERROR, "readonly mode not support access global temp table yet");
+
+	if (gtt_storage_local_hash == NULL)
+	{
+#define GTT_LOCAL_HASH_SIZE		1024
+		/* First time through: initialize the hash table */
+		HASHCTL		ctl;
+
+		MemSet(&ctl, 0, sizeof(ctl));
+		ctl.keysize = sizeof(Oid);
+		ctl.entrysize = sizeof(gtt_local_hash_entry);
+		gtt_storage_local_hash =
+			hash_create("global temp relation table",
+						GTT_LOCAL_HASH_SIZE,
+						&ctl, HASH_ELEM | HASH_BLOBS);
+
+		if (!CacheMemoryContext)
+			CreateCacheMemoryContext();
+
+		gtt_relstats_context =
+			AllocSetContextCreate(CacheMemoryContext,
+							"gtt relstats context",
+							ALLOCSET_DEFAULT_SIZES);
+	}
+
+	/* Look up or create an entry */
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_ENTER, &found);
+
+	if (found)
+	{
+		elog(ERROR, "backend %d relid %u already exists in global temp table local hash",
+					MyBackendId, relid);
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+
+	entry->spcnode = rnode.spcNode;
+	entry->relpages = 0;
+	entry->reltuples = 0;
+	entry->relallvisible = 0;
+	entry->relkind = rel->rd_rel->relkind;
+	/* only heap contain transaction information */
+	if (entry->relkind == RELKIND_RELATION)
+	{
+		int natts = RelationGetNumberOfAttributes(rel);
+		entry->natts = natts;
+		entry->attnum = palloc0(sizeof(int) * natts);
+		entry->att_stat_tups = palloc0(sizeof(HeapTuple) * natts);
+
+		if (RELATION_GTT_ON_COMMIT_DELETE(rel))
+		{
+			entry->on_commit_delete = true;
+			register_on_commit_action(rel->rd_node.relNode, ONCOMMIT_DELETE_ROWS);
+		}
+
+		entry->relfrozenxid = RecentXmin;
+		entry->relminmxid = GetOldestMultiXactId();
+		insert_gtt_relfrozenxid_to_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+		gtt_storage_checkin(rnode);
+	}
+	else
+	{
+		entry->natts = 0;
+		entry->attnum = 0;
+		entry->att_stat_tups = NULL;
+		entry->on_commit_delete = false;
+		entry->relfrozenxid = 0;
+		entry->relminmxid = 0;
+	}
+
+	MemoryContextSwitchTo(oldcontext);
+
+	if (!gtt_cleaner_exit_registered)
+	{
+		before_shmem_exit(gtt_storage_removeall, 0);
+		gtt_cleaner_exit_registered = true;
+	}
+
+	return;
+}
+
+void
+forget_gtt_storage_info(Oid relid)
+{
+	gtt_local_hash_entry		*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+				(void *) &(relid), HASH_FIND, NULL);
+
+	if (entry && entry->relkind == RELKIND_RELATION)
+	{
+		RelFileNode rnode;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		gtt_storage_checkout(rnode, false);
+
+		Assert(TransactionIdIsNormal(entry->relfrozenxid));
+		remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+	}
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_REMOVE, NULL);
+
+	return;
+}
+
+/* is the storage file was created in this backend */
+bool
+gtt_storage_attached(Oid relid)
+{
+	bool found;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	if (gtt_storage_local_hash == NULL)
+		return false;
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_FIND, &found);
+
+	return found;
+}
+
+static void
+gtt_storage_removeall(int code, Datum arg)
+{
+	HASH_SEQ_STATUS				status;
+	gtt_local_hash_entry		*entry;
+	int			nrels = 0,
+				maxrels = 0;
+	SMgrRelation	*srels = NULL;
+	RelFileNode		*rnodes = NULL;
+	char			*relkinds = NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	hash_seq_init(&status, gtt_storage_local_hash);
+	while ((entry = (gtt_local_hash_entry *) hash_seq_search(&status)) != NULL)
+	{
+		SMgrRelation srel;
+		RelFileNode rnode;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		srel = smgropen(rnode, MyBackendId);
+
+		/* allocate the initial array, or extend it, if needed */
+		if (maxrels == 0)
+		{
+			maxrels = 32;
+			srels = palloc(sizeof(SMgrRelation) * maxrels);
+			rnodes = palloc(sizeof(RelFileNode) * maxrels);
+			relkinds = palloc(sizeof(char) * maxrels);
+		}
+		else if (maxrels <= nrels)
+		{
+			maxrels *= 2;
+			srels = repalloc(srels, sizeof(SMgrRelation) * maxrels);
+			rnodes = repalloc(rnodes, sizeof(RelFileNode) * maxrels);
+			relkinds = repalloc(relkinds, sizeof(char) * maxrels);
+		}
+
+		srels[nrels] = srel;
+		rnodes[nrels] = rnode;
+		relkinds[nrels] = entry->relkind;
+		nrels++;
+	}
+
+	if (nrels > 0)
+	{
+		int i;
+
+		smgrdounlinkall(srels, nrels, false);
+
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+		for (i = 0; i < nrels; i++)
+		{
+			smgrclose(srels[i]);
+			if (relkinds[i] == RELKIND_RELATION)
+				gtt_storage_checkout(rnodes[i], true);
+		}
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+		pfree(srels);
+		pfree(rnodes);
+		pfree(relkinds);
+	}
+
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;
+
+	return;
+}
+
+/*
+ * Update global temp table relstats(relpage/reltuple/relallvisible) 
+ * to local hashtable
+ */
+void
+up_gtt_relstats(Relation relation,
+					BlockNumber num_pages,
+					double num_tuples,
+					BlockNumber num_all_visible_pages,
+					TransactionId relfrozenxid,
+					TransactionId relminmxid)
+{
+	Oid		relid = RelationGetRelid(relation);
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	Assert(entry->spcnode);
+
+	if (num_pages >= 0 &&
+		entry->relpages != (int32)num_pages)
+		entry->relpages = (int32)num_pages;
+
+	if (num_tuples >= 0 &&
+		num_tuples != (float4)entry->reltuples)
+		entry->reltuples = (float4)num_tuples;
+
+	/* only heap contain transaction information and relallvisible */
+	if (entry->relkind == RELKIND_RELATION)
+	{
+		if (entry->relallvisible >= 0 &&
+			entry->relallvisible != (int32)num_all_visible_pages)
+		{
+			entry->relallvisible = (int32)num_all_visible_pages;
+		}
+
+		if (TransactionIdIsNormal(relfrozenxid) &&
+			entry->relfrozenxid != relfrozenxid &&
+			(TransactionIdPrecedes(entry->relfrozenxid, relfrozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(), entry->relfrozenxid)))
+		{
+			remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+			entry->relfrozenxid = relfrozenxid;
+			insert_gtt_relfrozenxid_to_ordered_list(relfrozenxid);
+			set_gtt_session_relfrozenxid();
+		}
+
+		if (MultiXactIdIsValid(relminmxid) &&
+			entry->relminmxid != relminmxid &&
+			(MultiXactIdPrecedes(entry->relminmxid, relminmxid) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), entry->relminmxid)))
+		{
+			entry->relminmxid = relminmxid;
+		}
+	}
+
+	return;
+}
+
+/*
+ * Search global temp table relstats(relpage/reltuple/relallvisible) 
+ * from local hashtable.
+ */
+void
+get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+				BlockNumber *relallvisible, TransactionId *relfrozenxid,
+				TransactionId *relminmxid)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	Assert(entry->relid == relid);
+
+	if (relpages)
+		*relpages = entry->relpages;
+
+	if (reltuples)
+		*reltuples = entry->reltuples;
+
+	if (relallvisible)
+		*relallvisible = entry->relallvisible;
+
+	if (relfrozenxid)
+		*relfrozenxid = entry->relfrozenxid;
+
+	if (relminmxid)
+		*relminmxid = entry->relminmxid;
+
+	return;
+}
+
+/*
+ * Update global temp table statistic info(definition is same as pg_statistic)
+ * to local hashtable where ananyze global temp table
+ */
+void
+up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+					TupleDesc tupleDescriptor, Datum *values, bool *isnull)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	MemoryContext			oldcontext;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	if (entry->relkind != RELKIND_RELATION)
+	{
+		elog(WARNING, "oid %u not a relation", reloid);
+		return;
+	}
+
+	/* todo */
+	if (entry->natts < natts)
+	{
+		elog(WARNING, "reloid %u not support update attstat after add colunm", reloid);
+		return;
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	Assert(entry->relid == reloid);
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == 0)
+		{
+			entry->attnum[i] = attnum;
+			break;
+		}
+		else if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			heap_freetuple(entry->att_stat_tups[i]);
+			entry->att_stat_tups[i] = NULL;
+			break;
+		}
+	}
+
+	Assert(i < entry->natts);
+	Assert(entry->att_stat_tups[i] == NULL);
+	entry->att_stat_tups[i] = heap_form_tuple(tupleDescriptor, values, isnull);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+/*
+ * Search global temp table statistic info(definition is same as pg_statistic)
+ * from local hashtable.
+ */
+HeapTuple
+get_gtt_att_statistic(Oid reloid, int attnum, bool inh)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return NULL;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return NULL;
+
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			return entry->att_stat_tups[i];
+		}
+	}
+
+	return NULL;
+}
+
+void
+release_gtt_statistic_cache(HeapTuple tup)
+{
+	/* do nothing */
+	return;
+}
+
+static void
+insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid)
+{
+	MemoryContext	oldcontext;
+	ListCell	*cell;
+	int			i;
+
+	Assert(TransactionIdIsNormal(relfrozenxid));
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	/* Does the datum belong at the front? */
+	if (gtt_session_relfrozenxid_list == NIL ||
+		TransactionIdFollowsOrEquals(relfrozenxid,
+			linitial_oid(gtt_session_relfrozenxid_list)))
+	{
+		gtt_session_relfrozenxid_list =
+			lcons_oid(relfrozenxid, gtt_session_relfrozenxid_list);
+		MemoryContextSwitchTo(oldcontext);
+
+		return;
+	}
+
+	/* No, so find the entry it belongs after */
+	i = 0;
+	foreach (cell, gtt_session_relfrozenxid_list)
+	{
+		if (TransactionIdFollowsOrEquals(relfrozenxid, lfirst_oid(cell)))
+			break;
+
+		i++;
+	}
+	gtt_session_relfrozenxid_list =
+		list_insert_nth_oid(gtt_session_relfrozenxid_list, i, relfrozenxid);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+static void
+remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid)
+{
+	gtt_session_relfrozenxid_list =
+		list_delete_oid(gtt_session_relfrozenxid_list, relfrozenxid);
+}
+
+static void
+set_gtt_session_relfrozenxid(void)
+{
+	TransactionId gtt_frozenxid = InvalidTransactionId;
+
+	if (gtt_session_relfrozenxid_list)
+		gtt_frozenxid = llast_oid(gtt_session_relfrozenxid_list);
+
+	gtt_session_frozenxid = gtt_frozenxid;
+	if (MyProc->session_gtt_frozenxid != gtt_frozenxid)
+		MyProc->session_gtt_frozenxid = gtt_frozenxid;
+}
+
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 7accb95..e0dc376 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -65,6 +65,7 @@
 #include "utils/syscache.h"
 #include "utils/timestamp.h"
 
+#include "catalog/storage_gtt.h"
 
 /* Per-index data for ANALYZE */
 typedef struct AnlIndexData
@@ -102,7 +103,7 @@ static int	acquire_inherited_sample_rows(Relation onerel, int elevel,
 										  HeapTuple *rows, int targrows,
 										  double *totalrows, double *totaldeadrows);
 static void update_attstats(Oid relid, bool inh,
-							int natts, VacAttrStats **vacattrstats);
+							int natts, VacAttrStats **vacattrstats, char relpersistence);
 static Datum std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 static Datum ind_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 
@@ -575,14 +576,15 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 		 * pg_statistic for columns we didn't process, we leave them alone.)
 		 */
 		update_attstats(RelationGetRelid(onerel), inh,
-						attr_cnt, vacattrstats);
+						attr_cnt, vacattrstats, RelationGetRelPersistence(onerel));
 
 		for (ind = 0; ind < nindexes; ind++)
 		{
 			AnlIndexData *thisdata = &indexdata[ind];
 
 			update_attstats(RelationGetRelid(Irel[ind]), false,
-							thisdata->attr_cnt, thisdata->vacattrstats);
+							thisdata->attr_cnt, thisdata->vacattrstats,
+							RelationGetRelPersistence(Irel[ind]));
 		}
 
 		/*
@@ -659,11 +661,20 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 			IndexBulkDeleteResult *stats;
 			IndexVacuumInfo ivinfo;
 
+			memset(&ivinfo, 0, sizeof(IndexVacuumInfo));
 			ivinfo.index = Irel[ind];
 			ivinfo.analyze_only = true;
 			ivinfo.estimated_count = true;
 			ivinfo.message_level = elevel;
-			ivinfo.num_heap_tuples = onerel->rd_rel->reltuples;
+			/* get global temp relstats from localhash, not catalog */
+			if (RELATION_IS_GLOBAL_TEMP(onerel))
+			{
+				get_gtt_relstats(RelationGetRelid(onerel),
+								NULL, &ivinfo.num_heap_tuples, NULL,
+								NULL, NULL);
+			}
+			else
+				ivinfo.num_heap_tuples = onerel->rd_rel->reltuples;
 			ivinfo.strategy = vac_strategy;
 
 			stats = index_vacuum_cleanup(&ivinfo, NULL);
@@ -1425,7 +1436,7 @@ acquire_inherited_sample_rows(Relation onerel, int elevel,
  *		by taking a self-exclusive lock on the relation in analyze_rel().
  */
 static void
-update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
+update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats, char relpersistence)
 {
 	Relation	sd;
 	int			attno;
@@ -1527,31 +1538,45 @@ update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
 			}
 		}
 
-		/* Is there already a pg_statistic tuple for this attribute? */
-		oldtup = SearchSysCache3(STATRELATTINH,
-								 ObjectIdGetDatum(relid),
-								 Int16GetDatum(stats->attr->attnum),
-								 BoolGetDatum(inh));
-
-		if (HeapTupleIsValid(oldtup))
+		/* Update column statistic to localhash, not catalog */
+		if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		{
-			/* Yes, replace it */
-			stup = heap_modify_tuple(oldtup,
-									 RelationGetDescr(sd),
-									 values,
-									 nulls,
-									 replaces);
-			ReleaseSysCache(oldtup);
-			CatalogTupleUpdate(sd, &stup->t_self, stup);
+			up_gtt_att_statistic(relid,
+								stats->attr->attnum,
+								inh,
+								natts,
+								RelationGetDescr(sd),
+								values,
+								nulls);
 		}
 		else
 		{
-			/* No, insert new tuple */
-			stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
-			CatalogTupleInsert(sd, stup);
-		}
+			/* Is there already a pg_statistic tuple for this attribute? */
+			oldtup = SearchSysCache3(STATRELATTINH,
+									 ObjectIdGetDatum(relid),
+									 Int16GetDatum(stats->attr->attnum),
+									 BoolGetDatum(inh));
+
+			if (HeapTupleIsValid(oldtup))
+			{
+				/* Yes, replace it */
+				stup = heap_modify_tuple(oldtup,
+										 RelationGetDescr(sd),
+										 values,
+										 nulls,
+										 replaces);
+				ReleaseSysCache(oldtup);
+				CatalogTupleUpdate(sd, &stup->t_self, stup);
+			}
+			else
+			{
+				/* No, insert new tuple */
+				stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
+				CatalogTupleInsert(sd, stup);
+			}
 
-		heap_freetuple(stup);
+			heap_freetuple(stup);
+		}
 	}
 
 	table_close(sd, RowExclusiveLock);
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index a23128d..0d38988 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -392,6 +392,12 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 					 errmsg("cannot vacuum temporary tables of other sessions")));
 	}
 
+	/* not support cluster global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(OldHeap))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support cluster global temporary tables yet")));
+
 	/*
 	 * Also check for active uses of the relation in the current transaction,
 	 * including open scans and pending AFTER trigger events.
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 374e2d0..8e88a59 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -2585,6 +2585,16 @@ ReindexMultipleTables(const char *objectName, ReindexObjectType objectKind,
 			!isTempNamespace(classtuple->relnamespace))
 			continue;
 
+		/* not support reindex on global temp table, so skip it */
+		if (classtuple->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			ereport(WARNING,
+				(errmsg("global temp table \"%s.%s\" skip reindexed",
+					get_namespace_name(get_rel_namespace(relid)),
+					get_rel_name(relid))));
+			continue;
+		}
+
 		/* Check user/system classification, and optionally skip */
 		if (objectKind == REINDEX_OBJECT_SYSTEM &&
 			!IsSystemClass(relid, classtuple))
diff --git a/src/backend/commands/lockcmds.c b/src/backend/commands/lockcmds.c
index bae3b38..ff9d5cb 100644
--- a/src/backend/commands/lockcmds.c
+++ b/src/backend/commands/lockcmds.c
@@ -107,7 +107,8 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
 	 * transaction.
 	 */
 	relpersistence = get_rel_persistence(relid);
-	if (relpersistence == RELPERSISTENCE_TEMP)
+	if (relpersistence == RELPERSISTENCE_TEMP ||
+		relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		MyXactFlags |= XACT_FLAGS_ACCESSEDTEMPNAMESPACE;
 
 	/* Check permissions. */
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 5597be6..4bf4b9a 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -48,6 +48,7 @@
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
 #include "catalog/toasting.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/defrem.h"
@@ -531,6 +532,7 @@ static void refuseDupeIndexAttach(Relation parentIdx, Relation partIdx,
 								  Relation partitionTbl);
 static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
+static bool has_oncommit_option(List *options);
 
 
 /* ----------------------------------------------------------------
@@ -576,6 +578,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	LOCKMODE	parentLockmode;
 	const char *accessMethod = NULL;
 	Oid			accessMethodId = InvalidOid;
+	bool		has_oncommit_clause = false;
 
 	/*
 	 * Truncate relname to appropriate length (probably a waste of time, as
@@ -586,8 +589,10 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Check consistency of arguments
 	 */
+	/* global temp table same as local temp table */
 	if (stmt->oncommit != ONCOMMIT_NOOP
-		&& stmt->relation->relpersistence != RELPERSISTENCE_TEMP)
+		&& !(stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+			 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 				 errmsg("ON COMMIT can only be used on temporary tables")));
@@ -617,12 +622,28 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	 * code.  This is needed because calling code might not expect untrusted
 	 * tables to appear in pg_temp at the front of its search path.
 	 */
-	if (stmt->relation->relpersistence == RELPERSISTENCE_TEMP
+	/* global temp table same as local temp table */
+	if ((stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+		 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		&& InSecurityRestrictedOperation())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 errmsg("cannot create temporary table within security-restricted operation")));
 
+	/* Not support partitioned or inherited global temp table yet */
+	if (stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		if (relkind == RELKIND_PARTITIONED_TABLE)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support create global temporary partition table yet")));
+
+		if (stmt->inhRelations)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support create global temporary inheritance table yet")));
+	}
+
 	/*
 	 * Determine the lockmode to use when scanning parents.  A self-exclusive
 	 * lock is needed here.
@@ -718,6 +739,40 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Parse and validate reloptions, if any.
 	 */
+	/* global temp table */
+	has_oncommit_clause = has_oncommit_option(stmt->options);
+	if (stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		if (has_oncommit_clause)
+		{
+			if (stmt->oncommit != ONCOMMIT_NOOP)
+				elog(ERROR, "can not defeine global temp table with on commit and with clause at same time");
+		}
+		else
+		{
+			DefElem *opt = makeNode(DefElem);
+
+			opt->type = T_DefElem;
+			opt->defnamespace = NULL;
+			opt->defname = "on_commit_delete_rows";
+			opt->defaction = DEFELEM_UNSPEC;
+
+			/* use reloptions to remember on commit clause */
+			if (stmt->oncommit == ONCOMMIT_DELETE_ROWS)
+				opt->arg  = (Node *)makeString("true");
+			else if (stmt->oncommit == ONCOMMIT_PRESERVE_ROWS)
+				opt->arg  = (Node *)makeString("false");
+			else if (stmt->oncommit == ONCOMMIT_NOOP)
+				opt->arg  = (Node *)makeString("true");
+			else
+				elog(ERROR, "global temp table not support on commit drop clause");
+
+			stmt->options = lappend(stmt->options, opt);
+		}
+	}
+	else if (has_oncommit_clause)
+		elog(ERROR, "regular table cannot specifie on_commit_delete_rows");
+
 	reloptions = transformRelOptions((Datum) 0, stmt->options, NULL, validnsps,
 									 true, false);
 
@@ -1772,7 +1827,8 @@ ExecuteTruncateGuts(List *explicit_rels, List *relids, List *relids_logged,
 		 * table or the current physical file to be thrown away anyway.
 		 */
 		if (rel->rd_createSubid == mySubid ||
-			rel->rd_newRelfilenodeSubid == mySubid)
+			rel->rd_newRelfilenodeSubid == mySubid ||
+			RELATION_IS_GLOBAL_TEMP(rel))
 		{
 			/* Immediate, non-rollbackable truncation is OK */
 			heap_truncate_one_rel(rel);
@@ -3330,6 +3386,13 @@ RenameRelationInternal(Oid myrelid, const char *newrelname, bool is_internal, bo
 	 * specially.
 	 */
 	targetrelation = relation_open(myrelid, is_index ? ShareUpdateExclusiveLock : AccessExclusiveLock);
+
+	/* not support rename global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(targetrelation))
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("not support rename global temporary tables yet")));
+
 	namespaceId = RelationGetNamespace(targetrelation);
 
 	/*
@@ -3499,6 +3562,14 @@ AlterTable(Oid relid, LOCKMODE lockmode, AlterTableStmt *stmt)
 	/* Caller is required to provide an adequate lock. */
 	rel = relation_open(relid, NoLock);
 
+	/* not support alter global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("not support alter global temporary tables yet")));
+	}
+
 	CheckTableNotInUse(rel, "ALTER TABLE");
 
 	ATController(stmt, rel, stmt->cmds, stmt->relation->inh, lockmode);
@@ -7679,6 +7750,13 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 				 errmsg("referenced relation \"%s\" is not a table",
 						RelationGetRelationName(pkrel))));
 
+	/* global temp table not support foreign key constraint yet */
+	if (RELATION_IS_GLOBAL_TEMP(pkrel))
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("referenced relation \"%s\" is not a global temp table",
+						RelationGetRelationName(pkrel))));
+
 	if (!allowSystemTableMods && IsSystemRelation(pkrel))
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -7718,6 +7796,12 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 						 errmsg("constraints on temporary tables must involve temporary tables of this session")));
 			break;
+		/* global temp table not support foreign key constraint yet */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					 errmsg("not support foreign key constraints on global temp table yet")));
+			break;
 	}
 
 	/*
@@ -12726,7 +12810,7 @@ index_copy_data(Relation rel, RelFileNode newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
@@ -14133,7 +14217,9 @@ ATPrepChangePersistence(Relation rel, bool toLogged)
 	 */
 	switch (rel->rd_rel->relpersistence)
 	{
+		/* global temp table same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("cannot change logged status of table \"%s\" because it is temporary",
@@ -16723,3 +16809,20 @@ ATDetachCheckNoForeignKeyRefs(Relation partition)
 		table_close(rel, NoLock);
 	}
 }
+
+static bool
+has_oncommit_option(List *options)
+{
+	ListCell   *listptr;
+
+	foreach(listptr, options)
+	{
+		DefElem    *def = (DefElem *) lfirst(listptr);
+
+		if (pg_strcasecmp(def->defname, "on_commit_delete_rows") == 0)
+			return true;
+	}
+
+	return false;
+}
+
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index da1da23..70278a6 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -35,6 +35,7 @@
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
 #include "catalog/pg_namespace.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
 #include "commands/vacuum.h"
@@ -1070,12 +1071,25 @@ vac_estimate_reltuples(Relation relation,
 					   BlockNumber scanned_pages,
 					   double scanned_tuples)
 {
-	BlockNumber old_rel_pages = relation->rd_rel->relpages;
-	double		old_rel_tuples = relation->rd_rel->reltuples;
+	BlockNumber old_rel_pages = 0;
+	double		old_rel_tuples = 0;
 	double		old_density;
 	double		unscanned_pages;
 	double		total_tuples;
 
+	/* get relstat from gtt local hash */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+	{
+		get_gtt_relstats(RelationGetRelid(relation),
+						&old_rel_pages, &old_rel_tuples, NULL,
+						NULL, NULL);
+	}
+	else
+	{
+		old_rel_pages = relation->rd_rel->relpages;
+		old_rel_tuples = relation->rd_rel->reltuples;
+	}
+
 	/* If we did scan the whole table, just use the count as-is */
 	if (scanned_pages >= total_pages)
 		return scanned_tuples;
@@ -1175,24 +1189,8 @@ vac_update_relstats(Relation relation,
 	/* Apply statistical updates, if any, to copied tuple */
 
 	dirty = false;
-	if (pgcform->relpages != (int32) num_pages)
-	{
-		pgcform->relpages = (int32) num_pages;
-		dirty = true;
-	}
-	if (pgcform->reltuples != (float4) num_tuples)
-	{
-		pgcform->reltuples = (float4) num_tuples;
-		dirty = true;
-	}
-	if (pgcform->relallvisible != (int32) num_all_visible_pages)
-	{
-		pgcform->relallvisible = (int32) num_all_visible_pages;
-		dirty = true;
-	}
 
 	/* Apply DDL updates, but not inside an outer transaction (see above) */
-
 	if (!in_outer_xact)
 	{
 		/*
@@ -1217,37 +1215,64 @@ vac_update_relstats(Relation relation,
 		}
 	}
 
-	/*
-	 * Update relfrozenxid, unless caller passed InvalidTransactionId
-	 * indicating it has no new data.
-	 *
-	 * Ordinarily, we don't let relfrozenxid go backwards: if things are
-	 * working correctly, the only way the new frozenxid could be older would
-	 * be if a previous VACUUM was done with a tighter freeze_min_age, in
-	 * which case we don't want to forget the work it already did.  However,
-	 * if the stored relfrozenxid is "in the future", then it must be corrupt
-	 * and it seems best to overwrite it with the cutoff we used this time.
-	 * This should match vac_update_datfrozenxid() concerning what we consider
-	 * to be "in the future".
-	 */
-	if (TransactionIdIsNormal(frozenxid) &&
-		pgcform->relfrozenxid != frozenxid &&
-		(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
-		 TransactionIdPrecedes(ReadNewTransactionId(),
-							   pgcform->relfrozenxid)))
+	/* global temp table remember relstats to localhash not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
 	{
-		pgcform->relfrozenxid = frozenxid;
-		dirty = true;
+		up_gtt_relstats(relation,
+						num_pages, num_tuples,
+						num_all_visible_pages,
+						frozenxid, minmulti);
 	}
-
-	/* Similarly for relminmxid */
-	if (MultiXactIdIsValid(minmulti) &&
-		pgcform->relminmxid != minmulti &&
-		(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
-		 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
+	else
 	{
-		pgcform->relminmxid = minmulti;
-		dirty = true;
+		if (pgcform->relpages != (int32) num_pages)
+		{
+			pgcform->relpages = (int32) num_pages;
+			dirty = true;
+		}
+		if (pgcform->reltuples != (float4) num_tuples)
+		{
+			pgcform->reltuples = (float4) num_tuples;
+			dirty = true;
+		}
+		if (pgcform->relallvisible != (int32) num_all_visible_pages)
+		{
+			pgcform->relallvisible = (int32) num_all_visible_pages;
+			dirty = true;
+		}
+
+		/*
+		 * Update relfrozenxid, unless caller passed InvalidTransactionId
+		 * indicating it has no new data.
+		 *
+		 * Ordinarily, we don't let relfrozenxid go backwards: if things are
+		 * working correctly, the only way the new frozenxid could be older would
+		 * be if a previous VACUUM was done with a tighter freeze_min_age, in
+		 * which case we don't want to forget the work it already did.  However,
+		 * if the stored relfrozenxid is "in the future", then it must be corrupt
+		 * and it seems best to overwrite it with the cutoff we used this time.
+		 * This should match vac_update_datfrozenxid() concerning what we consider
+		 * to be "in the future".
+		 */
+		if (TransactionIdIsNormal(frozenxid) &&
+			pgcform->relfrozenxid != frozenxid &&
+			(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(),
+								   pgcform->relfrozenxid)))
+		{
+			pgcform->relfrozenxid = frozenxid;
+			dirty = true;
+		}
+
+		/* Similarly for relminmxid */
+		if (MultiXactIdIsValid(minmulti) &&
+			pgcform->relminmxid != minmulti &&
+			(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
+		{
+			pgcform->relminmxid = minmulti;
+			dirty = true;
+		}
 	}
 
 	/* If anything changed, write out the tuple. */
@@ -1339,6 +1364,10 @@ vac_update_datfrozenxid(void)
 			continue;
 		}
 
+		/* global temp table relstats not in pg_class */
+		if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			continue;
+
 		/*
 		 * Some table AMs might not need per-relation xid / multixid horizons.
 		 * It therefore seems reasonable to allow relfrozenxid and relminmxid
@@ -1396,6 +1425,25 @@ vac_update_datfrozenxid(void)
 	Assert(TransactionIdIsNormal(newFrozenXid));
 	Assert(MultiXactIdIsValid(newMinMulti));
 
+	/*
+	 * Global temp table get frozenxid from MyProc
+	 * to avoid the vacuum truncate clog that gtt need.
+	 */
+	if (max_active_gtt > 0)
+	{
+		TransactionId oldest_gtt_frozenxid =
+			list_all_session_gtt_frozenxids(0, NULL, NULL, NULL);
+
+		if (TransactionIdIsNormal(oldest_gtt_frozenxid) &&
+			TransactionIdPrecedes(oldest_gtt_frozenxid, newFrozenXid))
+		{
+			ereport(WARNING,
+				(errmsg("global temp table oldest FrozenXid is far in the past"),
+				 errhint("please truncate them or kill those sessions that use them.")));
+			newFrozenXid = oldest_gtt_frozenxid;
+		}
+	}
+
 	/* Now fetch the pg_database tuple we need to update. */
 	relation = table_open(DatabaseRelationId, RowExclusiveLock);
 
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index db3a68a..b41a920 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -591,6 +591,8 @@ static void
 set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 						  RangeTblEntry *rte)
 {
+	char relpersistence;
+
 	/*
 	 * The flag has previously been initialized to false, so we can just
 	 * return if it becomes clear that we can't safely set it.
@@ -618,7 +620,11 @@ set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 			 * the rest of the necessary infrastructure right now anyway.  So
 			 * for now, bail out if we see a temporary table.
 			 */
-			if (get_rel_persistence(rte->relid) == RELPERSISTENCE_TEMP)
+			/* global temp table is same as local temp table */
+			relpersistence = get_rel_persistence(rte->relid);
+
+			if (relpersistence == RELPERSISTENCE_TEMP ||
+				relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 				return;
 
 			/*
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 17c5f08..fa6aee5 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -6307,7 +6307,9 @@ plan_create_index_workers(Oid tableOid, Oid indexOid)
 	 * Furthermore, any index predicate or index expressions must be parallel
 	 * safe.
 	 */
+	/* global temp table is same as local temp table */
 	if (heap->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		heap->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexExpressions(index)) ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexPredicate(index)))
 	{
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index e5f9e04..ecc4543 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -53,6 +53,7 @@
 #include "utils/syscache.h"
 #include "utils/snapmgr.h"
 
+#include "catalog/storage_gtt.h"
 
 /* GUC parameter */
 int			constraint_exclusion = CONSTRAINT_EXCLUSION_PARTITION;
@@ -947,10 +948,10 @@ void
 estimate_rel_size(Relation rel, int32 *attr_widths,
 				  BlockNumber *pages, double *tuples, double *allvisfrac)
 {
-	BlockNumber curpages;
-	BlockNumber relpages;
-	double		reltuples;
-	BlockNumber relallvisible;
+	BlockNumber curpages = 0;
+	BlockNumber relpages = 0;
+	double		reltuples = 0;
+	BlockNumber relallvisible = 0;
 	double		density;
 
 	switch (rel->rd_rel->relkind)
@@ -964,6 +965,21 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 
 		case RELKIND_INDEX:
 
+			/* global temp table get relstats from localhash */
+			if (RELATION_IS_GLOBAL_TEMP(rel))
+			{
+				get_gtt_relstats(RelationGetRelid(rel),
+								&relpages, &reltuples, &relallvisible,
+								NULL, NULL);
+			}
+			else
+			{
+				/* coerce values in pg_class to more desirable types */
+				relpages = (BlockNumber) rel->rd_rel->relpages;
+				reltuples = (double) rel->rd_rel->reltuples;
+				relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
+			}
+
 			/*
 			 * XXX: It'd probably be good to move this into a callback,
 			 * individual index types e.g. know if they have a metapage.
@@ -972,11 +988,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 			/* it has storage, ok to call the smgr */
 			curpages = RelationGetNumberOfBlocks(rel);
 
-			/* coerce values in pg_class to more desirable types */
-			relpages = (BlockNumber) rel->rd_rel->relpages;
-			reltuples = (double) rel->rd_rel->reltuples;
-			relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
-
 			/* report estimated # pages */
 			*pages = curpages;
 			/* quick exit if rel is clearly empty */
@@ -986,10 +997,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 				*allvisfrac = 0;
 				break;
 			}
-			/* coerce values in pg_class to more desirable types */
-			relpages = (BlockNumber) rel->rd_rel->relpages;
-			reltuples = (double) rel->rd_rel->reltuples;
-			relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
 
 			/*
 			 * Discount the metapage while estimating the number of tuples.
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 85d7a96..67b200d 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -2579,6 +2579,11 @@ transformCreateTableAsStmt(ParseState *pstate, CreateTableAsStmt *stmt)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("materialized views must not use temporary tables or views")));
 
+		if (is_query_using_gtt(query))
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("materialized views must not use global temporary tables or views")));
+
 		/*
 		 * A materialized view would either need to save parameters for use in
 		 * maintaining/loading the data or prohibit them entirely.  The latter
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 3f67aaf..333e54f 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3268,17 +3268,11 @@ OptTemp:	TEMPORARY					{ $$ = RELPERSISTENCE_TEMP; }
 			| LOCAL TEMP				{ $$ = RELPERSISTENCE_TEMP; }
 			| GLOBAL TEMPORARY
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED					{ $$ = RELPERSISTENCE_UNLOGGED; }
 			| /*EMPTY*/					{ $$ = RELPERSISTENCE_PERMANENT; }
@@ -11505,19 +11499,13 @@ OptTempTableName:
 				}
 			| GLOBAL TEMPORARY opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED opt_table qualified_name
 				{
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 4dd8150..637a15c 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -59,6 +59,7 @@ static void expandTupleDesc(TupleDesc tupdesc, Alias *eref,
 							List **colnames, List **colvars);
 static int	specialAttNum(const char *attname);
 static bool isQueryUsingTempRelation_walker(Node *node, void *context);
+static bool is_query_using_gtt_walker(Node *node, void *context);
 
 
 /*
@@ -3420,3 +3421,49 @@ isQueryUsingTempRelation_walker(Node *node, void *context)
 								  isQueryUsingTempRelation_walker,
 								  context);
 }
+
+/* check if the query uses global temp table */
+static bool
+is_query_using_gtt_walker(Node *node, void *context)
+{
+	if (node == NULL)
+		return false;
+
+	if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+		ListCell   *rtable;
+
+		foreach(rtable, query->rtable)
+		{
+			RangeTblEntry *rte = lfirst(rtable);
+
+			if (rte->rtekind == RTE_RELATION)
+			{
+				Relation	rel = relation_open(rte->relid, AccessShareLock);
+				char		relpersistence = rel->rd_rel->relpersistence;
+
+				relation_close(rel, AccessShareLock);
+				if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+					return true;
+			}
+		}
+
+		return query_tree_walker(query,
+								 is_query_using_gtt_walker,
+								 context,
+								 QTW_IGNORE_JOINALIASES);
+	}
+
+	return expression_tree_walker(node,
+								  is_query_using_gtt_walker,
+								  context);
+}
+
+/* check if the query uses global temp table */
+bool
+is_query_using_gtt(Query *query)
+{
+	return is_query_using_gtt_walker((Node *) query, NULL);
+}
+
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index ee47547..d13e253 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -359,6 +359,13 @@ generateSerialExtraStmts(CreateStmtContext *cxt, ColumnDef *column,
 	AlterSeqStmt *altseqstmt;
 	List	   *attnamelist;
 
+	if (cxt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("Global temp table does not yet support serial column")));
+	}
+
 	/*
 	 * Determine namespace and name to use for the sequence.
 	 *
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index c1dd816..f2d3df9 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -2091,6 +2091,11 @@ do_autovacuum(void)
 			}
 			continue;
 		}
+		else if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			/* autovacuum skip vacuum global temp table */
+			continue;
+		}
 
 		/* Fetch reloptions and the pgstat entry for this table */
 		relopts = extract_autovac_opts(tuple, pg_class_desc);
@@ -2157,7 +2162,9 @@ do_autovacuum(void)
 		/*
 		 * We cannot safely process other backends' temp tables, so skip 'em.
 		 */
-		if (classForm->relpersistence == RELPERSISTENCE_TEMP)
+		/* autovacuum skip vacuum global temp table */
+		if (classForm->relpersistence == RELPERSISTENCE_TEMP || 
+			classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 			continue;
 
 		relid = classForm->oid;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 7ad1073..8e81701 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -53,6 +53,8 @@
 #include "utils/resowner_private.h"
 #include "utils/timestamp.h"
 
+#include "utils/guc.h"
+#include "catalog/storage_gtt.h"
 
 /* Note: these two macros only work on shared buffers, not local ones! */
 #define BufHdrGetBlock(bufHdr)	((Block) (BufferBlocks + ((Size) (bufHdr)->buf_id) * BLCKSZ))
@@ -432,7 +434,7 @@ ForgetPrivateRefCountEntry(PrivateRefCountEntry *ref)
 static Buffer ReadBuffer_common(SMgrRelation reln, char relpersistence,
 								ForkNumber forkNum, BlockNumber blockNum,
 								ReadBufferMode mode, BufferAccessStrategy strategy,
-								bool *hit);
+								bool *hit, Relation rel);
 static bool PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy);
 static void PinBuffer_Locked(BufferDesc *buf);
 static void UnpinBuffer(BufferDesc *buf, bool fixOwner);
@@ -664,7 +666,8 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
 	 */
 	pgstat_count_buffer_read(reln);
 	buf = ReadBuffer_common(reln->rd_smgr, reln->rd_rel->relpersistence,
-							forkNum, blockNum, mode, strategy, &hit);
+							forkNum, blockNum, mode, strategy, &hit,
+							reln);
 	if (hit)
 		pgstat_count_buffer_hit(reln);
 	return buf;
@@ -692,7 +695,7 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 	Assert(InRecovery);
 
 	return ReadBuffer_common(smgr, RELPERSISTENCE_PERMANENT, forkNum, blockNum,
-							 mode, strategy, &hit);
+							 mode, strategy, &hit, NULL);
 }
 
 
@@ -704,7 +707,8 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 static Buffer
 ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 				  BlockNumber blockNum, ReadBufferMode mode,
-				  BufferAccessStrategy strategy, bool *hit)
+				  BufferAccessStrategy strategy, bool *hit,
+				  Relation rel)
 {
 	BufferDesc *bufHdr;
 	Block		bufBlock;
@@ -719,6 +723,15 @@ ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 
 	isExtend = (blockNum == P_NEW);
 
+	/* create storage when first read data page for gtt */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP &&
+		(isExtend || blockNum == 0) &&
+		forkNum == MAIN_FORKNUM &&
+		!gtt_storage_attached(smgr->smgr_rnode.node.relNode))
+	{
+		RelationCreateStorage(smgr->smgr_rnode.node, relpersistence, rel);
+	}
+
 	TRACE_POSTGRESQL_BUFFER_READ_START(forkNum, blockNum,
 									   smgr->smgr_rnode.node.spcNode,
 									   smgr->smgr_rnode.node.dbNode,
@@ -2799,6 +2812,16 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln)
 BlockNumber
 RelationGetNumberOfBlocksInFork(Relation relation, ForkNumber forkNum)
 {
+	/*
+	 * When this backend not init gtt storage
+	 * return 0
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(relation) &&
+		!gtt_storage_attached(relation->rd_node.relNode))
+	{
+		return 0;
+	}
+
 	switch (relation->rd_rel->relkind)
 	{
 		case RELKIND_SEQUENCE:
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 8853706..b3544dd 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -21,6 +21,7 @@
 #include "access/nbtree.h"
 #include "access/subtrans.h"
 #include "access/twophase.h"
+#include "catalog/storage_gtt.h"
 #include "commands/async.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -147,6 +148,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, BTreeShmemSize());
 		size = add_size(size, SyncScanShmemSize());
 		size = add_size(size, AsyncShmemSize());
+		size = add_size(size, active_gtt_shared_hash_size());
 #ifdef EXEC_BACKEND
 		size = add_size(size, ShmemBackendArraySize());
 #endif
@@ -217,6 +219,8 @@ CreateSharedMemoryAndSemaphores(void)
 	SUBTRANSShmemInit();
 	MultiXactShmemInit();
 	InitBufferPool();
+	/* global temporary table */
+	active_gtt_shared_hash_init();
 
 	/*
 	 * Set up lock manager
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index 3da5307..21bd1f2 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -60,6 +60,7 @@
 #include "utils/builtins.h"
 #include "utils/rel.h"
 #include "utils/snapmgr.h"
+#include "utils/guc.h"
 
 #define UINT32_ACCESS_ONCE(var)		 ((uint32)(*((volatile uint32 *)&(var))))
 
@@ -3973,3 +3974,77 @@ KnownAssignedXidsReset(void)
 
 	LWLockRelease(ProcArrayLock);
 }
+
+/*
+ * search all active backend to get oldest frozenxid
+ * for global temp table.
+ */
+int
+list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n)
+{
+	ProcArrayStruct *arrayP = procArray;
+	TransactionId result = InvalidTransactionId;
+	int			index;
+	int			flags = 0;
+	int			i = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	if (max_size > 0)
+	{
+		Assert(pids);
+		Assert(xids);
+		Assert(n);
+		*n = 0;
+	}
+
+	if (max_active_gtt <= 0)
+		return InvalidTransactionId;
+
+	if (RecoveryInProgress())
+		return InvalidTransactionId;
+
+	flags |= PROC_IS_AUTOVACUUM;
+	flags |= PROC_IN_LOGICAL_DECODING;
+
+	LWLockAcquire(ProcArrayLock, LW_SHARED);
+	if (max_size > 0 && max_size < arrayP->numProcs)
+	{
+		LWLockRelease(ProcArrayLock);
+		elog(ERROR, "list_all_gtt_frozenxids require more array");
+	}
+
+	for (index = 0; index < arrayP->numProcs; index++)
+	{
+		int			pgprocno = arrayP->pgprocnos[index];
+		volatile PGPROC *proc = &allProcs[pgprocno];
+		volatile PGXACT *pgxact = &allPgXact[pgprocno];
+
+		if (pgxact->vacuumFlags & flags)
+			continue;
+
+		if (proc->databaseId == MyDatabaseId &&
+			TransactionIdIsNormal(proc->session_gtt_frozenxid))
+		{
+			if (result == InvalidTransactionId)
+				result = proc->session_gtt_frozenxid;
+			else if (TransactionIdPrecedes(proc->session_gtt_frozenxid, result))
+				result = proc->session_gtt_frozenxid;
+
+			if (max_size > 0)
+			{
+				pids[i] = proc->pid;
+				xids[i] = proc->session_gtt_frozenxid;
+				i++;
+			}
+		}
+	}
+	LWLockRelease(ProcArrayLock);
+
+	if (max_size > 0)
+		*n = i;
+
+	return result;
+}
+
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index b3c54a6..645456c 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -396,6 +396,7 @@ InitProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
@@ -578,6 +579,7 @@ InitAuxiliaryProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 07f3c93..cee8f9e 100644
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -654,6 +654,12 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 		 */
 		if (zero_damaged_pages || InRecovery)
 			MemSet(buffer, 0, BLCKSZ);
+		else if(SmgrIsTemp(reln) && blocknum == 0 && forknum == MAIN_FORKNUM)
+		{
+			/* global temp table init btree meta page */
+			MemSet(buffer, 0, BLCKSZ);
+			mdwrite(reln, forknum, blocknum, buffer, true);
+		}
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_DATA_CORRUPTED),
diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c
index a87e721..adce760 100644
--- a/src/backend/utils/adt/dbsize.c
+++ b/src/backend/utils/adt/dbsize.c
@@ -1008,6 +1008,10 @@ pg_relation_filepath(PG_FUNCTION_ARGS)
 				Assert(backend != InvalidBackendId);
 			}
 			break;
+		/* For global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			backend = BackendIdForTempRelations();
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relform->relpersistence);
 			backend = InvalidBackendId; /* placate compiler */
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 35a8995..42dc3a5 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -141,6 +141,7 @@
 #include "utils/timestamp.h"
 #include "utils/typcache.h"
 
+#include "catalog/storage_gtt.h"
 
 /* Hooks for plugins to get control when we ask for stats */
 get_relation_stats_hook_type get_relation_stats_hook = NULL;
@@ -4568,12 +4569,25 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
 						}
 						else if (index->indpred == NIL)
 						{
-							vardata->statsTuple =
-								SearchSysCache3(STATRELATTINH,
-												ObjectIdGetDatum(index->indexoid),
-												Int16GetDatum(pos + 1),
-												BoolGetDatum(false));
-							vardata->freefunc = ReleaseSysCache;
+							char rel_persistence = get_rel_persistence(index->indexoid);
+
+							if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+							{
+								vardata->statsTuple =
+									get_gtt_att_statistic(index->indexoid,
+														Int16GetDatum(pos + 1),
+														false);
+								vardata->freefunc = release_gtt_statistic_cache;
+							}
+							else
+							{
+								vardata->statsTuple =
+									SearchSysCache3(STATRELATTINH,
+													ObjectIdGetDatum(index->indexoid),
+													Int16GetDatum(pos + 1),
+													BoolGetDatum(false));
+								vardata->freefunc = ReleaseSysCache;
+							}
 
 							if (HeapTupleIsValid(vardata->statsTuple))
 							{
@@ -4652,15 +4666,27 @@ examine_simple_variable(PlannerInfo *root, Var *var,
 	}
 	else if (rte->rtekind == RTE_RELATION)
 	{
-		/*
-		 * Plain table or parent of an inheritance appendrel, so look up the
-		 * column in pg_statistic
-		 */
-		vardata->statsTuple = SearchSysCache3(STATRELATTINH,
-											  ObjectIdGetDatum(rte->relid),
-											  Int16GetDatum(var->varattno),
-											  BoolGetDatum(rte->inh));
-		vardata->freefunc = ReleaseSysCache;
+		char rel_persistence = get_rel_persistence(rte->relid);
+
+		if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata->statsTuple = get_gtt_att_statistic(rte->relid,
+														var->varattno,
+														rte->inh);
+			vardata->freefunc = release_gtt_statistic_cache;
+		}
+		else
+		{
+			/*
+			 * Plain table or parent of an inheritance appendrel, so look up the
+			 * column in pg_statistic
+			 */
+			vardata->statsTuple = SearchSysCache3(STATRELATTINH,
+												  ObjectIdGetDatum(rte->relid),
+												  Int16GetDatum(var->varattno),
+												  BoolGetDatum(rte->inh));
+			vardata->freefunc = ReleaseSysCache;
+		}
 
 		if (HeapTupleIsValid(vardata->statsTuple))
 		{
@@ -5972,6 +5998,7 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	{
 		/* Simple variable --- look to stats for the underlying table */
 		RangeTblEntry *rte = planner_rt_fetch(index->rel->relid, root);
+		char	rel_persistence = get_rel_persistence(rte->relid);
 
 		Assert(rte->rtekind == RTE_RELATION);
 		relid = rte->relid;
@@ -5989,6 +6016,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													rte->inh);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -6000,6 +6034,8 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	}
 	else
 	{
+		char	rel_persistence = get_rel_persistence(index->indexoid);
+
 		/* Expression --- maybe there are stats for the index itself */
 		relid = index->indexoid;
 		colnum = 1;
@@ -6015,6 +6051,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													false);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -6881,6 +6924,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		/* attempt to lookup stats in relation for this index column */
 		if (attnum != 0)
 		{
+			char	rel_persistence = get_rel_persistence(rte->relid);
+
 			/* Simple variable -- look to stats for the underlying table */
 			if (get_relation_stats_hook &&
 				(*get_relation_stats_hook) (root, rte, attnum, &vardata))
@@ -6893,6 +6938,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					elog(ERROR,
 						 "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(rte->relid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple =
@@ -6905,6 +6958,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		}
 		else
 		{
+			char	rel_persistence = get_rel_persistence(index->indexoid);
+
 			/*
 			 * Looks like we've found an expression column in the index. Let's
 			 * see if there's any stats for it.
@@ -6924,6 +6979,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					!vardata.freefunc)
 					elog(ERROR, "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(index->indexoid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple = SearchSysCache3(STATRELATTINH,
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 27602fa..25a411a 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -34,6 +34,7 @@
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_transform.h"
 #include "catalog/pg_type.h"
+#include "catalog/storage_gtt.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "utils/array.h"
@@ -46,6 +47,7 @@
 #include "utils/syscache.h"
 #include "utils/typcache.h"
 
+
 /* Hook for plugins to get control in get_attavgwidth() */
 get_attavgwidth_hook_type get_attavgwidth_hook = NULL;
 
@@ -2878,6 +2880,18 @@ get_attavgwidth(Oid relid, AttrNumber attnum)
 		if (stawidth > 0)
 			return stawidth;
 	}
+	if (get_rel_persistence(relid) == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		tp = get_gtt_att_statistic(relid, attnum, false);
+		if (!HeapTupleIsValid(tp))
+			return 0;
+
+		stawidth = ((Form_pg_statistic) GETSTRUCT(tp))->stawidth;
+		if (stawidth > 0)
+			return stawidth;
+		else
+			return 0;
+	}
 	tp = SearchSysCache3(STATRELATTINH,
 						 ObjectIdGetDatum(relid),
 						 Int16GetDatum(attnum),
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 585dcee..b8f2a41 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -1130,6 +1130,16 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
 				relation->rd_islocaltemp = false;
 			}
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			{
+				relation->rd_backend = BackendIdForTempRelations();
+				/*
+				 * For global temp table, all backend can use
+				 * this relation, so rd_islocaltemp always true.
+				 */
+				relation->rd_islocaltemp = true;
+			}
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c",
 				 relation->rd_rel->relpersistence);
@@ -3311,6 +3321,10 @@ RelationBuildLocalRelation(const char *relname,
 			rel->rd_backend = BackendIdForTempRelations();
 			rel->rd_islocaltemp = true;
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			rel->rd_backend = BackendIdForTempRelations();
+			rel->rd_islocaltemp = true;
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relpersistence);
 			break;
@@ -3425,6 +3439,9 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 	TransactionId freezeXid = InvalidTransactionId;
 	RelFileNode newrnode;
 
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+		elog(ERROR, "global temp table does not allow setting new relfilenode");
+
 	/* Allocate a new relfilenode */
 	newrelfilenode = GetNewRelFileNode(relation->rd_rel->reltablespace, NULL,
 									   persistence);
@@ -3465,7 +3482,7 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 				/* handle these directly, at least for now */
 				SMgrRelation srel;
 
-				srel = RelationCreateStorage(newrnode, persistence);
+				srel = RelationCreateStorage(newrnode, persistence, relation);
 				smgrclose(srel);
 			}
 			break;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index e84c8cc..3b921cd 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -138,6 +138,18 @@ char	   *GUC_check_errmsg_string;
 char	   *GUC_check_errdetail_string;
 char	   *GUC_check_errhint_string;
 
+/*
+ * num = 0 means disable global temp table feature.
+ * global temp table define can still storage in catalog
+ * just can not use.
+ * num > 0 means database can management num active global temp table.
+ */
+#define	MIN_NUM_ACTIVE_GTT			0
+#define	DEFAULT_NUM_ACTIVE_GTT			1000
+#define	MAX_NUM_ACTIVE_GTT			1000000
+
+int		max_active_gtt = MIN_NUM_ACTIVE_GTT;
+
 static void do_serialize(char **destptr, Size *maxbytes, const char *fmt,...) pg_attribute_printf(3, 4);
 
 static void set_config_sourcefile(const char *name, char *sourcefile,
@@ -1964,6 +1976,15 @@ static struct config_bool ConfigureNamesBool[] =
 static struct config_int ConfigureNamesInt[] =
 {
 	{
+		{"max_active_global_temporary_table", PGC_POSTMASTER, UNGROUPED,
+			gettext_noop("max active global temporary table."),
+			NULL
+		},
+		&max_active_gtt,
+		DEFAULT_NUM_ACTIVE_GTT, MIN_NUM_ACTIVE_GTT, MAX_NUM_ACTIVE_GTT,
+		NULL, NULL, NULL
+	},
+	{
 		{"archive_timeout", PGC_SIGHUP, WAL_ARCHIVING,
 			gettext_noop("Forces a switch to the next WAL file if a "
 						 "new file has not been started within N seconds."),
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index bf69adc..72e291b 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15585,6 +15585,7 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 	{
 		char	   *ftoptions = NULL;
 		char	   *srvname = NULL;
+		char		*table_type = NULL;
 
 		switch (tbinfo->relkind)
 		{
@@ -15636,9 +15637,15 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 			binary_upgrade_set_pg_class_oids(fout, q,
 											 tbinfo->dobj.catId.oid, false);
 
+		if (tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED)
+			table_type = "UNLOGGED ";
+		else if (tbinfo->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			table_type = "GLOBAL TEMPORARY ";
+		else
+			table_type = "";
+
 		appendPQExpBuffer(q, "CREATE %s%s %s",
-						  tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED ?
-						  "UNLOGGED " : "",
+						  table_type,
 						  reltypename,
 						  qualrelname);
 
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index 090b6ba..34b4683 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -165,6 +165,7 @@ typedef FormData_pg_class *Form_pg_class;
 #define		  RELPERSISTENCE_PERMANENT	'p' /* regular table */
 #define		  RELPERSISTENCE_UNLOGGED	'u' /* unlogged permanent table */
 #define		  RELPERSISTENCE_TEMP		't' /* temporary table */
+#define		  RELPERSISTENCE_GLOBAL_TEMP	'g' /* global temporary table */
 
 /* default selection for replica identity (primary key or nothing) */
 #define		  REPLICA_IDENTITY_DEFAULT	'd'
diff --git a/src/include/catalog/storage.h b/src/include/catalog/storage.h
index 3579d3f..2bde386 100644
--- a/src/include/catalog/storage.h
+++ b/src/include/catalog/storage.h
@@ -19,7 +19,7 @@
 #include "storage/smgr.h"
 #include "utils/relcache.h"
 
-extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence);
+extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel);
 extern void RelationDropStorage(Relation rel);
 extern void RelationPreserveStorage(RelFileNode rnode, bool atCommit);
 extern void RelationTruncate(Relation rel, BlockNumber nblocks);
diff --git a/src/include/catalog/storage_gtt.h b/src/include/catalog/storage_gtt.h
new file mode 100644
index 0000000..ea41e66
--- /dev/null
+++ b/src/include/catalog/storage_gtt.h
@@ -0,0 +1,39 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.h
+ *	  prototypes for functions in backend/catalog/storage_gtt.c
+ *
+ * src/include/catalog/storage_gtt.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef STORAGE_GTT_H
+#define STORAGE_GTT_H
+
+#include "access/htup.h"
+#include "storage/block.h"
+#include "storage/relfilenode.h"
+#include "utils/relcache.h"
+
+extern Size active_gtt_shared_hash_size(void);
+extern void active_gtt_shared_hash_init(void);
+extern void remember_gtt_storage_info(RelFileNode rnode, Relation rel);
+extern void forget_gtt_storage_info(Oid relid);
+extern bool is_other_backend_use_gtt(RelFileNode node);
+extern bool gtt_storage_attached(Oid relid);
+extern Bitmapset *copy_active_gtt_bitmap(RelFileNode node);
+extern void up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+								TupleDesc tupleDescriptor, Datum *values, bool *isnull);
+extern HeapTuple get_gtt_att_statistic(Oid reloid, int attnum, bool inh);
+extern void release_gtt_statistic_cache(HeapTuple tup);
+extern void up_gtt_relstats(Relation relation,
+							BlockNumber num_pages,
+							double num_tuples,
+							BlockNumber num_all_visible_pages,
+							TransactionId relfrozenxid,
+							TransactionId relminmxid);
+extern void get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+							BlockNumber *relallvisible, TransactionId *relfrozenxid,
+							TransactionId *relminmxid);
+
+#endif							/* STORAGE_H */
diff --git a/src/include/parser/parse_relation.h b/src/include/parser/parse_relation.h
index f7e0781..4f5a353 100644
--- a/src/include/parser/parse_relation.h
+++ b/src/include/parser/parse_relation.h
@@ -130,4 +130,7 @@ extern Oid	attnumTypeId(Relation rd, int attid);
 extern Oid	attnumCollationId(Relation rd, int attid);
 extern bool isQueryUsingTempRelation(Query *query);
 
+/* global temp table check */
+extern bool is_query_using_gtt(Query *query);
+
 #endif							/* PARSE_RELATION_H */
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index f627dfe..cfc6c78 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -220,6 +220,7 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_TBM,
 	LWTRANCHE_PARALLEL_APPEND,
 	LWTRANCHE_SXACT,
+	LWTRANCHE_GTT_CTL,
 	LWTRANCHE_FIRST_USER_DEFINED
 }			BuiltinTrancheIds;
 
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 281e1db..2ab8e91 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -117,6 +117,8 @@ struct PGPROC
 	Oid			tempNamespaceId;	/* OID of temp schema this backend is
 									 * using */
 
+	TransactionId session_gtt_frozenxid;	/* session level global temp table relfrozenxid */
+
 	bool		isBackgroundWorker; /* true if background worker. */
 
 	/*
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index da8b672..8e7d4c7 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -124,4 +124,6 @@ extern void ProcArraySetReplicationSlotXmin(TransactionId xmin,
 extern void ProcArrayGetReplicationSlotXmin(TransactionId *xmin,
 											TransactionId *catalog_xmin);
 
+extern int list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n);
+
 #endif							/* PROCARRAY_H */
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index 9aa3d02..1493cf4 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -278,6 +278,10 @@ extern int	tcp_user_timeout;
 extern bool trace_sort;
 #endif
 
+/* global temporary table */
+extern int	max_active_gtt;
+/* end */
+
 /*
  * Functions exported by guc.c
  */
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 8b8b237..c1962b7 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -272,6 +272,7 @@ typedef struct StdRdOptions
 	int			parallel_workers;	/* max number of parallel workers */
 	bool		vacuum_index_cleanup;	/* enables index vacuuming and cleanup */
 	bool		vacuum_truncate;	/* enables vacuum to truncate a relation */
+	bool		on_commit_delete_rows;	/* global temp table */
 } StdRdOptions;
 
 #define HEAP_MIN_FILLFACTOR			10
@@ -530,7 +531,8 @@ typedef struct ViewOptions
  *		True if relation's pages are stored in local buffers.
  */
 #define RelationUsesLocalBuffers(relation) \
-	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP || \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 
 /*
  * RELATION_IS_LOCAL
@@ -609,6 +611,17 @@ typedef struct ViewOptions
  */
 #define RelationGetPartitionDesc(relation) ((relation)->rd_partdesc)
 
+/* global temp table implementations */
+#define RELATION_IS_GLOBAL_TEMP(relation)	((relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+
+#define RELATION_GTT_ON_COMMIT_DELETE(relation)	\
+	((relation)->rd_options && \
+	 (relation)->rd_rel->relkind == RELKIND_RELATION && \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ? \
+	 ((StdRdOptions *) (relation)->rd_options)->on_commit_delete_rows : false)
+
+#define RelationGetRelPersistence(relation) ((relation)->rd_rel->relpersistence)
+
 /* routines in utils/cache/relcache.c */
 extern void RelationIncrementReferenceCount(Relation rel);
 extern void RelationDecrementReferenceCount(Relation rel);
diff --git a/src/test/regress/expected/gtt_clean.out b/src/test/regress/expected/gtt_clean.out
new file mode 100644
index 0000000..50ca9ac
--- /dev/null
+++ b/src/test/regress/expected/gtt_clean.out
@@ -0,0 +1,7 @@
+reset search_path;
+drop schema gtt cascade;
+NOTICE:  drop cascades to 4 other objects
+DETAIL:  drop cascades to table gtt.gtt1
+drop cascades to table gtt.gtt2
+drop cascades to table gtt.gtt3
+drop cascades to table gtt.gtt_t_kenyon
diff --git a/src/test/regress/expected/gtt_error.out b/src/test/regress/expected/gtt_error.out
new file mode 100644
index 0000000..80c16dc
--- /dev/null
+++ b/src/test/regress/expected/gtt_error.out
@@ -0,0 +1,106 @@
+CREATE SCHEMA IF NOT EXISTS gtt_error;
+set search_path=gtt_error,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+ERROR:  cannot create indexes on global temporary tables using concurrent mode
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+ERROR:  not support cluster global temporary tables yet
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+ERROR:  ON COMMIT can only be used on temporary tables
+-- ERROR
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+ERROR:  regular table cannot specifie on_commit_delete_rows
+-- ERROR
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+ERROR:  not support create global temporary partition table yet
+-- ERROR
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+ERROR:  not support create global temporary inheritance table yet
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+ERROR:  global temp table not support on commit drop clause
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+ERROR:  can not defeine global temp table with on commit and with clause at same time
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+--ERROR
+alter table gtt1 rename to gttx;
+ERROR:  not support rename global temporary tables yet
+-- ERROR
+ALTER TABLE gtt1 ADD COLUMN address varchar(30);
+ERROR:  not support alter global temporary tables yet
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  referenced relation "products" is not a global temp table
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  not support alter global temporary tables yet
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+ERROR:  Global temp table does not yet support serial column
+-- ERROR
+create global temp table gttx(id int GENERATED ALWAYS AS IDENTITY (START WITH 2));
+ERROR:  Global temp table does not yet support serial column
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+ERROR:  materialized views must not use global temporary tables or views
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+ERROR:  only support btree index on global temp table
+create index idx_err on gtt1 using gist (a);
+ERROR:  data type integer has no default operator class for access method "gist"
+HINT:  You must specify an operator class for the index or define a default operator class for the data type.
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+ERROR:  only support btree index on global temp table
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+ERROR:  only support btree index on global temp table
+reset search_path;
+drop schema gtt_error cascade;
+NOTICE:  drop cascades to 8 other objects
+DETAIL:  drop cascades to table gtt_error.gtt1
+drop cascades to table gtt_error.gtt2
+drop cascades to table gtt_error.gtt3
+drop cascades to table gtt_error.tmp_t0
+drop cascades to table gtt_error.tbl_inherits_parent
+drop cascades to table gtt_error.tbl_inherits_parent_global_temp
+drop cascades to table gtt_error.products
+drop cascades to table gtt_error.gtt5
diff --git a/src/test/regress/expected/gtt_parallel_1.out b/src/test/regress/expected/gtt_parallel_1.out
new file mode 100644
index 0000000..30d8a7b
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_1.out
@@ -0,0 +1,84 @@
+set search_path=gtt,sys;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_parallel_2.out b/src/test/regress/expected/gtt_parallel_2.out
new file mode 100644
index 0000000..70bf4a6
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_2.out
@@ -0,0 +1,142 @@
+set search_path=gtt,sys;
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+ 3 | test1
+(3 rows)
+
+rollback;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test2
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 3 | test3
+(1 row)
+
+rollback;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 5 | test5
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 6 | test6
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+ count  
+--------
+ 100000
+(1 row)
+
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+             QUERY PLAN             
+------------------------------------
+ Index Scan using gtt3_pkey on gtt3
+   Index Cond: (a = 300)
+(2 rows)
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',10000);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid) from pg_class where relname = 'gtt_t_kenyon';
+   relname    | pg_relation_size | pg_relation_size 
+--------------+------------------+------------------
+ gtt_t_kenyon |           450560 |            16384
+(1 row)
+
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+   relname    
+--------------
+ gtt_t_kenyon
+(1 row)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_prepare.out b/src/test/regress/expected/gtt_prepare.out
new file mode 100644
index 0000000..9e8f5f0
--- /dev/null
+++ b/src/test/regress/expected/gtt_prepare.out
@@ -0,0 +1,7 @@
+CREATE SCHEMA IF NOT EXISTS gtt;
+set search_path=gtt,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+reset search_path;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index fc0f141..6836eeb 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -121,3 +121,9 @@ test: fast_default
 
 # run stats by itself because its delay may be insufficient under heavy load
 test: stats
+
+# global temp table test
+test: gtt_error
+test: gtt_prepare
+test: gtt_parallel_1 gtt_parallel_2
+test: gtt_clean
diff --git a/src/test/regress/sql/gtt_clean.sql b/src/test/regress/sql/gtt_clean.sql
new file mode 100644
index 0000000..f3cf710
--- /dev/null
+++ b/src/test/regress/sql/gtt_clean.sql
@@ -0,0 +1,6 @@
+
+
+reset search_path;
+
+drop schema gtt cascade;
+
diff --git a/src/test/regress/sql/gtt_error.sql b/src/test/regress/sql/gtt_error.sql
new file mode 100644
index 0000000..e895574
--- /dev/null
+++ b/src/test/regress/sql/gtt_error.sql
@@ -0,0 +1,106 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt_error;
+
+set search_path=gtt_error,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+
+-- ERROR
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+
+-- ERROR
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+
+-- ERROR
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+
+--ERROR
+alter table gtt1 rename to gttx;
+
+-- ERROR
+ALTER TABLE gtt1 ADD COLUMN address varchar(30);
+
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+
+-- ERROR
+create global temp table gttx(id int GENERATED ALWAYS AS IDENTITY (START WITH 2));
+
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+create index idx_err on gtt1 using gist (a);
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+
+reset search_path;
+
+drop schema gtt_error cascade;
+
diff --git a/src/test/regress/sql/gtt_parallel_1.sql b/src/test/regress/sql/gtt_parallel_1.sql
new file mode 100644
index 0000000..d7d81de
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_1.sql
@@ -0,0 +1,42 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+commit;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+rollback;
+select * from gtt1 order by a;
+
+truncate gtt1;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+select * from gtt1 order by a;
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+
+begin;
+select * from gtt1 order by a;
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_parallel_2.sql b/src/test/regress/sql/gtt_parallel_2.sql
new file mode 100644
index 0000000..cb2f7a6
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_2.sql
@@ -0,0 +1,62 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+commit;
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+truncate gtt3;
+select * from gtt3 order by a;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+truncate gtt3;
+select * from gtt3 order by a;
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+begin;
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',10000);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid) from pg_class where relname = 'gtt_t_kenyon';
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_prepare.sql b/src/test/regress/sql/gtt_prepare.sql
new file mode 100644
index 0000000..042d9e6
--- /dev/null
+++ b/src/test/regress/sql/gtt_prepare.sql
@@ -0,0 +1,15 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt;
+
+set search_path=gtt,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+
+reset search_path;
+
--
libgit2 0.23.3

diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c
index 79430d2..b7173c7 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -158,6 +158,19 @@ static relopt_bool boolRelOpts[] =
 		},
 		true
 	},
+	/*
+	 * For global temp table only
+	 * use AccessExclusiveLock for ensure safety
+	 */
+	{
+		{
+			"on_commit_delete_rows",
+			"global temp table on commit options",
+			RELOPT_KIND_HEAP | RELOPT_KIND_PARTITIONED,
+			ShareUpdateExclusiveLock
+		},
+		true
+	},	
 	/* list terminator */
 	{{NULL}}
 };
@@ -1486,6 +1499,8 @@ bytea *
 default_reloptions(Datum reloptions, bool validate, relopt_kind kind)
 {
 	static const relopt_parse_elt tab[] = {
+		{"on_commit_delete_rows", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, on_commit_delete_rows)},
 		{"fillfactor", RELOPT_TYPE_INT, offsetof(StdRdOptions, fillfactor)},
 		{"autovacuum_enabled", RELOPT_TYPE_BOOL,
 		offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, enabled)},
@@ -1586,13 +1601,18 @@ build_reloptions(Datum reloptions, bool validate,
 bytea *
 partitioned_table_reloptions(Datum reloptions, bool validate)
 {
+	static const relopt_parse_elt tab[] = {
+		{"on_commit_delete_rows", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, on_commit_delete_rows)}
+	};
+
 	/*
 	 * There are no options for partitioned tables yet, but this is able to do
 	 * some validation.
 	 */
 	return (bytea *) build_reloptions(reloptions, validate,
 									  RELOPT_KIND_PARTITIONED,
-									  0, NULL, 0);
+									  sizeof(StdRdOptions), tab, lengthof(tab));
 }
 
 /*
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index dd975b1..1610e7d 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -1013,7 +1013,9 @@ gistGetFakeLSN(Relation rel)
 {
 	static XLogRecPtr counter = FirstNormalUnloggedLSN;
 
-	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	/* global temp is same as local temp table */
+	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		rel->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 	{
 		/*
 		 * Temporary relations are only accessible in our session, so a simple
diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index 4bb6efc..8dc8b03 100644
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -146,7 +146,9 @@ hashbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	 * metapage, nor the first bitmap page.
 	 */
 	sort_threshold = (maintenance_work_mem * 1024L) / BLCKSZ;
-	if (index->rd_rel->relpersistence != RELPERSISTENCE_TEMP)
+	/* global temp table is same as local temp table */
+	if (!(index->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		index->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		sort_threshold = Min(sort_threshold, NBuffers);
 	else
 		sort_threshold = Min(sort_threshold, NLocBuffer);
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index a6c369e..675c2b8 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -598,7 +598,7 @@ heapam_relation_set_new_filenode(Relation rel,
 	 */
 	*minmulti = GetOldestMultiXactId();
 
-	srel = RelationCreateStorage(*newrnode, persistence);
+	srel = RelationCreateStorage(*newrnode, persistence, rel);
 
 	/*
 	 * If required, set up an init fork for an unlogged table so that it can
@@ -651,7 +651,7 @@ heapam_relation_copy_data(Relation rel, const RelFileNode *newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index a5fe904..be6fc5f 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -60,6 +60,7 @@
 #include "utils/pg_rusage.h"
 #include "utils/timestamp.h"
 
+#include "catalog/storage_gtt.h"
 
 /*
  * Space/time tradeoff parameters: do these need to be user-tunable?
@@ -217,8 +218,10 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 	Assert(params->truncate != VACOPT_TERNARY_DEFAULT);
 
 	/* not every AM requires these to be valid, but heap does */
-	Assert(TransactionIdIsNormal(onerel->rd_rel->relfrozenxid));
-	Assert(MultiXactIdIsValid(onerel->rd_rel->relminmxid));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relfrozenxid == InvalidTransactionId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && TransactionIdIsNormal(onerel->rd_rel->relfrozenxid)));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relminmxid == InvalidMultiXactId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && MultiXactIdIsValid(onerel->rd_rel->relminmxid)));
 
 	/* measure elapsed time iff autovacuum logging requires it */
 	if (IsAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
@@ -277,8 +280,19 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 
 	vacrelstats = (LVRelStats *) palloc0(sizeof(LVRelStats));
 
-	vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
-	vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
+	/* get relstat from gtt localhash */
+	if (RELATION_IS_GLOBAL_TEMP(onerel))
+	{
+		get_gtt_relstats(RelationGetRelid(onerel),
+						&vacrelstats->old_rel_pages,
+						&vacrelstats->old_live_tuples,
+						NULL, NULL, NULL);
+	}
+	else
+	{
+		vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
+		vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
+	}
 	vacrelstats->num_index_scans = 0;
 	vacrelstats->pages_removed = 0;
 	vacrelstats->lock_waiter_detected = false;
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index f05cbe7..946c9d2 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -763,7 +763,14 @@ _bt_getbuf(Relation rel, BlockNumber blkno, int access)
 		/* Read an existing block of the relation */
 		buf = ReadBuffer(rel, blkno);
 		LockBuffer(buf, access);
-		_bt_checkpage(rel, buf);
+
+		/* global temp table may be not yet initialized for this backend. */
+		if (RELATION_IS_GLOBAL_TEMP(rel) &&
+			blkno == BTREE_METAPAGE &&
+			PageIsNew(BufferGetPage(buf)))
+			_bt_initmetapage(BufferGetPage(buf), P_NONE, 0);
+		else
+			_bt_checkpage(rel, buf);
 	}
 	else
 	{
diff --git a/src/backend/access/table/tableam.c b/src/backend/access/table/tableam.c
index c814733..ff51840 100644
--- a/src/backend/access/table/tableam.c
+++ b/src/backend/access/table/tableam.c
@@ -24,6 +24,7 @@
 #include "access/heapam.h"		/* for ss_* */
 #include "access/tableam.h"
 #include "access/xact.h"
+#include "catalog/storage_gtt.h"
 #include "optimizer/plancat.h"
 #include "storage/bufmgr.h"
 #include "storage/shmem.h"
@@ -560,10 +561,20 @@ table_block_relation_estimate_size(Relation rel, int32 *attr_widths,
 	/* it should have storage, so we can call the smgr */
 	curpages = RelationGetNumberOfBlocks(rel);
 
-	/* coerce values in pg_class to more desirable types */
-	relpages = (BlockNumber) rel->rd_rel->relpages;
-	reltuples = (double) rel->rd_rel->reltuples;
-	relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
+	/* global temp table get relstats from localhash */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		get_gtt_relstats(RelationGetRelid(rel),
+						&relpages, &reltuples, &relallvisible,
+						NULL, NULL);
+	}
+	else
+	{
+		/* coerce values in pg_class to more desirable types */
+		relpages = (BlockNumber) rel->rd_rel->relpages;
+		reltuples = (double) rel->rd_rel->reltuples;
+		relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
+	}
 
 	/*
 	 * HACK: if the relation has never yet been vacuumed, use a minimum size
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 7f4f784..aba8a9f 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6327,6 +6327,10 @@ StartupXLOG(void)
 	else
 		recoveryTargetTLI = ControlFile->checkPointCopy.ThisTimeLineID;
 
+	/* clean temp relation files */
+	if (max_active_gtt > 0)
+		RemovePgTempFiles();
+
 	/*
 	 * Check for signal files, and if so set up state for offline recovery
 	 */
diff --git a/src/backend/catalog/Makefile b/src/backend/catalog/Makefile
index 61db650..fb87816 100644
--- a/src/backend/catalog/Makefile
+++ b/src/backend/catalog/Makefile
@@ -44,6 +44,8 @@ OBJS = \
 	storage.o \
 	toasting.o
 
+OBJS += storage_gtt.o
+
 BKIFILES = postgres.bki postgres.description postgres.shdescription
 
 include $(top_srcdir)/src/backend/common.mk
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index 16cb6d8..f28f2c2 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -398,7 +398,9 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class, char relpersistence)
 
 	switch (relpersistence)
 	{
+		/* global temp table is same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			break;
 		case RELPERSISTENCE_UNLOGGED:
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 0fdff29..54a5243 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -61,6 +61,7 @@
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "commands/tablecmds.h"
 #include "commands/typecmds.h"
 #include "executor/executor.h"
@@ -99,6 +100,7 @@ static void AddNewRelationTuple(Relation pg_class_desc,
 								Oid reloftype,
 								Oid relowner,
 								char relkind,
+								char relpersistence,
 								TransactionId relfrozenxid,
 								TransactionId relminmxid,
 								Datum relacl,
@@ -404,6 +406,10 @@ heap_create(const char *relname,
 									 relpersistence,
 									 relkind);
 
+	/* global temp table not create storage file when catalog create */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		create_storage = false;
+
 	/*
 	 * Have the storage manager create the relation's disk file, if needed.
 	 *
@@ -427,7 +433,7 @@ heap_create(const char *relname,
 
 			case RELKIND_INDEX:
 			case RELKIND_SEQUENCE:
-				RelationCreateStorage(rel->rd_node, relpersistence);
+				RelationCreateStorage(rel->rd_node, relpersistence, rel);
 				break;
 
 			case RELKIND_RELATION:
@@ -956,6 +962,7 @@ AddNewRelationTuple(Relation pg_class_desc,
 					Oid reloftype,
 					Oid relowner,
 					char relkind,
+					char relpersistence,
 					TransactionId relfrozenxid,
 					TransactionId relminmxid,
 					Datum relacl,
@@ -994,8 +1001,18 @@ AddNewRelationTuple(Relation pg_class_desc,
 			break;
 	}
 
-	new_rel_reltup->relfrozenxid = relfrozenxid;
-	new_rel_reltup->relminmxid = relminmxid;
+	/* global temp table not remember transaction info in catalog */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		new_rel_reltup->relfrozenxid = InvalidTransactionId;
+		new_rel_reltup->relminmxid = InvalidMultiXactId;
+	}
+	else
+	{
+		new_rel_reltup->relfrozenxid = relfrozenxid;
+		new_rel_reltup->relminmxid = relminmxid;
+	}
+
 	new_rel_reltup->relowner = relowner;
 	new_rel_reltup->reltype = new_type_oid;
 	new_rel_reltup->reloftype = reloftype;
@@ -1357,6 +1374,7 @@ heap_create_with_catalog(const char *relname,
 						reloftypeid,
 						ownerid,
 						relkind,
+						relpersistence,
 						relfrozenxid,
 						relminmxid,
 						PointerGetDatum(relacl),
@@ -1441,11 +1459,15 @@ heap_create_with_catalog(const char *relname,
 	 */
 	StoreConstraints(new_rel_desc, cooked_constraints, is_internal);
 
-	/*
-	 * If there's a special on-commit action, remember it
-	 */
-	if (oncommit != ONCOMMIT_NOOP)
-		register_on_commit_action(relid, oncommit);
+	/* global temp table register action when storage init */
+	if (relpersistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		/*
+		 * If there's a special on-commit action, remember it
+		 */
+		if (oncommit != ONCOMMIT_NOOP)
+			register_on_commit_action(relid, oncommit);
+	}
 
 	/*
 	 * ok, the relation has been cataloged, so close our relations and return
@@ -1937,6 +1959,13 @@ heap_drop_with_catalog(Oid relid)
 	if (relid == defaultPartOid)
 		update_default_partition_oid(parentOid, InvalidOid);
 
+	/* We allow to drop global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (is_other_backend_use_gtt(rel->rd_node))
+			elog(ERROR, "can not drop relation when other backend attached this global temp table");
+	}
+
 	/*
 	 * Schedule unlinking of the relation's physical files at commit.
 	 */
@@ -3163,9 +3192,10 @@ RemoveStatistics(Oid relid, AttrNumber attnum)
  *
  * The routine will truncate and then reconstruct the indexes on
  * the specified relation.  Caller must hold exclusive lock on rel.
+ *
  */
 static void
-RelationTruncateIndexes(Relation heapRelation)
+RelationTruncateIndexes(Relation heapRelation, LOCKMODE lockmode)
 {
 	ListCell   *indlist;
 
@@ -3177,7 +3207,7 @@ RelationTruncateIndexes(Relation heapRelation)
 		IndexInfo  *indexInfo;
 
 		/* Open the index relation; use exclusive lock, just to be sure */
-		currentIndex = index_open(indexId, AccessExclusiveLock);
+		currentIndex = index_open(indexId, lockmode);
 
 		/*
 		 * Fetch info needed for index_build.  Since we know there are no
@@ -3223,8 +3253,13 @@ heap_truncate(List *relids)
 	{
 		Oid			rid = lfirst_oid(cell);
 		Relation	rel;
+		LOCKMODE	lockmode = AccessExclusiveLock;
 
-		rel = table_open(rid, AccessExclusiveLock);
+		/* truncate global temp table only need RowExclusiveLock */
+		if (get_rel_persistence(rid) == RELPERSISTENCE_GLOBAL_TEMP)
+			lockmode = RowExclusiveLock;
+
+		rel = table_open(rid, lockmode);
 		relations = lappend(relations, rel);
 	}
 
@@ -3257,6 +3292,8 @@ void
 heap_truncate_one_rel(Relation rel)
 {
 	Oid			toastrelid;
+	LOCKMODE	lockmode = AccessExclusiveLock;
+	bool		truncate_toastrel = false;
 
 	/*
 	 * Truncate the relation.  Partitioned tables have no storage, so there is
@@ -3265,23 +3302,40 @@ heap_truncate_one_rel(Relation rel)
 	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 		return;
 
+	toastrelid = rel->rd_rel->reltoastrelid;
+
+	/*
+	 * Truncate global temp table only need RowExclusiveLock
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		lockmode = RowExclusiveLock;
+		if (OidIsValid(toastrelid) &&
+			gtt_storage_attached(toastrelid))
+			truncate_toastrel = true;
+	}
+	else if (OidIsValid(toastrelid))
+		truncate_toastrel = true;
+
 	/* Truncate the underlying relation */
 	table_relation_nontransactional_truncate(rel);
 
 	/* If the relation has indexes, truncate the indexes too */
-	RelationTruncateIndexes(rel);
+	RelationTruncateIndexes(rel, lockmode);
 
 	/* If there is a toast table, truncate that too */
-	toastrelid = rel->rd_rel->reltoastrelid;
-	if (OidIsValid(toastrelid))
+	if (truncate_toastrel)
 	{
-		Relation	toastrel = table_open(toastrelid, AccessExclusiveLock);
+		Relation	toastrel = table_open(toastrelid, lockmode);
 
 		table_relation_nontransactional_truncate(toastrel);
-		RelationTruncateIndexes(toastrel);
+		RelationTruncateIndexes(toastrel, lockmode);
 		/* keep the lock... */
 		table_close(toastrel, NoLock);
 	}
+
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		up_gtt_relstats(rel, 0, 0, 0, RecentXmin, InvalidMultiXactId);
 }
 
 /*
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 3e59e64..1d6306d 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -52,6 +52,7 @@
 #include "catalog/pg_trigger.h"
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
+#include "catalog/storage_gtt.h"
 #include "commands/event_trigger.h"
 #include "commands/progress.h"
 #include "commands/tablecmds.h"
@@ -877,6 +878,26 @@ index_create(Relation heapRelation,
 						indexRelationName, RelationGetRelationName(heapRelation))));
 	}
 
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		if (accessMethodObjectId != BTREE_AM_OID)
+			elog(ERROR, "only support btree index on global temp table");
+
+		/* We allow to create index on global temp table only this session use it */
+		if (is_other_backend_use_gtt(heapRelation->rd_node))
+			elog(ERROR, "can not create index when have other backend attached this global temp table");
+
+		/* No support create index on global temp table use concurrent mode yet */
+		if (concurrent)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("cannot create indexes on global temporary tables using concurrent mode")));
+
+		/* if global temp table not init storage, then skip build index */
+		if (!gtt_storage_attached(heapRelation->rd_node.relNode))
+			flags |= INDEX_CREATE_SKIP_BUILD;
+	}
+
 	/*
 	 * construct tuple descriptor for index tuples
 	 */
@@ -2045,6 +2066,13 @@ index_drop(Oid indexId, bool concurrent, bool concurrent_lock_mode)
 	 */
 	CheckTableNotInUse(userIndexRelation, "DROP INDEX");
 
+	/* We allow to drop index on global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(userHeapRelation))
+	{
+		if (is_other_backend_use_gtt(userHeapRelation->rd_node))
+			elog(ERROR, "can not drop index when other backend attached this global temp table");
+	}
+
 	/*
 	 * Drop Index Concurrently is more or less the reverse process of Create
 	 * Index Concurrently.
@@ -2736,20 +2764,29 @@ index_update_stats(Relation rel,
 		else					/* don't bother for indexes */
 			relallvisible = 0;
 
-		if (rd_rel->relpages != (int32) relpages)
+		/* update index stats into localhash for global temp table */
+		if (RELATION_IS_GLOBAL_TEMP(rel))
 		{
-			rd_rel->relpages = (int32) relpages;
-			dirty = true;
+			up_gtt_relstats(rel, relpages, reltuples, relallvisible,
+							InvalidTransactionId, InvalidMultiXactId);
 		}
-		if (rd_rel->reltuples != (float4) reltuples)
-		{
-			rd_rel->reltuples = (float4) reltuples;
-			dirty = true;
-		}
-		if (rd_rel->relallvisible != (int32) relallvisible)
+		else
 		{
-			rd_rel->relallvisible = (int32) relallvisible;
-			dirty = true;
+			if (rd_rel->relpages != (int32) relpages)
+			{
+				rd_rel->relpages = (int32) relpages;
+				dirty = true;
+			}
+			if (rd_rel->reltuples != (float4) reltuples)
+			{
+				rd_rel->reltuples = (float4) reltuples;
+				dirty = true;
+			}
+			if (rd_rel->relallvisible != (int32) relallvisible)
+			{
+				rd_rel->relallvisible = (int32) relallvisible;
+				dirty = true;
+			}
 		}
 	}
 
@@ -2864,6 +2901,13 @@ index_build(Relation heapRelation,
 		pgstat_progress_update_multi_param(6, index, val);
 	}
 
+	/* POALR */
+	if (RELATION_IS_GLOBAL_TEMP(indexRelation))
+	{
+		if (!gtt_storage_attached(indexRelation->rd_node.relNode))
+			RelationCreateStorage(indexRelation->rd_node, RELPERSISTENCE_GLOBAL_TEMP, indexRelation);
+	}
+
 	/*
 	 * Call the access method's build procedure
 	 */
@@ -3196,12 +3240,22 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	/*
 	 * Scan the index and gather up all the TIDs into a tuplesort object.
 	 */
+	memset(&ivinfo, 0, sizeof(IndexVacuumInfo));
 	ivinfo.index = indexRelation;
 	ivinfo.analyze_only = false;
 	ivinfo.report_progress = true;
 	ivinfo.estimated_count = true;
 	ivinfo.message_level = DEBUG2;
-	ivinfo.num_heap_tuples = heapRelation->rd_rel->reltuples;
+
+	/* get relstats abort global temp table from hashtable, not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		get_gtt_relstats(RelationGetRelid(heapRelation),
+						NULL, &ivinfo.num_heap_tuples, NULL,
+						NULL, NULL);
+	}
+	else
+		ivinfo.num_heap_tuples = heapRelation->rd_rel->reltuples;
 	ivinfo.strategy = NULL;
 
 	/*
@@ -3459,6 +3513,15 @@ reindex_index(Oid indexId, bool skip_constraint_checks, char persistence,
 				 errmsg("cannot reindex temporary tables of other sessions")));
 
 	/*
+	 * Because global temp table cannot change relfilenode
+	 * no support reindex on global temp table yet.
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(iRel))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot reindex global temporary tables")));
+
+	/*
 	 * Also check for active uses of the index in the current transaction; we
 	 * don't want to reindex underneath an open indexscan.
 	 */
diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index c82f9fc..8248109 100644
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -647,6 +647,13 @@ RangeVarAdjustRelationPersistence(RangeVar *newRelation, Oid nspid)
 							 errmsg("cannot create temporary relation in non-temporary schema")));
 			}
 			break;
+		/* global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			if (isAnyTempNamespace(nspid))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+						 errmsg("cannot create global temp relations in temporary schemas")));
+			break;
 		case RELPERSISTENCE_PERMANENT:
 			if (isTempOrTempToastNamespace(nspid))
 				newRelation->relpersistence = RELPERSISTENCE_TEMP;
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index fddfbf1..03806ae 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -26,6 +26,7 @@
 #include "access/xlogutils.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "miscadmin.h"
 #include "storage/freespace.h"
 #include "storage/smgr.h"
@@ -73,9 +74,10 @@ static PendingRelDelete *pendingDeletes = NULL; /* head of linked list */
  *
  * This function is transactional. The creation is WAL-logged, and if the
  * transaction aborts later on, the storage will be destroyed.
+ *
  */
 SMgrRelation
-RelationCreateStorage(RelFileNode rnode, char relpersistence)
+RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel)
 {
 	PendingRelDelete *pending;
 	SMgrRelation srel;
@@ -85,6 +87,8 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	switch (relpersistence)
 	{
 		case RELPERSISTENCE_TEMP:
+		/* global temp table use same storage strategy as local temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			needs_wal = false;
 			break;
@@ -117,6 +121,10 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	pending->next = pendingDeletes;
 	pendingDeletes = pending;
 
+	/* remember global temp table storage info to localhash */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP && rel)
+		remember_gtt_storage_info(rnode, rel);
+
 	return srel;
 }
 
@@ -486,8 +494,15 @@ smgrDoPendingDeletes(bool isCommit)
 		smgrdounlinkall(srels, nrels, false);
 
 		for (i = 0; i < nrels; i++)
+		{
 			smgrclose(srels[i]);
 
+			/* clean global temp table flags when transaction commit or rollback */
+			if (SmgrIsTemp(srels[i]) && 
+				gtt_storage_attached(srels[i]->smgr_rnode.node.relNode))
+				forget_gtt_storage_info(srels[i]->smgr_rnode.node.relNode);
+		}
+
 		pfree(srels);
 	}
 }
diff --git a/src/backend/catalog/storage_gtt.c b/src/backend/catalog/storage_gtt.c
new file mode 100644
index 0000000..13cab8e
--- /dev/null
+++ b/src/backend/catalog/storage_gtt.c
@@ -0,0 +1,1130 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.c
+ *	  code to create and destroy physical storage for global temparary table
+ *
+ * IDENTIFICATION
+ *	  src/backend/catalog/storage_gtt.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/table.h"
+#include "access/visibilitymap.h"
+#include "access/xact.h"
+#include "access/xlog.h"
+#include "access/xloginsert.h"
+#include "access/xlogutils.h"
+#include "access/htup_details.h"
+#include "access/multixact.h"
+#include "catalog/storage.h"
+#include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/heap.h"
+#include "catalog/namespace.h"
+#include "catalog/pg_type.h"
+#include "catalog/pg_statistic.h"
+#include "commands/tablecmds.h"
+#include "funcapi.h"
+#include "nodes/primnodes.h"
+#include "nodes/pg_list.h"
+#include "nodes/execnodes.h"
+#include "miscadmin.h"
+#include "storage/freespace.h"
+#include "storage/smgr.h"
+#include "storage/ipc.h"
+#include "storage/proc.h"
+#include "storage/procarray.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "storage/sinvaladt.h"
+#include "utils/memutils.h"
+#include "utils/rel.h"
+#include "utils/hsearch.h"
+#include "utils/catcache.h"
+#include "utils/lsyscache.h"
+#include <utils/relcache.h>
+#include "utils/inval.h"
+#include "utils/guc.h"
+#include "utils/guc.h"
+
+
+/* Copy from bitmapset.c, because gtt used the function in bitmapset.c */
+#define WORDNUM(x)	((x) / BITS_PER_BITMAPWORD)
+#define BITNUM(x)	((x) % BITS_PER_BITMAPWORD)
+
+#define BITMAPSET_SIZE(nwords)	\
+	(offsetof(Bitmapset, words) + (nwords) * sizeof(bitmapword))
+
+static bool gtt_cleaner_exit_registered = false;
+static HTAB *gtt_storage_local_hash = NULL;
+static HTAB *active_gtt_shared_hash = NULL;
+static MemoryContext gtt_relstats_context = NULL;
+
+/* relfrozenxid of all gtts in the current session */
+static List *gtt_session_relfrozenxid_list = NIL;
+static TransactionId gtt_session_frozenxid = InvalidTransactionId;
+
+typedef struct gtt_ctl_data
+{
+	LWLock			lock;
+	int			max_entry;
+	int			entry_size;
+}gtt_ctl_data;
+
+static gtt_ctl_data *gtt_shared_ctl = NULL;
+
+typedef struct
+{
+	RelFileNode	rnode;
+	Bitmapset	*map;
+	/* bitmap data */
+} gtt_shared_hash_entry;
+
+typedef struct
+{
+	Oid			relid;
+
+	Oid			spcnode;
+	/* pg_class stat */
+	int32		relpages;
+	float4		reltuples;
+	int32		relallvisible;
+	TransactionId relfrozenxid;
+	TransactionId relminmxid;
+	char		relkind;
+	bool		on_commit_delete;
+
+	/* pg_statistic */
+	int			natts;
+	int			*attnum;
+	HeapTuple	*att_stat_tups;
+} gtt_local_hash_entry;
+
+static Size action_gtt_shared_hash_entry_size(void);
+static void gtt_storage_checkin(RelFileNode rnode);
+static void gtt_storage_checkout(RelFileNode rnode, bool skiplock);
+static void gtt_storage_removeall(int code, Datum arg);
+static void insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid);
+static void remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid);
+static void set_gtt_session_relfrozenxid(void);
+
+Datum pg_get_gtt_statistics(PG_FUNCTION_ARGS);
+Datum pg_get_gtt_relstats(PG_FUNCTION_ARGS);
+Datum pg_gtt_attached_pid(PG_FUNCTION_ARGS);
+Datum pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS);
+
+
+static Size
+action_gtt_shared_hash_entry_size(void)
+{
+	int 	wordnum;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	wordnum = WORDNUM(MaxBackends + 1);
+	hash_entry_size += MAXALIGN(sizeof(gtt_shared_hash_entry));
+	hash_entry_size += MAXALIGN(BITMAPSET_SIZE(wordnum + 1));
+
+	return hash_entry_size;
+}
+
+Size
+active_gtt_shared_hash_size(void)
+{
+	Size	size = 0;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	size = MAXALIGN(sizeof(gtt_ctl_data));
+	hash_entry_size = action_gtt_shared_hash_entry_size();
+	size += hash_estimate_size(max_active_gtt, hash_entry_size);
+
+	return size;
+}
+
+void
+active_gtt_shared_hash_init(void)
+{
+	HASHCTL info;
+	bool	found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	gtt_shared_ctl =
+		ShmemInitStruct("gtt_shared_ctl",
+						sizeof(gtt_ctl_data),
+						&found);
+
+	if (!found)
+	{
+		LWLockRegisterTranche(LWTRANCHE_GTT_CTL, "gtt_shared_ctl");
+		LWLockInitialize(&gtt_shared_ctl->lock, LWTRANCHE_GTT_CTL);
+		gtt_shared_ctl->max_entry = max_active_gtt;
+		gtt_shared_ctl->entry_size = action_gtt_shared_hash_entry_size();
+	}
+
+	info.keysize = sizeof(RelFileNode);
+	info.entrysize = gtt_shared_ctl->entry_size;
+	active_gtt_shared_hash =
+		ShmemInitHash("active gtt shared hash",
+						gtt_shared_ctl->max_entry,
+						gtt_shared_ctl->max_entry,
+						&info, HASH_ELEM | HASH_BLOBS | HASH_FIXED_SIZE);
+}
+
+static void
+gtt_storage_checkin(RelFileNode rnode)
+{
+	gtt_shared_hash_entry	*entry;
+	bool			found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+	entry = (gtt_shared_hash_entry *) hash_search(active_gtt_shared_hash,
+												&rnode, HASH_ENTER_NULL, &found);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		ereport(ERROR,
+				(errcode(ERRCODE_OUT_OF_MEMORY),
+				 errmsg("out of shared memory"),
+				 errhint("You might need to increase max_active_gtt.")));
+	}
+
+	if (found == false)
+	{
+		int			wordnum;
+
+		entry->map = (Bitmapset *)((char *)entry + MAXALIGN(sizeof(gtt_shared_hash_entry)));
+		wordnum = WORDNUM(MaxBackends + 1);
+		memset(entry->map, 0, BITMAPSET_SIZE(wordnum + 1));
+		entry->map->nwords = wordnum + 1;
+	}
+
+	bms_add_member(entry->map, MyBackendId);
+	LWLockRelease(&gtt_shared_ctl->lock);
+}
+
+static void
+gtt_storage_checkout(RelFileNode rnode, bool skiplock)
+{
+	gtt_shared_hash_entry	*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (!skiplock)
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(rnode), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		if (!skiplock)
+			LWLockRelease(&gtt_shared_ctl->lock);
+
+		elog(WARNING, "relfilenode %u/%u/%u not exist in gtt shared hash when forget",
+						rnode.dbNode, rnode.spcNode, rnode.relNode);
+		return;
+	}
+
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+	bms_del_member(entry->map, MyBackendId);
+
+	if (bms_is_empty(entry->map))
+	{
+		if (!hash_search(active_gtt_shared_hash, &rnode, HASH_REMOVE, NULL))
+			elog(PANIC, "gtt shared hash table corrupted");
+	}
+
+	if (!skiplock)
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+	return;
+}
+
+Bitmapset *
+copy_active_gtt_bitmap(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	Bitmapset	*map_copy = NULL;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return NULL;
+	}
+
+	Assert(entry->map);
+	if (!bms_is_empty(entry->map))
+		map_copy = bms_copy(entry->map);
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return map_copy;
+}
+
+bool
+is_other_backend_use_gtt(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	bool		in_use = false;
+	int			num_use = 0;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return false;
+	}
+
+	Assert(entry->map);
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+
+	num_use = bms_num_members(entry->map);
+	if (num_use == 0)
+		in_use = false;
+	else if (num_use == 1)
+	{
+		if(bms_is_member(MyBackendId, entry->map))
+			in_use = false;
+		else
+			in_use = true;
+	}
+	else
+		in_use = true;
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return in_use;
+}
+
+void
+remember_gtt_storage_info(RelFileNode rnode, Relation rel)
+{
+	gtt_local_hash_entry	*entry;
+	MemoryContext			oldcontext;
+	Oid			relid = rnode.relNode;
+	bool		found;
+
+	if (max_active_gtt <= 0)
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("Global temporary table feature is disable"),
+			 errhint("You might need to increase max_active_gtt to enable this feature.")));
+
+	if (RecoveryInProgress())
+		elog(ERROR, "readonly mode not support access global temp table yet");
+
+	if (gtt_storage_local_hash == NULL)
+	{
+#define GTT_LOCAL_HASH_SIZE		1024
+		/* First time through: initialize the hash table */
+		HASHCTL		ctl;
+
+		MemSet(&ctl, 0, sizeof(ctl));
+		ctl.keysize = sizeof(Oid);
+		ctl.entrysize = sizeof(gtt_local_hash_entry);
+		gtt_storage_local_hash =
+			hash_create("global temp relation table",
+						GTT_LOCAL_HASH_SIZE,
+						&ctl, HASH_ELEM | HASH_BLOBS);
+
+		if (!CacheMemoryContext)
+			CreateCacheMemoryContext();
+
+		gtt_relstats_context =
+			AllocSetContextCreate(CacheMemoryContext,
+							"gtt relstats context",
+							ALLOCSET_DEFAULT_SIZES);
+	}
+
+	/* Look up or create an entry */
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_ENTER, &found);
+
+	if (found)
+	{
+		elog(ERROR, "backend %d relid %u already exists in global temp table local hash",
+					MyBackendId, relid);
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+
+	entry->spcnode = rnode.spcNode;
+	entry->relpages = 0;
+	entry->reltuples = 0;
+	entry->relallvisible = 0;
+	entry->relkind = rel->rd_rel->relkind;
+	/* only heap contain transaction information */
+	if (entry->relkind == RELKIND_RELATION || entry->relkind == RELKIND_PARTITIONED_TABLE)
+	{
+		int natts = RelationGetNumberOfAttributes(rel);
+		entry->natts = natts;
+		entry->attnum = palloc0(sizeof(int) * natts);
+		entry->att_stat_tups = palloc0(sizeof(HeapTuple) * natts);
+
+		if (RELATION_GTT_ON_COMMIT_DELETE(rel))
+		{
+			entry->on_commit_delete = true;
+			register_on_commit_action(rel->rd_node.relNode, ONCOMMIT_DELETE_ROWS);
+		}
+
+		entry->relfrozenxid = RecentXmin;
+		entry->relminmxid = GetOldestMultiXactId();
+		insert_gtt_relfrozenxid_to_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+		gtt_storage_checkin(rnode);
+	}
+	else
+	{
+		entry->natts = 0;
+		entry->attnum = 0;
+		entry->att_stat_tups = NULL;
+		entry->on_commit_delete = false;
+		entry->relfrozenxid = 0;
+		entry->relminmxid = 0;
+	}
+
+	MemoryContextSwitchTo(oldcontext);
+
+	if (!gtt_cleaner_exit_registered)
+	{
+		before_shmem_exit(gtt_storage_removeall, 0);
+		gtt_cleaner_exit_registered = true;
+	}
+
+	return;
+}
+
+void
+forget_gtt_storage_info(Oid relid)
+{
+	gtt_local_hash_entry		*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+				(void *) &(relid), HASH_FIND, NULL);
+
+	if (entry && entry->relkind == RELKIND_RELATION)
+	{
+		RelFileNode rnode;
+		int			i;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		gtt_storage_checkout(rnode, false);
+
+		Assert(TransactionIdIsNormal(entry->relfrozenxid));
+		remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+
+		for (i = 0; i < entry->natts; i++)
+		{
+			if (entry->att_stat_tups[i])
+			{
+				heap_freetuple(entry->att_stat_tups[i]);
+				entry->att_stat_tups[i] = NULL;
+			}
+		}
+	}
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_REMOVE, NULL);
+
+	return;
+}
+
+/* is the storage file was created in this backend */
+bool
+gtt_storage_attached(Oid relid)
+{
+	bool found;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	if (gtt_storage_local_hash == NULL)
+		return false;
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_FIND, &found);
+
+	return found;
+}
+
+static void
+gtt_storage_removeall(int code, Datum arg)
+{
+	HASH_SEQ_STATUS				status;
+	gtt_local_hash_entry		*entry;
+	int			nrels = 0,
+				maxrels = 0;
+	SMgrRelation	*srels = NULL;
+	RelFileNode		*rnodes = NULL;
+	char			*relkinds = NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	hash_seq_init(&status, gtt_storage_local_hash);
+	while ((entry = (gtt_local_hash_entry *) hash_seq_search(&status)) != NULL)
+	{
+		SMgrRelation srel;
+		RelFileNode rnode;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		srel = smgropen(rnode, MyBackendId);
+
+		/* allocate the initial array, or extend it, if needed */
+		if (maxrels == 0)
+		{
+			maxrels = 32;
+			srels = palloc(sizeof(SMgrRelation) * maxrels);
+			rnodes = palloc(sizeof(RelFileNode) * maxrels);
+			relkinds = palloc(sizeof(char) * maxrels);
+		}
+		else if (maxrels <= nrels)
+		{
+			maxrels *= 2;
+			srels = repalloc(srels, sizeof(SMgrRelation) * maxrels);
+			rnodes = repalloc(rnodes, sizeof(RelFileNode) * maxrels);
+			relkinds = repalloc(relkinds, sizeof(char) * maxrels);
+		}
+
+		srels[nrels] = srel;
+		rnodes[nrels] = rnode;
+		relkinds[nrels] = entry->relkind;
+		nrels++;
+	}
+
+	if (nrels > 0)
+	{
+		int i;
+
+		smgrdounlinkall(srels, nrels, false);
+
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+		for (i = 0; i < nrels; i++)
+		{
+			smgrclose(srels[i]);
+			if (relkinds[i] == RELKIND_RELATION)
+				gtt_storage_checkout(rnodes[i], true);
+		}
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+		pfree(srels);
+		pfree(rnodes);
+		pfree(relkinds);
+	}
+
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;
+
+	return;
+}
+
+/*
+ * Update global temp table relstats(relpage/reltuple/relallvisible) 
+ * to local hashtable
+ */
+void
+up_gtt_relstats(Relation relation,
+					BlockNumber num_pages,
+					double num_tuples,
+					BlockNumber num_all_visible_pages,
+					TransactionId relfrozenxid,
+					TransactionId relminmxid)
+{
+	Oid		relid = RelationGetRelid(relation);
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	Assert(entry->spcnode);
+
+	if (num_pages >= 0 &&
+		entry->relpages != (int32)num_pages)
+		entry->relpages = (int32)num_pages;
+
+	if (num_tuples >= 0 &&
+		num_tuples != (float4)entry->reltuples)
+		entry->reltuples = (float4)num_tuples;
+
+	/* only heap contain transaction information and relallvisible */
+	if (entry->relkind == RELKIND_RELATION)
+	{
+		if (entry->relallvisible >= 0 &&
+			entry->relallvisible != (int32)num_all_visible_pages)
+		{
+			entry->relallvisible = (int32)num_all_visible_pages;
+		}
+
+		if (TransactionIdIsNormal(relfrozenxid) &&
+			entry->relfrozenxid != relfrozenxid &&
+			(TransactionIdPrecedes(entry->relfrozenxid, relfrozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(), entry->relfrozenxid)))
+		{
+			remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+			entry->relfrozenxid = relfrozenxid;
+			insert_gtt_relfrozenxid_to_ordered_list(relfrozenxid);
+			set_gtt_session_relfrozenxid();
+		}
+
+		if (MultiXactIdIsValid(relminmxid) &&
+			entry->relminmxid != relminmxid &&
+			(MultiXactIdPrecedes(entry->relminmxid, relminmxid) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), entry->relminmxid)))
+		{
+			entry->relminmxid = relminmxid;
+		}
+	}
+
+	return;
+}
+
+/*
+ * Search global temp table relstats(relpage/reltuple/relallvisible) 
+ * from local hashtable.
+ */
+bool
+get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+				BlockNumber *relallvisible, TransactionId *relfrozenxid,
+				TransactionId *relminmxid)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	if (gtt_storage_local_hash == NULL)
+		return false;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return false;
+
+	Assert(entry->relid == relid);
+
+	if (relpages)
+		*relpages = entry->relpages;
+
+	if (reltuples)
+		*reltuples = entry->reltuples;
+
+	if (relallvisible)
+		*relallvisible = entry->relallvisible;
+
+	if (relfrozenxid)
+		*relfrozenxid = entry->relfrozenxid;
+
+	if (relminmxid)
+		*relminmxid = entry->relminmxid;
+
+	return true;
+}
+
+/*
+ * Update global temp table statistic info(definition is same as pg_statistic)
+ * to local hashtable where ananyze global temp table
+ */
+void
+up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+					TupleDesc tupleDescriptor, Datum *values, bool *isnull)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	MemoryContext			oldcontext;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	if (entry->relkind != RELKIND_RELATION)
+	{
+		elog(WARNING, "oid %u not a relation", reloid);
+		return;
+	}
+
+	/* todo */
+	if (entry->natts < natts)
+	{
+		elog(WARNING, "reloid %u not support update attstat after add colunm", reloid);
+		return;
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	Assert(entry->relid == reloid);
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == 0)
+		{
+			entry->attnum[i] = attnum;
+			break;
+		}
+		else if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			heap_freetuple(entry->att_stat_tups[i]);
+			entry->att_stat_tups[i] = NULL;
+			break;
+		}
+	}
+
+	Assert(i < entry->natts);
+	Assert(entry->att_stat_tups[i] == NULL);
+	entry->att_stat_tups[i] = heap_form_tuple(tupleDescriptor, values, isnull);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+/*
+ * Search global temp table statistic info(definition is same as pg_statistic)
+ * from local hashtable.
+ */
+HeapTuple
+get_gtt_att_statistic(Oid reloid, int attnum, bool inh)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return NULL;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return NULL;
+
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			return entry->att_stat_tups[i];
+		}
+	}
+
+	return NULL;
+}
+
+void
+release_gtt_statistic_cache(HeapTuple tup)
+{
+	/* do nothing */
+	return;
+}
+
+static void
+insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid)
+{
+	MemoryContext	oldcontext;
+	ListCell	*cell;
+	int			i;
+
+	Assert(TransactionIdIsNormal(relfrozenxid));
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	/* Does the datum belong at the front? */
+	if (gtt_session_relfrozenxid_list == NIL ||
+		TransactionIdFollowsOrEquals(relfrozenxid,
+			linitial_oid(gtt_session_relfrozenxid_list)))
+	{
+		gtt_session_relfrozenxid_list =
+			lcons_oid(relfrozenxid, gtt_session_relfrozenxid_list);
+		MemoryContextSwitchTo(oldcontext);
+
+		return;
+	}
+
+	/* No, so find the entry it belongs after */
+	i = 0;
+	foreach (cell, gtt_session_relfrozenxid_list)
+	{
+		if (TransactionIdFollowsOrEquals(relfrozenxid, lfirst_oid(cell)))
+			break;
+
+		i++;
+	}
+	gtt_session_relfrozenxid_list =
+		list_insert_nth_oid(gtt_session_relfrozenxid_list, i, relfrozenxid);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+static void
+remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid)
+{
+	gtt_session_relfrozenxid_list =
+		list_delete_oid(gtt_session_relfrozenxid_list, relfrozenxid);
+}
+
+static void
+set_gtt_session_relfrozenxid(void)
+{
+	TransactionId gtt_frozenxid = InvalidTransactionId;
+
+	if (gtt_session_relfrozenxid_list)
+		gtt_frozenxid = llast_oid(gtt_session_relfrozenxid_list);
+
+	gtt_session_frozenxid = gtt_frozenxid;
+	if (MyProc->session_gtt_frozenxid != gtt_frozenxid)
+		MyProc->session_gtt_frozenxid = gtt_frozenxid;
+}
+
+Datum
+pg_get_gtt_statistics(PG_FUNCTION_ARGS)
+{
+	HeapTuple	tuple;
+	Relation	rel = NULL;
+	int		attnum = PG_GETARG_INT32(1);
+	Oid		reloid = PG_GETARG_OID(0);
+	char		rel_persistence;
+	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	  tupdesc;
+	MemoryContext oldcontext;
+	Tuplestorestate *tupstore;
+	Relation		pg_tatistic = NULL;
+	TupleDesc		sd;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("set-valued function called in context that cannot accept a set")));
+
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("materialize mode required, but it is not " \
+				"allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+				rsinfo->econtext->ecxt_per_query_memory);
+
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	pg_tatistic = table_open(StatisticRelationId, AccessShareLock);
+	sd = RelationGetDescr(pg_tatistic);
+
+	tuple = get_gtt_att_statistic(reloid, attnum, false);
+	if (tuple)
+	{
+		Datum	values[31];
+		bool	isnull[31];
+		HeapTuple	res = NULL;
+
+		memset(&values, 0, sizeof(values));
+		memset(&isnull, 0, sizeof(isnull));
+		heap_deform_tuple(tuple, sd, values, isnull);
+		res = heap_form_tuple(tupdesc, values, isnull);
+		tuplestore_puttuple(tupstore, res);
+	}
+
+	table_close(rel, NoLock);
+	table_close(pg_tatistic, AccessShareLock);
+	tuplestore_donestoring(tupstore);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_get_gtt_relstats(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc		tupdesc;
+	Tuplestorestate	*tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	Oid		reloid = PG_GETARG_OID(0);
+	char	rel_persistence;
+	BlockNumber	relpages = 0;
+	double		reltuples = 0;
+	BlockNumber	relallvisible = 0;
+	uint32		relfrozenxid = 0;
+	uint32		relminmxid = 0;
+	Relation	rel = NULL;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	if (get_gtt_relstats(reloid,
+						&relpages, &reltuples, &relallvisible,
+						&relfrozenxid, &relminmxid))
+	{
+		Datum	values[5];
+		bool	isnull[5];
+
+		memset(isnull, 0, sizeof(isnull));
+		memset(values, 0, sizeof(values));
+		values[0] = Int32GetDatum(relpages);
+		values[1] = Float4GetDatum((float4)reltuples);
+		values[2] = Int32GetDatum(relallvisible);
+		values[3] = UInt32GetDatum(relfrozenxid);
+		values[4] = UInt32GetDatum(relminmxid);
+		tuple = heap_form_tuple(tupdesc, values, isnull);
+		tuplestore_puttuple(tupstore, tuple);
+	}
+
+	tuplestore_donestoring(tupstore);
+	table_close(rel, NoLock);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_gtt_attached_pid(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	Oid		reloid = PG_GETARG_OID(0);
+	char	rel_persistence;
+	Relation	rel = NULL;
+	PGPROC		*proc = NULL;
+	Bitmapset	*map = NULL;
+	pid_t		pid = 0;
+	int			backendid = 0;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	map = copy_active_gtt_bitmap(rel->rd_node);
+	if (map)
+	{
+		backendid = bms_first_member(map);
+
+		do
+		{
+			proc = BackendIdGetProc(backendid);
+			pid = proc->pid;
+			if (pid > 0)
+			{
+				Datum	values[2];
+				bool	isnull[2];
+
+				memset(isnull, false, sizeof(isnull));
+				memset(values, 0, sizeof(values));
+				values[0] = UInt32GetDatum(reloid);
+				values[1] = Int32GetDatum(pid);
+				tuple = heap_form_tuple(tupdesc, values, isnull);
+				tuplestore_puttuple(tupstore, tuple);
+			}
+			backendid = bms_next_member(map, backendid);
+		} while (backendid > 0);
+
+		pfree(map);
+	}
+
+	tuplestore_donestoring(tupstore);
+	table_close(rel, NoLock);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	int			num_xid = MaxBackends + 1;
+	int			*pids = NULL;
+	uint32		*xids = NULL;
+	int			i = 0;
+	int			j = 0;
+	uint32		oldest = 0;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (max_active_gtt <= 0)
+		return (Datum) 0;
+
+	if (RecoveryInProgress())
+		return (Datum) 0;
+
+	pids = palloc0(sizeof(int) * num_xid);
+	xids = palloc0(sizeof(int) * num_xid);
+	oldest = list_all_session_gtt_frozenxids(num_xid, pids, xids, &i);
+	if (i > 0)
+	{
+		if (i > 0)
+		{
+			pids[i] = 0;
+			xids[i] = oldest;
+			i++;
+		}
+
+		for(j = 0; j < i; j++)
+		{
+			Datum	values[2];
+			bool	isnull[2];
+
+			memset(isnull, false, sizeof(isnull));
+			memset(values, 0, sizeof(values));
+			values[0] = Int32GetDatum(pids[j]);
+			values[1] = UInt32GetDatum(xids[j]);
+			tuple = heap_form_tuple(tupdesc, values, isnull);
+			tuplestore_puttuple(tupstore, tuple);
+		}
+	}
+	tuplestore_donestoring(tupstore);
+	pfree(pids);
+	pfree(xids);
+
+	return (Datum) 0;
+}
+
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index 2fc3e3f..d0efd18 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -186,6 +186,91 @@ CREATE OR REPLACE VIEW pg_sequences AS
     WHERE NOT pg_is_other_temp_schema(N.oid)
           AND relkind = 'S';
 
+-- For global temporary table
+CREATE VIEW pg_gtt_relstats WITH (security_barrier) AS
+ SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.*
+ FROM
+     pg_class c
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_get_gtt_relstats(c.oid) as s
+ WHERE c.relpersistence='g' AND c.relkind in('r','p') AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
+CREATE VIEW pg_gtt_attached_pids WITH (security_barrier) AS
+ SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.*
+ FROM
+     pg_class c
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_gtt_attached_pid(c.oid) as s
+ WHERE c.relpersistence='g' AND c.relkind in('r','p') AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
+CREATE VIEW pg_gtt_stats WITH (security_barrier) AS
+SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    a.attname,
+    s.stainherit AS inherited,
+    s.stanullfrac AS null_frac,
+    s.stawidth AS avg_width,
+    s.stadistinct AS n_distinct,
+        CASE
+            WHEN s.stakind1 = 1 THEN s.stavalues1
+            WHEN s.stakind2 = 1 THEN s.stavalues2
+            WHEN s.stakind3 = 1 THEN s.stavalues3
+            WHEN s.stakind4 = 1 THEN s.stavalues4
+            WHEN s.stakind5 = 1 THEN s.stavalues5
+        END AS most_common_vals,
+        CASE
+            WHEN s.stakind1 = 1 THEN s.stanumbers1
+            WHEN s.stakind2 = 1 THEN s.stanumbers2
+            WHEN s.stakind3 = 1 THEN s.stanumbers3
+            WHEN s.stakind4 = 1 THEN s.stanumbers4
+            WHEN s.stakind5 = 1 THEN s.stanumbers5
+        END AS most_common_freqs,
+        CASE
+            WHEN s.stakind1 = 2 THEN s.stavalues1
+            WHEN s.stakind2 = 2 THEN s.stavalues2
+            WHEN s.stakind3 = 2 THEN s.stavalues3
+            WHEN s.stakind4 = 2 THEN s.stavalues4
+            WHEN s.stakind5 = 2 THEN s.stavalues5
+        END AS histogram_bounds,
+        CASE
+            WHEN s.stakind1 = 3 THEN s.stanumbers1[1]
+            WHEN s.stakind2 = 3 THEN s.stanumbers2[1]
+            WHEN s.stakind3 = 3 THEN s.stanumbers3[1]
+            WHEN s.stakind4 = 3 THEN s.stanumbers4[1]
+            WHEN s.stakind5 = 3 THEN s.stanumbers5[1]
+        END AS correlation,
+        CASE
+            WHEN s.stakind1 = 4 THEN s.stavalues1
+            WHEN s.stakind2 = 4 THEN s.stavalues2
+            WHEN s.stakind3 = 4 THEN s.stavalues3
+            WHEN s.stakind4 = 4 THEN s.stavalues4
+            WHEN s.stakind5 = 4 THEN s.stavalues5
+        END AS most_common_elems,
+        CASE
+            WHEN s.stakind1 = 4 THEN s.stanumbers1
+            WHEN s.stakind2 = 4 THEN s.stanumbers2
+            WHEN s.stakind3 = 4 THEN s.stanumbers3
+            WHEN s.stakind4 = 4 THEN s.stanumbers4
+            WHEN s.stakind5 = 4 THEN s.stanumbers5
+        END AS most_common_elem_freqs,
+        CASE
+            WHEN s.stakind1 = 5 THEN s.stanumbers1
+            WHEN s.stakind2 = 5 THEN s.stanumbers2
+            WHEN s.stakind3 = 5 THEN s.stanumbers3
+            WHEN s.stakind4 = 5 THEN s.stanumbers4
+            WHEN s.stakind5 = 5 THEN s.stanumbers5
+        END AS elem_count_histogram
+   FROM 
+     pg_class c
+     JOIN pg_attribute a ON c.oid = a.attrelid
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_get_gtt_statistics(c.oid, a.attnum, ''::text) as s
+  WHERE c.relpersistence='g' AND c.relkind in('r','p') and NOT a.attisdropped AND has_column_privilege(c.oid, a.attnum, 'select'::text) AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
 CREATE VIEW pg_stats WITH (security_barrier) AS
     SELECT
         nspname AS schemaname,
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 53b11d7..104d6ce 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -65,6 +65,7 @@
 #include "utils/syscache.h"
 #include "utils/timestamp.h"
 
+#include "catalog/storage_gtt.h"
 
 /* Per-index data for ANALYZE */
 typedef struct AnlIndexData
@@ -102,7 +103,7 @@ static int	acquire_inherited_sample_rows(Relation onerel, int elevel,
 										  HeapTuple *rows, int targrows,
 										  double *totalrows, double *totaldeadrows);
 static void update_attstats(Oid relid, bool inh,
-							int natts, VacAttrStats **vacattrstats);
+							int natts, VacAttrStats **vacattrstats, char relpersistence);
 static Datum std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 static Datum ind_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 
@@ -575,14 +576,15 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 		 * pg_statistic for columns we didn't process, we leave them alone.)
 		 */
 		update_attstats(RelationGetRelid(onerel), inh,
-						attr_cnt, vacattrstats);
+						attr_cnt, vacattrstats, RelationGetRelPersistence(onerel));
 
 		for (ind = 0; ind < nindexes; ind++)
 		{
 			AnlIndexData *thisdata = &indexdata[ind];
 
 			update_attstats(RelationGetRelid(Irel[ind]), false,
-							thisdata->attr_cnt, thisdata->vacattrstats);
+							thisdata->attr_cnt, thisdata->vacattrstats,
+							RelationGetRelPersistence(Irel[ind]));
 		}
 
 		/*
@@ -659,11 +661,20 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 			IndexBulkDeleteResult *stats;
 			IndexVacuumInfo ivinfo;
 
+			memset(&ivinfo, 0, sizeof(IndexVacuumInfo));
 			ivinfo.index = Irel[ind];
 			ivinfo.analyze_only = true;
 			ivinfo.estimated_count = true;
 			ivinfo.message_level = elevel;
-			ivinfo.num_heap_tuples = onerel->rd_rel->reltuples;
+			/* get global temp relstats from localhash, not catalog */
+			if (RELATION_IS_GLOBAL_TEMP(onerel))
+			{
+				get_gtt_relstats(RelationGetRelid(onerel),
+								NULL, &ivinfo.num_heap_tuples, NULL,
+								NULL, NULL);
+			}
+			else
+				ivinfo.num_heap_tuples = onerel->rd_rel->reltuples;
 			ivinfo.strategy = vac_strategy;
 
 			stats = index_vacuum_cleanup(&ivinfo, NULL);
@@ -1425,7 +1436,7 @@ acquire_inherited_sample_rows(Relation onerel, int elevel,
  *		by taking a self-exclusive lock on the relation in analyze_rel().
  */
 static void
-update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
+update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats, char relpersistence)
 {
 	Relation	sd;
 	int			attno;
@@ -1527,31 +1538,45 @@ update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
 			}
 		}
 
-		/* Is there already a pg_statistic tuple for this attribute? */
-		oldtup = SearchSysCache3(STATRELATTINH,
-								 ObjectIdGetDatum(relid),
-								 Int16GetDatum(stats->attr->attnum),
-								 BoolGetDatum(inh));
-
-		if (HeapTupleIsValid(oldtup))
+		/* Update column statistic to localhash, not catalog */
+		if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		{
-			/* Yes, replace it */
-			stup = heap_modify_tuple(oldtup,
-									 RelationGetDescr(sd),
-									 values,
-									 nulls,
-									 replaces);
-			ReleaseSysCache(oldtup);
-			CatalogTupleUpdate(sd, &stup->t_self, stup);
+			up_gtt_att_statistic(relid,
+								stats->attr->attnum,
+								inh,
+								natts,
+								RelationGetDescr(sd),
+								values,
+								nulls);
 		}
 		else
 		{
-			/* No, insert new tuple */
-			stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
-			CatalogTupleInsert(sd, stup);
-		}
+			/* Is there already a pg_statistic tuple for this attribute? */
+			oldtup = SearchSysCache3(STATRELATTINH,
+									 ObjectIdGetDatum(relid),
+									 Int16GetDatum(stats->attr->attnum),
+									 BoolGetDatum(inh));
+
+			if (HeapTupleIsValid(oldtup))
+			{
+				/* Yes, replace it */
+				stup = heap_modify_tuple(oldtup,
+										 RelationGetDescr(sd),
+										 values,
+										 nulls,
+										 replaces);
+				ReleaseSysCache(oldtup);
+				CatalogTupleUpdate(sd, &stup->t_self, stup);
+			}
+			else
+			{
+				/* No, insert new tuple */
+				stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
+				CatalogTupleInsert(sd, stup);
+			}
 
-		heap_freetuple(stup);
+			heap_freetuple(stup);
+		}
 	}
 
 	table_close(sd, RowExclusiveLock);
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index e9d7a7f..3088e26 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -391,6 +391,12 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 					 errmsg("cannot vacuum temporary tables of other sessions")));
 	}
 
+	/* not support cluster global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(OldHeap))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support cluster global temporary tables yet")));
+
 	/*
 	 * Also check for active uses of the relation in the current transaction,
 	 * including open scans and pending AFTER trigger events.
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 52ce02f..3d3f7dc 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -2583,6 +2583,16 @@ ReindexMultipleTables(const char *objectName, ReindexObjectType objectKind,
 			!isTempNamespace(classtuple->relnamespace))
 			continue;
 
+		/* not support reindex on global temp table, so skip it */
+		if (classtuple->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			ereport(WARNING,
+				(errmsg("global temp table \"%s.%s\" skip reindexed",
+					get_namespace_name(get_rel_namespace(relid)),
+					get_rel_name(relid))));
+			continue;
+		}
+
 		/* Check user/system classification, and optionally skip */
 		if (objectKind == REINDEX_OBJECT_SYSTEM &&
 			!IsSystemClass(relid, classtuple))
diff --git a/src/backend/commands/lockcmds.c b/src/backend/commands/lockcmds.c
index 75410f0..eb1acea 100644
--- a/src/backend/commands/lockcmds.c
+++ b/src/backend/commands/lockcmds.c
@@ -107,7 +107,8 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
 	 * transaction.
 	 */
 	relpersistence = get_rel_persistence(relid);
-	if (relpersistence == RELPERSISTENCE_TEMP)
+	if (relpersistence == RELPERSISTENCE_TEMP ||
+		relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		MyXactFlags |= XACT_FLAGS_ACCESSEDTEMPNAMESPACE;
 
 	/* Check permissions. */
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index 6aab73b..44f350d 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -94,7 +94,7 @@ static HTAB *seqhashtab = NULL; /* hash table for SeqTable items */
  */
 static SeqTableData *last_used_seq = NULL;
 
-static void fill_seq_with_data(Relation rel, HeapTuple tuple);
+static void fill_seq_with_data(Relation rel, HeapTuple tuple, Buffer buf);
 static Relation lock_and_open_sequence(SeqTable seq);
 static void create_seq_hashtable(void);
 static void init_sequence(Oid relid, SeqTable *p_elm, Relation *p_rel);
@@ -108,6 +108,7 @@ static void init_params(ParseState *pstate, List *options, bool for_identity,
 						List **owned_by);
 static void do_setval(Oid relid, int64 next, bool iscalled);
 static void process_owned_by(Relation seqrel, List *owned_by, bool for_identity);
+int64 get_seqence_start_value(Oid seqid);
 
 
 /*
@@ -222,7 +223,7 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 
 	/* now initialize the sequence's data */
 	tuple = heap_form_tuple(tupDesc, value, null);
-	fill_seq_with_data(rel, tuple);
+	fill_seq_with_data(rel, tuple, InvalidBuffer);
 
 	/* process OWNED BY if given */
 	if (owned_by)
@@ -327,7 +328,7 @@ ResetSequence(Oid seq_relid)
 	/*
 	 * Insert the modified tuple into the new storage file.
 	 */
-	fill_seq_with_data(seq_rel, tuple);
+	fill_seq_with_data(seq_rel, tuple, InvalidBuffer);
 
 	/* Clear local cache so that we don't think we have cached numbers */
 	/* Note that we do not change the currval() state */
@@ -340,17 +341,21 @@ ResetSequence(Oid seq_relid)
  * Initialize a sequence's relation with the specified tuple as content
  */
 static void
-fill_seq_with_data(Relation rel, HeapTuple tuple)
+fill_seq_with_data(Relation rel, HeapTuple tuple, Buffer buf)
 {
-	Buffer		buf;
 	Page		page;
 	sequence_magic *sm;
 	OffsetNumber offnum;
+	bool lockBuffer = false;
 
 	/* Initialize first page of relation with special magic number */
 
-	buf = ReadBuffer(rel, P_NEW);
-	Assert(BufferGetBlockNumber(buf) == 0);
+	if (buf == InvalidBuffer)
+	{
+		buf = ReadBuffer(rel, P_NEW);
+		Assert(BufferGetBlockNumber(buf) == 0);
+		lockBuffer = true;
+	}
 
 	page = BufferGetPage(buf);
 
@@ -360,7 +365,8 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	/* Now insert sequence tuple */
 
-	LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
+	if (lockBuffer)
+		LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 
 	/*
 	 * Since VACUUM does not process sequences, we have to force the tuple to
@@ -410,7 +416,8 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	END_CRIT_SECTION();
 
-	UnlockReleaseBuffer(buf);
+	if (lockBuffer)
+		UnlockReleaseBuffer(buf);
 }
 
 /*
@@ -502,7 +509,7 @@ AlterSequence(ParseState *pstate, AlterSeqStmt *stmt)
 		/*
 		 * Insert the modified tuple into the new storage file.
 		 */
-		fill_seq_with_data(seqrel, newdatatuple);
+		fill_seq_with_data(seqrel, newdatatuple, InvalidBuffer);
 	}
 
 	/* process OWNED BY if given */
@@ -1178,6 +1185,25 @@ read_seq_tuple(Relation rel, Buffer *buf, HeapTuple seqdatatuple)
 	LockBuffer(*buf, BUFFER_LOCK_EXCLUSIVE);
 
 	page = BufferGetPage(*buf);
+	if (GlobalTempRelationPageIsNotInitialized(rel, page))
+	{
+		/* Initialize sequence for global temporary tables */
+		Datum		value[SEQ_COL_LASTCOL] = {0};
+		bool		null[SEQ_COL_LASTCOL] = {false};
+		HeapTuple	tuple;
+		int64		startv = get_seqence_start_value(RelationGetRelid(rel));
+
+		/*
+		 * last_value from pg_sequence.seqstart
+		 * log_cnt = 0
+		 * is_called = false
+		 */
+		value[SEQ_COL_LASTVAL-1] = Int64GetDatumFast(startv); /* start sequence with 1 */
+
+		tuple = heap_form_tuple(RelationGetDescr(rel), value, null);
+		fill_seq_with_data(rel, tuple, *buf);
+		heap_freetuple(tuple);
+	}
 	sm = (sequence_magic *) PageGetSpecialPointer(page);
 
 	if (sm->magic != SEQ_MAGIC)
@@ -1954,3 +1980,23 @@ seq_mask(char *page, BlockNumber blkno)
 
 	mask_unused_space(page);
 }
+
+int64
+get_seqence_start_value(Oid seqid)
+{
+	HeapTuple	seqtuple;
+	Form_pg_sequence	seqform;
+	int64		start;
+
+	seqtuple = SearchSysCache1(SEQRELID, ObjectIdGetDatum(seqid));
+	if (!HeapTupleIsValid(seqtuple))
+		elog(ERROR, "cache lookup failed for sequence %u",
+			 seqid);
+
+	seqform = (Form_pg_sequence) GETSTRUCT(seqtuple);
+	start = seqform->seqstart;
+	ReleaseSysCache(seqtuple);
+
+	return start;
+}
+
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 1c4394a..84bc81e 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -47,6 +47,7 @@
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
 #include "catalog/toasting.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/defrem.h"
@@ -527,6 +528,7 @@ static void refuseDupeIndexAttach(Relation parentIdx, Relation partIdx,
 								  Relation partitionTbl);
 static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
+static bool has_oncommit_option(List *options);
 
 
 /* ----------------------------------------------------------------
@@ -572,6 +574,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	LOCKMODE	parentLockmode;
 	const char *accessMethod = NULL;
 	Oid			accessMethodId = InvalidOid;
+	bool		has_oncommit_clause = false;
 
 	/*
 	 * Truncate relname to appropriate length (probably a waste of time, as
@@ -582,8 +585,10 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Check consistency of arguments
 	 */
+	/* global temp table same as local temp table */
 	if (stmt->oncommit != ONCOMMIT_NOOP
-		&& stmt->relation->relpersistence != RELPERSISTENCE_TEMP)
+		&& !(stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+			 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 				 errmsg("ON COMMIT can only be used on temporary tables")));
@@ -613,7 +618,9 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	 * code.  This is needed because calling code might not expect untrusted
 	 * tables to appear in pg_temp at the front of its search path.
 	 */
-	if (stmt->relation->relpersistence == RELPERSISTENCE_TEMP
+	/* global temp table same as local temp table */
+	if ((stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+		 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		&& InSecurityRestrictedOperation())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -714,6 +721,57 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Parse and validate reloptions, if any.
 	 */
+	/* global temp table */
+	has_oncommit_clause = has_oncommit_option(stmt->options);
+	if (stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP &&
+		(relkind == RELKIND_RELATION || relkind == RELKIND_PARTITIONED_TABLE))
+	{
+		/* inherit table or parition table inherit on commit property from parent table*/
+		if (inheritOids && stmt->oncommit == ONCOMMIT_NOOP && !has_oncommit_clause)
+		{
+			Oid			parent = linitial_oid(inheritOids);
+			Relation	relation = table_open(parent, NoLock);
+
+			if (!RELATION_IS_GLOBAL_TEMP(relation))
+				elog(ERROR, "The parent table must be global temporary table");
+
+			if (RELATION_GTT_ON_COMMIT_DELETE(relation))
+				stmt->oncommit = ONCOMMIT_DELETE_ROWS;
+			else
+				stmt->oncommit = ONCOMMIT_PRESERVE_ROWS;
+			table_close(relation, NoLock);
+		}
+
+		if (has_oncommit_clause)
+		{
+			if (stmt->oncommit != ONCOMMIT_NOOP)
+				elog(ERROR, "can not defeine global temp table with on commit and with clause at same time");
+		}
+		else
+		{
+			DefElem *opt = makeNode(DefElem);
+
+			opt->type = T_DefElem;
+			opt->defnamespace = NULL;
+			opt->defname = "on_commit_delete_rows";
+			opt->defaction = DEFELEM_UNSPEC;
+
+			/* use reloptions to remember on commit clause */
+			if (stmt->oncommit == ONCOMMIT_DELETE_ROWS)
+				opt->arg  = (Node *)makeString("true");
+			else if (stmt->oncommit == ONCOMMIT_PRESERVE_ROWS)
+				opt->arg  = (Node *)makeString("false");
+			else if (stmt->oncommit == ONCOMMIT_NOOP)
+				opt->arg  = (Node *)makeString("true");
+			else
+				elog(ERROR, "global temp table not support on commit drop clause");
+
+			stmt->options = lappend(stmt->options, opt);
+		}
+	}
+	else if (has_oncommit_clause)
+		elog(ERROR, "regular table cannot specifie on_commit_delete_rows");
+
 	reloptions = transformRelOptions((Datum) 0, stmt->options, NULL, validnsps,
 									 true, false);
 
@@ -1775,7 +1833,8 @@ ExecuteTruncateGuts(List *explicit_rels, List *relids, List *relids_logged,
 		 * table or the current physical file to be thrown away anyway.
 		 */
 		if (rel->rd_createSubid == mySubid ||
-			rel->rd_newRelfilenodeSubid == mySubid)
+			rel->rd_newRelfilenodeSubid == mySubid ||
+			RELATION_IS_GLOBAL_TEMP(rel))
 		{
 			/* Immediate, non-rollbackable truncation is OK */
 			heap_truncate_one_rel(rel);
@@ -3334,6 +3393,13 @@ RenameRelationInternal(Oid myrelid, const char *newrelname, bool is_internal, bo
 	 * specially.
 	 */
 	targetrelation = relation_open(myrelid, is_index ? ShareUpdateExclusiveLock : AccessExclusiveLock);
+
+	if (RELATION_IS_GLOBAL_TEMP(targetrelation))
+	{
+		if (is_other_backend_use_gtt(targetrelation->rd_node))
+			elog(ERROR, "can not rename relation when other backend attached this global temp table");
+	}
+
 	namespaceId = RelationGetNamespace(targetrelation);
 
 	/*
@@ -3503,6 +3569,13 @@ AlterTable(Oid relid, LOCKMODE lockmode, AlterTableStmt *stmt)
 	/* Caller is required to provide an adequate lock. */
 	rel = relation_open(relid, NoLock);
 
+	/* We allow to alter global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (is_other_backend_use_gtt(rel->rd_node))
+			elog(ERROR, "can not alter relation when other backend attached this global temp table");
+	}
+
 	CheckTableNotInUse(rel, "ALTER TABLE");
 
 	ATController(stmt, rel, stmt->cmds, stmt->relation->inh, lockmode);
@@ -7656,6 +7729,13 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 				 errmsg("referenced relation \"%s\" is not a table",
 						RelationGetRelationName(pkrel))));
 
+	/* global temp table not support foreign key constraint yet */
+	if (RELATION_IS_GLOBAL_TEMP(pkrel))
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("referenced relation \"%s\" is not a global temp table",
+						RelationGetRelationName(pkrel))));
+
 	if (!allowSystemTableMods && IsSystemRelation(pkrel))
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -7695,6 +7775,12 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 						 errmsg("constraints on temporary tables must involve temporary tables of this session")));
 			break;
+		/* global temp table not support foreign key constraint yet */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					 errmsg("not support foreign key constraints on global temp table yet")));
+			break;
 	}
 
 	/*
@@ -12706,7 +12792,7 @@ index_copy_data(Relation rel, RelFileNode newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
@@ -14113,7 +14199,9 @@ ATPrepChangePersistence(Relation rel, bool toLogged)
 	 */
 	switch (rel->rd_rel->relpersistence)
 	{
+		/* global temp table same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("cannot change logged status of table \"%s\" because it is temporary",
@@ -16753,3 +16841,20 @@ ATDetachCheckNoForeignKeyRefs(Relation partition)
 		table_close(rel, NoLock);
 	}
 }
+
+static bool
+has_oncommit_option(List *options)
+{
+	ListCell   *listptr;
+
+	foreach(listptr, options)
+	{
+		DefElem    *def = (DefElem *) lfirst(listptr);
+
+		if (pg_strcasecmp(def->defname, "on_commit_delete_rows") == 0)
+			return true;
+	}
+
+	return false;
+}
+
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index bb34e25..6e1896f 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -35,6 +35,7 @@
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
 #include "catalog/pg_namespace.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
 #include "commands/vacuum.h"
@@ -1070,12 +1071,25 @@ vac_estimate_reltuples(Relation relation,
 					   BlockNumber scanned_pages,
 					   double scanned_tuples)
 {
-	BlockNumber old_rel_pages = relation->rd_rel->relpages;
-	double		old_rel_tuples = relation->rd_rel->reltuples;
+	BlockNumber old_rel_pages = 0;
+	double		old_rel_tuples = 0;
 	double		old_density;
 	double		unscanned_pages;
 	double		total_tuples;
 
+	/* get relstat from gtt local hash */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+	{
+		get_gtt_relstats(RelationGetRelid(relation),
+						&old_rel_pages, &old_rel_tuples, NULL,
+						NULL, NULL);
+	}
+	else
+	{
+		old_rel_pages = relation->rd_rel->relpages;
+		old_rel_tuples = relation->rd_rel->reltuples;
+	}
+
 	/* If we did scan the whole table, just use the count as-is */
 	if (scanned_pages >= total_pages)
 		return scanned_tuples;
@@ -1175,24 +1189,8 @@ vac_update_relstats(Relation relation,
 	/* Apply statistical updates, if any, to copied tuple */
 
 	dirty = false;
-	if (pgcform->relpages != (int32) num_pages)
-	{
-		pgcform->relpages = (int32) num_pages;
-		dirty = true;
-	}
-	if (pgcform->reltuples != (float4) num_tuples)
-	{
-		pgcform->reltuples = (float4) num_tuples;
-		dirty = true;
-	}
-	if (pgcform->relallvisible != (int32) num_all_visible_pages)
-	{
-		pgcform->relallvisible = (int32) num_all_visible_pages;
-		dirty = true;
-	}
 
 	/* Apply DDL updates, but not inside an outer transaction (see above) */
-
 	if (!in_outer_xact)
 	{
 		/*
@@ -1217,37 +1215,64 @@ vac_update_relstats(Relation relation,
 		}
 	}
 
-	/*
-	 * Update relfrozenxid, unless caller passed InvalidTransactionId
-	 * indicating it has no new data.
-	 *
-	 * Ordinarily, we don't let relfrozenxid go backwards: if things are
-	 * working correctly, the only way the new frozenxid could be older would
-	 * be if a previous VACUUM was done with a tighter freeze_min_age, in
-	 * which case we don't want to forget the work it already did.  However,
-	 * if the stored relfrozenxid is "in the future", then it must be corrupt
-	 * and it seems best to overwrite it with the cutoff we used this time.
-	 * This should match vac_update_datfrozenxid() concerning what we consider
-	 * to be "in the future".
-	 */
-	if (TransactionIdIsNormal(frozenxid) &&
-		pgcform->relfrozenxid != frozenxid &&
-		(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
-		 TransactionIdPrecedes(ReadNewTransactionId(),
-							   pgcform->relfrozenxid)))
+	/* global temp table remember relstats to localhash not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
 	{
-		pgcform->relfrozenxid = frozenxid;
-		dirty = true;
+		up_gtt_relstats(relation,
+						num_pages, num_tuples,
+						num_all_visible_pages,
+						frozenxid, minmulti);
 	}
-
-	/* Similarly for relminmxid */
-	if (MultiXactIdIsValid(minmulti) &&
-		pgcform->relminmxid != minmulti &&
-		(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
-		 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
+	else
 	{
-		pgcform->relminmxid = minmulti;
-		dirty = true;
+		if (pgcform->relpages != (int32) num_pages)
+		{
+			pgcform->relpages = (int32) num_pages;
+			dirty = true;
+		}
+		if (pgcform->reltuples != (float4) num_tuples)
+		{
+			pgcform->reltuples = (float4) num_tuples;
+			dirty = true;
+		}
+		if (pgcform->relallvisible != (int32) num_all_visible_pages)
+		{
+			pgcform->relallvisible = (int32) num_all_visible_pages;
+			dirty = true;
+		}
+
+		/*
+		 * Update relfrozenxid, unless caller passed InvalidTransactionId
+		 * indicating it has no new data.
+		 *
+		 * Ordinarily, we don't let relfrozenxid go backwards: if things are
+		 * working correctly, the only way the new frozenxid could be older would
+		 * be if a previous VACUUM was done with a tighter freeze_min_age, in
+		 * which case we don't want to forget the work it already did.  However,
+		 * if the stored relfrozenxid is "in the future", then it must be corrupt
+		 * and it seems best to overwrite it with the cutoff we used this time.
+		 * This should match vac_update_datfrozenxid() concerning what we consider
+		 * to be "in the future".
+		 */
+		if (TransactionIdIsNormal(frozenxid) &&
+			pgcform->relfrozenxid != frozenxid &&
+			(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(),
+								   pgcform->relfrozenxid)))
+		{
+			pgcform->relfrozenxid = frozenxid;
+			dirty = true;
+		}
+
+		/* Similarly for relminmxid */
+		if (MultiXactIdIsValid(minmulti) &&
+			pgcform->relminmxid != minmulti &&
+			(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
+		{
+			pgcform->relminmxid = minmulti;
+			dirty = true;
+		}
 	}
 
 	/* If anything changed, write out the tuple. */
@@ -1339,6 +1364,10 @@ vac_update_datfrozenxid(void)
 			continue;
 		}
 
+		/* global temp table relstats not in pg_class */
+		if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			continue;
+
 		/*
 		 * Some table AMs might not need per-relation xid / multixid horizons.
 		 * It therefore seems reasonable to allow relfrozenxid and relminmxid
@@ -1396,6 +1425,25 @@ vac_update_datfrozenxid(void)
 	Assert(TransactionIdIsNormal(newFrozenXid));
 	Assert(MultiXactIdIsValid(newMinMulti));
 
+	/*
+	 * Global temp table get frozenxid from MyProc
+	 * to avoid the vacuum truncate clog that gtt need.
+	 */
+	if (max_active_gtt > 0)
+	{
+		TransactionId oldest_gtt_frozenxid =
+			list_all_session_gtt_frozenxids(0, NULL, NULL, NULL);
+
+		if (TransactionIdIsNormal(oldest_gtt_frozenxid) &&
+			TransactionIdPrecedes(oldest_gtt_frozenxid, newFrozenXid))
+		{
+			ereport(WARNING,
+				(errmsg("global temp table oldest FrozenXid is far in the past"),
+				 errhint("please truncate them or kill those sessions that use them.")));
+			newFrozenXid = oldest_gtt_frozenxid;
+		}
+	}
+
 	/* Now fetch the pg_database tuple we need to update. */
 	relation = table_open(DatabaseRelationId, RowExclusiveLock);
 
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 8286d9c..c3992a4 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -591,6 +591,8 @@ static void
 set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 						  RangeTblEntry *rte)
 {
+	char relpersistence;
+
 	/*
 	 * The flag has previously been initialized to false, so we can just
 	 * return if it becomes clear that we can't safely set it.
@@ -618,7 +620,11 @@ set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 			 * the rest of the necessary infrastructure right now anyway.  So
 			 * for now, bail out if we see a temporary table.
 			 */
-			if (get_rel_persistence(rte->relid) == RELPERSISTENCE_TEMP)
+			/* global temp table is same as local temp table */
+			relpersistence = get_rel_persistence(rte->relid);
+
+			if (relpersistence == RELPERSISTENCE_TEMP ||
+				relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 				return;
 
 			/*
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index d6f2153..310a9e2 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -6312,7 +6312,9 @@ plan_create_index_workers(Oid tableOid, Oid indexOid)
 	 * Furthermore, any index predicate or index expressions must be parallel
 	 * safe.
 	 */
+	/* global temp table is same as local temp table */
 	if (heap->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		heap->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexExpressions(index)) ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexPredicate(index)))
 	{
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index d82fc5a..189286b 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -31,6 +31,7 @@
 #include "catalog/pg_am.h"
 #include "catalog/pg_proc.h"
 #include "catalog/pg_statistic_ext.h"
+#include "catalog/storage_gtt.h"
 #include "foreign/fdwapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
@@ -53,6 +54,7 @@
 #include "utils/snapmgr.h"
 #include "utils/syscache.h"
 
+
 /* GUC parameter */
 int			constraint_exclusion = CONSTRAINT_EXCLUSION_PARTITION;
 
@@ -946,10 +948,10 @@ void
 estimate_rel_size(Relation rel, int32 *attr_widths,
 				  BlockNumber *pages, double *tuples, double *allvisfrac)
 {
-	BlockNumber curpages;
-	BlockNumber relpages;
-	double		reltuples;
-	BlockNumber relallvisible;
+	BlockNumber curpages = 0;
+	BlockNumber relpages = 0;
+	double		reltuples = 0;
+	BlockNumber relallvisible = 0;
 	double		density;
 
 	switch (rel->rd_rel->relkind)
@@ -963,6 +965,21 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 
 		case RELKIND_INDEX:
 
+			/* global temp table get relstats from localhash */
+			if (RELATION_IS_GLOBAL_TEMP(rel))
+			{
+				get_gtt_relstats(RelationGetRelid(rel),
+								&relpages, &reltuples, &relallvisible,
+								NULL, NULL);
+			}
+			else
+			{
+				/* coerce values in pg_class to more desirable types */
+				relpages = (BlockNumber) rel->rd_rel->relpages;
+				reltuples = (double) rel->rd_rel->reltuples;
+				relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
+			}
+
 			/*
 			 * XXX: It'd probably be good to move this into a callback,
 			 * individual index types e.g. know if they have a metapage.
@@ -971,11 +988,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 			/* it has storage, ok to call the smgr */
 			curpages = RelationGetNumberOfBlocks(rel);
 
-			/* coerce values in pg_class to more desirable types */
-			relpages = (BlockNumber) rel->rd_rel->relpages;
-			reltuples = (double) rel->rd_rel->reltuples;
-			relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
-
 			/* report estimated # pages */
 			*pages = curpages;
 			/* quick exit if rel is clearly empty */
@@ -985,10 +997,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 				*allvisfrac = 0;
 				break;
 			}
-			/* coerce values in pg_class to more desirable types */
-			relpages = (BlockNumber) rel->rd_rel->relpages;
-			reltuples = (double) rel->rd_rel->reltuples;
-			relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
 
 			/*
 			 * Discount the metapage while estimating the number of tuples.
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 447a61e..a27f57f 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -2576,6 +2576,11 @@ transformCreateTableAsStmt(ParseState *pstate, CreateTableAsStmt *stmt)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("materialized views must not use temporary tables or views")));
 
+		if (is_query_using_gtt(query))
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("materialized views must not use global temporary tables or views")));
+
 		/*
 		 * A materialized view would either need to save parameters for use in
 		 * maintaining/loading the data or prohibit them entirely.  The latter
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index ad5be90..dff21e0 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3270,17 +3270,11 @@ OptTemp:	TEMPORARY					{ $$ = RELPERSISTENCE_TEMP; }
 			| LOCAL TEMP				{ $$ = RELPERSISTENCE_TEMP; }
 			| GLOBAL TEMPORARY
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED					{ $$ = RELPERSISTENCE_UNLOGGED; }
 			| /*EMPTY*/					{ $$ = RELPERSISTENCE_PERMANENT; }
@@ -11568,19 +11562,13 @@ OptTempTableName:
 				}
 			| GLOBAL TEMPORARY opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED opt_table qualified_name
 				{
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index ceed0ce..cd1ca50 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -81,6 +81,7 @@ static void expandTupleDesc(TupleDesc tupdesc, Alias *eref,
 							List **colnames, List **colvars);
 static int	specialAttNum(const char *attname);
 static bool isQueryUsingTempRelation_walker(Node *node, void *context);
+static bool is_query_using_gtt_walker(Node *node, void *context);
 
 
 /*
@@ -3564,3 +3565,49 @@ isQueryUsingTempRelation_walker(Node *node, void *context)
 								  isQueryUsingTempRelation_walker,
 								  context);
 }
+
+/* check if the query uses global temp table */
+static bool
+is_query_using_gtt_walker(Node *node, void *context)
+{
+	if (node == NULL)
+		return false;
+
+	if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+		ListCell   *rtable;
+
+		foreach(rtable, query->rtable)
+		{
+			RangeTblEntry *rte = lfirst(rtable);
+
+			if (rte->rtekind == RTE_RELATION)
+			{
+				Relation	rel = relation_open(rte->relid, AccessShareLock);
+				char		relpersistence = rel->rd_rel->relpersistence;
+
+				relation_close(rel, AccessShareLock);
+				if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+					return true;
+			}
+		}
+
+		return query_tree_walker(query,
+								 is_query_using_gtt_walker,
+								 context,
+								 QTW_IGNORE_JOINALIASES);
+	}
+
+	return expression_tree_walker(node,
+								  is_query_using_gtt_walker,
+								  context);
+}
+
+/* check if the query uses global temp table */
+bool
+is_query_using_gtt(Query *query)
+{
+	return is_query_using_gtt_walker((Node *) query, NULL);
+}
+
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 42095ab..d5fcbed 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -436,6 +436,9 @@ generateSerialExtraStmts(CreateStmtContext *cxt, ColumnDef *column,
 	seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
 	seqstmt->options = seqoptions;
 
+	if (cxt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		seqstmt->sequence->relpersistence = cxt->relation->relpersistence;
+
 	/*
 	 * If a sequence data type was specified, add it to the options.  Prepend
 	 * to the list rather than append; in case a user supplied their own AS
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index f0e40e3..bb60926 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -2086,6 +2086,11 @@ do_autovacuum(void)
 			}
 			continue;
 		}
+		else if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			/* autovacuum skip vacuum global temp table */
+			continue;
+		}
 
 		/* Fetch reloptions and the pgstat entry for this table */
 		relopts = extract_autovac_opts(tuple, pg_class_desc);
@@ -2152,7 +2157,9 @@ do_autovacuum(void)
 		/*
 		 * We cannot safely process other backends' temp tables, so skip 'em.
 		 */
-		if (classForm->relpersistence == RELPERSISTENCE_TEMP)
+		/* autovacuum skip vacuum global temp table */
+		if (classForm->relpersistence == RELPERSISTENCE_TEMP || 
+			classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 			continue;
 
 		relid = classForm->oid;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index aba3960..68adcd5 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -53,6 +53,8 @@
 #include "utils/resowner_private.h"
 #include "utils/timestamp.h"
 
+#include "utils/guc.h"
+#include "catalog/storage_gtt.h"
 
 /* Note: these two macros only work on shared buffers, not local ones! */
 #define BufHdrGetBlock(bufHdr)	((Block) (BufferBlocks + ((Size) (bufHdr)->buf_id) * BLCKSZ))
@@ -432,7 +434,7 @@ ForgetPrivateRefCountEntry(PrivateRefCountEntry *ref)
 static Buffer ReadBuffer_common(SMgrRelation reln, char relpersistence,
 								ForkNumber forkNum, BlockNumber blockNum,
 								ReadBufferMode mode, BufferAccessStrategy strategy,
-								bool *hit);
+								bool *hit, Relation rel);
 static bool PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy);
 static void PinBuffer_Locked(BufferDesc *buf);
 static void UnpinBuffer(BufferDesc *buf, bool fixOwner);
@@ -664,7 +666,8 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
 	 */
 	pgstat_count_buffer_read(reln);
 	buf = ReadBuffer_common(reln->rd_smgr, reln->rd_rel->relpersistence,
-							forkNum, blockNum, mode, strategy, &hit);
+							forkNum, blockNum, mode, strategy, &hit,
+							reln);
 	if (hit)
 		pgstat_count_buffer_hit(reln);
 	return buf;
@@ -692,7 +695,7 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 	Assert(InRecovery);
 
 	return ReadBuffer_common(smgr, RELPERSISTENCE_PERMANENT, forkNum, blockNum,
-							 mode, strategy, &hit);
+							 mode, strategy, &hit, NULL);
 }
 
 
@@ -704,7 +707,8 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 static Buffer
 ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 				  BlockNumber blockNum, ReadBufferMode mode,
-				  BufferAccessStrategy strategy, bool *hit)
+				  BufferAccessStrategy strategy, bool *hit,
+				  Relation rel)
 {
 	BufferDesc *bufHdr;
 	Block		bufBlock;
@@ -719,6 +723,15 @@ ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 
 	isExtend = (blockNum == P_NEW);
 
+	/* create storage when first read data page for gtt */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP &&
+		(isExtend || blockNum == 0) &&
+		forkNum == MAIN_FORKNUM &&
+		!gtt_storage_attached(smgr->smgr_rnode.node.relNode))
+	{
+		RelationCreateStorage(smgr->smgr_rnode.node, relpersistence, rel);
+	}
+
 	TRACE_POSTGRESQL_BUFFER_READ_START(forkNum, blockNum,
 									   smgr->smgr_rnode.node.spcNode,
 									   smgr->smgr_rnode.node.dbNode,
@@ -2809,6 +2822,16 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln)
 BlockNumber
 RelationGetNumberOfBlocksInFork(Relation relation, ForkNumber forkNum)
 {
+	/*
+	 * When this backend not init gtt storage
+	 * return 0
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(relation) &&
+		!gtt_storage_attached(relation->rd_node.relNode))
+	{
+		return 0;
+	}
+
 	switch (relation->rd_rel->relkind)
 	{
 		case RELKIND_SEQUENCE:
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 427b0d5..7adb969 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -21,6 +21,7 @@
 #include "access/nbtree.h"
 #include "access/subtrans.h"
 #include "access/twophase.h"
+#include "catalog/storage_gtt.h"
 #include "commands/async.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -147,6 +148,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, BTreeShmemSize());
 		size = add_size(size, SyncScanShmemSize());
 		size = add_size(size, AsyncShmemSize());
+		size = add_size(size, active_gtt_shared_hash_size());
 #ifdef EXEC_BACKEND
 		size = add_size(size, ShmemBackendArraySize());
 #endif
@@ -217,6 +219,8 @@ CreateSharedMemoryAndSemaphores(void)
 	SUBTRANSShmemInit();
 	MultiXactShmemInit();
 	InitBufferPool();
+	/* global temporary table */
+	active_gtt_shared_hash_init();
 
 	/*
 	 * Set up lock manager
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index c3adb2e..eb95e5f 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -62,6 +62,7 @@
 #include "utils/builtins.h"
 #include "utils/rel.h"
 #include "utils/snapmgr.h"
+#include "utils/guc.h"
 
 #define UINT32_ACCESS_ONCE(var)		 ((uint32)(*((volatile uint32 *)&(var))))
 
@@ -4087,3 +4088,77 @@ KnownAssignedXidsReset(void)
 
 	LWLockRelease(ProcArrayLock);
 }
+
+/*
+ * search all active backend to get oldest frozenxid
+ * for global temp table.
+ */
+int
+list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n)
+{
+	ProcArrayStruct *arrayP = procArray;
+	TransactionId result = InvalidTransactionId;
+	int			index;
+	int			flags = 0;
+	int			i = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	if (max_size > 0)
+	{
+		Assert(pids);
+		Assert(xids);
+		Assert(n);
+		*n = 0;
+	}
+
+	if (max_active_gtt <= 0)
+		return InvalidTransactionId;
+
+	if (RecoveryInProgress())
+		return InvalidTransactionId;
+
+	flags |= PROC_IS_AUTOVACUUM;
+	flags |= PROC_IN_LOGICAL_DECODING;
+
+	LWLockAcquire(ProcArrayLock, LW_SHARED);
+	if (max_size > 0 && max_size < arrayP->numProcs)
+	{
+		LWLockRelease(ProcArrayLock);
+		elog(ERROR, "list_all_gtt_frozenxids require more array");
+	}
+
+	for (index = 0; index < arrayP->numProcs; index++)
+	{
+		int			pgprocno = arrayP->pgprocnos[index];
+		volatile PGPROC *proc = &allProcs[pgprocno];
+		volatile PGXACT *pgxact = &allPgXact[pgprocno];
+
+		if (pgxact->vacuumFlags & flags)
+			continue;
+
+		if (proc->databaseId == MyDatabaseId &&
+			TransactionIdIsNormal(proc->session_gtt_frozenxid))
+		{
+			if (result == InvalidTransactionId)
+				result = proc->session_gtt_frozenxid;
+			else if (TransactionIdPrecedes(proc->session_gtt_frozenxid, result))
+				result = proc->session_gtt_frozenxid;
+
+			if (max_size > 0)
+			{
+				pids[i] = proc->pid;
+				xids[i] = proc->session_gtt_frozenxid;
+				i++;
+			}
+		}
+	}
+	LWLockRelease(ProcArrayLock);
+
+	if (max_size > 0)
+		*n = i;
+
+	return result;
+}
+
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 99e5221..d3a0a18 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -395,6 +395,7 @@ InitProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
@@ -577,6 +578,7 @@ InitAuxiliaryProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 199c722..92aefd0 100644
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -654,6 +654,12 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 		 */
 		if (zero_damaged_pages || InRecovery)
 			MemSet(buffer, 0, BLCKSZ);
+		else if(SmgrIsTemp(reln) && blocknum == 0 && forknum == MAIN_FORKNUM)
+		{
+			/* global temp table init btree meta page */
+			MemSet(buffer, 0, BLCKSZ);
+			mdwrite(reln, forknum, blocknum, buffer, true);
+		}
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_DATA_CORRUPTED),
diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c
index 8406644..46eb23a 100644
--- a/src/backend/utils/adt/dbsize.c
+++ b/src/backend/utils/adt/dbsize.c
@@ -1008,6 +1008,10 @@ pg_relation_filepath(PG_FUNCTION_ARGS)
 				Assert(backend != InvalidBackendId);
 			}
 			break;
+		/* For global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			backend = BackendIdForTempRelations();
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relform->relpersistence);
 			backend = InvalidBackendId; /* placate compiler */
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 18d77ac..eaeebfe 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -142,6 +142,7 @@
 #include "utils/timestamp.h"
 #include "utils/typcache.h"
 
+#include "catalog/storage_gtt.h"
 
 /* Hooks for plugins to get control when we ask for stats */
 get_relation_stats_hook_type get_relation_stats_hook = NULL;
@@ -4578,12 +4579,25 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
 						}
 						else if (index->indpred == NIL)
 						{
-							vardata->statsTuple =
-								SearchSysCache3(STATRELATTINH,
-												ObjectIdGetDatum(index->indexoid),
-												Int16GetDatum(pos + 1),
-												BoolGetDatum(false));
-							vardata->freefunc = ReleaseSysCache;
+							char rel_persistence = get_rel_persistence(index->indexoid);
+
+							if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+							{
+								vardata->statsTuple =
+									get_gtt_att_statistic(index->indexoid,
+														Int16GetDatum(pos + 1),
+														false);
+								vardata->freefunc = release_gtt_statistic_cache;
+							}
+							else
+							{
+								vardata->statsTuple =
+									SearchSysCache3(STATRELATTINH,
+													ObjectIdGetDatum(index->indexoid),
+													Int16GetDatum(pos + 1),
+													BoolGetDatum(false));
+								vardata->freefunc = ReleaseSysCache;
+							}
 
 							if (HeapTupleIsValid(vardata->statsTuple))
 							{
@@ -4708,15 +4722,27 @@ examine_simple_variable(PlannerInfo *root, Var *var,
 	}
 	else if (rte->rtekind == RTE_RELATION)
 	{
-		/*
-		 * Plain table or parent of an inheritance appendrel, so look up the
-		 * column in pg_statistic
-		 */
-		vardata->statsTuple = SearchSysCache3(STATRELATTINH,
-											  ObjectIdGetDatum(rte->relid),
-											  Int16GetDatum(var->varattno),
-											  BoolGetDatum(rte->inh));
-		vardata->freefunc = ReleaseSysCache;
+		char rel_persistence = get_rel_persistence(rte->relid);
+
+		if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata->statsTuple = get_gtt_att_statistic(rte->relid,
+														var->varattno,
+														rte->inh);
+			vardata->freefunc = release_gtt_statistic_cache;
+		}
+		else
+		{
+			/*
+			 * Plain table or parent of an inheritance appendrel, so look up the
+			 * column in pg_statistic
+			 */
+			vardata->statsTuple = SearchSysCache3(STATRELATTINH,
+												  ObjectIdGetDatum(rte->relid),
+												  Int16GetDatum(var->varattno),
+												  BoolGetDatum(rte->inh));
+			vardata->freefunc = ReleaseSysCache;
+		}
 
 		if (HeapTupleIsValid(vardata->statsTuple))
 		{
@@ -6098,6 +6124,7 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	{
 		/* Simple variable --- look to stats for the underlying table */
 		RangeTblEntry *rte = planner_rt_fetch(index->rel->relid, root);
+		char	rel_persistence = get_rel_persistence(rte->relid);
 
 		Assert(rte->rtekind == RTE_RELATION);
 		relid = rte->relid;
@@ -6115,6 +6142,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													rte->inh);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -6126,6 +6160,8 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	}
 	else
 	{
+		char	rel_persistence = get_rel_persistence(index->indexoid);
+
 		/* Expression --- maybe there are stats for the index itself */
 		relid = index->indexoid;
 		colnum = 1;
@@ -6141,6 +6177,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													false);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -7029,6 +7072,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		/* attempt to lookup stats in relation for this index column */
 		if (attnum != 0)
 		{
+			char	rel_persistence = get_rel_persistence(rte->relid);
+
 			/* Simple variable -- look to stats for the underlying table */
 			if (get_relation_stats_hook &&
 				(*get_relation_stats_hook) (root, rte, attnum, &vardata))
@@ -7041,6 +7086,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					elog(ERROR,
 						 "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(rte->relid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple =
@@ -7053,6 +7106,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		}
 		else
 		{
+			char	rel_persistence = get_rel_persistence(index->indexoid);
+
 			/*
 			 * Looks like we've found an expression column in the index. Let's
 			 * see if there's any stats for it.
@@ -7072,6 +7127,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					!vardata.freefunc)
 					elog(ERROR, "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(index->indexoid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple = SearchSysCache3(STATRELATTINH,
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 1e3e6d3..44686ce 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -34,6 +34,7 @@
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_transform.h"
 #include "catalog/pg_type.h"
+#include "catalog/storage_gtt.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "utils/array.h"
@@ -46,6 +47,7 @@
 #include "utils/syscache.h"
 #include "utils/typcache.h"
 
+
 /* Hook for plugins to get control in get_attavgwidth() */
 get_attavgwidth_hook_type get_attavgwidth_hook = NULL;
 
@@ -2878,6 +2880,18 @@ get_attavgwidth(Oid relid, AttrNumber attnum)
 		if (stawidth > 0)
 			return stawidth;
 	}
+	if (get_rel_persistence(relid) == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		tp = get_gtt_att_statistic(relid, attnum, false);
+		if (!HeapTupleIsValid(tp))
+			return 0;
+
+		stawidth = ((Form_pg_statistic) GETSTRUCT(tp))->stawidth;
+		if (stawidth > 0)
+			return stawidth;
+		else
+			return 0;
+	}
 	tp = SearchSysCache3(STATRELATTINH,
 						 ObjectIdGetDatum(relid),
 						 Int16GetDatum(attnum),
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index df025a5..1c30d86 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -1124,6 +1124,16 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
 				relation->rd_islocaltemp = false;
 			}
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			{
+				relation->rd_backend = BackendIdForTempRelations();
+				/*
+				 * For global temp table, all backend can use
+				 * this relation, so rd_islocaltemp always true.
+				 */
+				relation->rd_islocaltemp = true;
+			}
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c",
 				 relation->rd_rel->relpersistence);
@@ -3313,6 +3323,10 @@ RelationBuildLocalRelation(const char *relname,
 			rel->rd_backend = BackendIdForTempRelations();
 			rel->rd_islocaltemp = true;
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			rel->rd_backend = BackendIdForTempRelations();
+			rel->rd_islocaltemp = true;
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relpersistence);
 			break;
@@ -3427,6 +3441,9 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 	TransactionId freezeXid = InvalidTransactionId;
 	RelFileNode newrnode;
 
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+		elog(ERROR, "global temp table does not allow setting new relfilenode");
+
 	/* Allocate a new relfilenode */
 	newrelfilenode = GetNewRelFileNode(relation->rd_rel->reltablespace, NULL,
 									   persistence);
@@ -3467,7 +3484,7 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 				/* handle these directly, at least for now */
 				SMgrRelation srel;
 
-				srel = RelationCreateStorage(newrnode, persistence);
+				srel = RelationCreateStorage(newrnode, persistence, relation);
 				smgrclose(srel);
 			}
 			break;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index a4e5d08..37ce83d 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -139,6 +139,18 @@ char	   *GUC_check_errmsg_string;
 char	   *GUC_check_errdetail_string;
 char	   *GUC_check_errhint_string;
 
+/*
+ * num = 0 means disable global temp table feature.
+ * global temp table define can still storage in catalog
+ * just can not use.
+ * num > 0 means database can management num active global temp table.
+ */
+#define	MIN_NUM_ACTIVE_GTT			0
+#define	DEFAULT_NUM_ACTIVE_GTT			1000
+#define	MAX_NUM_ACTIVE_GTT			1000000
+
+int		max_active_gtt = MIN_NUM_ACTIVE_GTT;
+
 static void do_serialize(char **destptr, Size *maxbytes, const char *fmt,...) pg_attribute_printf(3, 4);
 
 static void set_config_sourcefile(const char *name, char *sourcefile,
@@ -1979,6 +1991,15 @@ static struct config_bool ConfigureNamesBool[] =
 static struct config_int ConfigureNamesInt[] =
 {
 	{
+		{"max_active_global_temporary_table", PGC_POSTMASTER, UNGROUPED,
+			gettext_noop("max active global temporary table."),
+			NULL
+		},
+		&max_active_gtt,
+		DEFAULT_NUM_ACTIVE_GTT, MIN_NUM_ACTIVE_GTT, MAX_NUM_ACTIVE_GTT,
+		NULL, NULL, NULL
+	},
+	{
 		{"archive_timeout", PGC_SIGHUP, WAL_ARCHIVING,
 			gettext_noop("Forces a switch to the next WAL file if a "
 						 "new file has not been started within N seconds."),
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 799b698..b98d396 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15583,6 +15583,7 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 	{
 		char	   *ftoptions = NULL;
 		char	   *srvname = NULL;
+		char		*table_type = NULL;
 
 		switch (tbinfo->relkind)
 		{
@@ -15634,9 +15635,15 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 			binary_upgrade_set_pg_class_oids(fout, q,
 											 tbinfo->dobj.catId.oid, false);
 
+		if (tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED)
+			table_type = "UNLOGGED ";
+		else if (tbinfo->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			table_type = "GLOBAL TEMPORARY ";
+		else
+			table_type = "";
+
 		appendPQExpBuffer(q, "CREATE %s%s %s",
-						  tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED ?
-						  "UNLOGGED " : "",
+						  table_type,
 						  reltypename,
 						  qualrelname);
 
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index a12fc1f..78958e4 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -165,6 +165,7 @@ typedef FormData_pg_class *Form_pg_class;
 #define		  RELPERSISTENCE_PERMANENT	'p' /* regular table */
 #define		  RELPERSISTENCE_UNLOGGED	'u' /* unlogged permanent table */
 #define		  RELPERSISTENCE_TEMP		't' /* temporary table */
+#define		  RELPERSISTENCE_GLOBAL_TEMP	'g' /* global temporary table */
 
 /* default selection for replica identity (primary key or nothing) */
 #define		  REPLICA_IDENTITY_DEFAULT	'd'
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 0b6045a..6bc884e 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -5477,6 +5477,40 @@
   proparallel => 'r', prorettype => 'float8', proargtypes => 'oid',
   prosrc => 'pg_stat_get_xact_function_self_time' },
 
+# For global temporary table
+{ oid => '4191',
+  descr => 'List local statistics for global temporary table',
+  proname => 'pg_get_gtt_statistics', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid int4 anyelement',
+  proallargtypes => '{oid,int4,anyelement,oid,int2,bool,float4,int4,float4,int2,int2,int2,int2,int2,oid,oid,oid,oid,oid,oid,oid,oid,oid,oid,_float4,_float4,_float4,_float4,_float4,anyarray,anyarray,anyarray,anyarray,anyarray}',
+  proargmodes => '{i,i,i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
+  proargnames => '{relid,att,x,starelid,staattnum,stainherit,stanullfrac,stawidth,stadistinct,stakind1,stakind2,stakind3,stakind4,stakind5,staop1,staop2,staop3,staop4,staop5,stacoll1,stacoll2,stacoll3,stacoll4,stacoll5,stanumbers1,stanumbers2,stanumbers3,stanumbers4,stanumbers5,stavalues1,stavalues2,stavalues3,stavalues4,stavalues5}',
+  prosrc => 'pg_get_gtt_statistics' },
+{ oid => '4192',
+  descr => 'List local relstats for global temporary table',
+  proname => 'pg_get_gtt_relstats', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid',
+  proallargtypes => '{oid,int4,float4,int4,xid,xid}',
+  proargmodes => '{i,o,o,o,o,o}',
+  proargnames => '{relid,relpages,reltuples,relallvisible,relfrozenxid,relminmxid}',
+  prosrc => 'pg_get_gtt_relstats' },
+{ oid => '4193',
+  descr => 'List attached pid for one global temporary table',
+  proname => 'pg_gtt_attached_pid', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid',
+  proallargtypes => '{oid,oid,int4}',
+  proargmodes => '{i,o,o}',
+  proargnames => '{relid,relid,pid}',
+  prosrc => 'pg_gtt_attached_pid' },
+{ oid => '4194',
+  descr => 'List those backends that have used global temporary table',
+  proname => 'pg_list_gtt_relfrozenxids', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => '',
+  proallargtypes => '{int4,xid}',
+  proargmodes => '{o,o}',
+  proargnames => '{pid,relfrozenxid}',
+  prosrc => 'pg_list_gtt_relfrozenxids' },
+
 { oid => '3788',
   descr => 'statistics: timestamp of the current statistics snapshot',
   proname => 'pg_stat_get_snapshot_timestamp', provolatile => 's',
diff --git a/src/include/catalog/storage.h b/src/include/catalog/storage.h
index 048003c..af48cdf 100644
--- a/src/include/catalog/storage.h
+++ b/src/include/catalog/storage.h
@@ -19,7 +19,7 @@
 #include "storage/smgr.h"
 #include "utils/relcache.h"
 
-extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence);
+extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel);
 extern void RelationDropStorage(Relation rel);
 extern void RelationPreserveStorage(RelFileNode rnode, bool atCommit);
 extern void RelationTruncate(Relation rel, BlockNumber nblocks);
diff --git a/src/include/catalog/storage_gtt.h b/src/include/catalog/storage_gtt.h
new file mode 100644
index 0000000..eacc214
--- /dev/null
+++ b/src/include/catalog/storage_gtt.h
@@ -0,0 +1,39 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.h
+ *	  prototypes for functions in backend/catalog/storage_gtt.c
+ *
+ * src/include/catalog/storage_gtt.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef STORAGE_GTT_H
+#define STORAGE_GTT_H
+
+#include "access/htup.h"
+#include "storage/block.h"
+#include "storage/relfilenode.h"
+#include "utils/relcache.h"
+
+extern Size active_gtt_shared_hash_size(void);
+extern void active_gtt_shared_hash_init(void);
+extern void remember_gtt_storage_info(RelFileNode rnode, Relation rel);
+extern void forget_gtt_storage_info(Oid relid);
+extern bool is_other_backend_use_gtt(RelFileNode node);
+extern bool gtt_storage_attached(Oid relid);
+extern Bitmapset *copy_active_gtt_bitmap(RelFileNode node);
+extern void up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+								TupleDesc tupleDescriptor, Datum *values, bool *isnull);
+extern HeapTuple get_gtt_att_statistic(Oid reloid, int attnum, bool inh);
+extern void release_gtt_statistic_cache(HeapTuple tup);
+extern void up_gtt_relstats(Relation relation,
+							BlockNumber num_pages,
+							double num_tuples,
+							BlockNumber num_all_visible_pages,
+							TransactionId relfrozenxid,
+							TransactionId relminmxid);
+extern bool get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+							BlockNumber *relallvisible, TransactionId *relfrozenxid,
+							TransactionId *relminmxid);
+
+#endif							/* STORAGE_H */
diff --git a/src/include/parser/parse_relation.h b/src/include/parser/parse_relation.h
index b8bff23..70c01f7 100644
--- a/src/include/parser/parse_relation.h
+++ b/src/include/parser/parse_relation.h
@@ -117,4 +117,7 @@ extern Oid	attnumTypeId(Relation rd, int attid);
 extern Oid	attnumCollationId(Relation rd, int attid);
 extern bool isQueryUsingTempRelation(Query *query);
 
+/* global temp table check */
+extern bool is_query_using_gtt(Query *query);
+
 #endif							/* PARSE_RELATION_H */
diff --git a/src/include/storage/bufpage.h b/src/include/storage/bufpage.h
index 870ecb5..92c590e 100644
--- a/src/include/storage/bufpage.h
+++ b/src/include/storage/bufpage.h
@@ -405,6 +405,8 @@ do { \
 #define PageClearPrunable(page) \
 	(((PageHeader) (page))->pd_prune_xid = InvalidTransactionId)
 
+#define GlobalTempRelationPageIsNotInitialized(rel, page) \
+	((rel)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP && PageIsNew(page))
 
 /* ----------------------------------------------------------------
  *		extern declarations
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 8fda8e4..172eae9 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -220,6 +220,7 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_TBM,
 	LWTRANCHE_PARALLEL_APPEND,
 	LWTRANCHE_SXACT,
+	LWTRANCHE_GTT_CTL,
 	LWTRANCHE_FIRST_USER_DEFINED
 }			BuiltinTrancheIds;
 
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 5b407e6..f13250a 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -117,6 +117,8 @@ struct PGPROC
 	Oid			tempNamespaceId;	/* OID of temp schema this backend is
 									 * using */
 
+	TransactionId session_gtt_frozenxid;	/* session level global temp table relfrozenxid */
+
 	bool		isBackgroundWorker; /* true if background worker. */
 
 	/*
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index a5c7d0c..a86f61f 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -125,4 +125,6 @@ extern void ProcArraySetReplicationSlotXmin(TransactionId xmin,
 extern void ProcArrayGetReplicationSlotXmin(TransactionId *xmin,
 											TransactionId *catalog_xmin);
 
+extern int list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n);
+
 #endif							/* PROCARRAY_H */
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index ce93ace..0f7262e 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -281,6 +281,10 @@ extern int	tcp_user_timeout;
 extern bool trace_sort;
 #endif
 
+/* global temporary table */
+extern int	max_active_gtt;
+/* end */
+
 /*
  * Functions exported by guc.c
  */
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 44ed04d..3f9720d 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -277,6 +277,7 @@ typedef struct StdRdOptions
 	int			parallel_workers;	/* max number of parallel workers */
 	bool		vacuum_index_cleanup;	/* enables index vacuuming and cleanup */
 	bool		vacuum_truncate;	/* enables vacuum to truncate a relation */
+	bool		on_commit_delete_rows;	/* global temp table */
 } StdRdOptions;
 
 #define HEAP_MIN_FILLFACTOR			10
@@ -535,7 +536,8 @@ typedef struct ViewOptions
  *		True if relation's pages are stored in local buffers.
  */
 #define RelationUsesLocalBuffers(relation) \
-	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP || \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 
 /*
  * RELATION_IS_LOCAL
@@ -602,6 +604,17 @@ typedef struct ViewOptions
 	 RelationNeedsWAL(relation) && \
 	 !IsCatalogRelation(relation))
 
+/* global temp table implementations */
+#define RELATION_IS_GLOBAL_TEMP(relation)	((relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+
+#define RELATION_GTT_ON_COMMIT_DELETE(relation)	\
+	((relation)->rd_options && \
+	 ((relation)->rd_rel->relkind == RELKIND_RELATION || (relation)->rd_rel->relkind == RELKIND_PARTITIONED_TABLE) && \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ? \
+	 ((StdRdOptions *) (relation)->rd_options)->on_commit_delete_rows : false)
+
+#define RelationGetRelPersistence(relation) ((relation)->rd_rel->relpersistence)
+
 /* routines in utils/cache/relcache.c */
 extern void RelationIncrementReferenceCount(Relation rel);
 extern void RelationDecrementReferenceCount(Relation rel);
diff --git a/src/test/regress/expected/gtt_clean.out b/src/test/regress/expected/gtt_clean.out
new file mode 100644
index 0000000..50ca9ac
--- /dev/null
+++ b/src/test/regress/expected/gtt_clean.out
@@ -0,0 +1,7 @@
+reset search_path;
+drop schema gtt cascade;
+NOTICE:  drop cascades to 4 other objects
+DETAIL:  drop cascades to table gtt.gtt1
+drop cascades to table gtt.gtt2
+drop cascades to table gtt.gtt3
+drop cascades to table gtt.gtt_t_kenyon
diff --git a/src/test/regress/expected/gtt_function.out b/src/test/regress/expected/gtt_function.out
new file mode 100644
index 0000000..2c69f14
--- /dev/null
+++ b/src/test/regress/expected/gtt_function.out
@@ -0,0 +1,197 @@
+CREATE SCHEMA IF NOT EXISTS gtt_function;
+set search_path=gtt_function,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt_test_rename(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+ERROR:  cannot create indexes on global temporary tables using concurrent mode
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+ERROR:  not support cluster global temporary tables yet
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+ERROR:  ON COMMIT can only be used on temporary tables
+-- ok
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+ERROR:  regular table cannot specifie on_commit_delete_rows
+-- ok
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+--ok
+CREATE global temp TABLE p_table01 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+);
+ 
+CREATE global temp TABLE p_table01_2018
+PARTITION OF p_table01
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+ 
+CREATE global temp TABLE p_table01_2017
+PARTITION OF p_table01
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+begin;
+insert into p_table01 values(1,'2018-01-02 00:00:00','test1');
+insert into p_table01 values(1,'2018-01-02 00:00:00','test2');
+select count(*) from p_table01;
+ count 
+-------
+     2
+(1 row)
+
+commit;
+select count(*) from p_table01;
+ count 
+-------
+     0
+(1 row)
+
+--ok
+CREATE global temp TABLE p_table02 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)
+on commit PRESERVE rows;
+CREATE global temp TABLE p_table02_2018
+PARTITION OF p_table02
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+CREATE global temp TABLE p_table02_2017
+PARTITION OF p_table02
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+-- ok
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+ERROR:  The parent table must be global temporary table
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent_global_temp);
+select relname ,relkind, relpersistence, reloptions from pg_class where relname like 'p_table0%' or  relname like 'tbl_inherits%' order by relname;
+             relname             | relkind | relpersistence |          reloptions           
+---------------------------------+---------+----------------+-------------------------------
+ p_table01                       | p       | g              | {on_commit_delete_rows=true}
+ p_table01_2017                  | r       | g              | {on_commit_delete_rows=true}
+ p_table01_2018                  | r       | g              | {on_commit_delete_rows=true}
+ p_table01_id_seq                | S       | g              | 
+ p_table02                       | p       | g              | {on_commit_delete_rows=false}
+ p_table02_2017                  | r       | g              | {on_commit_delete_rows=false}
+ p_table02_2018                  | r       | g              | {on_commit_delete_rows=false}
+ p_table02_id_seq                | S       | g              | 
+ tbl_inherits_parent             | r       | p              | 
+ tbl_inherits_parent_global_temp | r       | g              | {on_commit_delete_rows=true}
+ tbl_inherits_partition          | r       | g              | {on_commit_delete_rows=true}
+(11 rows)
+
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+ERROR:  global temp table not support on commit drop clause
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+ERROR:  can not defeine global temp table with on commit and with clause at same time
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+--ok
+alter table gtt_test_rename rename to gtt_test;
+-- ok
+ALTER TABLE gtt_test ADD COLUMN address varchar(30);
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  referenced relation "products" is not a global temp table
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  referenced relation "products" is not a global temp table
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+-- ok
+create global temp table gtt_seq(id int GENERATED ALWAYS AS IDENTITY (START WITH 2) primary key, a int)  on commit PRESERVE rows;
+insert into gtt_seq (a) values(1);
+insert into gtt_seq (a) values(2);
+select * from gtt_seq order by id;
+ id | a 
+----+---
+  2 | 1
+  3 | 2
+(2 rows)
+
+truncate gtt_seq;
+select * from gtt_seq order by id;
+ id | a 
+----+---
+(0 rows)
+
+insert into gtt_seq (a) values(3);
+select * from gtt_seq order by id;
+ id | a 
+----+---
+  4 | 3
+(1 row)
+
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+ERROR:  materialized views must not use global temporary tables or views
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+ERROR:  only support btree index on global temp table
+create index idx_err on gtt1 using gist (a);
+ERROR:  data type integer has no default operator class for access method "gist"
+HINT:  You must specify an operator class for the index or define a default operator class for the data type.
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+ERROR:  only support btree index on global temp table
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+ERROR:  only support btree index on global temp table
+reset search_path;
+drop schema gtt_function cascade;
+NOTICE:  drop cascades to 15 other objects
+DETAIL:  drop cascades to table gtt_function.gtt1
+drop cascades to table gtt_function.gtt_test
+drop cascades to table gtt_function.gtt2
+drop cascades to table gtt_function.gtt3
+drop cascades to table gtt_function.tmp_t0
+drop cascades to table gtt_function.tbl_inherits_parent
+drop cascades to table gtt_function.tbl_inherits_parent_global_temp
+drop cascades to table gtt_function.products
+drop cascades to table gtt_function.measurement
+drop cascades to table gtt_function.p_table01
+drop cascades to table gtt_function.p_table02
+drop cascades to table gtt_function.tbl_inherits_partition
+drop cascades to table gtt_function.gtt5
+drop cascades to table gtt_function.mytable
+drop cascades to table gtt_function.gtt_seq
diff --git a/src/test/regress/expected/gtt_parallel_1.out b/src/test/regress/expected/gtt_parallel_1.out
new file mode 100644
index 0000000..30d8a7b
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_1.out
@@ -0,0 +1,84 @@
+set search_path=gtt,sys;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_parallel_2.out b/src/test/regress/expected/gtt_parallel_2.out
new file mode 100644
index 0000000..70bf4a6
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_2.out
@@ -0,0 +1,142 @@
+set search_path=gtt,sys;
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+ 3 | test1
+(3 rows)
+
+rollback;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test2
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 3 | test3
+(1 row)
+
+rollback;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 5 | test5
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 6 | test6
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+ count  
+--------
+ 100000
+(1 row)
+
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+             QUERY PLAN             
+------------------------------------
+ Index Scan using gtt3_pkey on gtt3
+   Index Cond: (a = 300)
+(2 rows)
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',10000);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid) from pg_class where relname = 'gtt_t_kenyon';
+   relname    | pg_relation_size | pg_relation_size 
+--------------+------------------+------------------
+ gtt_t_kenyon |           450560 |            16384
+(1 row)
+
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+   relname    
+--------------
+ gtt_t_kenyon
+(1 row)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_prepare.out b/src/test/regress/expected/gtt_prepare.out
new file mode 100644
index 0000000..9e8f5f0
--- /dev/null
+++ b/src/test/regress/expected/gtt_prepare.out
@@ -0,0 +1,7 @@
+CREATE SCHEMA IF NOT EXISTS gtt;
+set search_path=gtt,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+reset search_path;
diff --git a/src/test/regress/expected/gtt_stats.out b/src/test/regress/expected/gtt_stats.out
new file mode 100644
index 0000000..b258b7c
--- /dev/null
+++ b/src/test/regress/expected/gtt_stats.out
@@ -0,0 +1,76 @@
+CREATE SCHEMA IF NOT EXISTS gtt_stats;
+set search_path=gtt_stats,sys;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     0
+(1 row)
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     0
+(1 row)
+
+create global temp table gtt(a int primary key, b text) on commit PRESERVE rows;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     0
+(1 row)
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     0
+(1 row)
+
+insert into gtt values(generate_series(1,10000),'test');
+-- expect 1
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     1
+(1 row)
+
+-- expect 2
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     2
+(1 row)
+
+-- expect 0
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+ schemaname | tablename | relpages | reltuples | relallvisible 
+------------+-----------+----------+-----------+---------------
+ gtt_stats  | gtt       |        0 |         0 |             0
+(1 row)
+
+-- expect 0
+select * from pg_gtt_stats order by tablename;
+ schemaname | tablename | attname | inherited | null_frac | avg_width | n_distinct | most_common_vals | most_common_freqs | histogram_bounds | correlation | most_common_elems | most_common_elem_freqs | elem_count_histogram 
+------------+-----------+---------+-----------+-----------+-----------+------------+------------------+-------------------+------------------+-------------+-------------------+------------------------+----------------------
+(0 rows)
+
+analyze gtt;
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+ schemaname | tablename | relpages | reltuples | relallvisible 
+------------+-----------+----------+-----------+---------------
+ gtt_stats  | gtt       |       55 |     10000 |             0
+(1 row)
+
+select * from pg_gtt_stats order by tablename;
+ schemaname | tablename | attname | inherited | null_frac | avg_width | n_distinct | most_common_vals | most_common_freqs |                                                                                                                                                                                                                                                histogram_bounds                                                                                                                                                                                                                                                 | correlation | most_common_elems | most_common_elem_freqs | elem_count_histogram 
+------------+-----------+---------+-----------+-----------+-----------+------------+------------------+-------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+-------------------+------------------------+----------------------
+ gtt_stats  | gtt       | a       | f         |         0 |         4 |         -1 |                  |                   | {1,100,200,300,400,500,600,700,800,900,1000,1100,1200,1300,1400,1500,1600,1700,1800,1900,2000,2100,2200,2300,2400,2500,2600,2700,2800,2900,3000,3100,3200,3300,3400,3500,3600,3700,3800,3900,4000,4100,4200,4300,4400,4500,4600,4700,4800,4900,5000,5100,5200,5300,5400,5500,5600,5700,5800,5900,6000,6100,6200,6300,6400,6500,6600,6700,6800,6900,7000,7100,7200,7300,7400,7500,7600,7700,7800,7900,8000,8100,8200,8300,8400,8500,8600,8700,8800,8900,9000,9100,9200,9300,9400,9500,9600,9700,9800,9900,10000} |           1 |                   |                        | 
+ gtt_stats  | gtt       | b       | f         |         0 |         5 |          1 | {test}           | {1}               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |           1 |                   |                        | 
+(2 rows)
+
+reset search_path;
+drop schema gtt_stats cascade;
+NOTICE:  drop cascades to table gtt_stats.gtt
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index 80a0782..d3d9927 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1348,6 +1348,93 @@ pg_group| SELECT pg_authid.rolname AS groname,
           WHERE (pg_auth_members.roleid = pg_authid.oid)) AS grolist
    FROM pg_authid
   WHERE (NOT pg_authid.rolcanlogin);
+pg_gtt_attached_pids| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.relid,
+    s.pid
+   FROM (pg_class c
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_gtt_attached_pid(c.oid) s(relid, pid)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
+pg_gtt_relstats| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.relpages,
+    s.reltuples,
+    s.relallvisible,
+    s.relfrozenxid,
+    s.relminmxid
+   FROM (pg_class c
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_get_gtt_relstats(c.oid) s(relpages, reltuples, relallvisible, relfrozenxid, relminmxid)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
+pg_gtt_stats| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    a.attname,
+    s.stainherit AS inherited,
+    s.stanullfrac AS null_frac,
+    s.stawidth AS avg_width,
+    s.stadistinct AS n_distinct,
+        CASE
+            WHEN (s.stakind1 = 1) THEN s.stavalues1
+            WHEN (s.stakind2 = 1) THEN s.stavalues2
+            WHEN (s.stakind3 = 1) THEN s.stavalues3
+            WHEN (s.stakind4 = 1) THEN s.stavalues4
+            WHEN (s.stakind5 = 1) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS most_common_vals,
+        CASE
+            WHEN (s.stakind1 = 1) THEN s.stanumbers1
+            WHEN (s.stakind2 = 1) THEN s.stanumbers2
+            WHEN (s.stakind3 = 1) THEN s.stanumbers3
+            WHEN (s.stakind4 = 1) THEN s.stanumbers4
+            WHEN (s.stakind5 = 1) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS most_common_freqs,
+        CASE
+            WHEN (s.stakind1 = 2) THEN s.stavalues1
+            WHEN (s.stakind2 = 2) THEN s.stavalues2
+            WHEN (s.stakind3 = 2) THEN s.stavalues3
+            WHEN (s.stakind4 = 2) THEN s.stavalues4
+            WHEN (s.stakind5 = 2) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS histogram_bounds,
+        CASE
+            WHEN (s.stakind1 = 3) THEN s.stanumbers1[1]
+            WHEN (s.stakind2 = 3) THEN s.stanumbers2[1]
+            WHEN (s.stakind3 = 3) THEN s.stanumbers3[1]
+            WHEN (s.stakind4 = 3) THEN s.stanumbers4[1]
+            WHEN (s.stakind5 = 3) THEN s.stanumbers5[1]
+            ELSE NULL::real
+        END AS correlation,
+        CASE
+            WHEN (s.stakind1 = 4) THEN s.stavalues1
+            WHEN (s.stakind2 = 4) THEN s.stavalues2
+            WHEN (s.stakind3 = 4) THEN s.stavalues3
+            WHEN (s.stakind4 = 4) THEN s.stavalues4
+            WHEN (s.stakind5 = 4) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS most_common_elems,
+        CASE
+            WHEN (s.stakind1 = 4) THEN s.stanumbers1
+            WHEN (s.stakind2 = 4) THEN s.stanumbers2
+            WHEN (s.stakind3 = 4) THEN s.stanumbers3
+            WHEN (s.stakind4 = 4) THEN s.stanumbers4
+            WHEN (s.stakind5 = 4) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS most_common_elem_freqs,
+        CASE
+            WHEN (s.stakind1 = 5) THEN s.stanumbers1
+            WHEN (s.stakind2 = 5) THEN s.stanumbers2
+            WHEN (s.stakind3 = 5) THEN s.stanumbers3
+            WHEN (s.stakind4 = 5) THEN s.stanumbers4
+            WHEN (s.stakind5 = 5) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS elem_count_histogram
+   FROM ((pg_class c
+     JOIN pg_attribute a ON ((c.oid = a.attrelid)))
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_get_gtt_statistics(c.oid, (a.attnum)::integer, ''::text) s(starelid, staattnum, stainherit, stanullfrac, stawidth, stadistinct, stakind1, stakind2, stakind3, stakind4, stakind5, staop1, staop2, staop3, staop4, staop5, stacoll1, stacoll2, stacoll3, stacoll4, stacoll5, stanumbers1, stanumbers2, stanumbers3, stanumbers4, stanumbers5, stavalues1, stavalues2, stavalues3, stavalues4, stavalues5)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND (NOT a.attisdropped) AND has_column_privilege(c.oid, a.attnum, 'select'::text) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
 pg_hba_file_rules| SELECT a.line_number,
     a.type,
     a.database,
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index d33a4e1..643afe4 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -121,3 +121,10 @@ test: fast_default
 
 # run stats by itself because its delay may be insufficient under heavy load
 test: stats
+
+# global temp table test
+test: gtt_stats
+test: gtt_function
+test: gtt_prepare
+test: gtt_parallel_1 gtt_parallel_2
+test: gtt_clean
diff --git a/src/test/regress/sql/gtt_clean.sql b/src/test/regress/sql/gtt_clean.sql
new file mode 100644
index 0000000..f3cf710
--- /dev/null
+++ b/src/test/regress/sql/gtt_clean.sql
@@ -0,0 +1,6 @@
+
+
+reset search_path;
+
+drop schema gtt cascade;
+
diff --git a/src/test/regress/sql/gtt_function.sql b/src/test/regress/sql/gtt_function.sql
new file mode 100644
index 0000000..49c3f11
--- /dev/null
+++ b/src/test/regress/sql/gtt_function.sql
@@ -0,0 +1,163 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt_function;
+
+set search_path=gtt_function,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt_test_rename(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+
+-- ok
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+
+-- ok
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+
+--ok
+CREATE global temp TABLE p_table01 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+);
+ 
+CREATE global temp TABLE p_table01_2018
+PARTITION OF p_table01
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+ 
+CREATE global temp TABLE p_table01_2017
+PARTITION OF p_table01
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+
+begin;
+insert into p_table01 values(1,'2018-01-02 00:00:00','test1');
+insert into p_table01 values(1,'2018-01-02 00:00:00','test2');
+select count(*) from p_table01;
+commit;
+
+select count(*) from p_table01;
+
+--ok
+CREATE global temp TABLE p_table02 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)
+on commit PRESERVE rows;
+
+CREATE global temp TABLE p_table02_2018
+PARTITION OF p_table02
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+
+CREATE global temp TABLE p_table02_2017
+PARTITION OF p_table02
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+
+-- ok
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent_global_temp);
+
+select relname ,relkind, relpersistence, reloptions from pg_class where relname like 'p_table0%' or  relname like 'tbl_inherits%' order by relname;
+
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+
+--ok
+alter table gtt_test_rename rename to gtt_test;
+
+-- ok
+ALTER TABLE gtt_test ADD COLUMN address varchar(30);
+
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+
+-- ok
+create global temp table gtt_seq(id int GENERATED ALWAYS AS IDENTITY (START WITH 2) primary key, a int)  on commit PRESERVE rows;
+insert into gtt_seq (a) values(1);
+insert into gtt_seq (a) values(2);
+select * from gtt_seq order by id;
+truncate gtt_seq;
+select * from gtt_seq order by id;
+insert into gtt_seq (a) values(3);
+select * from gtt_seq order by id;
+
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+create index idx_err on gtt1 using gist (a);
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+
+reset search_path;
+
+drop schema gtt_function cascade;
+
diff --git a/src/test/regress/sql/gtt_parallel_1.sql b/src/test/regress/sql/gtt_parallel_1.sql
new file mode 100644
index 0000000..d7d81de
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_1.sql
@@ -0,0 +1,42 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+commit;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+rollback;
+select * from gtt1 order by a;
+
+truncate gtt1;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+select * from gtt1 order by a;
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+
+begin;
+select * from gtt1 order by a;
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_parallel_2.sql b/src/test/regress/sql/gtt_parallel_2.sql
new file mode 100644
index 0000000..cb2f7a6
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_2.sql
@@ -0,0 +1,62 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+commit;
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+truncate gtt3;
+select * from gtt3 order by a;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+truncate gtt3;
+select * from gtt3 order by a;
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+begin;
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',10000);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid) from pg_class where relname = 'gtt_t_kenyon';
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_prepare.sql b/src/test/regress/sql/gtt_prepare.sql
new file mode 100644
index 0000000..042d9e6
--- /dev/null
+++ b/src/test/regress/sql/gtt_prepare.sql
@@ -0,0 +1,15 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt;
+
+set search_path=gtt,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_stats.sql b/src/test/regress/sql/gtt_stats.sql
new file mode 100644
index 0000000..f041892
--- /dev/null
+++ b/src/test/regress/sql/gtt_stats.sql
@@ -0,0 +1,42 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt_stats;
+
+set search_path=gtt_stats,sys;
+
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+
+create global temp table gtt(a int primary key, b text) on commit PRESERVE rows;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+
+insert into gtt values(generate_series(1,10000),'test');
+
+-- expect 1
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 2
+select count(*) from pg_list_gtt_relfrozenxids();
+
+-- expect 0
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+
+-- expect 0
+select * from pg_gtt_stats order by tablename;
+
+analyze gtt;
+
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+
+select * from pg_gtt_stats order by tablename;
+
+reset search_path;
+
+drop schema gtt_stats cascade;
+

diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c
index 79430d2..b7173c7 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -158,6 +158,19 @@ static relopt_bool boolRelOpts[] =
 		},
 		true
 	},
+	/*
+	 * For global temp table only
+	 * use AccessExclusiveLock for ensure safety
+	 */
+	{
+		{
+			"on_commit_delete_rows",
+			"global temp table on commit options",
+			RELOPT_KIND_HEAP | RELOPT_KIND_PARTITIONED,
+			ShareUpdateExclusiveLock
+		},
+		true
+	},	
 	/* list terminator */
 	{{NULL}}
 };
@@ -1486,6 +1499,8 @@ bytea *
 default_reloptions(Datum reloptions, bool validate, relopt_kind kind)
 {
 	static const relopt_parse_elt tab[] = {
+		{"on_commit_delete_rows", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, on_commit_delete_rows)},
 		{"fillfactor", RELOPT_TYPE_INT, offsetof(StdRdOptions, fillfactor)},
 		{"autovacuum_enabled", RELOPT_TYPE_BOOL,
 		offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, enabled)},
@@ -1586,13 +1601,18 @@ build_reloptions(Datum reloptions, bool validate,
 bytea *
 partitioned_table_reloptions(Datum reloptions, bool validate)
 {
+	static const relopt_parse_elt tab[] = {
+		{"on_commit_delete_rows", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, on_commit_delete_rows)}
+	};
+
 	/*
 	 * There are no options for partitioned tables yet, but this is able to do
 	 * some validation.
 	 */
 	return (bytea *) build_reloptions(reloptions, validate,
 									  RELOPT_KIND_PARTITIONED,
-									  0, NULL, 0);
+									  sizeof(StdRdOptions), tab, lengthof(tab));
 }
 
 /*
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index dd975b1..1610e7d 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -1013,7 +1013,9 @@ gistGetFakeLSN(Relation rel)
 {
 	static XLogRecPtr counter = FirstNormalUnloggedLSN;
 
-	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	/* global temp is same as local temp table */
+	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		rel->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 	{
 		/*
 		 * Temporary relations are only accessible in our session, so a simple
diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index 4bb6efc..8dc8b03 100644
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -146,7 +146,9 @@ hashbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	 * metapage, nor the first bitmap page.
 	 */
 	sort_threshold = (maintenance_work_mem * 1024L) / BLCKSZ;
-	if (index->rd_rel->relpersistence != RELPERSISTENCE_TEMP)
+	/* global temp table is same as local temp table */
+	if (!(index->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		index->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		sort_threshold = Min(sort_threshold, NBuffers);
 	else
 		sort_threshold = Min(sort_threshold, NLocBuffer);
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index a6c369e..675c2b8 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -598,7 +598,7 @@ heapam_relation_set_new_filenode(Relation rel,
 	 */
 	*minmulti = GetOldestMultiXactId();
 
-	srel = RelationCreateStorage(*newrnode, persistence);
+	srel = RelationCreateStorage(*newrnode, persistence, rel);
 
 	/*
 	 * If required, set up an init fork for an unlogged table so that it can
@@ -651,7 +651,7 @@ heapam_relation_copy_data(Relation rel, const RelFileNode *newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index a5fe904..be6fc5f 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -60,6 +60,7 @@
 #include "utils/pg_rusage.h"
 #include "utils/timestamp.h"
 
+#include "catalog/storage_gtt.h"
 
 /*
  * Space/time tradeoff parameters: do these need to be user-tunable?
@@ -217,8 +218,10 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 	Assert(params->truncate != VACOPT_TERNARY_DEFAULT);
 
 	/* not every AM requires these to be valid, but heap does */
-	Assert(TransactionIdIsNormal(onerel->rd_rel->relfrozenxid));
-	Assert(MultiXactIdIsValid(onerel->rd_rel->relminmxid));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relfrozenxid == InvalidTransactionId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && TransactionIdIsNormal(onerel->rd_rel->relfrozenxid)));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relminmxid == InvalidMultiXactId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && MultiXactIdIsValid(onerel->rd_rel->relminmxid)));
 
 	/* measure elapsed time iff autovacuum logging requires it */
 	if (IsAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
@@ -277,8 +280,19 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 
 	vacrelstats = (LVRelStats *) palloc0(sizeof(LVRelStats));
 
-	vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
-	vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
+	/* get relstat from gtt localhash */
+	if (RELATION_IS_GLOBAL_TEMP(onerel))
+	{
+		get_gtt_relstats(RelationGetRelid(onerel),
+						&vacrelstats->old_rel_pages,
+						&vacrelstats->old_live_tuples,
+						NULL, NULL, NULL);
+	}
+	else
+	{
+		vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
+		vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
+	}
 	vacrelstats->num_index_scans = 0;
 	vacrelstats->pages_removed = 0;
 	vacrelstats->lock_waiter_detected = false;
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index f05cbe7..946c9d2 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -763,7 +763,14 @@ _bt_getbuf(Relation rel, BlockNumber blkno, int access)
 		/* Read an existing block of the relation */
 		buf = ReadBuffer(rel, blkno);
 		LockBuffer(buf, access);
-		_bt_checkpage(rel, buf);
+
+		/* global temp table may be not yet initialized for this backend. */
+		if (RELATION_IS_GLOBAL_TEMP(rel) &&
+			blkno == BTREE_METAPAGE &&
+			PageIsNew(BufferGetPage(buf)))
+			_bt_initmetapage(BufferGetPage(buf), P_NONE, 0);
+		else
+			_bt_checkpage(rel, buf);
 	}
 	else
 	{
diff --git a/src/backend/access/table/tableam.c b/src/backend/access/table/tableam.c
index c814733..ff51840 100644
--- a/src/backend/access/table/tableam.c
+++ b/src/backend/access/table/tableam.c
@@ -24,6 +24,7 @@
 #include "access/heapam.h"		/* for ss_* */
 #include "access/tableam.h"
 #include "access/xact.h"
+#include "catalog/storage_gtt.h"
 #include "optimizer/plancat.h"
 #include "storage/bufmgr.h"
 #include "storage/shmem.h"
@@ -560,10 +561,20 @@ table_block_relation_estimate_size(Relation rel, int32 *attr_widths,
 	/* it should have storage, so we can call the smgr */
 	curpages = RelationGetNumberOfBlocks(rel);
 
-	/* coerce values in pg_class to more desirable types */
-	relpages = (BlockNumber) rel->rd_rel->relpages;
-	reltuples = (double) rel->rd_rel->reltuples;
-	relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
+	/* global temp table get relstats from localhash */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		get_gtt_relstats(RelationGetRelid(rel),
+						&relpages, &reltuples, &relallvisible,
+						NULL, NULL);
+	}
+	else
+	{
+		/* coerce values in pg_class to more desirable types */
+		relpages = (BlockNumber) rel->rd_rel->relpages;
+		reltuples = (double) rel->rd_rel->reltuples;
+		relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
+	}
 
 	/*
 	 * HACK: if the relation has never yet been vacuumed, use a minimum size
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 7f4f784..aba8a9f 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6327,6 +6327,10 @@ StartupXLOG(void)
 	else
 		recoveryTargetTLI = ControlFile->checkPointCopy.ThisTimeLineID;
 
+	/* clean temp relation files */
+	if (max_active_gtt > 0)
+		RemovePgTempFiles();
+
 	/*
 	 * Check for signal files, and if so set up state for offline recovery
 	 */
diff --git a/src/backend/catalog/Makefile b/src/backend/catalog/Makefile
index 61db650..fb87816 100644
--- a/src/backend/catalog/Makefile
+++ b/src/backend/catalog/Makefile
@@ -44,6 +44,8 @@ OBJS = \
 	storage.o \
 	toasting.o
 
+OBJS += storage_gtt.o
+
 BKIFILES = postgres.bki postgres.description postgres.shdescription
 
 include $(top_srcdir)/src/backend/common.mk
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index 16cb6d8..f28f2c2 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -398,7 +398,9 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class, char relpersistence)
 
 	switch (relpersistence)
 	{
+		/* global temp table is same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			break;
 		case RELPERSISTENCE_UNLOGGED:
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 0fdff29..54a5243 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -61,6 +61,7 @@
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "commands/tablecmds.h"
 #include "commands/typecmds.h"
 #include "executor/executor.h"
@@ -99,6 +100,7 @@ static void AddNewRelationTuple(Relation pg_class_desc,
 								Oid reloftype,
 								Oid relowner,
 								char relkind,
+								char relpersistence,
 								TransactionId relfrozenxid,
 								TransactionId relminmxid,
 								Datum relacl,
@@ -404,6 +406,10 @@ heap_create(const char *relname,
 									 relpersistence,
 									 relkind);
 
+	/* global temp table not create storage file when catalog create */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		create_storage = false;
+
 	/*
 	 * Have the storage manager create the relation's disk file, if needed.
 	 *
@@ -427,7 +433,7 @@ heap_create(const char *relname,
 
 			case RELKIND_INDEX:
 			case RELKIND_SEQUENCE:
-				RelationCreateStorage(rel->rd_node, relpersistence);
+				RelationCreateStorage(rel->rd_node, relpersistence, rel);
 				break;
 
 			case RELKIND_RELATION:
@@ -956,6 +962,7 @@ AddNewRelationTuple(Relation pg_class_desc,
 					Oid reloftype,
 					Oid relowner,
 					char relkind,
+					char relpersistence,
 					TransactionId relfrozenxid,
 					TransactionId relminmxid,
 					Datum relacl,
@@ -994,8 +1001,18 @@ AddNewRelationTuple(Relation pg_class_desc,
 			break;
 	}
 
-	new_rel_reltup->relfrozenxid = relfrozenxid;
-	new_rel_reltup->relminmxid = relminmxid;
+	/* global temp table not remember transaction info in catalog */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		new_rel_reltup->relfrozenxid = InvalidTransactionId;
+		new_rel_reltup->relminmxid = InvalidMultiXactId;
+	}
+	else
+	{
+		new_rel_reltup->relfrozenxid = relfrozenxid;
+		new_rel_reltup->relminmxid = relminmxid;
+	}
+
 	new_rel_reltup->relowner = relowner;
 	new_rel_reltup->reltype = new_type_oid;
 	new_rel_reltup->reloftype = reloftype;
@@ -1357,6 +1374,7 @@ heap_create_with_catalog(const char *relname,
 						reloftypeid,
 						ownerid,
 						relkind,
+						relpersistence,
 						relfrozenxid,
 						relminmxid,
 						PointerGetDatum(relacl),
@@ -1441,11 +1459,15 @@ heap_create_with_catalog(const char *relname,
 	 */
 	StoreConstraints(new_rel_desc, cooked_constraints, is_internal);
 
-	/*
-	 * If there's a special on-commit action, remember it
-	 */
-	if (oncommit != ONCOMMIT_NOOP)
-		register_on_commit_action(relid, oncommit);
+	/* global temp table register action when storage init */
+	if (relpersistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		/*
+		 * If there's a special on-commit action, remember it
+		 */
+		if (oncommit != ONCOMMIT_NOOP)
+			register_on_commit_action(relid, oncommit);
+	}
 
 	/*
 	 * ok, the relation has been cataloged, so close our relations and return
@@ -1937,6 +1959,13 @@ heap_drop_with_catalog(Oid relid)
 	if (relid == defaultPartOid)
 		update_default_partition_oid(parentOid, InvalidOid);
 
+	/* We allow to drop global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (is_other_backend_use_gtt(rel->rd_node))
+			elog(ERROR, "can not drop relation when other backend attached this global temp table");
+	}
+
 	/*
 	 * Schedule unlinking of the relation's physical files at commit.
 	 */
@@ -3163,9 +3192,10 @@ RemoveStatistics(Oid relid, AttrNumber attnum)
  *
  * The routine will truncate and then reconstruct the indexes on
  * the specified relation.  Caller must hold exclusive lock on rel.
+ *
  */
 static void
-RelationTruncateIndexes(Relation heapRelation)
+RelationTruncateIndexes(Relation heapRelation, LOCKMODE lockmode)
 {
 	ListCell   *indlist;
 
@@ -3177,7 +3207,7 @@ RelationTruncateIndexes(Relation heapRelation)
 		IndexInfo  *indexInfo;
 
 		/* Open the index relation; use exclusive lock, just to be sure */
-		currentIndex = index_open(indexId, AccessExclusiveLock);
+		currentIndex = index_open(indexId, lockmode);
 
 		/*
 		 * Fetch info needed for index_build.  Since we know there are no
@@ -3223,8 +3253,13 @@ heap_truncate(List *relids)
 	{
 		Oid			rid = lfirst_oid(cell);
 		Relation	rel;
+		LOCKMODE	lockmode = AccessExclusiveLock;
 
-		rel = table_open(rid, AccessExclusiveLock);
+		/* truncate global temp table only need RowExclusiveLock */
+		if (get_rel_persistence(rid) == RELPERSISTENCE_GLOBAL_TEMP)
+			lockmode = RowExclusiveLock;
+
+		rel = table_open(rid, lockmode);
 		relations = lappend(relations, rel);
 	}
 
@@ -3257,6 +3292,8 @@ void
 heap_truncate_one_rel(Relation rel)
 {
 	Oid			toastrelid;
+	LOCKMODE	lockmode = AccessExclusiveLock;
+	bool		truncate_toastrel = false;
 
 	/*
 	 * Truncate the relation.  Partitioned tables have no storage, so there is
@@ -3265,23 +3302,40 @@ heap_truncate_one_rel(Relation rel)
 	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 		return;
 
+	toastrelid = rel->rd_rel->reltoastrelid;
+
+	/*
+	 * Truncate global temp table only need RowExclusiveLock
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		lockmode = RowExclusiveLock;
+		if (OidIsValid(toastrelid) &&
+			gtt_storage_attached(toastrelid))
+			truncate_toastrel = true;
+	}
+	else if (OidIsValid(toastrelid))
+		truncate_toastrel = true;
+
 	/* Truncate the underlying relation */
 	table_relation_nontransactional_truncate(rel);
 
 	/* If the relation has indexes, truncate the indexes too */
-	RelationTruncateIndexes(rel);
+	RelationTruncateIndexes(rel, lockmode);
 
 	/* If there is a toast table, truncate that too */
-	toastrelid = rel->rd_rel->reltoastrelid;
-	if (OidIsValid(toastrelid))
+	if (truncate_toastrel)
 	{
-		Relation	toastrel = table_open(toastrelid, AccessExclusiveLock);
+		Relation	toastrel = table_open(toastrelid, lockmode);
 
 		table_relation_nontransactional_truncate(toastrel);
-		RelationTruncateIndexes(toastrel);
+		RelationTruncateIndexes(toastrel, lockmode);
 		/* keep the lock... */
 		table_close(toastrel, NoLock);
 	}
+
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		up_gtt_relstats(rel, 0, 0, 0, RecentXmin, InvalidMultiXactId);
 }
 
 /*
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 3e59e64..9867d6f 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -52,6 +52,7 @@
 #include "catalog/pg_trigger.h"
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
+#include "catalog/storage_gtt.h"
 #include "commands/event_trigger.h"
 #include "commands/progress.h"
 #include "commands/tablecmds.h"
@@ -877,6 +878,26 @@ index_create(Relation heapRelation,
 						indexRelationName, RelationGetRelationName(heapRelation))));
 	}
 
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		if (accessMethodObjectId != BTREE_AM_OID)
+			elog(ERROR, "only support btree index on global temp table");
+
+		/* We allow to create index on global temp table only this session use it */
+		if (is_other_backend_use_gtt(heapRelation->rd_node))
+			elog(ERROR, "can not create index when have other backend attached this global temp table");
+
+		/* No support create index on global temp table use concurrent mode yet */
+		if (concurrent)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("cannot create indexes on global temporary tables using concurrent mode")));
+
+		/* if global temp table not init storage, then skip build index */
+		if (!gtt_storage_attached(heapRelation->rd_node.relNode))
+			flags |= INDEX_CREATE_SKIP_BUILD;
+	}
+
 	/*
 	 * construct tuple descriptor for index tuples
 	 */
@@ -2045,6 +2066,13 @@ index_drop(Oid indexId, bool concurrent, bool concurrent_lock_mode)
 	 */
 	CheckTableNotInUse(userIndexRelation, "DROP INDEX");
 
+	/* We allow to drop index on global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(userHeapRelation))
+	{
+		if (is_other_backend_use_gtt(userHeapRelation->rd_node))
+			elog(ERROR, "can not drop index when other backend attached this global temp table");
+	}
+
 	/*
 	 * Drop Index Concurrently is more or less the reverse process of Create
 	 * Index Concurrently.
@@ -2736,20 +2764,29 @@ index_update_stats(Relation rel,
 		else					/* don't bother for indexes */
 			relallvisible = 0;
 
-		if (rd_rel->relpages != (int32) relpages)
+		/* update index stats into localhash for global temp table */
+		if (RELATION_IS_GLOBAL_TEMP(rel))
 		{
-			rd_rel->relpages = (int32) relpages;
-			dirty = true;
+			up_gtt_relstats(rel, relpages, reltuples, relallvisible,
+							InvalidTransactionId, InvalidMultiXactId);
 		}
-		if (rd_rel->reltuples != (float4) reltuples)
-		{
-			rd_rel->reltuples = (float4) reltuples;
-			dirty = true;
-		}
-		if (rd_rel->relallvisible != (int32) relallvisible)
+		else
 		{
-			rd_rel->relallvisible = (int32) relallvisible;
-			dirty = true;
+			if (rd_rel->relpages != (int32) relpages)
+			{
+				rd_rel->relpages = (int32) relpages;
+				dirty = true;
+			}
+			if (rd_rel->reltuples != (float4) reltuples)
+			{
+				rd_rel->reltuples = (float4) reltuples;
+				dirty = true;
+			}
+			if (rd_rel->relallvisible != (int32) relallvisible)
+			{
+				rd_rel->relallvisible = (int32) relallvisible;
+				dirty = true;
+			}
 		}
 	}
 
@@ -2864,6 +2901,12 @@ index_build(Relation heapRelation,
 		pgstat_progress_update_multi_param(6, index, val);
 	}
 
+	if (RELATION_IS_GLOBAL_TEMP(indexRelation))
+	{
+		if (!gtt_storage_attached(indexRelation->rd_node.relNode))
+			RelationCreateStorage(indexRelation->rd_node, RELPERSISTENCE_GLOBAL_TEMP, indexRelation);
+	}
+
 	/*
 	 * Call the access method's build procedure
 	 */
@@ -3196,12 +3239,22 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	/*
 	 * Scan the index and gather up all the TIDs into a tuplesort object.
 	 */
+	memset(&ivinfo, 0, sizeof(IndexVacuumInfo));
 	ivinfo.index = indexRelation;
 	ivinfo.analyze_only = false;
 	ivinfo.report_progress = true;
 	ivinfo.estimated_count = true;
 	ivinfo.message_level = DEBUG2;
-	ivinfo.num_heap_tuples = heapRelation->rd_rel->reltuples;
+
+	/* get relstats abort global temp table from hashtable, not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		get_gtt_relstats(RelationGetRelid(heapRelation),
+						NULL, &ivinfo.num_heap_tuples, NULL,
+						NULL, NULL);
+	}
+	else
+		ivinfo.num_heap_tuples = heapRelation->rd_rel->reltuples;
 	ivinfo.strategy = NULL;
 
 	/*
@@ -3459,6 +3512,15 @@ reindex_index(Oid indexId, bool skip_constraint_checks, char persistence,
 				 errmsg("cannot reindex temporary tables of other sessions")));
 
 	/*
+	 * Because global temp table cannot change relfilenode
+	 * no support reindex on global temp table yet.
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(iRel))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot reindex global temporary tables")));
+
+	/*
 	 * Also check for active uses of the index in the current transaction; we
 	 * don't want to reindex underneath an open indexscan.
 	 */
diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index c82f9fc..8248109 100644
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -647,6 +647,13 @@ RangeVarAdjustRelationPersistence(RangeVar *newRelation, Oid nspid)
 							 errmsg("cannot create temporary relation in non-temporary schema")));
 			}
 			break;
+		/* global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			if (isAnyTempNamespace(nspid))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+						 errmsg("cannot create global temp relations in temporary schemas")));
+			break;
 		case RELPERSISTENCE_PERMANENT:
 			if (isTempOrTempToastNamespace(nspid))
 				newRelation->relpersistence = RELPERSISTENCE_TEMP;
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index fddfbf1..03806ae 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -26,6 +26,7 @@
 #include "access/xlogutils.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "miscadmin.h"
 #include "storage/freespace.h"
 #include "storage/smgr.h"
@@ -73,9 +74,10 @@ static PendingRelDelete *pendingDeletes = NULL; /* head of linked list */
  *
  * This function is transactional. The creation is WAL-logged, and if the
  * transaction aborts later on, the storage will be destroyed.
+ *
  */
 SMgrRelation
-RelationCreateStorage(RelFileNode rnode, char relpersistence)
+RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel)
 {
 	PendingRelDelete *pending;
 	SMgrRelation srel;
@@ -85,6 +87,8 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	switch (relpersistence)
 	{
 		case RELPERSISTENCE_TEMP:
+		/* global temp table use same storage strategy as local temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			needs_wal = false;
 			break;
@@ -117,6 +121,10 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	pending->next = pendingDeletes;
 	pendingDeletes = pending;
 
+	/* remember global temp table storage info to localhash */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP && rel)
+		remember_gtt_storage_info(rnode, rel);
+
 	return srel;
 }
 
@@ -486,8 +494,15 @@ smgrDoPendingDeletes(bool isCommit)
 		smgrdounlinkall(srels, nrels, false);
 
 		for (i = 0; i < nrels; i++)
+		{
 			smgrclose(srels[i]);
 
+			/* clean global temp table flags when transaction commit or rollback */
+			if (SmgrIsTemp(srels[i]) && 
+				gtt_storage_attached(srels[i]->smgr_rnode.node.relNode))
+				forget_gtt_storage_info(srels[i]->smgr_rnode.node.relNode);
+		}
+
 		pfree(srels);
 	}
 }
diff --git a/src/backend/catalog/storage_gtt.c b/src/backend/catalog/storage_gtt.c
new file mode 100644
index 0000000..f489cd3
--- /dev/null
+++ b/src/backend/catalog/storage_gtt.c
@@ -0,0 +1,1129 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.c
+ *	  code to create and destroy physical storage for global temparary table
+ *
+ * IDENTIFICATION
+ *	  src/backend/catalog/storage_gtt.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/table.h"
+#include "access/visibilitymap.h"
+#include "access/xact.h"
+#include "access/xlog.h"
+#include "access/xloginsert.h"
+#include "access/xlogutils.h"
+#include "access/htup_details.h"
+#include "access/multixact.h"
+#include "catalog/storage.h"
+#include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/heap.h"
+#include "catalog/namespace.h"
+#include "catalog/pg_type.h"
+#include "catalog/pg_statistic.h"
+#include "commands/tablecmds.h"
+#include "funcapi.h"
+#include "nodes/primnodes.h"
+#include "nodes/pg_list.h"
+#include "nodes/execnodes.h"
+#include "miscadmin.h"
+#include "storage/freespace.h"
+#include "storage/smgr.h"
+#include "storage/ipc.h"
+#include "storage/proc.h"
+#include "storage/procarray.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "storage/sinvaladt.h"
+#include "utils/memutils.h"
+#include "utils/rel.h"
+#include "utils/hsearch.h"
+#include "utils/catcache.h"
+#include "utils/lsyscache.h"
+#include <utils/relcache.h>
+#include "utils/inval.h"
+#include "utils/guc.h"
+
+
+/* Copy from bitmapset.c, because gtt used the function in bitmapset.c */
+#define WORDNUM(x)	((x) / BITS_PER_BITMAPWORD)
+#define BITNUM(x)	((x) % BITS_PER_BITMAPWORD)
+
+#define BITMAPSET_SIZE(nwords)	\
+	(offsetof(Bitmapset, words) + (nwords) * sizeof(bitmapword))
+
+static bool gtt_cleaner_exit_registered = false;
+static HTAB *gtt_storage_local_hash = NULL;
+static HTAB *active_gtt_shared_hash = NULL;
+static MemoryContext gtt_relstats_context = NULL;
+
+/* relfrozenxid of all gtts in the current session */
+static List *gtt_session_relfrozenxid_list = NIL;
+static TransactionId gtt_session_frozenxid = InvalidTransactionId;
+
+typedef struct gtt_ctl_data
+{
+	LWLock			lock;
+	int			max_entry;
+	int			entry_size;
+}gtt_ctl_data;
+
+static gtt_ctl_data *gtt_shared_ctl = NULL;
+
+typedef struct
+{
+	RelFileNode	rnode;
+	Bitmapset	*map;
+	/* bitmap data */
+} gtt_shared_hash_entry;
+
+typedef struct
+{
+	Oid			relid;
+
+	Oid			spcnode;
+	/* pg_class stat */
+	int32		relpages;
+	float4		reltuples;
+	int32		relallvisible;
+	TransactionId relfrozenxid;
+	TransactionId relminmxid;
+	char		relkind;
+	bool		on_commit_delete;
+
+	/* pg_statistic */
+	int			natts;
+	int			*attnum;
+	HeapTuple	*att_stat_tups;
+} gtt_local_hash_entry;
+
+static Size action_gtt_shared_hash_entry_size(void);
+static void gtt_storage_checkin(RelFileNode rnode);
+static void gtt_storage_checkout(RelFileNode rnode, bool skiplock);
+static void gtt_storage_removeall(int code, Datum arg);
+static void insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid);
+static void remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid);
+static void set_gtt_session_relfrozenxid(void);
+
+Datum pg_get_gtt_statistics(PG_FUNCTION_ARGS);
+Datum pg_get_gtt_relstats(PG_FUNCTION_ARGS);
+Datum pg_gtt_attached_pid(PG_FUNCTION_ARGS);
+Datum pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS);
+
+
+static Size
+action_gtt_shared_hash_entry_size(void)
+{
+	int 	wordnum;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	wordnum = WORDNUM(MaxBackends + 1);
+	hash_entry_size += MAXALIGN(sizeof(gtt_shared_hash_entry));
+	hash_entry_size += MAXALIGN(BITMAPSET_SIZE(wordnum + 1));
+
+	return hash_entry_size;
+}
+
+Size
+active_gtt_shared_hash_size(void)
+{
+	Size	size = 0;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	size = MAXALIGN(sizeof(gtt_ctl_data));
+	hash_entry_size = action_gtt_shared_hash_entry_size();
+	size += hash_estimate_size(max_active_gtt, hash_entry_size);
+
+	return size;
+}
+
+void
+active_gtt_shared_hash_init(void)
+{
+	HASHCTL info;
+	bool	found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	gtt_shared_ctl =
+		ShmemInitStruct("gtt_shared_ctl",
+						sizeof(gtt_ctl_data),
+						&found);
+
+	if (!found)
+	{
+		LWLockRegisterTranche(LWTRANCHE_GTT_CTL, "gtt_shared_ctl");
+		LWLockInitialize(&gtt_shared_ctl->lock, LWTRANCHE_GTT_CTL);
+		gtt_shared_ctl->max_entry = max_active_gtt;
+		gtt_shared_ctl->entry_size = action_gtt_shared_hash_entry_size();
+	}
+
+	info.keysize = sizeof(RelFileNode);
+	info.entrysize = gtt_shared_ctl->entry_size;
+	active_gtt_shared_hash =
+		ShmemInitHash("active gtt shared hash",
+						gtt_shared_ctl->max_entry,
+						gtt_shared_ctl->max_entry,
+						&info, HASH_ELEM | HASH_BLOBS | HASH_FIXED_SIZE);
+}
+
+static void
+gtt_storage_checkin(RelFileNode rnode)
+{
+	gtt_shared_hash_entry	*entry;
+	bool			found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+	entry = (gtt_shared_hash_entry *) hash_search(active_gtt_shared_hash,
+												&rnode, HASH_ENTER_NULL, &found);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		ereport(ERROR,
+				(errcode(ERRCODE_OUT_OF_MEMORY),
+				 errmsg("out of shared memory"),
+				 errhint("You might need to increase max_active_gtt.")));
+	}
+
+	if (found == false)
+	{
+		int			wordnum;
+
+		entry->map = (Bitmapset *)((char *)entry + MAXALIGN(sizeof(gtt_shared_hash_entry)));
+		wordnum = WORDNUM(MaxBackends + 1);
+		memset(entry->map, 0, BITMAPSET_SIZE(wordnum + 1));
+		entry->map->nwords = wordnum + 1;
+	}
+
+	bms_add_member(entry->map, MyBackendId);
+	LWLockRelease(&gtt_shared_ctl->lock);
+}
+
+static void
+gtt_storage_checkout(RelFileNode rnode, bool skiplock)
+{
+	gtt_shared_hash_entry	*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (!skiplock)
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(rnode), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		if (!skiplock)
+			LWLockRelease(&gtt_shared_ctl->lock);
+
+		elog(WARNING, "relfilenode %u/%u/%u not exist in gtt shared hash when forget",
+						rnode.dbNode, rnode.spcNode, rnode.relNode);
+		return;
+	}
+
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+	bms_del_member(entry->map, MyBackendId);
+
+	if (bms_is_empty(entry->map))
+	{
+		if (!hash_search(active_gtt_shared_hash, &rnode, HASH_REMOVE, NULL))
+			elog(PANIC, "gtt shared hash table corrupted");
+	}
+
+	if (!skiplock)
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+	return;
+}
+
+Bitmapset *
+copy_active_gtt_bitmap(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	Bitmapset	*map_copy = NULL;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return NULL;
+	}
+
+	Assert(entry->map);
+	if (!bms_is_empty(entry->map))
+		map_copy = bms_copy(entry->map);
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return map_copy;
+}
+
+bool
+is_other_backend_use_gtt(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	bool		in_use = false;
+	int			num_use = 0;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return false;
+	}
+
+	Assert(entry->map);
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+
+	num_use = bms_num_members(entry->map);
+	if (num_use == 0)
+		in_use = false;
+	else if (num_use == 1)
+	{
+		if(bms_is_member(MyBackendId, entry->map))
+			in_use = false;
+		else
+			in_use = true;
+	}
+	else
+		in_use = true;
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return in_use;
+}
+
+void
+remember_gtt_storage_info(RelFileNode rnode, Relation rel)
+{
+	gtt_local_hash_entry	*entry;
+	MemoryContext			oldcontext;
+	Oid			relid = rnode.relNode;
+	bool		found;
+
+	if (max_active_gtt <= 0)
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("Global temporary table feature is disable"),
+			 errhint("You might need to increase max_active_gtt to enable this feature.")));
+
+	if (RecoveryInProgress())
+		elog(ERROR, "readonly mode not support access global temp table yet");
+
+	if (gtt_storage_local_hash == NULL)
+	{
+#define GTT_LOCAL_HASH_SIZE		1024
+		/* First time through: initialize the hash table */
+		HASHCTL		ctl;
+
+		MemSet(&ctl, 0, sizeof(ctl));
+		ctl.keysize = sizeof(Oid);
+		ctl.entrysize = sizeof(gtt_local_hash_entry);
+		gtt_storage_local_hash =
+			hash_create("global temp relation table",
+						GTT_LOCAL_HASH_SIZE,
+						&ctl, HASH_ELEM | HASH_BLOBS);
+
+		if (!CacheMemoryContext)
+			CreateCacheMemoryContext();
+
+		gtt_relstats_context =
+			AllocSetContextCreate(CacheMemoryContext,
+							"gtt relstats context",
+							ALLOCSET_DEFAULT_SIZES);
+	}
+
+	/* Look up or create an entry */
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_ENTER, &found);
+
+	if (found)
+	{
+		elog(ERROR, "backend %d relid %u already exists in global temp table local hash",
+					MyBackendId, relid);
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+
+	entry->spcnode = rnode.spcNode;
+	entry->relpages = 0;
+	entry->reltuples = 0;
+	entry->relallvisible = 0;
+	entry->relkind = rel->rd_rel->relkind;
+	/* only heap contain transaction information */
+	if (entry->relkind == RELKIND_RELATION || entry->relkind == RELKIND_PARTITIONED_TABLE)
+	{
+		int natts = RelationGetNumberOfAttributes(rel);
+		entry->natts = natts;
+		entry->attnum = palloc0(sizeof(int) * natts);
+		entry->att_stat_tups = palloc0(sizeof(HeapTuple) * natts);
+
+		if (RELATION_GTT_ON_COMMIT_DELETE(rel))
+		{
+			entry->on_commit_delete = true;
+			register_on_commit_action(rel->rd_node.relNode, ONCOMMIT_DELETE_ROWS);
+		}
+
+		entry->relfrozenxid = RecentXmin;
+		entry->relminmxid = GetOldestMultiXactId();
+		insert_gtt_relfrozenxid_to_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+		gtt_storage_checkin(rnode);
+	}
+	else
+	{
+		entry->natts = 0;
+		entry->attnum = 0;
+		entry->att_stat_tups = NULL;
+		entry->on_commit_delete = false;
+		entry->relfrozenxid = 0;
+		entry->relminmxid = 0;
+	}
+
+	MemoryContextSwitchTo(oldcontext);
+
+	if (!gtt_cleaner_exit_registered)
+	{
+		before_shmem_exit(gtt_storage_removeall, 0);
+		gtt_cleaner_exit_registered = true;
+	}
+
+	return;
+}
+
+void
+forget_gtt_storage_info(Oid relid)
+{
+	gtt_local_hash_entry		*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+				(void *) &(relid), HASH_FIND, NULL);
+
+	if (entry && entry->relkind == RELKIND_RELATION)
+	{
+		RelFileNode rnode;
+		int			i;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		gtt_storage_checkout(rnode, false);
+
+		Assert(TransactionIdIsNormal(entry->relfrozenxid));
+		remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+
+		for (i = 0; i < entry->natts; i++)
+		{
+			if (entry->att_stat_tups[i])
+			{
+				heap_freetuple(entry->att_stat_tups[i]);
+				entry->att_stat_tups[i] = NULL;
+			}
+		}
+	}
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_REMOVE, NULL);
+
+	return;
+}
+
+/* is the storage file was created in this backend */
+bool
+gtt_storage_attached(Oid relid)
+{
+	bool found;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	if (gtt_storage_local_hash == NULL)
+		return false;
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_FIND, &found);
+
+	return found;
+}
+
+static void
+gtt_storage_removeall(int code, Datum arg)
+{
+	HASH_SEQ_STATUS				status;
+	gtt_local_hash_entry		*entry;
+	int			nrels = 0,
+				maxrels = 0;
+	SMgrRelation	*srels = NULL;
+	RelFileNode		*rnodes = NULL;
+	char			*relkinds = NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	hash_seq_init(&status, gtt_storage_local_hash);
+	while ((entry = (gtt_local_hash_entry *) hash_seq_search(&status)) != NULL)
+	{
+		SMgrRelation srel;
+		RelFileNode rnode;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		srel = smgropen(rnode, MyBackendId);
+
+		/* allocate the initial array, or extend it, if needed */
+		if (maxrels == 0)
+		{
+			maxrels = 32;
+			srels = palloc(sizeof(SMgrRelation) * maxrels);
+			rnodes = palloc(sizeof(RelFileNode) * maxrels);
+			relkinds = palloc(sizeof(char) * maxrels);
+		}
+		else if (maxrels <= nrels)
+		{
+			maxrels *= 2;
+			srels = repalloc(srels, sizeof(SMgrRelation) * maxrels);
+			rnodes = repalloc(rnodes, sizeof(RelFileNode) * maxrels);
+			relkinds = repalloc(relkinds, sizeof(char) * maxrels);
+		}
+
+		srels[nrels] = srel;
+		rnodes[nrels] = rnode;
+		relkinds[nrels] = entry->relkind;
+		nrels++;
+	}
+
+	if (nrels > 0)
+	{
+		int i;
+
+		smgrdounlinkall(srels, nrels, false);
+
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+		for (i = 0; i < nrels; i++)
+		{
+			smgrclose(srels[i]);
+			if (relkinds[i] == RELKIND_RELATION)
+				gtt_storage_checkout(rnodes[i], true);
+		}
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+		pfree(srels);
+		pfree(rnodes);
+		pfree(relkinds);
+	}
+
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;
+
+	return;
+}
+
+/*
+ * Update global temp table relstats(relpage/reltuple/relallvisible) 
+ * to local hashtable
+ */
+void
+up_gtt_relstats(Relation relation,
+					BlockNumber num_pages,
+					double num_tuples,
+					BlockNumber num_all_visible_pages,
+					TransactionId relfrozenxid,
+					TransactionId relminmxid)
+{
+	Oid		relid = RelationGetRelid(relation);
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	Assert(entry->spcnode);
+
+	if (num_pages >= 0 &&
+		entry->relpages != (int32)num_pages)
+		entry->relpages = (int32)num_pages;
+
+	if (num_tuples >= 0 &&
+		num_tuples != (float4)entry->reltuples)
+		entry->reltuples = (float4)num_tuples;
+
+	/* only heap contain transaction information and relallvisible */
+	if (entry->relkind == RELKIND_RELATION)
+	{
+		if (entry->relallvisible >= 0 &&
+			entry->relallvisible != (int32)num_all_visible_pages)
+		{
+			entry->relallvisible = (int32)num_all_visible_pages;
+		}
+
+		if (TransactionIdIsNormal(relfrozenxid) &&
+			entry->relfrozenxid != relfrozenxid &&
+			(TransactionIdPrecedes(entry->relfrozenxid, relfrozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(), entry->relfrozenxid)))
+		{
+			remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+			entry->relfrozenxid = relfrozenxid;
+			insert_gtt_relfrozenxid_to_ordered_list(relfrozenxid);
+			set_gtt_session_relfrozenxid();
+		}
+
+		if (MultiXactIdIsValid(relminmxid) &&
+			entry->relminmxid != relminmxid &&
+			(MultiXactIdPrecedes(entry->relminmxid, relminmxid) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), entry->relminmxid)))
+		{
+			entry->relminmxid = relminmxid;
+		}
+	}
+
+	return;
+}
+
+/*
+ * Search global temp table relstats(relpage/reltuple/relallvisible) 
+ * from local hashtable.
+ */
+bool
+get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+				BlockNumber *relallvisible, TransactionId *relfrozenxid,
+				TransactionId *relminmxid)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	if (gtt_storage_local_hash == NULL)
+		return false;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return false;
+
+	Assert(entry->relid == relid);
+
+	if (relpages)
+		*relpages = entry->relpages;
+
+	if (reltuples)
+		*reltuples = entry->reltuples;
+
+	if (relallvisible)
+		*relallvisible = entry->relallvisible;
+
+	if (relfrozenxid)
+		*relfrozenxid = entry->relfrozenxid;
+
+	if (relminmxid)
+		*relminmxid = entry->relminmxid;
+
+	return true;
+}
+
+/*
+ * Update global temp table statistic info(definition is same as pg_statistic)
+ * to local hashtable where ananyze global temp table
+ */
+void
+up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+					TupleDesc tupleDescriptor, Datum *values, bool *isnull)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	MemoryContext			oldcontext;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	if (entry->relkind != RELKIND_RELATION)
+	{
+		elog(WARNING, "oid %u not a relation", reloid);
+		return;
+	}
+
+	/* todo */
+	if (entry->natts < natts)
+	{
+		elog(WARNING, "reloid %u not support update attstat after add colunm", reloid);
+		return;
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	Assert(entry->relid == reloid);
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == 0)
+		{
+			entry->attnum[i] = attnum;
+			break;
+		}
+		else if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			heap_freetuple(entry->att_stat_tups[i]);
+			entry->att_stat_tups[i] = NULL;
+			break;
+		}
+	}
+
+	Assert(i < entry->natts);
+	Assert(entry->att_stat_tups[i] == NULL);
+	entry->att_stat_tups[i] = heap_form_tuple(tupleDescriptor, values, isnull);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+/*
+ * Search global temp table statistic info(definition is same as pg_statistic)
+ * from local hashtable.
+ */
+HeapTuple
+get_gtt_att_statistic(Oid reloid, int attnum, bool inh)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return NULL;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return NULL;
+
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			return entry->att_stat_tups[i];
+		}
+	}
+
+	return NULL;
+}
+
+void
+release_gtt_statistic_cache(HeapTuple tup)
+{
+	/* do nothing */
+	return;
+}
+
+static void
+insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid)
+{
+	MemoryContext	oldcontext;
+	ListCell	*cell;
+	int			i;
+
+	Assert(TransactionIdIsNormal(relfrozenxid));
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	/* Does the datum belong at the front? */
+	if (gtt_session_relfrozenxid_list == NIL ||
+		TransactionIdFollowsOrEquals(relfrozenxid,
+			linitial_oid(gtt_session_relfrozenxid_list)))
+	{
+		gtt_session_relfrozenxid_list =
+			lcons_oid(relfrozenxid, gtt_session_relfrozenxid_list);
+		MemoryContextSwitchTo(oldcontext);
+
+		return;
+	}
+
+	/* No, so find the entry it belongs after */
+	i = 0;
+	foreach (cell, gtt_session_relfrozenxid_list)
+	{
+		if (TransactionIdFollowsOrEquals(relfrozenxid, lfirst_oid(cell)))
+			break;
+
+		i++;
+	}
+	gtt_session_relfrozenxid_list =
+		list_insert_nth_oid(gtt_session_relfrozenxid_list, i, relfrozenxid);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+static void
+remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid)
+{
+	gtt_session_relfrozenxid_list =
+		list_delete_oid(gtt_session_relfrozenxid_list, relfrozenxid);
+}
+
+static void
+set_gtt_session_relfrozenxid(void)
+{
+	TransactionId gtt_frozenxid = InvalidTransactionId;
+
+	if (gtt_session_relfrozenxid_list)
+		gtt_frozenxid = llast_oid(gtt_session_relfrozenxid_list);
+
+	gtt_session_frozenxid = gtt_frozenxid;
+	if (MyProc->session_gtt_frozenxid != gtt_frozenxid)
+		MyProc->session_gtt_frozenxid = gtt_frozenxid;
+}
+
+Datum
+pg_get_gtt_statistics(PG_FUNCTION_ARGS)
+{
+	HeapTuple	tuple;
+	Relation	rel = NULL;
+	int		attnum = PG_GETARG_INT32(1);
+	Oid		reloid = PG_GETARG_OID(0);
+	char		rel_persistence;
+	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	  tupdesc;
+	MemoryContext oldcontext;
+	Tuplestorestate *tupstore;
+	Relation		pg_tatistic = NULL;
+	TupleDesc		sd;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("set-valued function called in context that cannot accept a set")));
+
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("materialize mode required, but it is not " \
+				"allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+				rsinfo->econtext->ecxt_per_query_memory);
+
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	pg_tatistic = table_open(StatisticRelationId, AccessShareLock);
+	sd = RelationGetDescr(pg_tatistic);
+
+	tuple = get_gtt_att_statistic(reloid, attnum, false);
+	if (tuple)
+	{
+		Datum	values[31];
+		bool	isnull[31];
+		HeapTuple	res = NULL;
+
+		memset(&values, 0, sizeof(values));
+		memset(&isnull, 0, sizeof(isnull));
+		heap_deform_tuple(tuple, sd, values, isnull);
+		res = heap_form_tuple(tupdesc, values, isnull);
+		tuplestore_puttuple(tupstore, res);
+	}
+
+	table_close(rel, NoLock);
+	table_close(pg_tatistic, AccessShareLock);
+	tuplestore_donestoring(tupstore);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_get_gtt_relstats(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc		tupdesc;
+	Tuplestorestate	*tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	Oid		reloid = PG_GETARG_OID(0);
+	char	rel_persistence;
+	BlockNumber	relpages = 0;
+	double		reltuples = 0;
+	BlockNumber	relallvisible = 0;
+	uint32		relfrozenxid = 0;
+	uint32		relminmxid = 0;
+	Relation	rel = NULL;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	if (get_gtt_relstats(reloid,
+						&relpages, &reltuples, &relallvisible,
+						&relfrozenxid, &relminmxid))
+	{
+		Datum	values[5];
+		bool	isnull[5];
+
+		memset(isnull, 0, sizeof(isnull));
+		memset(values, 0, sizeof(values));
+		values[0] = Int32GetDatum(relpages);
+		values[1] = Float4GetDatum((float4)reltuples);
+		values[2] = Int32GetDatum(relallvisible);
+		values[3] = UInt32GetDatum(relfrozenxid);
+		values[4] = UInt32GetDatum(relminmxid);
+		tuple = heap_form_tuple(tupdesc, values, isnull);
+		tuplestore_puttuple(tupstore, tuple);
+	}
+
+	tuplestore_donestoring(tupstore);
+	table_close(rel, NoLock);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_gtt_attached_pid(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	Oid		reloid = PG_GETARG_OID(0);
+	char	rel_persistence;
+	Relation	rel = NULL;
+	PGPROC		*proc = NULL;
+	Bitmapset	*map = NULL;
+	pid_t		pid = 0;
+	int			backendid = 0;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	map = copy_active_gtt_bitmap(rel->rd_node);
+	if (map)
+	{
+		backendid = bms_first_member(map);
+
+		do
+		{
+			proc = BackendIdGetProc(backendid);
+			pid = proc->pid;
+			if (pid > 0)
+			{
+				Datum	values[2];
+				bool	isnull[2];
+
+				memset(isnull, false, sizeof(isnull));
+				memset(values, 0, sizeof(values));
+				values[0] = UInt32GetDatum(reloid);
+				values[1] = Int32GetDatum(pid);
+				tuple = heap_form_tuple(tupdesc, values, isnull);
+				tuplestore_puttuple(tupstore, tuple);
+			}
+			backendid = bms_next_member(map, backendid);
+		} while (backendid > 0);
+
+		pfree(map);
+	}
+
+	tuplestore_donestoring(tupstore);
+	table_close(rel, NoLock);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	int			num_xid = MaxBackends + 1;
+	int			*pids = NULL;
+	uint32		*xids = NULL;
+	int			i = 0;
+	int			j = 0;
+	uint32		oldest = 0;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (max_active_gtt <= 0)
+		return (Datum) 0;
+
+	if (RecoveryInProgress())
+		return (Datum) 0;
+
+	pids = palloc0(sizeof(int) * num_xid);
+	xids = palloc0(sizeof(int) * num_xid);
+	oldest = list_all_session_gtt_frozenxids(num_xid, pids, xids, &i);
+	if (i > 0)
+	{
+		if (i > 0)
+		{
+			pids[i] = 0;
+			xids[i] = oldest;
+			i++;
+		}
+
+		for(j = 0; j < i; j++)
+		{
+			Datum	values[2];
+			bool	isnull[2];
+
+			memset(isnull, false, sizeof(isnull));
+			memset(values, 0, sizeof(values));
+			values[0] = Int32GetDatum(pids[j]);
+			values[1] = UInt32GetDatum(xids[j]);
+			tuple = heap_form_tuple(tupdesc, values, isnull);
+			tuplestore_puttuple(tupstore, tuple);
+		}
+	}
+	tuplestore_donestoring(tupstore);
+	pfree(pids);
+	pfree(xids);
+
+	return (Datum) 0;
+}
+
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index 2fc3e3f..d0efd18 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -186,6 +186,91 @@ CREATE OR REPLACE VIEW pg_sequences AS
     WHERE NOT pg_is_other_temp_schema(N.oid)
           AND relkind = 'S';
 
+-- For global temporary table
+CREATE VIEW pg_gtt_relstats WITH (security_barrier) AS
+ SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.*
+ FROM
+     pg_class c
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_get_gtt_relstats(c.oid) as s
+ WHERE c.relpersistence='g' AND c.relkind in('r','p') AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
+CREATE VIEW pg_gtt_attached_pids WITH (security_barrier) AS
+ SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.*
+ FROM
+     pg_class c
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_gtt_attached_pid(c.oid) as s
+ WHERE c.relpersistence='g' AND c.relkind in('r','p') AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
+CREATE VIEW pg_gtt_stats WITH (security_barrier) AS
+SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    a.attname,
+    s.stainherit AS inherited,
+    s.stanullfrac AS null_frac,
+    s.stawidth AS avg_width,
+    s.stadistinct AS n_distinct,
+        CASE
+            WHEN s.stakind1 = 1 THEN s.stavalues1
+            WHEN s.stakind2 = 1 THEN s.stavalues2
+            WHEN s.stakind3 = 1 THEN s.stavalues3
+            WHEN s.stakind4 = 1 THEN s.stavalues4
+            WHEN s.stakind5 = 1 THEN s.stavalues5
+        END AS most_common_vals,
+        CASE
+            WHEN s.stakind1 = 1 THEN s.stanumbers1
+            WHEN s.stakind2 = 1 THEN s.stanumbers2
+            WHEN s.stakind3 = 1 THEN s.stanumbers3
+            WHEN s.stakind4 = 1 THEN s.stanumbers4
+            WHEN s.stakind5 = 1 THEN s.stanumbers5
+        END AS most_common_freqs,
+        CASE
+            WHEN s.stakind1 = 2 THEN s.stavalues1
+            WHEN s.stakind2 = 2 THEN s.stavalues2
+            WHEN s.stakind3 = 2 THEN s.stavalues3
+            WHEN s.stakind4 = 2 THEN s.stavalues4
+            WHEN s.stakind5 = 2 THEN s.stavalues5
+        END AS histogram_bounds,
+        CASE
+            WHEN s.stakind1 = 3 THEN s.stanumbers1[1]
+            WHEN s.stakind2 = 3 THEN s.stanumbers2[1]
+            WHEN s.stakind3 = 3 THEN s.stanumbers3[1]
+            WHEN s.stakind4 = 3 THEN s.stanumbers4[1]
+            WHEN s.stakind5 = 3 THEN s.stanumbers5[1]
+        END AS correlation,
+        CASE
+            WHEN s.stakind1 = 4 THEN s.stavalues1
+            WHEN s.stakind2 = 4 THEN s.stavalues2
+            WHEN s.stakind3 = 4 THEN s.stavalues3
+            WHEN s.stakind4 = 4 THEN s.stavalues4
+            WHEN s.stakind5 = 4 THEN s.stavalues5
+        END AS most_common_elems,
+        CASE
+            WHEN s.stakind1 = 4 THEN s.stanumbers1
+            WHEN s.stakind2 = 4 THEN s.stanumbers2
+            WHEN s.stakind3 = 4 THEN s.stanumbers3
+            WHEN s.stakind4 = 4 THEN s.stanumbers4
+            WHEN s.stakind5 = 4 THEN s.stanumbers5
+        END AS most_common_elem_freqs,
+        CASE
+            WHEN s.stakind1 = 5 THEN s.stanumbers1
+            WHEN s.stakind2 = 5 THEN s.stanumbers2
+            WHEN s.stakind3 = 5 THEN s.stanumbers3
+            WHEN s.stakind4 = 5 THEN s.stanumbers4
+            WHEN s.stakind5 = 5 THEN s.stanumbers5
+        END AS elem_count_histogram
+   FROM 
+     pg_class c
+     JOIN pg_attribute a ON c.oid = a.attrelid
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_get_gtt_statistics(c.oid, a.attnum, ''::text) as s
+  WHERE c.relpersistence='g' AND c.relkind in('r','p') and NOT a.attisdropped AND has_column_privilege(c.oid, a.attnum, 'select'::text) AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
 CREATE VIEW pg_stats WITH (security_barrier) AS
     SELECT
         nspname AS schemaname,
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 53b11d7..104d6ce 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -65,6 +65,7 @@
 #include "utils/syscache.h"
 #include "utils/timestamp.h"
 
+#include "catalog/storage_gtt.h"
 
 /* Per-index data for ANALYZE */
 typedef struct AnlIndexData
@@ -102,7 +103,7 @@ static int	acquire_inherited_sample_rows(Relation onerel, int elevel,
 										  HeapTuple *rows, int targrows,
 										  double *totalrows, double *totaldeadrows);
 static void update_attstats(Oid relid, bool inh,
-							int natts, VacAttrStats **vacattrstats);
+							int natts, VacAttrStats **vacattrstats, char relpersistence);
 static Datum std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 static Datum ind_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 
@@ -575,14 +576,15 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 		 * pg_statistic for columns we didn't process, we leave them alone.)
 		 */
 		update_attstats(RelationGetRelid(onerel), inh,
-						attr_cnt, vacattrstats);
+						attr_cnt, vacattrstats, RelationGetRelPersistence(onerel));
 
 		for (ind = 0; ind < nindexes; ind++)
 		{
 			AnlIndexData *thisdata = &indexdata[ind];
 
 			update_attstats(RelationGetRelid(Irel[ind]), false,
-							thisdata->attr_cnt, thisdata->vacattrstats);
+							thisdata->attr_cnt, thisdata->vacattrstats,
+							RelationGetRelPersistence(Irel[ind]));
 		}
 
 		/*
@@ -659,11 +661,20 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 			IndexBulkDeleteResult *stats;
 			IndexVacuumInfo ivinfo;
 
+			memset(&ivinfo, 0, sizeof(IndexVacuumInfo));
 			ivinfo.index = Irel[ind];
 			ivinfo.analyze_only = true;
 			ivinfo.estimated_count = true;
 			ivinfo.message_level = elevel;
-			ivinfo.num_heap_tuples = onerel->rd_rel->reltuples;
+			/* get global temp relstats from localhash, not catalog */
+			if (RELATION_IS_GLOBAL_TEMP(onerel))
+			{
+				get_gtt_relstats(RelationGetRelid(onerel),
+								NULL, &ivinfo.num_heap_tuples, NULL,
+								NULL, NULL);
+			}
+			else
+				ivinfo.num_heap_tuples = onerel->rd_rel->reltuples;
 			ivinfo.strategy = vac_strategy;
 
 			stats = index_vacuum_cleanup(&ivinfo, NULL);
@@ -1425,7 +1436,7 @@ acquire_inherited_sample_rows(Relation onerel, int elevel,
  *		by taking a self-exclusive lock on the relation in analyze_rel().
  */
 static void
-update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
+update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats, char relpersistence)
 {
 	Relation	sd;
 	int			attno;
@@ -1527,31 +1538,45 @@ update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
 			}
 		}
 
-		/* Is there already a pg_statistic tuple for this attribute? */
-		oldtup = SearchSysCache3(STATRELATTINH,
-								 ObjectIdGetDatum(relid),
-								 Int16GetDatum(stats->attr->attnum),
-								 BoolGetDatum(inh));
-
-		if (HeapTupleIsValid(oldtup))
+		/* Update column statistic to localhash, not catalog */
+		if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		{
-			/* Yes, replace it */
-			stup = heap_modify_tuple(oldtup,
-									 RelationGetDescr(sd),
-									 values,
-									 nulls,
-									 replaces);
-			ReleaseSysCache(oldtup);
-			CatalogTupleUpdate(sd, &stup->t_self, stup);
+			up_gtt_att_statistic(relid,
+								stats->attr->attnum,
+								inh,
+								natts,
+								RelationGetDescr(sd),
+								values,
+								nulls);
 		}
 		else
 		{
-			/* No, insert new tuple */
-			stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
-			CatalogTupleInsert(sd, stup);
-		}
+			/* Is there already a pg_statistic tuple for this attribute? */
+			oldtup = SearchSysCache3(STATRELATTINH,
+									 ObjectIdGetDatum(relid),
+									 Int16GetDatum(stats->attr->attnum),
+									 BoolGetDatum(inh));
+
+			if (HeapTupleIsValid(oldtup))
+			{
+				/* Yes, replace it */
+				stup = heap_modify_tuple(oldtup,
+										 RelationGetDescr(sd),
+										 values,
+										 nulls,
+										 replaces);
+				ReleaseSysCache(oldtup);
+				CatalogTupleUpdate(sd, &stup->t_self, stup);
+			}
+			else
+			{
+				/* No, insert new tuple */
+				stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
+				CatalogTupleInsert(sd, stup);
+			}
 
-		heap_freetuple(stup);
+			heap_freetuple(stup);
+		}
 	}
 
 	table_close(sd, RowExclusiveLock);
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index e9d7a7f..3088e26 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -391,6 +391,12 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 					 errmsg("cannot vacuum temporary tables of other sessions")));
 	}
 
+	/* not support cluster global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(OldHeap))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support cluster global temporary tables yet")));
+
 	/*
 	 * Also check for active uses of the relation in the current transaction,
 	 * including open scans and pending AFTER trigger events.
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 52ce02f..3d3f7dc 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -2583,6 +2583,16 @@ ReindexMultipleTables(const char *objectName, ReindexObjectType objectKind,
 			!isTempNamespace(classtuple->relnamespace))
 			continue;
 
+		/* not support reindex on global temp table, so skip it */
+		if (classtuple->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			ereport(WARNING,
+				(errmsg("global temp table \"%s.%s\" skip reindexed",
+					get_namespace_name(get_rel_namespace(relid)),
+					get_rel_name(relid))));
+			continue;
+		}
+
 		/* Check user/system classification, and optionally skip */
 		if (objectKind == REINDEX_OBJECT_SYSTEM &&
 			!IsSystemClass(relid, classtuple))
diff --git a/src/backend/commands/lockcmds.c b/src/backend/commands/lockcmds.c
index 75410f0..eb1acea 100644
--- a/src/backend/commands/lockcmds.c
+++ b/src/backend/commands/lockcmds.c
@@ -107,7 +107,8 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
 	 * transaction.
 	 */
 	relpersistence = get_rel_persistence(relid);
-	if (relpersistence == RELPERSISTENCE_TEMP)
+	if (relpersistence == RELPERSISTENCE_TEMP ||
+		relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		MyXactFlags |= XACT_FLAGS_ACCESSEDTEMPNAMESPACE;
 
 	/* Check permissions. */
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index 6aab73b..44f350d 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -94,7 +94,7 @@ static HTAB *seqhashtab = NULL; /* hash table for SeqTable items */
  */
 static SeqTableData *last_used_seq = NULL;
 
-static void fill_seq_with_data(Relation rel, HeapTuple tuple);
+static void fill_seq_with_data(Relation rel, HeapTuple tuple, Buffer buf);
 static Relation lock_and_open_sequence(SeqTable seq);
 static void create_seq_hashtable(void);
 static void init_sequence(Oid relid, SeqTable *p_elm, Relation *p_rel);
@@ -108,6 +108,7 @@ static void init_params(ParseState *pstate, List *options, bool for_identity,
 						List **owned_by);
 static void do_setval(Oid relid, int64 next, bool iscalled);
 static void process_owned_by(Relation seqrel, List *owned_by, bool for_identity);
+int64 get_seqence_start_value(Oid seqid);
 
 
 /*
@@ -222,7 +223,7 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 
 	/* now initialize the sequence's data */
 	tuple = heap_form_tuple(tupDesc, value, null);
-	fill_seq_with_data(rel, tuple);
+	fill_seq_with_data(rel, tuple, InvalidBuffer);
 
 	/* process OWNED BY if given */
 	if (owned_by)
@@ -327,7 +328,7 @@ ResetSequence(Oid seq_relid)
 	/*
 	 * Insert the modified tuple into the new storage file.
 	 */
-	fill_seq_with_data(seq_rel, tuple);
+	fill_seq_with_data(seq_rel, tuple, InvalidBuffer);
 
 	/* Clear local cache so that we don't think we have cached numbers */
 	/* Note that we do not change the currval() state */
@@ -340,17 +341,21 @@ ResetSequence(Oid seq_relid)
  * Initialize a sequence's relation with the specified tuple as content
  */
 static void
-fill_seq_with_data(Relation rel, HeapTuple tuple)
+fill_seq_with_data(Relation rel, HeapTuple tuple, Buffer buf)
 {
-	Buffer		buf;
 	Page		page;
 	sequence_magic *sm;
 	OffsetNumber offnum;
+	bool lockBuffer = false;
 
 	/* Initialize first page of relation with special magic number */
 
-	buf = ReadBuffer(rel, P_NEW);
-	Assert(BufferGetBlockNumber(buf) == 0);
+	if (buf == InvalidBuffer)
+	{
+		buf = ReadBuffer(rel, P_NEW);
+		Assert(BufferGetBlockNumber(buf) == 0);
+		lockBuffer = true;
+	}
 
 	page = BufferGetPage(buf);
 
@@ -360,7 +365,8 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	/* Now insert sequence tuple */
 
-	LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
+	if (lockBuffer)
+		LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 
 	/*
 	 * Since VACUUM does not process sequences, we have to force the tuple to
@@ -410,7 +416,8 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	END_CRIT_SECTION();
 
-	UnlockReleaseBuffer(buf);
+	if (lockBuffer)
+		UnlockReleaseBuffer(buf);
 }
 
 /*
@@ -502,7 +509,7 @@ AlterSequence(ParseState *pstate, AlterSeqStmt *stmt)
 		/*
 		 * Insert the modified tuple into the new storage file.
 		 */
-		fill_seq_with_data(seqrel, newdatatuple);
+		fill_seq_with_data(seqrel, newdatatuple, InvalidBuffer);
 	}
 
 	/* process OWNED BY if given */
@@ -1178,6 +1185,25 @@ read_seq_tuple(Relation rel, Buffer *buf, HeapTuple seqdatatuple)
 	LockBuffer(*buf, BUFFER_LOCK_EXCLUSIVE);
 
 	page = BufferGetPage(*buf);
+	if (GlobalTempRelationPageIsNotInitialized(rel, page))
+	{
+		/* Initialize sequence for global temporary tables */
+		Datum		value[SEQ_COL_LASTCOL] = {0};
+		bool		null[SEQ_COL_LASTCOL] = {false};
+		HeapTuple	tuple;
+		int64		startv = get_seqence_start_value(RelationGetRelid(rel));
+
+		/*
+		 * last_value from pg_sequence.seqstart
+		 * log_cnt = 0
+		 * is_called = false
+		 */
+		value[SEQ_COL_LASTVAL-1] = Int64GetDatumFast(startv); /* start sequence with 1 */
+
+		tuple = heap_form_tuple(RelationGetDescr(rel), value, null);
+		fill_seq_with_data(rel, tuple, *buf);
+		heap_freetuple(tuple);
+	}
 	sm = (sequence_magic *) PageGetSpecialPointer(page);
 
 	if (sm->magic != SEQ_MAGIC)
@@ -1954,3 +1980,23 @@ seq_mask(char *page, BlockNumber blkno)
 
 	mask_unused_space(page);
 }
+
+int64
+get_seqence_start_value(Oid seqid)
+{
+	HeapTuple	seqtuple;
+	Form_pg_sequence	seqform;
+	int64		start;
+
+	seqtuple = SearchSysCache1(SEQRELID, ObjectIdGetDatum(seqid));
+	if (!HeapTupleIsValid(seqtuple))
+		elog(ERROR, "cache lookup failed for sequence %u",
+			 seqid);
+
+	seqform = (Form_pg_sequence) GETSTRUCT(seqtuple);
+	start = seqform->seqstart;
+	ReleaseSysCache(seqtuple);
+
+	return start;
+}
+
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 1c4394a..84bc81e 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -47,6 +47,7 @@
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
 #include "catalog/toasting.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/defrem.h"
@@ -527,6 +528,7 @@ static void refuseDupeIndexAttach(Relation parentIdx, Relation partIdx,
 								  Relation partitionTbl);
 static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
+static bool has_oncommit_option(List *options);
 
 
 /* ----------------------------------------------------------------
@@ -572,6 +574,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	LOCKMODE	parentLockmode;
 	const char *accessMethod = NULL;
 	Oid			accessMethodId = InvalidOid;
+	bool		has_oncommit_clause = false;
 
 	/*
 	 * Truncate relname to appropriate length (probably a waste of time, as
@@ -582,8 +585,10 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Check consistency of arguments
 	 */
+	/* global temp table same as local temp table */
 	if (stmt->oncommit != ONCOMMIT_NOOP
-		&& stmt->relation->relpersistence != RELPERSISTENCE_TEMP)
+		&& !(stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+			 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 				 errmsg("ON COMMIT can only be used on temporary tables")));
@@ -613,7 +618,9 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	 * code.  This is needed because calling code might not expect untrusted
 	 * tables to appear in pg_temp at the front of its search path.
 	 */
-	if (stmt->relation->relpersistence == RELPERSISTENCE_TEMP
+	/* global temp table same as local temp table */
+	if ((stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+		 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		&& InSecurityRestrictedOperation())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -714,6 +721,57 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Parse and validate reloptions, if any.
 	 */
+	/* global temp table */
+	has_oncommit_clause = has_oncommit_option(stmt->options);
+	if (stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP &&
+		(relkind == RELKIND_RELATION || relkind == RELKIND_PARTITIONED_TABLE))
+	{
+		/* inherit table or parition table inherit on commit property from parent table*/
+		if (inheritOids && stmt->oncommit == ONCOMMIT_NOOP && !has_oncommit_clause)
+		{
+			Oid			parent = linitial_oid(inheritOids);
+			Relation	relation = table_open(parent, NoLock);
+
+			if (!RELATION_IS_GLOBAL_TEMP(relation))
+				elog(ERROR, "The parent table must be global temporary table");
+
+			if (RELATION_GTT_ON_COMMIT_DELETE(relation))
+				stmt->oncommit = ONCOMMIT_DELETE_ROWS;
+			else
+				stmt->oncommit = ONCOMMIT_PRESERVE_ROWS;
+			table_close(relation, NoLock);
+		}
+
+		if (has_oncommit_clause)
+		{
+			if (stmt->oncommit != ONCOMMIT_NOOP)
+				elog(ERROR, "can not defeine global temp table with on commit and with clause at same time");
+		}
+		else
+		{
+			DefElem *opt = makeNode(DefElem);
+
+			opt->type = T_DefElem;
+			opt->defnamespace = NULL;
+			opt->defname = "on_commit_delete_rows";
+			opt->defaction = DEFELEM_UNSPEC;
+
+			/* use reloptions to remember on commit clause */
+			if (stmt->oncommit == ONCOMMIT_DELETE_ROWS)
+				opt->arg  = (Node *)makeString("true");
+			else if (stmt->oncommit == ONCOMMIT_PRESERVE_ROWS)
+				opt->arg  = (Node *)makeString("false");
+			else if (stmt->oncommit == ONCOMMIT_NOOP)
+				opt->arg  = (Node *)makeString("true");
+			else
+				elog(ERROR, "global temp table not support on commit drop clause");
+
+			stmt->options = lappend(stmt->options, opt);
+		}
+	}
+	else if (has_oncommit_clause)
+		elog(ERROR, "regular table cannot specifie on_commit_delete_rows");
+
 	reloptions = transformRelOptions((Datum) 0, stmt->options, NULL, validnsps,
 									 true, false);
 
@@ -1775,7 +1833,8 @@ ExecuteTruncateGuts(List *explicit_rels, List *relids, List *relids_logged,
 		 * table or the current physical file to be thrown away anyway.
 		 */
 		if (rel->rd_createSubid == mySubid ||
-			rel->rd_newRelfilenodeSubid == mySubid)
+			rel->rd_newRelfilenodeSubid == mySubid ||
+			RELATION_IS_GLOBAL_TEMP(rel))
 		{
 			/* Immediate, non-rollbackable truncation is OK */
 			heap_truncate_one_rel(rel);
@@ -3334,6 +3393,13 @@ RenameRelationInternal(Oid myrelid, const char *newrelname, bool is_internal, bo
 	 * specially.
 	 */
 	targetrelation = relation_open(myrelid, is_index ? ShareUpdateExclusiveLock : AccessExclusiveLock);
+
+	if (RELATION_IS_GLOBAL_TEMP(targetrelation))
+	{
+		if (is_other_backend_use_gtt(targetrelation->rd_node))
+			elog(ERROR, "can not rename relation when other backend attached this global temp table");
+	}
+
 	namespaceId = RelationGetNamespace(targetrelation);
 
 	/*
@@ -3503,6 +3569,13 @@ AlterTable(Oid relid, LOCKMODE lockmode, AlterTableStmt *stmt)
 	/* Caller is required to provide an adequate lock. */
 	rel = relation_open(relid, NoLock);
 
+	/* We allow to alter global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (is_other_backend_use_gtt(rel->rd_node))
+			elog(ERROR, "can not alter relation when other backend attached this global temp table");
+	}
+
 	CheckTableNotInUse(rel, "ALTER TABLE");
 
 	ATController(stmt, rel, stmt->cmds, stmt->relation->inh, lockmode);
@@ -7656,6 +7729,13 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 				 errmsg("referenced relation \"%s\" is not a table",
 						RelationGetRelationName(pkrel))));
 
+	/* global temp table not support foreign key constraint yet */
+	if (RELATION_IS_GLOBAL_TEMP(pkrel))
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("referenced relation \"%s\" is not a global temp table",
+						RelationGetRelationName(pkrel))));
+
 	if (!allowSystemTableMods && IsSystemRelation(pkrel))
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -7695,6 +7775,12 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 						 errmsg("constraints on temporary tables must involve temporary tables of this session")));
 			break;
+		/* global temp table not support foreign key constraint yet */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					 errmsg("not support foreign key constraints on global temp table yet")));
+			break;
 	}
 
 	/*
@@ -12706,7 +12792,7 @@ index_copy_data(Relation rel, RelFileNode newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
@@ -14113,7 +14199,9 @@ ATPrepChangePersistence(Relation rel, bool toLogged)
 	 */
 	switch (rel->rd_rel->relpersistence)
 	{
+		/* global temp table same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("cannot change logged status of table \"%s\" because it is temporary",
@@ -16753,3 +16841,20 @@ ATDetachCheckNoForeignKeyRefs(Relation partition)
 		table_close(rel, NoLock);
 	}
 }
+
+static bool
+has_oncommit_option(List *options)
+{
+	ListCell   *listptr;
+
+	foreach(listptr, options)
+	{
+		DefElem    *def = (DefElem *) lfirst(listptr);
+
+		if (pg_strcasecmp(def->defname, "on_commit_delete_rows") == 0)
+			return true;
+	}
+
+	return false;
+}
+
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index bb34e25..6e1896f 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -35,6 +35,7 @@
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
 #include "catalog/pg_namespace.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
 #include "commands/vacuum.h"
@@ -1070,12 +1071,25 @@ vac_estimate_reltuples(Relation relation,
 					   BlockNumber scanned_pages,
 					   double scanned_tuples)
 {
-	BlockNumber old_rel_pages = relation->rd_rel->relpages;
-	double		old_rel_tuples = relation->rd_rel->reltuples;
+	BlockNumber old_rel_pages = 0;
+	double		old_rel_tuples = 0;
 	double		old_density;
 	double		unscanned_pages;
 	double		total_tuples;
 
+	/* get relstat from gtt local hash */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+	{
+		get_gtt_relstats(RelationGetRelid(relation),
+						&old_rel_pages, &old_rel_tuples, NULL,
+						NULL, NULL);
+	}
+	else
+	{
+		old_rel_pages = relation->rd_rel->relpages;
+		old_rel_tuples = relation->rd_rel->reltuples;
+	}
+
 	/* If we did scan the whole table, just use the count as-is */
 	if (scanned_pages >= total_pages)
 		return scanned_tuples;
@@ -1175,24 +1189,8 @@ vac_update_relstats(Relation relation,
 	/* Apply statistical updates, if any, to copied tuple */
 
 	dirty = false;
-	if (pgcform->relpages != (int32) num_pages)
-	{
-		pgcform->relpages = (int32) num_pages;
-		dirty = true;
-	}
-	if (pgcform->reltuples != (float4) num_tuples)
-	{
-		pgcform->reltuples = (float4) num_tuples;
-		dirty = true;
-	}
-	if (pgcform->relallvisible != (int32) num_all_visible_pages)
-	{
-		pgcform->relallvisible = (int32) num_all_visible_pages;
-		dirty = true;
-	}
 
 	/* Apply DDL updates, but not inside an outer transaction (see above) */
-
 	if (!in_outer_xact)
 	{
 		/*
@@ -1217,37 +1215,64 @@ vac_update_relstats(Relation relation,
 		}
 	}
 
-	/*
-	 * Update relfrozenxid, unless caller passed InvalidTransactionId
-	 * indicating it has no new data.
-	 *
-	 * Ordinarily, we don't let relfrozenxid go backwards: if things are
-	 * working correctly, the only way the new frozenxid could be older would
-	 * be if a previous VACUUM was done with a tighter freeze_min_age, in
-	 * which case we don't want to forget the work it already did.  However,
-	 * if the stored relfrozenxid is "in the future", then it must be corrupt
-	 * and it seems best to overwrite it with the cutoff we used this time.
-	 * This should match vac_update_datfrozenxid() concerning what we consider
-	 * to be "in the future".
-	 */
-	if (TransactionIdIsNormal(frozenxid) &&
-		pgcform->relfrozenxid != frozenxid &&
-		(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
-		 TransactionIdPrecedes(ReadNewTransactionId(),
-							   pgcform->relfrozenxid)))
+	/* global temp table remember relstats to localhash not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
 	{
-		pgcform->relfrozenxid = frozenxid;
-		dirty = true;
+		up_gtt_relstats(relation,
+						num_pages, num_tuples,
+						num_all_visible_pages,
+						frozenxid, minmulti);
 	}
-
-	/* Similarly for relminmxid */
-	if (MultiXactIdIsValid(minmulti) &&
-		pgcform->relminmxid != minmulti &&
-		(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
-		 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
+	else
 	{
-		pgcform->relminmxid = minmulti;
-		dirty = true;
+		if (pgcform->relpages != (int32) num_pages)
+		{
+			pgcform->relpages = (int32) num_pages;
+			dirty = true;
+		}
+		if (pgcform->reltuples != (float4) num_tuples)
+		{
+			pgcform->reltuples = (float4) num_tuples;
+			dirty = true;
+		}
+		if (pgcform->relallvisible != (int32) num_all_visible_pages)
+		{
+			pgcform->relallvisible = (int32) num_all_visible_pages;
+			dirty = true;
+		}
+
+		/*
+		 * Update relfrozenxid, unless caller passed InvalidTransactionId
+		 * indicating it has no new data.
+		 *
+		 * Ordinarily, we don't let relfrozenxid go backwards: if things are
+		 * working correctly, the only way the new frozenxid could be older would
+		 * be if a previous VACUUM was done with a tighter freeze_min_age, in
+		 * which case we don't want to forget the work it already did.  However,
+		 * if the stored relfrozenxid is "in the future", then it must be corrupt
+		 * and it seems best to overwrite it with the cutoff we used this time.
+		 * This should match vac_update_datfrozenxid() concerning what we consider
+		 * to be "in the future".
+		 */
+		if (TransactionIdIsNormal(frozenxid) &&
+			pgcform->relfrozenxid != frozenxid &&
+			(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(),
+								   pgcform->relfrozenxid)))
+		{
+			pgcform->relfrozenxid = frozenxid;
+			dirty = true;
+		}
+
+		/* Similarly for relminmxid */
+		if (MultiXactIdIsValid(minmulti) &&
+			pgcform->relminmxid != minmulti &&
+			(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
+		{
+			pgcform->relminmxid = minmulti;
+			dirty = true;
+		}
 	}
 
 	/* If anything changed, write out the tuple. */
@@ -1339,6 +1364,10 @@ vac_update_datfrozenxid(void)
 			continue;
 		}
 
+		/* global temp table relstats not in pg_class */
+		if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			continue;
+
 		/*
 		 * Some table AMs might not need per-relation xid / multixid horizons.
 		 * It therefore seems reasonable to allow relfrozenxid and relminmxid
@@ -1396,6 +1425,25 @@ vac_update_datfrozenxid(void)
 	Assert(TransactionIdIsNormal(newFrozenXid));
 	Assert(MultiXactIdIsValid(newMinMulti));
 
+	/*
+	 * Global temp table get frozenxid from MyProc
+	 * to avoid the vacuum truncate clog that gtt need.
+	 */
+	if (max_active_gtt > 0)
+	{
+		TransactionId oldest_gtt_frozenxid =
+			list_all_session_gtt_frozenxids(0, NULL, NULL, NULL);
+
+		if (TransactionIdIsNormal(oldest_gtt_frozenxid) &&
+			TransactionIdPrecedes(oldest_gtt_frozenxid, newFrozenXid))
+		{
+			ereport(WARNING,
+				(errmsg("global temp table oldest FrozenXid is far in the past"),
+				 errhint("please truncate them or kill those sessions that use them.")));
+			newFrozenXid = oldest_gtt_frozenxid;
+		}
+	}
+
 	/* Now fetch the pg_database tuple we need to update. */
 	relation = table_open(DatabaseRelationId, RowExclusiveLock);
 
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 8286d9c..c3992a4 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -591,6 +591,8 @@ static void
 set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 						  RangeTblEntry *rte)
 {
+	char relpersistence;
+
 	/*
 	 * The flag has previously been initialized to false, so we can just
 	 * return if it becomes clear that we can't safely set it.
@@ -618,7 +620,11 @@ set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 			 * the rest of the necessary infrastructure right now anyway.  So
 			 * for now, bail out if we see a temporary table.
 			 */
-			if (get_rel_persistence(rte->relid) == RELPERSISTENCE_TEMP)
+			/* global temp table is same as local temp table */
+			relpersistence = get_rel_persistence(rte->relid);
+
+			if (relpersistence == RELPERSISTENCE_TEMP ||
+				relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 				return;
 
 			/*
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index d6f2153..310a9e2 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -6312,7 +6312,9 @@ plan_create_index_workers(Oid tableOid, Oid indexOid)
 	 * Furthermore, any index predicate or index expressions must be parallel
 	 * safe.
 	 */
+	/* global temp table is same as local temp table */
 	if (heap->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		heap->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexExpressions(index)) ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexPredicate(index)))
 	{
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index d82fc5a..189286b 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -31,6 +31,7 @@
 #include "catalog/pg_am.h"
 #include "catalog/pg_proc.h"
 #include "catalog/pg_statistic_ext.h"
+#include "catalog/storage_gtt.h"
 #include "foreign/fdwapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
@@ -53,6 +54,7 @@
 #include "utils/snapmgr.h"
 #include "utils/syscache.h"
 
+
 /* GUC parameter */
 int			constraint_exclusion = CONSTRAINT_EXCLUSION_PARTITION;
 
@@ -946,10 +948,10 @@ void
 estimate_rel_size(Relation rel, int32 *attr_widths,
 				  BlockNumber *pages, double *tuples, double *allvisfrac)
 {
-	BlockNumber curpages;
-	BlockNumber relpages;
-	double		reltuples;
-	BlockNumber relallvisible;
+	BlockNumber curpages = 0;
+	BlockNumber relpages = 0;
+	double		reltuples = 0;
+	BlockNumber relallvisible = 0;
 	double		density;
 
 	switch (rel->rd_rel->relkind)
@@ -963,6 +965,21 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 
 		case RELKIND_INDEX:
 
+			/* global temp table get relstats from localhash */
+			if (RELATION_IS_GLOBAL_TEMP(rel))
+			{
+				get_gtt_relstats(RelationGetRelid(rel),
+								&relpages, &reltuples, &relallvisible,
+								NULL, NULL);
+			}
+			else
+			{
+				/* coerce values in pg_class to more desirable types */
+				relpages = (BlockNumber) rel->rd_rel->relpages;
+				reltuples = (double) rel->rd_rel->reltuples;
+				relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
+			}
+
 			/*
 			 * XXX: It'd probably be good to move this into a callback,
 			 * individual index types e.g. know if they have a metapage.
@@ -971,11 +988,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 			/* it has storage, ok to call the smgr */
 			curpages = RelationGetNumberOfBlocks(rel);
 
-			/* coerce values in pg_class to more desirable types */
-			relpages = (BlockNumber) rel->rd_rel->relpages;
-			reltuples = (double) rel->rd_rel->reltuples;
-			relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
-
 			/* report estimated # pages */
 			*pages = curpages;
 			/* quick exit if rel is clearly empty */
@@ -985,10 +997,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 				*allvisfrac = 0;
 				break;
 			}
-			/* coerce values in pg_class to more desirable types */
-			relpages = (BlockNumber) rel->rd_rel->relpages;
-			reltuples = (double) rel->rd_rel->reltuples;
-			relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
 
 			/*
 			 * Discount the metapage while estimating the number of tuples.
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 447a61e..a27f57f 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -2576,6 +2576,11 @@ transformCreateTableAsStmt(ParseState *pstate, CreateTableAsStmt *stmt)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("materialized views must not use temporary tables or views")));
 
+		if (is_query_using_gtt(query))
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("materialized views must not use global temporary tables or views")));
+
 		/*
 		 * A materialized view would either need to save parameters for use in
 		 * maintaining/loading the data or prohibit them entirely.  The latter
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index ad5be90..dff21e0 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3270,17 +3270,11 @@ OptTemp:	TEMPORARY					{ $$ = RELPERSISTENCE_TEMP; }
 			| LOCAL TEMP				{ $$ = RELPERSISTENCE_TEMP; }
 			| GLOBAL TEMPORARY
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED					{ $$ = RELPERSISTENCE_UNLOGGED; }
 			| /*EMPTY*/					{ $$ = RELPERSISTENCE_PERMANENT; }
@@ -11568,19 +11562,13 @@ OptTempTableName:
 				}
 			| GLOBAL TEMPORARY opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED opt_table qualified_name
 				{
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index ceed0ce..cd1ca50 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -81,6 +81,7 @@ static void expandTupleDesc(TupleDesc tupdesc, Alias *eref,
 							List **colnames, List **colvars);
 static int	specialAttNum(const char *attname);
 static bool isQueryUsingTempRelation_walker(Node *node, void *context);
+static bool is_query_using_gtt_walker(Node *node, void *context);
 
 
 /*
@@ -3564,3 +3565,49 @@ isQueryUsingTempRelation_walker(Node *node, void *context)
 								  isQueryUsingTempRelation_walker,
 								  context);
 }
+
+/* check if the query uses global temp table */
+static bool
+is_query_using_gtt_walker(Node *node, void *context)
+{
+	if (node == NULL)
+		return false;
+
+	if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+		ListCell   *rtable;
+
+		foreach(rtable, query->rtable)
+		{
+			RangeTblEntry *rte = lfirst(rtable);
+
+			if (rte->rtekind == RTE_RELATION)
+			{
+				Relation	rel = relation_open(rte->relid, AccessShareLock);
+				char		relpersistence = rel->rd_rel->relpersistence;
+
+				relation_close(rel, AccessShareLock);
+				if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+					return true;
+			}
+		}
+
+		return query_tree_walker(query,
+								 is_query_using_gtt_walker,
+								 context,
+								 QTW_IGNORE_JOINALIASES);
+	}
+
+	return expression_tree_walker(node,
+								  is_query_using_gtt_walker,
+								  context);
+}
+
+/* check if the query uses global temp table */
+bool
+is_query_using_gtt(Query *query)
+{
+	return is_query_using_gtt_walker((Node *) query, NULL);
+}
+
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 42095ab..d5fcbed 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -436,6 +436,9 @@ generateSerialExtraStmts(CreateStmtContext *cxt, ColumnDef *column,
 	seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
 	seqstmt->options = seqoptions;
 
+	if (cxt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		seqstmt->sequence->relpersistence = cxt->relation->relpersistence;
+
 	/*
 	 * If a sequence data type was specified, add it to the options.  Prepend
 	 * to the list rather than append; in case a user supplied their own AS
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index f0e40e3..bb60926 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -2086,6 +2086,11 @@ do_autovacuum(void)
 			}
 			continue;
 		}
+		else if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			/* autovacuum skip vacuum global temp table */
+			continue;
+		}
 
 		/* Fetch reloptions and the pgstat entry for this table */
 		relopts = extract_autovac_opts(tuple, pg_class_desc);
@@ -2152,7 +2157,9 @@ do_autovacuum(void)
 		/*
 		 * We cannot safely process other backends' temp tables, so skip 'em.
 		 */
-		if (classForm->relpersistence == RELPERSISTENCE_TEMP)
+		/* autovacuum skip vacuum global temp table */
+		if (classForm->relpersistence == RELPERSISTENCE_TEMP || 
+			classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 			continue;
 
 		relid = classForm->oid;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index aba3960..68adcd5 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -53,6 +53,8 @@
 #include "utils/resowner_private.h"
 #include "utils/timestamp.h"
 
+#include "utils/guc.h"
+#include "catalog/storage_gtt.h"
 
 /* Note: these two macros only work on shared buffers, not local ones! */
 #define BufHdrGetBlock(bufHdr)	((Block) (BufferBlocks + ((Size) (bufHdr)->buf_id) * BLCKSZ))
@@ -432,7 +434,7 @@ ForgetPrivateRefCountEntry(PrivateRefCountEntry *ref)
 static Buffer ReadBuffer_common(SMgrRelation reln, char relpersistence,
 								ForkNumber forkNum, BlockNumber blockNum,
 								ReadBufferMode mode, BufferAccessStrategy strategy,
-								bool *hit);
+								bool *hit, Relation rel);
 static bool PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy);
 static void PinBuffer_Locked(BufferDesc *buf);
 static void UnpinBuffer(BufferDesc *buf, bool fixOwner);
@@ -664,7 +666,8 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
 	 */
 	pgstat_count_buffer_read(reln);
 	buf = ReadBuffer_common(reln->rd_smgr, reln->rd_rel->relpersistence,
-							forkNum, blockNum, mode, strategy, &hit);
+							forkNum, blockNum, mode, strategy, &hit,
+							reln);
 	if (hit)
 		pgstat_count_buffer_hit(reln);
 	return buf;
@@ -692,7 +695,7 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 	Assert(InRecovery);
 
 	return ReadBuffer_common(smgr, RELPERSISTENCE_PERMANENT, forkNum, blockNum,
-							 mode, strategy, &hit);
+							 mode, strategy, &hit, NULL);
 }
 
 
@@ -704,7 +707,8 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 static Buffer
 ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 				  BlockNumber blockNum, ReadBufferMode mode,
-				  BufferAccessStrategy strategy, bool *hit)
+				  BufferAccessStrategy strategy, bool *hit,
+				  Relation rel)
 {
 	BufferDesc *bufHdr;
 	Block		bufBlock;
@@ -719,6 +723,15 @@ ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 
 	isExtend = (blockNum == P_NEW);
 
+	/* create storage when first read data page for gtt */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP &&
+		(isExtend || blockNum == 0) &&
+		forkNum == MAIN_FORKNUM &&
+		!gtt_storage_attached(smgr->smgr_rnode.node.relNode))
+	{
+		RelationCreateStorage(smgr->smgr_rnode.node, relpersistence, rel);
+	}
+
 	TRACE_POSTGRESQL_BUFFER_READ_START(forkNum, blockNum,
 									   smgr->smgr_rnode.node.spcNode,
 									   smgr->smgr_rnode.node.dbNode,
@@ -2809,6 +2822,16 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln)
 BlockNumber
 RelationGetNumberOfBlocksInFork(Relation relation, ForkNumber forkNum)
 {
+	/*
+	 * When this backend not init gtt storage
+	 * return 0
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(relation) &&
+		!gtt_storage_attached(relation->rd_node.relNode))
+	{
+		return 0;
+	}
+
 	switch (relation->rd_rel->relkind)
 	{
 		case RELKIND_SEQUENCE:
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 427b0d5..7adb969 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -21,6 +21,7 @@
 #include "access/nbtree.h"
 #include "access/subtrans.h"
 #include "access/twophase.h"
+#include "catalog/storage_gtt.h"
 #include "commands/async.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -147,6 +148,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, BTreeShmemSize());
 		size = add_size(size, SyncScanShmemSize());
 		size = add_size(size, AsyncShmemSize());
+		size = add_size(size, active_gtt_shared_hash_size());
 #ifdef EXEC_BACKEND
 		size = add_size(size, ShmemBackendArraySize());
 #endif
@@ -217,6 +219,8 @@ CreateSharedMemoryAndSemaphores(void)
 	SUBTRANSShmemInit();
 	MultiXactShmemInit();
 	InitBufferPool();
+	/* global temporary table */
+	active_gtt_shared_hash_init();
 
 	/*
 	 * Set up lock manager
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index c3adb2e..eb95e5f 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -62,6 +62,7 @@
 #include "utils/builtins.h"
 #include "utils/rel.h"
 #include "utils/snapmgr.h"
+#include "utils/guc.h"
 
 #define UINT32_ACCESS_ONCE(var)		 ((uint32)(*((volatile uint32 *)&(var))))
 
@@ -4087,3 +4088,77 @@ KnownAssignedXidsReset(void)
 
 	LWLockRelease(ProcArrayLock);
 }
+
+/*
+ * search all active backend to get oldest frozenxid
+ * for global temp table.
+ */
+int
+list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n)
+{
+	ProcArrayStruct *arrayP = procArray;
+	TransactionId result = InvalidTransactionId;
+	int			index;
+	int			flags = 0;
+	int			i = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	if (max_size > 0)
+	{
+		Assert(pids);
+		Assert(xids);
+		Assert(n);
+		*n = 0;
+	}
+
+	if (max_active_gtt <= 0)
+		return InvalidTransactionId;
+
+	if (RecoveryInProgress())
+		return InvalidTransactionId;
+
+	flags |= PROC_IS_AUTOVACUUM;
+	flags |= PROC_IN_LOGICAL_DECODING;
+
+	LWLockAcquire(ProcArrayLock, LW_SHARED);
+	if (max_size > 0 && max_size < arrayP->numProcs)
+	{
+		LWLockRelease(ProcArrayLock);
+		elog(ERROR, "list_all_gtt_frozenxids require more array");
+	}
+
+	for (index = 0; index < arrayP->numProcs; index++)
+	{
+		int			pgprocno = arrayP->pgprocnos[index];
+		volatile PGPROC *proc = &allProcs[pgprocno];
+		volatile PGXACT *pgxact = &allPgXact[pgprocno];
+
+		if (pgxact->vacuumFlags & flags)
+			continue;
+
+		if (proc->databaseId == MyDatabaseId &&
+			TransactionIdIsNormal(proc->session_gtt_frozenxid))
+		{
+			if (result == InvalidTransactionId)
+				result = proc->session_gtt_frozenxid;
+			else if (TransactionIdPrecedes(proc->session_gtt_frozenxid, result))
+				result = proc->session_gtt_frozenxid;
+
+			if (max_size > 0)
+			{
+				pids[i] = proc->pid;
+				xids[i] = proc->session_gtt_frozenxid;
+				i++;
+			}
+		}
+	}
+	LWLockRelease(ProcArrayLock);
+
+	if (max_size > 0)
+		*n = i;
+
+	return result;
+}
+
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 99e5221..d3a0a18 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -395,6 +395,7 @@ InitProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
@@ -577,6 +578,7 @@ InitAuxiliaryProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 199c722..92aefd0 100644
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -654,6 +654,12 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 		 */
 		if (zero_damaged_pages || InRecovery)
 			MemSet(buffer, 0, BLCKSZ);
+		else if(SmgrIsTemp(reln) && blocknum == 0 && forknum == MAIN_FORKNUM)
+		{
+			/* global temp table init btree meta page */
+			MemSet(buffer, 0, BLCKSZ);
+			mdwrite(reln, forknum, blocknum, buffer, true);
+		}
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_DATA_CORRUPTED),
diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c
index 8406644..92f028e 100644
--- a/src/backend/utils/adt/dbsize.c
+++ b/src/backend/utils/adt/dbsize.c
@@ -19,6 +19,8 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_authid.h"
 #include "catalog/pg_tablespace.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/index.h"
 #include "commands/dbcommands.h"
 #include "commands/tablespace.h"
 #include "miscadmin.h"
@@ -262,7 +264,6 @@ pg_tablespace_size_name(PG_FUNCTION_ARGS)
 	PG_RETURN_INT64(size);
 }
 
-
 /*
  * calculate size of (one fork of) a relation
  *
@@ -307,6 +308,41 @@ calculate_relation_size(RelFileNode *rfn, BackendId backend, ForkNumber forknum)
 	return totalsize;
 }
 
+static int64
+calculate_relation_size_all_file(Relation rel, const Bitmapset *gtt_map)
+{
+	int64		size = 0;
+	ForkNumber	forkNum;
+	BackendId	backendid;
+
+	/* For global temp table */
+	if (gtt_map)
+	{
+		Bitmapset *map_copy = bms_copy(gtt_map);
+
+		backendid = bms_first_member(map_copy);
+
+		do
+		{
+			for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
+				size += calculate_relation_size(&(rel->rd_node),
+										backendid,
+										forkNum);
+			backendid = bms_next_member(map_copy, backendid);
+		} while (backendid > 0);
+
+		pfree(map_copy);
+	}
+	else
+	{
+		for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
+			size += calculate_relation_size(&(rel->rd_node),
+											rel->rd_backend, forkNum);
+	}
+
+	return size;
+}
+
 Datum
 pg_relation_size(PG_FUNCTION_ARGS)
 {
@@ -340,20 +376,17 @@ pg_relation_size(PG_FUNCTION_ARGS)
  * Must not be applied to non-TOAST relations.
  */
 static int64
-calculate_toast_table_size(Oid toastrelid)
+calculate_toast_table_size(Oid toastrelid, Bitmapset *gtt_map)
 {
 	int64		size = 0;
 	Relation	toastRel;
-	ForkNumber	forkNum;
 	ListCell   *lc;
 	List	   *indexlist;
 
 	toastRel = relation_open(toastrelid, AccessShareLock);
 
 	/* toast heap size, including FSM and VM size */
-	for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-		size += calculate_relation_size(&(toastRel->rd_node),
-										toastRel->rd_backend, forkNum);
+	size += calculate_relation_size_all_file(toastRel, gtt_map);
 
 	/* toast index size, including FSM and VM size */
 	indexlist = RelationGetIndexList(toastRel);
@@ -365,9 +398,8 @@ calculate_toast_table_size(Oid toastrelid)
 
 		toastIdxRel = relation_open(lfirst_oid(lc),
 									AccessShareLock);
-		for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-			size += calculate_relation_size(&(toastIdxRel->rd_node),
-											toastIdxRel->rd_backend, forkNum);
+
+		size += calculate_relation_size_all_file(toastIdxRel, gtt_map);
 
 		relation_close(toastIdxRel, AccessShareLock);
 	}
@@ -386,23 +418,20 @@ calculate_toast_table_size(Oid toastrelid)
  * those won't have attached toast tables, but they can have multiple forks.
  */
 static int64
-calculate_table_size(Relation rel)
+calculate_table_size(Relation rel, Bitmapset *gtt_map)
 {
 	int64		size = 0;
-	ForkNumber	forkNum;
 
 	/*
 	 * heap size, including FSM and VM
 	 */
-	for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-		size += calculate_relation_size(&(rel->rd_node), rel->rd_backend,
-										forkNum);
+	size += calculate_relation_size_all_file(rel, gtt_map);
 
 	/*
 	 * Size of toast relation
 	 */
 	if (OidIsValid(rel->rd_rel->reltoastrelid))
-		size += calculate_toast_table_size(rel->rd_rel->reltoastrelid);
+		size += calculate_toast_table_size(rel->rd_rel->reltoastrelid, gtt_map);
 
 	return size;
 }
@@ -413,7 +442,7 @@ calculate_table_size(Relation rel)
  * Can be applied safely to an index, but you'll just get zero.
  */
 static int64
-calculate_indexes_size(Relation rel)
+calculate_indexes_size(Relation rel, Bitmapset *gtt_map)
 {
 	int64		size = 0;
 
@@ -429,14 +458,10 @@ calculate_indexes_size(Relation rel)
 		{
 			Oid			idxOid = lfirst_oid(cell);
 			Relation	idxRel;
-			ForkNumber	forkNum;
 
 			idxRel = relation_open(idxOid, AccessShareLock);
 
-			for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-				size += calculate_relation_size(&(idxRel->rd_node),
-												idxRel->rd_backend,
-												forkNum);
+			size += calculate_relation_size_all_file(idxRel, gtt_map);
 
 			relation_close(idxRel, AccessShareLock);
 		}
@@ -453,16 +478,40 @@ pg_table_size(PG_FUNCTION_ARGS)
 	Oid			relOid = PG_GETARG_OID(0);
 	Relation	rel;
 	int64		size;
+	Bitmapset	*gtt_map = NULL;
 
 	rel = try_relation_open(relOid, AccessShareLock);
 
 	if (rel == NULL)
 		PG_RETURN_NULL();
 
-	size = calculate_table_size(rel);
+	/* For GTT, calculate the size of the data file in the session where the GTT has been initialized */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (rel->rd_rel->relkind == RELKIND_INDEX)
+		{
+			Relation	relation;
+			Oid			relid;
+
+			relid = IndexGetRelation(RelationGetRelid(rel), false);
+			relation = try_relation_open(relid, AccessShareLock);
+			if (relation)
+			{
+				gtt_map = copy_active_gtt_bitmap(relation->rd_node);
+				relation_close(relation, AccessShareLock);
+			}
+		}
+		else
+			gtt_map = copy_active_gtt_bitmap(rel->rd_node);
+	}
+
+	size = calculate_table_size(rel, gtt_map);
 
 	relation_close(rel, AccessShareLock);
 
+	if(gtt_map)
+		pfree(gtt_map);
+
 	PG_RETURN_INT64(size);
 }
 
@@ -472,16 +521,24 @@ pg_indexes_size(PG_FUNCTION_ARGS)
 	Oid			relOid = PG_GETARG_OID(0);
 	Relation	rel;
 	int64		size;
+	Bitmapset	*gtt_map = NULL;
 
 	rel = try_relation_open(relOid, AccessShareLock);
 
 	if (rel == NULL)
 		PG_RETURN_NULL();
 
-	size = calculate_indexes_size(rel);
+	/* For GTT, calculate the size of the data file in the session where the GTT has been initialized */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		gtt_map = copy_active_gtt_bitmap(rel->rd_node);
+
+	size = calculate_indexes_size(rel, gtt_map);
 
 	relation_close(rel, AccessShareLock);
 
+	if (gtt_map)
+		pfree(gtt_map);
+
 	PG_RETURN_INT64(size);
 }
 
@@ -493,17 +550,25 @@ static int64
 calculate_total_relation_size(Relation rel)
 {
 	int64		size;
+	Bitmapset	*gtt_map = NULL;
+
+	/* For GTT, calculate the size of the data file in the session where the GTT has been initialized */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		gtt_map = copy_active_gtt_bitmap(rel->rd_node);
 
 	/*
 	 * Aggregate the table size, this includes size of the heap, toast and
 	 * toast index with free space and visibility map
 	 */
-	size = calculate_table_size(rel);
+	size = calculate_table_size(rel, gtt_map);
 
 	/*
 	 * Add size of all attached indexes as well
 	 */
-	size += calculate_indexes_size(rel);
+	size += calculate_indexes_size(rel, gtt_map);
+
+	if (gtt_map)
+		pfree(gtt_map);
 
 	return size;
 }
@@ -1008,6 +1073,10 @@ pg_relation_filepath(PG_FUNCTION_ARGS)
 				Assert(backend != InvalidBackendId);
 			}
 			break;
+		/* For global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			backend = BackendIdForTempRelations();
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relform->relpersistence);
 			backend = InvalidBackendId; /* placate compiler */
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 18d77ac..eaeebfe 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -142,6 +142,7 @@
 #include "utils/timestamp.h"
 #include "utils/typcache.h"
 
+#include "catalog/storage_gtt.h"
 
 /* Hooks for plugins to get control when we ask for stats */
 get_relation_stats_hook_type get_relation_stats_hook = NULL;
@@ -4578,12 +4579,25 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
 						}
 						else if (index->indpred == NIL)
 						{
-							vardata->statsTuple =
-								SearchSysCache3(STATRELATTINH,
-												ObjectIdGetDatum(index->indexoid),
-												Int16GetDatum(pos + 1),
-												BoolGetDatum(false));
-							vardata->freefunc = ReleaseSysCache;
+							char rel_persistence = get_rel_persistence(index->indexoid);
+
+							if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+							{
+								vardata->statsTuple =
+									get_gtt_att_statistic(index->indexoid,
+														Int16GetDatum(pos + 1),
+														false);
+								vardata->freefunc = release_gtt_statistic_cache;
+							}
+							else
+							{
+								vardata->statsTuple =
+									SearchSysCache3(STATRELATTINH,
+													ObjectIdGetDatum(index->indexoid),
+													Int16GetDatum(pos + 1),
+													BoolGetDatum(false));
+								vardata->freefunc = ReleaseSysCache;
+							}
 
 							if (HeapTupleIsValid(vardata->statsTuple))
 							{
@@ -4708,15 +4722,27 @@ examine_simple_variable(PlannerInfo *root, Var *var,
 	}
 	else if (rte->rtekind == RTE_RELATION)
 	{
-		/*
-		 * Plain table or parent of an inheritance appendrel, so look up the
-		 * column in pg_statistic
-		 */
-		vardata->statsTuple = SearchSysCache3(STATRELATTINH,
-											  ObjectIdGetDatum(rte->relid),
-											  Int16GetDatum(var->varattno),
-											  BoolGetDatum(rte->inh));
-		vardata->freefunc = ReleaseSysCache;
+		char rel_persistence = get_rel_persistence(rte->relid);
+
+		if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata->statsTuple = get_gtt_att_statistic(rte->relid,
+														var->varattno,
+														rte->inh);
+			vardata->freefunc = release_gtt_statistic_cache;
+		}
+		else
+		{
+			/*
+			 * Plain table or parent of an inheritance appendrel, so look up the
+			 * column in pg_statistic
+			 */
+			vardata->statsTuple = SearchSysCache3(STATRELATTINH,
+												  ObjectIdGetDatum(rte->relid),
+												  Int16GetDatum(var->varattno),
+												  BoolGetDatum(rte->inh));
+			vardata->freefunc = ReleaseSysCache;
+		}
 
 		if (HeapTupleIsValid(vardata->statsTuple))
 		{
@@ -6098,6 +6124,7 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	{
 		/* Simple variable --- look to stats for the underlying table */
 		RangeTblEntry *rte = planner_rt_fetch(index->rel->relid, root);
+		char	rel_persistence = get_rel_persistence(rte->relid);
 
 		Assert(rte->rtekind == RTE_RELATION);
 		relid = rte->relid;
@@ -6115,6 +6142,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													rte->inh);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -6126,6 +6160,8 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	}
 	else
 	{
+		char	rel_persistence = get_rel_persistence(index->indexoid);
+
 		/* Expression --- maybe there are stats for the index itself */
 		relid = index->indexoid;
 		colnum = 1;
@@ -6141,6 +6177,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													false);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -7029,6 +7072,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		/* attempt to lookup stats in relation for this index column */
 		if (attnum != 0)
 		{
+			char	rel_persistence = get_rel_persistence(rte->relid);
+
 			/* Simple variable -- look to stats for the underlying table */
 			if (get_relation_stats_hook &&
 				(*get_relation_stats_hook) (root, rte, attnum, &vardata))
@@ -7041,6 +7086,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					elog(ERROR,
 						 "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(rte->relid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple =
@@ -7053,6 +7106,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		}
 		else
 		{
+			char	rel_persistence = get_rel_persistence(index->indexoid);
+
 			/*
 			 * Looks like we've found an expression column in the index. Let's
 			 * see if there's any stats for it.
@@ -7072,6 +7127,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					!vardata.freefunc)
 					elog(ERROR, "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(index->indexoid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple = SearchSysCache3(STATRELATTINH,
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 1e3e6d3..44686ce 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -34,6 +34,7 @@
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_transform.h"
 #include "catalog/pg_type.h"
+#include "catalog/storage_gtt.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "utils/array.h"
@@ -46,6 +47,7 @@
 #include "utils/syscache.h"
 #include "utils/typcache.h"
 
+
 /* Hook for plugins to get control in get_attavgwidth() */
 get_attavgwidth_hook_type get_attavgwidth_hook = NULL;
 
@@ -2878,6 +2880,18 @@ get_attavgwidth(Oid relid, AttrNumber attnum)
 		if (stawidth > 0)
 			return stawidth;
 	}
+	if (get_rel_persistence(relid) == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		tp = get_gtt_att_statistic(relid, attnum, false);
+		if (!HeapTupleIsValid(tp))
+			return 0;
+
+		stawidth = ((Form_pg_statistic) GETSTRUCT(tp))->stawidth;
+		if (stawidth > 0)
+			return stawidth;
+		else
+			return 0;
+	}
 	tp = SearchSysCache3(STATRELATTINH,
 						 ObjectIdGetDatum(relid),
 						 Int16GetDatum(attnum),
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index df025a5..1c30d86 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -1124,6 +1124,16 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
 				relation->rd_islocaltemp = false;
 			}
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			{
+				relation->rd_backend = BackendIdForTempRelations();
+				/*
+				 * For global temp table, all backend can use
+				 * this relation, so rd_islocaltemp always true.
+				 */
+				relation->rd_islocaltemp = true;
+			}
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c",
 				 relation->rd_rel->relpersistence);
@@ -3313,6 +3323,10 @@ RelationBuildLocalRelation(const char *relname,
 			rel->rd_backend = BackendIdForTempRelations();
 			rel->rd_islocaltemp = true;
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			rel->rd_backend = BackendIdForTempRelations();
+			rel->rd_islocaltemp = true;
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relpersistence);
 			break;
@@ -3427,6 +3441,9 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 	TransactionId freezeXid = InvalidTransactionId;
 	RelFileNode newrnode;
 
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+		elog(ERROR, "global temp table does not allow setting new relfilenode");
+
 	/* Allocate a new relfilenode */
 	newrelfilenode = GetNewRelFileNode(relation->rd_rel->reltablespace, NULL,
 									   persistence);
@@ -3467,7 +3484,7 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 				/* handle these directly, at least for now */
 				SMgrRelation srel;
 
-				srel = RelationCreateStorage(newrnode, persistence);
+				srel = RelationCreateStorage(newrnode, persistence, relation);
 				smgrclose(srel);
 			}
 			break;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index a4e5d08..37ce83d 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -139,6 +139,18 @@ char	   *GUC_check_errmsg_string;
 char	   *GUC_check_errdetail_string;
 char	   *GUC_check_errhint_string;
 
+/*
+ * num = 0 means disable global temp table feature.
+ * global temp table define can still storage in catalog
+ * just can not use.
+ * num > 0 means database can management num active global temp table.
+ */
+#define	MIN_NUM_ACTIVE_GTT			0
+#define	DEFAULT_NUM_ACTIVE_GTT			1000
+#define	MAX_NUM_ACTIVE_GTT			1000000
+
+int		max_active_gtt = MIN_NUM_ACTIVE_GTT;
+
 static void do_serialize(char **destptr, Size *maxbytes, const char *fmt,...) pg_attribute_printf(3, 4);
 
 static void set_config_sourcefile(const char *name, char *sourcefile,
@@ -1979,6 +1991,15 @@ static struct config_bool ConfigureNamesBool[] =
 static struct config_int ConfigureNamesInt[] =
 {
 	{
+		{"max_active_global_temporary_table", PGC_POSTMASTER, UNGROUPED,
+			gettext_noop("max active global temporary table."),
+			NULL
+		},
+		&max_active_gtt,
+		DEFAULT_NUM_ACTIVE_GTT, MIN_NUM_ACTIVE_GTT, MAX_NUM_ACTIVE_GTT,
+		NULL, NULL, NULL
+	},
+	{
 		{"archive_timeout", PGC_SIGHUP, WAL_ARCHIVING,
 			gettext_noop("Forces a switch to the next WAL file if a "
 						 "new file has not been started within N seconds."),
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 799b698..b98d396 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15583,6 +15583,7 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 	{
 		char	   *ftoptions = NULL;
 		char	   *srvname = NULL;
+		char		*table_type = NULL;
 
 		switch (tbinfo->relkind)
 		{
@@ -15634,9 +15635,15 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 			binary_upgrade_set_pg_class_oids(fout, q,
 											 tbinfo->dobj.catId.oid, false);
 
+		if (tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED)
+			table_type = "UNLOGGED ";
+		else if (tbinfo->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			table_type = "GLOBAL TEMPORARY ";
+		else
+			table_type = "";
+
 		appendPQExpBuffer(q, "CREATE %s%s %s",
-						  tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED ?
-						  "UNLOGGED " : "",
+						  table_type,
 						  reltypename,
 						  qualrelname);
 
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index f3c7eb9..28134e2 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3723,7 +3723,8 @@ listTables(const char *tabtypes, const char *pattern, bool verbose, bool showSys
 		if (pset.sversion >= 90100)
 		{
 			appendPQExpBuffer(&buf,
-							  ",\n  CASE c.relpersistence WHEN 'p' THEN '%s' WHEN 't' THEN '%s' WHEN 'u' THEN '%s' END as \"%s\"",
+							  ",\n  CASE c.relpersistence WHEN 'g' THEN '%s' WHEN 'p' THEN '%s' WHEN 't' THEN '%s' WHEN 'u' THEN '%s' END as \"%s\"",
+							  gettext_noop("session"),
 							  gettext_noop("permanent"),
 							  gettext_noop("temporary"),
 							  gettext_noop("unlogged"),
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index a12fc1f..78958e4 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -165,6 +165,7 @@ typedef FormData_pg_class *Form_pg_class;
 #define		  RELPERSISTENCE_PERMANENT	'p' /* regular table */
 #define		  RELPERSISTENCE_UNLOGGED	'u' /* unlogged permanent table */
 #define		  RELPERSISTENCE_TEMP		't' /* temporary table */
+#define		  RELPERSISTENCE_GLOBAL_TEMP	'g' /* global temporary table */
 
 /* default selection for replica identity (primary key or nothing) */
 #define		  REPLICA_IDENTITY_DEFAULT	'd'
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 0b6045a..6bc884e 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -5477,6 +5477,40 @@
   proparallel => 'r', prorettype => 'float8', proargtypes => 'oid',
   prosrc => 'pg_stat_get_xact_function_self_time' },
 
+# For global temporary table
+{ oid => '4191',
+  descr => 'List local statistics for global temporary table',
+  proname => 'pg_get_gtt_statistics', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid int4 anyelement',
+  proallargtypes => '{oid,int4,anyelement,oid,int2,bool,float4,int4,float4,int2,int2,int2,int2,int2,oid,oid,oid,oid,oid,oid,oid,oid,oid,oid,_float4,_float4,_float4,_float4,_float4,anyarray,anyarray,anyarray,anyarray,anyarray}',
+  proargmodes => '{i,i,i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
+  proargnames => '{relid,att,x,starelid,staattnum,stainherit,stanullfrac,stawidth,stadistinct,stakind1,stakind2,stakind3,stakind4,stakind5,staop1,staop2,staop3,staop4,staop5,stacoll1,stacoll2,stacoll3,stacoll4,stacoll5,stanumbers1,stanumbers2,stanumbers3,stanumbers4,stanumbers5,stavalues1,stavalues2,stavalues3,stavalues4,stavalues5}',
+  prosrc => 'pg_get_gtt_statistics' },
+{ oid => '4192',
+  descr => 'List local relstats for global temporary table',
+  proname => 'pg_get_gtt_relstats', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid',
+  proallargtypes => '{oid,int4,float4,int4,xid,xid}',
+  proargmodes => '{i,o,o,o,o,o}',
+  proargnames => '{relid,relpages,reltuples,relallvisible,relfrozenxid,relminmxid}',
+  prosrc => 'pg_get_gtt_relstats' },
+{ oid => '4193',
+  descr => 'List attached pid for one global temporary table',
+  proname => 'pg_gtt_attached_pid', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid',
+  proallargtypes => '{oid,oid,int4}',
+  proargmodes => '{i,o,o}',
+  proargnames => '{relid,relid,pid}',
+  prosrc => 'pg_gtt_attached_pid' },
+{ oid => '4194',
+  descr => 'List those backends that have used global temporary table',
+  proname => 'pg_list_gtt_relfrozenxids', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => '',
+  proallargtypes => '{int4,xid}',
+  proargmodes => '{o,o}',
+  proargnames => '{pid,relfrozenxid}',
+  prosrc => 'pg_list_gtt_relfrozenxids' },
+
 { oid => '3788',
   descr => 'statistics: timestamp of the current statistics snapshot',
   proname => 'pg_stat_get_snapshot_timestamp', provolatile => 's',
diff --git a/src/include/catalog/storage.h b/src/include/catalog/storage.h
index 048003c..af48cdf 100644
--- a/src/include/catalog/storage.h
+++ b/src/include/catalog/storage.h
@@ -19,7 +19,7 @@
 #include "storage/smgr.h"
 #include "utils/relcache.h"
 
-extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence);
+extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel);
 extern void RelationDropStorage(Relation rel);
 extern void RelationPreserveStorage(RelFileNode rnode, bool atCommit);
 extern void RelationTruncate(Relation rel, BlockNumber nblocks);
diff --git a/src/include/catalog/storage_gtt.h b/src/include/catalog/storage_gtt.h
new file mode 100644
index 0000000..eacc214
--- /dev/null
+++ b/src/include/catalog/storage_gtt.h
@@ -0,0 +1,39 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.h
+ *	  prototypes for functions in backend/catalog/storage_gtt.c
+ *
+ * src/include/catalog/storage_gtt.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef STORAGE_GTT_H
+#define STORAGE_GTT_H
+
+#include "access/htup.h"
+#include "storage/block.h"
+#include "storage/relfilenode.h"
+#include "utils/relcache.h"
+
+extern Size active_gtt_shared_hash_size(void);
+extern void active_gtt_shared_hash_init(void);
+extern void remember_gtt_storage_info(RelFileNode rnode, Relation rel);
+extern void forget_gtt_storage_info(Oid relid);
+extern bool is_other_backend_use_gtt(RelFileNode node);
+extern bool gtt_storage_attached(Oid relid);
+extern Bitmapset *copy_active_gtt_bitmap(RelFileNode node);
+extern void up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+								TupleDesc tupleDescriptor, Datum *values, bool *isnull);
+extern HeapTuple get_gtt_att_statistic(Oid reloid, int attnum, bool inh);
+extern void release_gtt_statistic_cache(HeapTuple tup);
+extern void up_gtt_relstats(Relation relation,
+							BlockNumber num_pages,
+							double num_tuples,
+							BlockNumber num_all_visible_pages,
+							TransactionId relfrozenxid,
+							TransactionId relminmxid);
+extern bool get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+							BlockNumber *relallvisible, TransactionId *relfrozenxid,
+							TransactionId *relminmxid);
+
+#endif							/* STORAGE_H */
diff --git a/src/include/parser/parse_relation.h b/src/include/parser/parse_relation.h
index b8bff23..70c01f7 100644
--- a/src/include/parser/parse_relation.h
+++ b/src/include/parser/parse_relation.h
@@ -117,4 +117,7 @@ extern Oid	attnumTypeId(Relation rd, int attid);
 extern Oid	attnumCollationId(Relation rd, int attid);
 extern bool isQueryUsingTempRelation(Query *query);
 
+/* global temp table check */
+extern bool is_query_using_gtt(Query *query);
+
 #endif							/* PARSE_RELATION_H */
diff --git a/src/include/storage/bufpage.h b/src/include/storage/bufpage.h
index 870ecb5..92c590e 100644
--- a/src/include/storage/bufpage.h
+++ b/src/include/storage/bufpage.h
@@ -405,6 +405,8 @@ do { \
 #define PageClearPrunable(page) \
 	(((PageHeader) (page))->pd_prune_xid = InvalidTransactionId)
 
+#define GlobalTempRelationPageIsNotInitialized(rel, page) \
+	((rel)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP && PageIsNew(page))
 
 /* ----------------------------------------------------------------
  *		extern declarations
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 8fda8e4..172eae9 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -220,6 +220,7 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_TBM,
 	LWTRANCHE_PARALLEL_APPEND,
 	LWTRANCHE_SXACT,
+	LWTRANCHE_GTT_CTL,
 	LWTRANCHE_FIRST_USER_DEFINED
 }			BuiltinTrancheIds;
 
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 5b407e6..f13250a 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -117,6 +117,8 @@ struct PGPROC
 	Oid			tempNamespaceId;	/* OID of temp schema this backend is
 									 * using */
 
+	TransactionId session_gtt_frozenxid;	/* session level global temp table relfrozenxid */
+
 	bool		isBackgroundWorker; /* true if background worker. */
 
 	/*
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index a5c7d0c..a86f61f 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -125,4 +125,6 @@ extern void ProcArraySetReplicationSlotXmin(TransactionId xmin,
 extern void ProcArrayGetReplicationSlotXmin(TransactionId *xmin,
 											TransactionId *catalog_xmin);
 
+extern int list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n);
+
 #endif							/* PROCARRAY_H */
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index ce93ace..0f7262e 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -281,6 +281,10 @@ extern int	tcp_user_timeout;
 extern bool trace_sort;
 #endif
 
+/* global temporary table */
+extern int	max_active_gtt;
+/* end */
+
 /*
  * Functions exported by guc.c
  */
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 44ed04d..3f9720d 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -277,6 +277,7 @@ typedef struct StdRdOptions
 	int			parallel_workers;	/* max number of parallel workers */
 	bool		vacuum_index_cleanup;	/* enables index vacuuming and cleanup */
 	bool		vacuum_truncate;	/* enables vacuum to truncate a relation */
+	bool		on_commit_delete_rows;	/* global temp table */
 } StdRdOptions;
 
 #define HEAP_MIN_FILLFACTOR			10
@@ -535,7 +536,8 @@ typedef struct ViewOptions
  *		True if relation's pages are stored in local buffers.
  */
 #define RelationUsesLocalBuffers(relation) \
-	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP || \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 
 /*
  * RELATION_IS_LOCAL
@@ -602,6 +604,17 @@ typedef struct ViewOptions
 	 RelationNeedsWAL(relation) && \
 	 !IsCatalogRelation(relation))
 
+/* global temp table implementations */
+#define RELATION_IS_GLOBAL_TEMP(relation)	((relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+
+#define RELATION_GTT_ON_COMMIT_DELETE(relation)	\
+	((relation)->rd_options && \
+	 ((relation)->rd_rel->relkind == RELKIND_RELATION || (relation)->rd_rel->relkind == RELKIND_PARTITIONED_TABLE) && \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ? \
+	 ((StdRdOptions *) (relation)->rd_options)->on_commit_delete_rows : false)
+
+#define RelationGetRelPersistence(relation) ((relation)->rd_rel->relpersistence)
+
 /* routines in utils/cache/relcache.c */
 extern void RelationIncrementReferenceCount(Relation rel);
 extern void RelationDecrementReferenceCount(Relation rel);
diff --git a/src/test/regress/expected/gtt_clean.out b/src/test/regress/expected/gtt_clean.out
new file mode 100644
index 0000000..50ca9ac
--- /dev/null
+++ b/src/test/regress/expected/gtt_clean.out
@@ -0,0 +1,7 @@
+reset search_path;
+drop schema gtt cascade;
+NOTICE:  drop cascades to 4 other objects
+DETAIL:  drop cascades to table gtt.gtt1
+drop cascades to table gtt.gtt2
+drop cascades to table gtt.gtt3
+drop cascades to table gtt.gtt_t_kenyon
diff --git a/src/test/regress/expected/gtt_function.out b/src/test/regress/expected/gtt_function.out
new file mode 100644
index 0000000..2c69f14
--- /dev/null
+++ b/src/test/regress/expected/gtt_function.out
@@ -0,0 +1,197 @@
+CREATE SCHEMA IF NOT EXISTS gtt_function;
+set search_path=gtt_function,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt_test_rename(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+ERROR:  cannot create indexes on global temporary tables using concurrent mode
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+ERROR:  not support cluster global temporary tables yet
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+ERROR:  ON COMMIT can only be used on temporary tables
+-- ok
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+ERROR:  regular table cannot specifie on_commit_delete_rows
+-- ok
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+--ok
+CREATE global temp TABLE p_table01 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+);
+ 
+CREATE global temp TABLE p_table01_2018
+PARTITION OF p_table01
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+ 
+CREATE global temp TABLE p_table01_2017
+PARTITION OF p_table01
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+begin;
+insert into p_table01 values(1,'2018-01-02 00:00:00','test1');
+insert into p_table01 values(1,'2018-01-02 00:00:00','test2');
+select count(*) from p_table01;
+ count 
+-------
+     2
+(1 row)
+
+commit;
+select count(*) from p_table01;
+ count 
+-------
+     0
+(1 row)
+
+--ok
+CREATE global temp TABLE p_table02 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)
+on commit PRESERVE rows;
+CREATE global temp TABLE p_table02_2018
+PARTITION OF p_table02
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+CREATE global temp TABLE p_table02_2017
+PARTITION OF p_table02
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+-- ok
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+ERROR:  The parent table must be global temporary table
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent_global_temp);
+select relname ,relkind, relpersistence, reloptions from pg_class where relname like 'p_table0%' or  relname like 'tbl_inherits%' order by relname;
+             relname             | relkind | relpersistence |          reloptions           
+---------------------------------+---------+----------------+-------------------------------
+ p_table01                       | p       | g              | {on_commit_delete_rows=true}
+ p_table01_2017                  | r       | g              | {on_commit_delete_rows=true}
+ p_table01_2018                  | r       | g              | {on_commit_delete_rows=true}
+ p_table01_id_seq                | S       | g              | 
+ p_table02                       | p       | g              | {on_commit_delete_rows=false}
+ p_table02_2017                  | r       | g              | {on_commit_delete_rows=false}
+ p_table02_2018                  | r       | g              | {on_commit_delete_rows=false}
+ p_table02_id_seq                | S       | g              | 
+ tbl_inherits_parent             | r       | p              | 
+ tbl_inherits_parent_global_temp | r       | g              | {on_commit_delete_rows=true}
+ tbl_inherits_partition          | r       | g              | {on_commit_delete_rows=true}
+(11 rows)
+
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+ERROR:  global temp table not support on commit drop clause
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+ERROR:  can not defeine global temp table with on commit and with clause at same time
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+--ok
+alter table gtt_test_rename rename to gtt_test;
+-- ok
+ALTER TABLE gtt_test ADD COLUMN address varchar(30);
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  referenced relation "products" is not a global temp table
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  referenced relation "products" is not a global temp table
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+-- ok
+create global temp table gtt_seq(id int GENERATED ALWAYS AS IDENTITY (START WITH 2) primary key, a int)  on commit PRESERVE rows;
+insert into gtt_seq (a) values(1);
+insert into gtt_seq (a) values(2);
+select * from gtt_seq order by id;
+ id | a 
+----+---
+  2 | 1
+  3 | 2
+(2 rows)
+
+truncate gtt_seq;
+select * from gtt_seq order by id;
+ id | a 
+----+---
+(0 rows)
+
+insert into gtt_seq (a) values(3);
+select * from gtt_seq order by id;
+ id | a 
+----+---
+  4 | 3
+(1 row)
+
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+ERROR:  materialized views must not use global temporary tables or views
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+ERROR:  only support btree index on global temp table
+create index idx_err on gtt1 using gist (a);
+ERROR:  data type integer has no default operator class for access method "gist"
+HINT:  You must specify an operator class for the index or define a default operator class for the data type.
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+ERROR:  only support btree index on global temp table
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+ERROR:  only support btree index on global temp table
+reset search_path;
+drop schema gtt_function cascade;
+NOTICE:  drop cascades to 15 other objects
+DETAIL:  drop cascades to table gtt_function.gtt1
+drop cascades to table gtt_function.gtt_test
+drop cascades to table gtt_function.gtt2
+drop cascades to table gtt_function.gtt3
+drop cascades to table gtt_function.tmp_t0
+drop cascades to table gtt_function.tbl_inherits_parent
+drop cascades to table gtt_function.tbl_inherits_parent_global_temp
+drop cascades to table gtt_function.products
+drop cascades to table gtt_function.measurement
+drop cascades to table gtt_function.p_table01
+drop cascades to table gtt_function.p_table02
+drop cascades to table gtt_function.tbl_inherits_partition
+drop cascades to table gtt_function.gtt5
+drop cascades to table gtt_function.mytable
+drop cascades to table gtt_function.gtt_seq
diff --git a/src/test/regress/expected/gtt_parallel_1.out b/src/test/regress/expected/gtt_parallel_1.out
new file mode 100644
index 0000000..30d8a7b
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_1.out
@@ -0,0 +1,84 @@
+set search_path=gtt,sys;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_parallel_2.out b/src/test/regress/expected/gtt_parallel_2.out
new file mode 100644
index 0000000..850ef3e
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_2.out
@@ -0,0 +1,161 @@
+set search_path=gtt,sys;
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+ 3 | test1
+(3 rows)
+
+rollback;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test2
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 3 | test3
+(1 row)
+
+rollback;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 5 | test5
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 6 | test6
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+ count  
+--------
+ 100000
+(1 row)
+
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+             QUERY PLAN             
+------------------------------------
+ Index Scan using gtt3_pkey on gtt3
+   Index Cond: (a = 300)
+(2 rows)
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid),pg_table_size(oid),pg_indexes_size(oid),pg_total_relation_size(oid) from pg_class where relname = 'gtt_t_kenyon';
+   relname    | pg_relation_size | pg_relation_size | pg_table_size | pg_indexes_size | pg_total_relation_size 
+--------------+------------------+------------------+---------------+-----------------+------------------------
+ gtt_t_kenyon |           450560 |             8192 |        499712 |          475136 |                 974848
+(1 row)
+
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+   relname    
+--------------
+ gtt_t_kenyon
+(1 row)
+
+select
+c.relname, pg_relation_size(c.oid),pg_table_size(c.oid),pg_total_relation_size(c.oid)
+from
+pg_class c
+where
+c.oid in
+(
+select
+i.indexrelid as indexrelid
+from 
+pg_index i ,pg_class cc
+where cc.relname = 'gtt_t_kenyon' and cc.oid = i.indrelid
+)
+order by c.relname;
+      relname       | pg_relation_size | pg_table_size | pg_total_relation_size 
+--------------------+------------------+---------------+------------------------
+ idx_gtt_t_kenyon_1 |            65536 |         65536 |                  65536
+ idx_gtt_t_kenyon_2 |           409600 |        409600 |                 409600
+(2 rows)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_prepare.out b/src/test/regress/expected/gtt_prepare.out
new file mode 100644
index 0000000..9735a93
--- /dev/null
+++ b/src/test/regress/expected/gtt_prepare.out
@@ -0,0 +1,9 @@
+CREATE SCHEMA IF NOT EXISTS gtt;
+set search_path=gtt,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+create index idx_gtt_t_kenyon_1 on gtt_t_kenyon(id);
+create index idx_gtt_t_kenyon_2 on gtt_t_kenyon(remark);
+reset search_path;
diff --git a/src/test/regress/expected/gtt_stats.out b/src/test/regress/expected/gtt_stats.out
new file mode 100644
index 0000000..b258b7c
--- /dev/null
+++ b/src/test/regress/expected/gtt_stats.out
@@ -0,0 +1,76 @@
+CREATE SCHEMA IF NOT EXISTS gtt_stats;
+set search_path=gtt_stats,sys;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     0
+(1 row)
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     0
+(1 row)
+
+create global temp table gtt(a int primary key, b text) on commit PRESERVE rows;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     0
+(1 row)
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     0
+(1 row)
+
+insert into gtt values(generate_series(1,10000),'test');
+-- expect 1
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     1
+(1 row)
+
+-- expect 2
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     2
+(1 row)
+
+-- expect 0
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+ schemaname | tablename | relpages | reltuples | relallvisible 
+------------+-----------+----------+-----------+---------------
+ gtt_stats  | gtt       |        0 |         0 |             0
+(1 row)
+
+-- expect 0
+select * from pg_gtt_stats order by tablename;
+ schemaname | tablename | attname | inherited | null_frac | avg_width | n_distinct | most_common_vals | most_common_freqs | histogram_bounds | correlation | most_common_elems | most_common_elem_freqs | elem_count_histogram 
+------------+-----------+---------+-----------+-----------+-----------+------------+------------------+-------------------+------------------+-------------+-------------------+------------------------+----------------------
+(0 rows)
+
+analyze gtt;
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+ schemaname | tablename | relpages | reltuples | relallvisible 
+------------+-----------+----------+-----------+---------------
+ gtt_stats  | gtt       |       55 |     10000 |             0
+(1 row)
+
+select * from pg_gtt_stats order by tablename;
+ schemaname | tablename | attname | inherited | null_frac | avg_width | n_distinct | most_common_vals | most_common_freqs |                                                                                                                                                                                                                                                histogram_bounds                                                                                                                                                                                                                                                 | correlation | most_common_elems | most_common_elem_freqs | elem_count_histogram 
+------------+-----------+---------+-----------+-----------+-----------+------------+------------------+-------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+-------------------+------------------------+----------------------
+ gtt_stats  | gtt       | a       | f         |         0 |         4 |         -1 |                  |                   | {1,100,200,300,400,500,600,700,800,900,1000,1100,1200,1300,1400,1500,1600,1700,1800,1900,2000,2100,2200,2300,2400,2500,2600,2700,2800,2900,3000,3100,3200,3300,3400,3500,3600,3700,3800,3900,4000,4100,4200,4300,4400,4500,4600,4700,4800,4900,5000,5100,5200,5300,5400,5500,5600,5700,5800,5900,6000,6100,6200,6300,6400,6500,6600,6700,6800,6900,7000,7100,7200,7300,7400,7500,7600,7700,7800,7900,8000,8100,8200,8300,8400,8500,8600,8700,8800,8900,9000,9100,9200,9300,9400,9500,9600,9700,9800,9900,10000} |           1 |                   |                        | 
+ gtt_stats  | gtt       | b       | f         |         0 |         5 |          1 | {test}           | {1}               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |           1 |                   |                        | 
+(2 rows)
+
+reset search_path;
+drop schema gtt_stats cascade;
+NOTICE:  drop cascades to table gtt_stats.gtt
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index 80a0782..d3d9927 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1348,6 +1348,93 @@ pg_group| SELECT pg_authid.rolname AS groname,
           WHERE (pg_auth_members.roleid = pg_authid.oid)) AS grolist
    FROM pg_authid
   WHERE (NOT pg_authid.rolcanlogin);
+pg_gtt_attached_pids| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.relid,
+    s.pid
+   FROM (pg_class c
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_gtt_attached_pid(c.oid) s(relid, pid)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
+pg_gtt_relstats| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.relpages,
+    s.reltuples,
+    s.relallvisible,
+    s.relfrozenxid,
+    s.relminmxid
+   FROM (pg_class c
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_get_gtt_relstats(c.oid) s(relpages, reltuples, relallvisible, relfrozenxid, relminmxid)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
+pg_gtt_stats| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    a.attname,
+    s.stainherit AS inherited,
+    s.stanullfrac AS null_frac,
+    s.stawidth AS avg_width,
+    s.stadistinct AS n_distinct,
+        CASE
+            WHEN (s.stakind1 = 1) THEN s.stavalues1
+            WHEN (s.stakind2 = 1) THEN s.stavalues2
+            WHEN (s.stakind3 = 1) THEN s.stavalues3
+            WHEN (s.stakind4 = 1) THEN s.stavalues4
+            WHEN (s.stakind5 = 1) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS most_common_vals,
+        CASE
+            WHEN (s.stakind1 = 1) THEN s.stanumbers1
+            WHEN (s.stakind2 = 1) THEN s.stanumbers2
+            WHEN (s.stakind3 = 1) THEN s.stanumbers3
+            WHEN (s.stakind4 = 1) THEN s.stanumbers4
+            WHEN (s.stakind5 = 1) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS most_common_freqs,
+        CASE
+            WHEN (s.stakind1 = 2) THEN s.stavalues1
+            WHEN (s.stakind2 = 2) THEN s.stavalues2
+            WHEN (s.stakind3 = 2) THEN s.stavalues3
+            WHEN (s.stakind4 = 2) THEN s.stavalues4
+            WHEN (s.stakind5 = 2) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS histogram_bounds,
+        CASE
+            WHEN (s.stakind1 = 3) THEN s.stanumbers1[1]
+            WHEN (s.stakind2 = 3) THEN s.stanumbers2[1]
+            WHEN (s.stakind3 = 3) THEN s.stanumbers3[1]
+            WHEN (s.stakind4 = 3) THEN s.stanumbers4[1]
+            WHEN (s.stakind5 = 3) THEN s.stanumbers5[1]
+            ELSE NULL::real
+        END AS correlation,
+        CASE
+            WHEN (s.stakind1 = 4) THEN s.stavalues1
+            WHEN (s.stakind2 = 4) THEN s.stavalues2
+            WHEN (s.stakind3 = 4) THEN s.stavalues3
+            WHEN (s.stakind4 = 4) THEN s.stavalues4
+            WHEN (s.stakind5 = 4) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS most_common_elems,
+        CASE
+            WHEN (s.stakind1 = 4) THEN s.stanumbers1
+            WHEN (s.stakind2 = 4) THEN s.stanumbers2
+            WHEN (s.stakind3 = 4) THEN s.stanumbers3
+            WHEN (s.stakind4 = 4) THEN s.stanumbers4
+            WHEN (s.stakind5 = 4) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS most_common_elem_freqs,
+        CASE
+            WHEN (s.stakind1 = 5) THEN s.stanumbers1
+            WHEN (s.stakind2 = 5) THEN s.stanumbers2
+            WHEN (s.stakind3 = 5) THEN s.stanumbers3
+            WHEN (s.stakind4 = 5) THEN s.stanumbers4
+            WHEN (s.stakind5 = 5) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS elem_count_histogram
+   FROM ((pg_class c
+     JOIN pg_attribute a ON ((c.oid = a.attrelid)))
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_get_gtt_statistics(c.oid, (a.attnum)::integer, ''::text) s(starelid, staattnum, stainherit, stanullfrac, stawidth, stadistinct, stakind1, stakind2, stakind3, stakind4, stakind5, staop1, staop2, staop3, staop4, staop5, stacoll1, stacoll2, stacoll3, stacoll4, stacoll5, stanumbers1, stanumbers2, stanumbers3, stanumbers4, stanumbers5, stavalues1, stavalues2, stavalues3, stavalues4, stavalues5)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND (NOT a.attisdropped) AND has_column_privilege(c.oid, a.attnum, 'select'::text) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
 pg_hba_file_rules| SELECT a.line_number,
     a.type,
     a.database,
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index d33a4e1..643afe4 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -121,3 +121,10 @@ test: fast_default
 
 # run stats by itself because its delay may be insufficient under heavy load
 test: stats
+
+# global temp table test
+test: gtt_stats
+test: gtt_function
+test: gtt_prepare
+test: gtt_parallel_1 gtt_parallel_2
+test: gtt_clean
diff --git a/src/test/regress/sql/gtt_clean.sql b/src/test/regress/sql/gtt_clean.sql
new file mode 100644
index 0000000..f3cf710
--- /dev/null
+++ b/src/test/regress/sql/gtt_clean.sql
@@ -0,0 +1,6 @@
+
+
+reset search_path;
+
+drop schema gtt cascade;
+
diff --git a/src/test/regress/sql/gtt_function.sql b/src/test/regress/sql/gtt_function.sql
new file mode 100644
index 0000000..49c3f11
--- /dev/null
+++ b/src/test/regress/sql/gtt_function.sql
@@ -0,0 +1,163 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt_function;
+
+set search_path=gtt_function,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt_test_rename(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+
+-- ok
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+
+-- ok
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+
+--ok
+CREATE global temp TABLE p_table01 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+);
+ 
+CREATE global temp TABLE p_table01_2018
+PARTITION OF p_table01
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+ 
+CREATE global temp TABLE p_table01_2017
+PARTITION OF p_table01
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+
+begin;
+insert into p_table01 values(1,'2018-01-02 00:00:00','test1');
+insert into p_table01 values(1,'2018-01-02 00:00:00','test2');
+select count(*) from p_table01;
+commit;
+
+select count(*) from p_table01;
+
+--ok
+CREATE global temp TABLE p_table02 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)
+on commit PRESERVE rows;
+
+CREATE global temp TABLE p_table02_2018
+PARTITION OF p_table02
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+
+CREATE global temp TABLE p_table02_2017
+PARTITION OF p_table02
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+
+-- ok
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent_global_temp);
+
+select relname ,relkind, relpersistence, reloptions from pg_class where relname like 'p_table0%' or  relname like 'tbl_inherits%' order by relname;
+
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+
+--ok
+alter table gtt_test_rename rename to gtt_test;
+
+-- ok
+ALTER TABLE gtt_test ADD COLUMN address varchar(30);
+
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+
+-- ok
+create global temp table gtt_seq(id int GENERATED ALWAYS AS IDENTITY (START WITH 2) primary key, a int)  on commit PRESERVE rows;
+insert into gtt_seq (a) values(1);
+insert into gtt_seq (a) values(2);
+select * from gtt_seq order by id;
+truncate gtt_seq;
+select * from gtt_seq order by id;
+insert into gtt_seq (a) values(3);
+select * from gtt_seq order by id;
+
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+create index idx_err on gtt1 using gist (a);
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+
+reset search_path;
+
+drop schema gtt_function cascade;
+
diff --git a/src/test/regress/sql/gtt_parallel_1.sql b/src/test/regress/sql/gtt_parallel_1.sql
new file mode 100644
index 0000000..d7d81de
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_1.sql
@@ -0,0 +1,42 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+commit;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+rollback;
+select * from gtt1 order by a;
+
+truncate gtt1;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+select * from gtt1 order by a;
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+
+begin;
+select * from gtt1 order by a;
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_parallel_2.sql b/src/test/regress/sql/gtt_parallel_2.sql
new file mode 100644
index 0000000..5203c2b
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_2.sql
@@ -0,0 +1,76 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+commit;
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+truncate gtt3;
+select * from gtt3 order by a;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+truncate gtt3;
+select * from gtt3 order by a;
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+begin;
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid),pg_table_size(oid),pg_indexes_size(oid),pg_total_relation_size(oid) from pg_class where relname = 'gtt_t_kenyon';
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+
+select
+c.relname, pg_relation_size(c.oid),pg_table_size(c.oid),pg_total_relation_size(c.oid)
+from
+pg_class c
+where
+c.oid in
+(
+select
+i.indexrelid as indexrelid
+from 
+pg_index i ,pg_class cc
+where cc.relname = 'gtt_t_kenyon' and cc.oid = i.indrelid
+)
+order by c.relname;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_prepare.sql b/src/test/regress/sql/gtt_prepare.sql
new file mode 100644
index 0000000..1e4cf27
--- /dev/null
+++ b/src/test/regress/sql/gtt_prepare.sql
@@ -0,0 +1,16 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt;
+
+set search_path=gtt,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+create index idx_gtt_t_kenyon_1 on gtt_t_kenyon(id);
+create index idx_gtt_t_kenyon_2 on gtt_t_kenyon(remark);
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_stats.sql b/src/test/regress/sql/gtt_stats.sql
new file mode 100644
index 0000000..f041892
--- /dev/null
+++ b/src/test/regress/sql/gtt_stats.sql
@@ -0,0 +1,42 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt_stats;
+
+set search_path=gtt_stats,sys;
+
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+
+create global temp table gtt(a int primary key, b text) on commit PRESERVE rows;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+
+insert into gtt values(generate_series(1,10000),'test');
+
+-- expect 1
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 2
+select count(*) from pg_list_gtt_relfrozenxids();
+
+-- expect 0
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+
+-- expect 0
+select * from pg_gtt_stats order by tablename;
+
+analyze gtt;
+
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+
+select * from pg_gtt_stats order by tablename;
+
+reset search_path;
+
+drop schema gtt_stats cascade;
+

diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c
index 79430d2..b7173c7 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -158,6 +158,19 @@ static relopt_bool boolRelOpts[] =
 		},
 		true
 	},
+	/*
+	 * For global temp table only
+	 * use AccessExclusiveLock for ensure safety
+	 */
+	{
+		{
+			"on_commit_delete_rows",
+			"global temp table on commit options",
+			RELOPT_KIND_HEAP | RELOPT_KIND_PARTITIONED,
+			ShareUpdateExclusiveLock
+		},
+		true
+	},	
 	/* list terminator */
 	{{NULL}}
 };
@@ -1486,6 +1499,8 @@ bytea *
 default_reloptions(Datum reloptions, bool validate, relopt_kind kind)
 {
 	static const relopt_parse_elt tab[] = {
+		{"on_commit_delete_rows", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, on_commit_delete_rows)},
 		{"fillfactor", RELOPT_TYPE_INT, offsetof(StdRdOptions, fillfactor)},
 		{"autovacuum_enabled", RELOPT_TYPE_BOOL,
 		offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, enabled)},
@@ -1586,13 +1601,18 @@ build_reloptions(Datum reloptions, bool validate,
 bytea *
 partitioned_table_reloptions(Datum reloptions, bool validate)
 {
+	static const relopt_parse_elt tab[] = {
+		{"on_commit_delete_rows", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, on_commit_delete_rows)}
+	};
+
 	/*
 	 * There are no options for partitioned tables yet, but this is able to do
 	 * some validation.
 	 */
 	return (bytea *) build_reloptions(reloptions, validate,
 									  RELOPT_KIND_PARTITIONED,
-									  0, NULL, 0);
+									  sizeof(StdRdOptions), tab, lengthof(tab));
 }
 
 /*
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index dd975b1..1610e7d 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -1013,7 +1013,9 @@ gistGetFakeLSN(Relation rel)
 {
 	static XLogRecPtr counter = FirstNormalUnloggedLSN;
 
-	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	/* global temp is same as local temp table */
+	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		rel->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 	{
 		/*
 		 * Temporary relations are only accessible in our session, so a simple
diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index 4871b7f..16b00c9 100644
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -149,7 +149,9 @@ hashbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	 * metapage, nor the first bitmap page.
 	 */
 	sort_threshold = (maintenance_work_mem * 1024L) / BLCKSZ;
-	if (index->rd_rel->relpersistence != RELPERSISTENCE_TEMP)
+	/* global temp table is same as local temp table */
+	if (!(index->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		index->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		sort_threshold = Min(sort_threshold, NBuffers);
 	else
 		sort_threshold = Min(sort_threshold, NLocBuffer);
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 1f6f6d0..5727ccd 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -598,7 +598,7 @@ heapam_relation_set_new_filenode(Relation rel,
 	 */
 	*minmulti = GetOldestMultiXactId();
 
-	srel = RelationCreateStorage(*newrnode, persistence);
+	srel = RelationCreateStorage(*newrnode, persistence, rel);
 
 	/*
 	 * If required, set up an init fork for an unlogged table so that it can
@@ -651,7 +651,7 @@ heapam_relation_copy_data(Relation rel, const RelFileNode *newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index b331f4c..5bd681f 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -79,6 +79,7 @@
 #include "utils/pg_rusage.h"
 #include "utils/timestamp.h"
 
+#include "catalog/storage_gtt.h"
 
 /*
  * Space/time tradeoff parameters: do these need to be user-tunable?
@@ -397,8 +398,10 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 	Assert(params->truncate != VACOPT_TERNARY_DEFAULT);
 
 	/* not every AM requires these to be valid, but heap does */
-	Assert(TransactionIdIsNormal(onerel->rd_rel->relfrozenxid));
-	Assert(MultiXactIdIsValid(onerel->rd_rel->relminmxid));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relfrozenxid == InvalidTransactionId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && TransactionIdIsNormal(onerel->rd_rel->relfrozenxid)));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relminmxid == InvalidMultiXactId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && MultiXactIdIsValid(onerel->rd_rel->relminmxid)));
 
 	/* measure elapsed time iff autovacuum logging requires it */
 	if (IsAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
@@ -457,8 +460,19 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 
 	vacrelstats = (LVRelStats *) palloc0(sizeof(LVRelStats));
 
-	vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
-	vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
+	/* get relstat from gtt localhash */
+	if (RELATION_IS_GLOBAL_TEMP(onerel))
+	{
+		get_gtt_relstats(RelationGetRelid(onerel),
+						&vacrelstats->old_rel_pages,
+						&vacrelstats->old_live_tuples,
+						NULL, NULL, NULL);
+	}
+	else
+	{
+		vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
+		vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
+	}
 	vacrelstats->num_index_scans = 0;
 	vacrelstats->pages_removed = 0;
 	vacrelstats->lock_waiter_detected = false;
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index f05cbe7..946c9d2 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -763,7 +763,14 @@ _bt_getbuf(Relation rel, BlockNumber blkno, int access)
 		/* Read an existing block of the relation */
 		buf = ReadBuffer(rel, blkno);
 		LockBuffer(buf, access);
-		_bt_checkpage(rel, buf);
+
+		/* global temp table may be not yet initialized for this backend. */
+		if (RELATION_IS_GLOBAL_TEMP(rel) &&
+			blkno == BTREE_METAPAGE &&
+			PageIsNew(BufferGetPage(buf)))
+			_bt_initmetapage(BufferGetPage(buf), P_NONE, 0);
+		else
+			_bt_checkpage(rel, buf);
 	}
 	else
 	{
diff --git a/src/backend/access/table/tableam.c b/src/backend/access/table/tableam.c
index c814733..ff51840 100644
--- a/src/backend/access/table/tableam.c
+++ b/src/backend/access/table/tableam.c
@@ -24,6 +24,7 @@
 #include "access/heapam.h"		/* for ss_* */
 #include "access/tableam.h"
 #include "access/xact.h"
+#include "catalog/storage_gtt.h"
 #include "optimizer/plancat.h"
 #include "storage/bufmgr.h"
 #include "storage/shmem.h"
@@ -560,10 +561,20 @@ table_block_relation_estimate_size(Relation rel, int32 *attr_widths,
 	/* it should have storage, so we can call the smgr */
 	curpages = RelationGetNumberOfBlocks(rel);
 
-	/* coerce values in pg_class to more desirable types */
-	relpages = (BlockNumber) rel->rd_rel->relpages;
-	reltuples = (double) rel->rd_rel->reltuples;
-	relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
+	/* global temp table get relstats from localhash */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		get_gtt_relstats(RelationGetRelid(rel),
+						&relpages, &reltuples, &relallvisible,
+						NULL, NULL);
+	}
+	else
+	{
+		/* coerce values in pg_class to more desirable types */
+		relpages = (BlockNumber) rel->rd_rel->relpages;
+		reltuples = (double) rel->rd_rel->reltuples;
+		relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
+	}
 
 	/*
 	 * HACK: if the relation has never yet been vacuumed, use a minimum size
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 7f4f784..aba8a9f 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6327,6 +6327,10 @@ StartupXLOG(void)
 	else
 		recoveryTargetTLI = ControlFile->checkPointCopy.ThisTimeLineID;
 
+	/* clean temp relation files */
+	if (max_active_gtt > 0)
+		RemovePgTempFiles();
+
 	/*
 	 * Check for signal files, and if so set up state for offline recovery
 	 */
diff --git a/src/backend/catalog/Makefile b/src/backend/catalog/Makefile
index d5da81c..c753b0e 100644
--- a/src/backend/catalog/Makefile
+++ b/src/backend/catalog/Makefile
@@ -42,6 +42,7 @@ OBJS = \
 	pg_subscription.o \
 	pg_type.o \
 	storage.o \
+	storage_gtt.o \
 	toasting.o
 
 include $(top_srcdir)/src/backend/common.mk
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index 16cb6d8..f28f2c2 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -398,7 +398,9 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class, char relpersistence)
 
 	switch (relpersistence)
 	{
+		/* global temp table is same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			break;
 		case RELPERSISTENCE_UNLOGGED:
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 0fdff29..54a5243 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -61,6 +61,7 @@
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "commands/tablecmds.h"
 #include "commands/typecmds.h"
 #include "executor/executor.h"
@@ -99,6 +100,7 @@ static void AddNewRelationTuple(Relation pg_class_desc,
 								Oid reloftype,
 								Oid relowner,
 								char relkind,
+								char relpersistence,
 								TransactionId relfrozenxid,
 								TransactionId relminmxid,
 								Datum relacl,
@@ -404,6 +406,10 @@ heap_create(const char *relname,
 									 relpersistence,
 									 relkind);
 
+	/* global temp table not create storage file when catalog create */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		create_storage = false;
+
 	/*
 	 * Have the storage manager create the relation's disk file, if needed.
 	 *
@@ -427,7 +433,7 @@ heap_create(const char *relname,
 
 			case RELKIND_INDEX:
 			case RELKIND_SEQUENCE:
-				RelationCreateStorage(rel->rd_node, relpersistence);
+				RelationCreateStorage(rel->rd_node, relpersistence, rel);
 				break;
 
 			case RELKIND_RELATION:
@@ -956,6 +962,7 @@ AddNewRelationTuple(Relation pg_class_desc,
 					Oid reloftype,
 					Oid relowner,
 					char relkind,
+					char relpersistence,
 					TransactionId relfrozenxid,
 					TransactionId relminmxid,
 					Datum relacl,
@@ -994,8 +1001,18 @@ AddNewRelationTuple(Relation pg_class_desc,
 			break;
 	}
 
-	new_rel_reltup->relfrozenxid = relfrozenxid;
-	new_rel_reltup->relminmxid = relminmxid;
+	/* global temp table not remember transaction info in catalog */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		new_rel_reltup->relfrozenxid = InvalidTransactionId;
+		new_rel_reltup->relminmxid = InvalidMultiXactId;
+	}
+	else
+	{
+		new_rel_reltup->relfrozenxid = relfrozenxid;
+		new_rel_reltup->relminmxid = relminmxid;
+	}
+
 	new_rel_reltup->relowner = relowner;
 	new_rel_reltup->reltype = new_type_oid;
 	new_rel_reltup->reloftype = reloftype;
@@ -1357,6 +1374,7 @@ heap_create_with_catalog(const char *relname,
 						reloftypeid,
 						ownerid,
 						relkind,
+						relpersistence,
 						relfrozenxid,
 						relminmxid,
 						PointerGetDatum(relacl),
@@ -1441,11 +1459,15 @@ heap_create_with_catalog(const char *relname,
 	 */
 	StoreConstraints(new_rel_desc, cooked_constraints, is_internal);
 
-	/*
-	 * If there's a special on-commit action, remember it
-	 */
-	if (oncommit != ONCOMMIT_NOOP)
-		register_on_commit_action(relid, oncommit);
+	/* global temp table register action when storage init */
+	if (relpersistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		/*
+		 * If there's a special on-commit action, remember it
+		 */
+		if (oncommit != ONCOMMIT_NOOP)
+			register_on_commit_action(relid, oncommit);
+	}
 
 	/*
 	 * ok, the relation has been cataloged, so close our relations and return
@@ -1937,6 +1959,13 @@ heap_drop_with_catalog(Oid relid)
 	if (relid == defaultPartOid)
 		update_default_partition_oid(parentOid, InvalidOid);
 
+	/* We allow to drop global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (is_other_backend_use_gtt(rel->rd_node))
+			elog(ERROR, "can not drop relation when other backend attached this global temp table");
+	}
+
 	/*
 	 * Schedule unlinking of the relation's physical files at commit.
 	 */
@@ -3163,9 +3192,10 @@ RemoveStatistics(Oid relid, AttrNumber attnum)
  *
  * The routine will truncate and then reconstruct the indexes on
  * the specified relation.  Caller must hold exclusive lock on rel.
+ *
  */
 static void
-RelationTruncateIndexes(Relation heapRelation)
+RelationTruncateIndexes(Relation heapRelation, LOCKMODE lockmode)
 {
 	ListCell   *indlist;
 
@@ -3177,7 +3207,7 @@ RelationTruncateIndexes(Relation heapRelation)
 		IndexInfo  *indexInfo;
 
 		/* Open the index relation; use exclusive lock, just to be sure */
-		currentIndex = index_open(indexId, AccessExclusiveLock);
+		currentIndex = index_open(indexId, lockmode);
 
 		/*
 		 * Fetch info needed for index_build.  Since we know there are no
@@ -3223,8 +3253,13 @@ heap_truncate(List *relids)
 	{
 		Oid			rid = lfirst_oid(cell);
 		Relation	rel;
+		LOCKMODE	lockmode = AccessExclusiveLock;
 
-		rel = table_open(rid, AccessExclusiveLock);
+		/* truncate global temp table only need RowExclusiveLock */
+		if (get_rel_persistence(rid) == RELPERSISTENCE_GLOBAL_TEMP)
+			lockmode = RowExclusiveLock;
+
+		rel = table_open(rid, lockmode);
 		relations = lappend(relations, rel);
 	}
 
@@ -3257,6 +3292,8 @@ void
 heap_truncate_one_rel(Relation rel)
 {
 	Oid			toastrelid;
+	LOCKMODE	lockmode = AccessExclusiveLock;
+	bool		truncate_toastrel = false;
 
 	/*
 	 * Truncate the relation.  Partitioned tables have no storage, so there is
@@ -3265,23 +3302,40 @@ heap_truncate_one_rel(Relation rel)
 	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 		return;
 
+	toastrelid = rel->rd_rel->reltoastrelid;
+
+	/*
+	 * Truncate global temp table only need RowExclusiveLock
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		lockmode = RowExclusiveLock;
+		if (OidIsValid(toastrelid) &&
+			gtt_storage_attached(toastrelid))
+			truncate_toastrel = true;
+	}
+	else if (OidIsValid(toastrelid))
+		truncate_toastrel = true;
+
 	/* Truncate the underlying relation */
 	table_relation_nontransactional_truncate(rel);
 
 	/* If the relation has indexes, truncate the indexes too */
-	RelationTruncateIndexes(rel);
+	RelationTruncateIndexes(rel, lockmode);
 
 	/* If there is a toast table, truncate that too */
-	toastrelid = rel->rd_rel->reltoastrelid;
-	if (OidIsValid(toastrelid))
+	if (truncate_toastrel)
 	{
-		Relation	toastrel = table_open(toastrelid, AccessExclusiveLock);
+		Relation	toastrel = table_open(toastrelid, lockmode);
 
 		table_relation_nontransactional_truncate(toastrel);
-		RelationTruncateIndexes(toastrel);
+		RelationTruncateIndexes(toastrel, lockmode);
 		/* keep the lock... */
 		table_close(toastrel, NoLock);
 	}
+
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		up_gtt_relstats(rel, 0, 0, 0, RecentXmin, InvalidMultiXactId);
 }
 
 /*
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 3e59e64..9867d6f 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -52,6 +52,7 @@
 #include "catalog/pg_trigger.h"
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
+#include "catalog/storage_gtt.h"
 #include "commands/event_trigger.h"
 #include "commands/progress.h"
 #include "commands/tablecmds.h"
@@ -877,6 +878,26 @@ index_create(Relation heapRelation,
 						indexRelationName, RelationGetRelationName(heapRelation))));
 	}
 
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		if (accessMethodObjectId != BTREE_AM_OID)
+			elog(ERROR, "only support btree index on global temp table");
+
+		/* We allow to create index on global temp table only this session use it */
+		if (is_other_backend_use_gtt(heapRelation->rd_node))
+			elog(ERROR, "can not create index when have other backend attached this global temp table");
+
+		/* No support create index on global temp table use concurrent mode yet */
+		if (concurrent)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("cannot create indexes on global temporary tables using concurrent mode")));
+
+		/* if global temp table not init storage, then skip build index */
+		if (!gtt_storage_attached(heapRelation->rd_node.relNode))
+			flags |= INDEX_CREATE_SKIP_BUILD;
+	}
+
 	/*
 	 * construct tuple descriptor for index tuples
 	 */
@@ -2045,6 +2066,13 @@ index_drop(Oid indexId, bool concurrent, bool concurrent_lock_mode)
 	 */
 	CheckTableNotInUse(userIndexRelation, "DROP INDEX");
 
+	/* We allow to drop index on global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(userHeapRelation))
+	{
+		if (is_other_backend_use_gtt(userHeapRelation->rd_node))
+			elog(ERROR, "can not drop index when other backend attached this global temp table");
+	}
+
 	/*
 	 * Drop Index Concurrently is more or less the reverse process of Create
 	 * Index Concurrently.
@@ -2736,20 +2764,29 @@ index_update_stats(Relation rel,
 		else					/* don't bother for indexes */
 			relallvisible = 0;
 
-		if (rd_rel->relpages != (int32) relpages)
+		/* update index stats into localhash for global temp table */
+		if (RELATION_IS_GLOBAL_TEMP(rel))
 		{
-			rd_rel->relpages = (int32) relpages;
-			dirty = true;
+			up_gtt_relstats(rel, relpages, reltuples, relallvisible,
+							InvalidTransactionId, InvalidMultiXactId);
 		}
-		if (rd_rel->reltuples != (float4) reltuples)
-		{
-			rd_rel->reltuples = (float4) reltuples;
-			dirty = true;
-		}
-		if (rd_rel->relallvisible != (int32) relallvisible)
+		else
 		{
-			rd_rel->relallvisible = (int32) relallvisible;
-			dirty = true;
+			if (rd_rel->relpages != (int32) relpages)
+			{
+				rd_rel->relpages = (int32) relpages;
+				dirty = true;
+			}
+			if (rd_rel->reltuples != (float4) reltuples)
+			{
+				rd_rel->reltuples = (float4) reltuples;
+				dirty = true;
+			}
+			if (rd_rel->relallvisible != (int32) relallvisible)
+			{
+				rd_rel->relallvisible = (int32) relallvisible;
+				dirty = true;
+			}
 		}
 	}
 
@@ -2864,6 +2901,12 @@ index_build(Relation heapRelation,
 		pgstat_progress_update_multi_param(6, index, val);
 	}
 
+	if (RELATION_IS_GLOBAL_TEMP(indexRelation))
+	{
+		if (!gtt_storage_attached(indexRelation->rd_node.relNode))
+			RelationCreateStorage(indexRelation->rd_node, RELPERSISTENCE_GLOBAL_TEMP, indexRelation);
+	}
+
 	/*
 	 * Call the access method's build procedure
 	 */
@@ -3196,12 +3239,22 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	/*
 	 * Scan the index and gather up all the TIDs into a tuplesort object.
 	 */
+	memset(&ivinfo, 0, sizeof(IndexVacuumInfo));
 	ivinfo.index = indexRelation;
 	ivinfo.analyze_only = false;
 	ivinfo.report_progress = true;
 	ivinfo.estimated_count = true;
 	ivinfo.message_level = DEBUG2;
-	ivinfo.num_heap_tuples = heapRelation->rd_rel->reltuples;
+
+	/* get relstats abort global temp table from hashtable, not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		get_gtt_relstats(RelationGetRelid(heapRelation),
+						NULL, &ivinfo.num_heap_tuples, NULL,
+						NULL, NULL);
+	}
+	else
+		ivinfo.num_heap_tuples = heapRelation->rd_rel->reltuples;
 	ivinfo.strategy = NULL;
 
 	/*
@@ -3459,6 +3512,15 @@ reindex_index(Oid indexId, bool skip_constraint_checks, char persistence,
 				 errmsg("cannot reindex temporary tables of other sessions")));
 
 	/*
+	 * Because global temp table cannot change relfilenode
+	 * no support reindex on global temp table yet.
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(iRel))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot reindex global temporary tables")));
+
+	/*
 	 * Also check for active uses of the index in the current transaction; we
 	 * don't want to reindex underneath an open indexscan.
 	 */
diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index e70243a..301da79 100644
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -647,6 +647,13 @@ RangeVarAdjustRelationPersistence(RangeVar *newRelation, Oid nspid)
 							 errmsg("cannot create temporary relation in non-temporary schema")));
 			}
 			break;
+		/* global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			if (isAnyTempNamespace(nspid))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+						 errmsg("cannot create global temp relations in temporary schemas")));
+			break;
 		case RELPERSISTENCE_PERMANENT:
 			if (isTempOrTempToastNamespace(nspid))
 				newRelation->relpersistence = RELPERSISTENCE_TEMP;
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index fddfbf1..03806ae 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -26,6 +26,7 @@
 #include "access/xlogutils.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "miscadmin.h"
 #include "storage/freespace.h"
 #include "storage/smgr.h"
@@ -73,9 +74,10 @@ static PendingRelDelete *pendingDeletes = NULL; /* head of linked list */
  *
  * This function is transactional. The creation is WAL-logged, and if the
  * transaction aborts later on, the storage will be destroyed.
+ *
  */
 SMgrRelation
-RelationCreateStorage(RelFileNode rnode, char relpersistence)
+RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel)
 {
 	PendingRelDelete *pending;
 	SMgrRelation srel;
@@ -85,6 +87,8 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	switch (relpersistence)
 	{
 		case RELPERSISTENCE_TEMP:
+		/* global temp table use same storage strategy as local temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			needs_wal = false;
 			break;
@@ -117,6 +121,10 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	pending->next = pendingDeletes;
 	pendingDeletes = pending;
 
+	/* remember global temp table storage info to localhash */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP && rel)
+		remember_gtt_storage_info(rnode, rel);
+
 	return srel;
 }
 
@@ -486,8 +494,15 @@ smgrDoPendingDeletes(bool isCommit)
 		smgrdounlinkall(srels, nrels, false);
 
 		for (i = 0; i < nrels; i++)
+		{
 			smgrclose(srels[i]);
 
+			/* clean global temp table flags when transaction commit or rollback */
+			if (SmgrIsTemp(srels[i]) && 
+				gtt_storage_attached(srels[i]->smgr_rnode.node.relNode))
+				forget_gtt_storage_info(srels[i]->smgr_rnode.node.relNode);
+		}
+
 		pfree(srels);
 	}
 }
diff --git a/src/backend/catalog/storage_gtt.c b/src/backend/catalog/storage_gtt.c
new file mode 100644
index 0000000..f489cd3
--- /dev/null
+++ b/src/backend/catalog/storage_gtt.c
@@ -0,0 +1,1129 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.c
+ *	  code to create and destroy physical storage for global temparary table
+ *
+ * IDENTIFICATION
+ *	  src/backend/catalog/storage_gtt.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/table.h"
+#include "access/visibilitymap.h"
+#include "access/xact.h"
+#include "access/xlog.h"
+#include "access/xloginsert.h"
+#include "access/xlogutils.h"
+#include "access/htup_details.h"
+#include "access/multixact.h"
+#include "catalog/storage.h"
+#include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/heap.h"
+#include "catalog/namespace.h"
+#include "catalog/pg_type.h"
+#include "catalog/pg_statistic.h"
+#include "commands/tablecmds.h"
+#include "funcapi.h"
+#include "nodes/primnodes.h"
+#include "nodes/pg_list.h"
+#include "nodes/execnodes.h"
+#include "miscadmin.h"
+#include "storage/freespace.h"
+#include "storage/smgr.h"
+#include "storage/ipc.h"
+#include "storage/proc.h"
+#include "storage/procarray.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "storage/sinvaladt.h"
+#include "utils/memutils.h"
+#include "utils/rel.h"
+#include "utils/hsearch.h"
+#include "utils/catcache.h"
+#include "utils/lsyscache.h"
+#include <utils/relcache.h>
+#include "utils/inval.h"
+#include "utils/guc.h"
+
+
+/* Copy from bitmapset.c, because gtt used the function in bitmapset.c */
+#define WORDNUM(x)	((x) / BITS_PER_BITMAPWORD)
+#define BITNUM(x)	((x) % BITS_PER_BITMAPWORD)
+
+#define BITMAPSET_SIZE(nwords)	\
+	(offsetof(Bitmapset, words) + (nwords) * sizeof(bitmapword))
+
+static bool gtt_cleaner_exit_registered = false;
+static HTAB *gtt_storage_local_hash = NULL;
+static HTAB *active_gtt_shared_hash = NULL;
+static MemoryContext gtt_relstats_context = NULL;
+
+/* relfrozenxid of all gtts in the current session */
+static List *gtt_session_relfrozenxid_list = NIL;
+static TransactionId gtt_session_frozenxid = InvalidTransactionId;
+
+typedef struct gtt_ctl_data
+{
+	LWLock			lock;
+	int			max_entry;
+	int			entry_size;
+}gtt_ctl_data;
+
+static gtt_ctl_data *gtt_shared_ctl = NULL;
+
+typedef struct
+{
+	RelFileNode	rnode;
+	Bitmapset	*map;
+	/* bitmap data */
+} gtt_shared_hash_entry;
+
+typedef struct
+{
+	Oid			relid;
+
+	Oid			spcnode;
+	/* pg_class stat */
+	int32		relpages;
+	float4		reltuples;
+	int32		relallvisible;
+	TransactionId relfrozenxid;
+	TransactionId relminmxid;
+	char		relkind;
+	bool		on_commit_delete;
+
+	/* pg_statistic */
+	int			natts;
+	int			*attnum;
+	HeapTuple	*att_stat_tups;
+} gtt_local_hash_entry;
+
+static Size action_gtt_shared_hash_entry_size(void);
+static void gtt_storage_checkin(RelFileNode rnode);
+static void gtt_storage_checkout(RelFileNode rnode, bool skiplock);
+static void gtt_storage_removeall(int code, Datum arg);
+static void insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid);
+static void remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid);
+static void set_gtt_session_relfrozenxid(void);
+
+Datum pg_get_gtt_statistics(PG_FUNCTION_ARGS);
+Datum pg_get_gtt_relstats(PG_FUNCTION_ARGS);
+Datum pg_gtt_attached_pid(PG_FUNCTION_ARGS);
+Datum pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS);
+
+
+static Size
+action_gtt_shared_hash_entry_size(void)
+{
+	int 	wordnum;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	wordnum = WORDNUM(MaxBackends + 1);
+	hash_entry_size += MAXALIGN(sizeof(gtt_shared_hash_entry));
+	hash_entry_size += MAXALIGN(BITMAPSET_SIZE(wordnum + 1));
+
+	return hash_entry_size;
+}
+
+Size
+active_gtt_shared_hash_size(void)
+{
+	Size	size = 0;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	size = MAXALIGN(sizeof(gtt_ctl_data));
+	hash_entry_size = action_gtt_shared_hash_entry_size();
+	size += hash_estimate_size(max_active_gtt, hash_entry_size);
+
+	return size;
+}
+
+void
+active_gtt_shared_hash_init(void)
+{
+	HASHCTL info;
+	bool	found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	gtt_shared_ctl =
+		ShmemInitStruct("gtt_shared_ctl",
+						sizeof(gtt_ctl_data),
+						&found);
+
+	if (!found)
+	{
+		LWLockRegisterTranche(LWTRANCHE_GTT_CTL, "gtt_shared_ctl");
+		LWLockInitialize(&gtt_shared_ctl->lock, LWTRANCHE_GTT_CTL);
+		gtt_shared_ctl->max_entry = max_active_gtt;
+		gtt_shared_ctl->entry_size = action_gtt_shared_hash_entry_size();
+	}
+
+	info.keysize = sizeof(RelFileNode);
+	info.entrysize = gtt_shared_ctl->entry_size;
+	active_gtt_shared_hash =
+		ShmemInitHash("active gtt shared hash",
+						gtt_shared_ctl->max_entry,
+						gtt_shared_ctl->max_entry,
+						&info, HASH_ELEM | HASH_BLOBS | HASH_FIXED_SIZE);
+}
+
+static void
+gtt_storage_checkin(RelFileNode rnode)
+{
+	gtt_shared_hash_entry	*entry;
+	bool			found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+	entry = (gtt_shared_hash_entry *) hash_search(active_gtt_shared_hash,
+												&rnode, HASH_ENTER_NULL, &found);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		ereport(ERROR,
+				(errcode(ERRCODE_OUT_OF_MEMORY),
+				 errmsg("out of shared memory"),
+				 errhint("You might need to increase max_active_gtt.")));
+	}
+
+	if (found == false)
+	{
+		int			wordnum;
+
+		entry->map = (Bitmapset *)((char *)entry + MAXALIGN(sizeof(gtt_shared_hash_entry)));
+		wordnum = WORDNUM(MaxBackends + 1);
+		memset(entry->map, 0, BITMAPSET_SIZE(wordnum + 1));
+		entry->map->nwords = wordnum + 1;
+	}
+
+	bms_add_member(entry->map, MyBackendId);
+	LWLockRelease(&gtt_shared_ctl->lock);
+}
+
+static void
+gtt_storage_checkout(RelFileNode rnode, bool skiplock)
+{
+	gtt_shared_hash_entry	*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (!skiplock)
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(rnode), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		if (!skiplock)
+			LWLockRelease(&gtt_shared_ctl->lock);
+
+		elog(WARNING, "relfilenode %u/%u/%u not exist in gtt shared hash when forget",
+						rnode.dbNode, rnode.spcNode, rnode.relNode);
+		return;
+	}
+
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+	bms_del_member(entry->map, MyBackendId);
+
+	if (bms_is_empty(entry->map))
+	{
+		if (!hash_search(active_gtt_shared_hash, &rnode, HASH_REMOVE, NULL))
+			elog(PANIC, "gtt shared hash table corrupted");
+	}
+
+	if (!skiplock)
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+	return;
+}
+
+Bitmapset *
+copy_active_gtt_bitmap(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	Bitmapset	*map_copy = NULL;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return NULL;
+	}
+
+	Assert(entry->map);
+	if (!bms_is_empty(entry->map))
+		map_copy = bms_copy(entry->map);
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return map_copy;
+}
+
+bool
+is_other_backend_use_gtt(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	bool		in_use = false;
+	int			num_use = 0;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return false;
+	}
+
+	Assert(entry->map);
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+
+	num_use = bms_num_members(entry->map);
+	if (num_use == 0)
+		in_use = false;
+	else if (num_use == 1)
+	{
+		if(bms_is_member(MyBackendId, entry->map))
+			in_use = false;
+		else
+			in_use = true;
+	}
+	else
+		in_use = true;
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return in_use;
+}
+
+void
+remember_gtt_storage_info(RelFileNode rnode, Relation rel)
+{
+	gtt_local_hash_entry	*entry;
+	MemoryContext			oldcontext;
+	Oid			relid = rnode.relNode;
+	bool		found;
+
+	if (max_active_gtt <= 0)
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("Global temporary table feature is disable"),
+			 errhint("You might need to increase max_active_gtt to enable this feature.")));
+
+	if (RecoveryInProgress())
+		elog(ERROR, "readonly mode not support access global temp table yet");
+
+	if (gtt_storage_local_hash == NULL)
+	{
+#define GTT_LOCAL_HASH_SIZE		1024
+		/* First time through: initialize the hash table */
+		HASHCTL		ctl;
+
+		MemSet(&ctl, 0, sizeof(ctl));
+		ctl.keysize = sizeof(Oid);
+		ctl.entrysize = sizeof(gtt_local_hash_entry);
+		gtt_storage_local_hash =
+			hash_create("global temp relation table",
+						GTT_LOCAL_HASH_SIZE,
+						&ctl, HASH_ELEM | HASH_BLOBS);
+
+		if (!CacheMemoryContext)
+			CreateCacheMemoryContext();
+
+		gtt_relstats_context =
+			AllocSetContextCreate(CacheMemoryContext,
+							"gtt relstats context",
+							ALLOCSET_DEFAULT_SIZES);
+	}
+
+	/* Look up or create an entry */
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_ENTER, &found);
+
+	if (found)
+	{
+		elog(ERROR, "backend %d relid %u already exists in global temp table local hash",
+					MyBackendId, relid);
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+
+	entry->spcnode = rnode.spcNode;
+	entry->relpages = 0;
+	entry->reltuples = 0;
+	entry->relallvisible = 0;
+	entry->relkind = rel->rd_rel->relkind;
+	/* only heap contain transaction information */
+	if (entry->relkind == RELKIND_RELATION || entry->relkind == RELKIND_PARTITIONED_TABLE)
+	{
+		int natts = RelationGetNumberOfAttributes(rel);
+		entry->natts = natts;
+		entry->attnum = palloc0(sizeof(int) * natts);
+		entry->att_stat_tups = palloc0(sizeof(HeapTuple) * natts);
+
+		if (RELATION_GTT_ON_COMMIT_DELETE(rel))
+		{
+			entry->on_commit_delete = true;
+			register_on_commit_action(rel->rd_node.relNode, ONCOMMIT_DELETE_ROWS);
+		}
+
+		entry->relfrozenxid = RecentXmin;
+		entry->relminmxid = GetOldestMultiXactId();
+		insert_gtt_relfrozenxid_to_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+		gtt_storage_checkin(rnode);
+	}
+	else
+	{
+		entry->natts = 0;
+		entry->attnum = 0;
+		entry->att_stat_tups = NULL;
+		entry->on_commit_delete = false;
+		entry->relfrozenxid = 0;
+		entry->relminmxid = 0;
+	}
+
+	MemoryContextSwitchTo(oldcontext);
+
+	if (!gtt_cleaner_exit_registered)
+	{
+		before_shmem_exit(gtt_storage_removeall, 0);
+		gtt_cleaner_exit_registered = true;
+	}
+
+	return;
+}
+
+void
+forget_gtt_storage_info(Oid relid)
+{
+	gtt_local_hash_entry		*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+				(void *) &(relid), HASH_FIND, NULL);
+
+	if (entry && entry->relkind == RELKIND_RELATION)
+	{
+		RelFileNode rnode;
+		int			i;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		gtt_storage_checkout(rnode, false);
+
+		Assert(TransactionIdIsNormal(entry->relfrozenxid));
+		remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+
+		for (i = 0; i < entry->natts; i++)
+		{
+			if (entry->att_stat_tups[i])
+			{
+				heap_freetuple(entry->att_stat_tups[i]);
+				entry->att_stat_tups[i] = NULL;
+			}
+		}
+	}
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_REMOVE, NULL);
+
+	return;
+}
+
+/* is the storage file was created in this backend */
+bool
+gtt_storage_attached(Oid relid)
+{
+	bool found;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	if (gtt_storage_local_hash == NULL)
+		return false;
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_FIND, &found);
+
+	return found;
+}
+
+static void
+gtt_storage_removeall(int code, Datum arg)
+{
+	HASH_SEQ_STATUS				status;
+	gtt_local_hash_entry		*entry;
+	int			nrels = 0,
+				maxrels = 0;
+	SMgrRelation	*srels = NULL;
+	RelFileNode		*rnodes = NULL;
+	char			*relkinds = NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	hash_seq_init(&status, gtt_storage_local_hash);
+	while ((entry = (gtt_local_hash_entry *) hash_seq_search(&status)) != NULL)
+	{
+		SMgrRelation srel;
+		RelFileNode rnode;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		srel = smgropen(rnode, MyBackendId);
+
+		/* allocate the initial array, or extend it, if needed */
+		if (maxrels == 0)
+		{
+			maxrels = 32;
+			srels = palloc(sizeof(SMgrRelation) * maxrels);
+			rnodes = palloc(sizeof(RelFileNode) * maxrels);
+			relkinds = palloc(sizeof(char) * maxrels);
+		}
+		else if (maxrels <= nrels)
+		{
+			maxrels *= 2;
+			srels = repalloc(srels, sizeof(SMgrRelation) * maxrels);
+			rnodes = repalloc(rnodes, sizeof(RelFileNode) * maxrels);
+			relkinds = repalloc(relkinds, sizeof(char) * maxrels);
+		}
+
+		srels[nrels] = srel;
+		rnodes[nrels] = rnode;
+		relkinds[nrels] = entry->relkind;
+		nrels++;
+	}
+
+	if (nrels > 0)
+	{
+		int i;
+
+		smgrdounlinkall(srels, nrels, false);
+
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+		for (i = 0; i < nrels; i++)
+		{
+			smgrclose(srels[i]);
+			if (relkinds[i] == RELKIND_RELATION)
+				gtt_storage_checkout(rnodes[i], true);
+		}
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+		pfree(srels);
+		pfree(rnodes);
+		pfree(relkinds);
+	}
+
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;
+
+	return;
+}
+
+/*
+ * Update global temp table relstats(relpage/reltuple/relallvisible) 
+ * to local hashtable
+ */
+void
+up_gtt_relstats(Relation relation,
+					BlockNumber num_pages,
+					double num_tuples,
+					BlockNumber num_all_visible_pages,
+					TransactionId relfrozenxid,
+					TransactionId relminmxid)
+{
+	Oid		relid = RelationGetRelid(relation);
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	Assert(entry->spcnode);
+
+	if (num_pages >= 0 &&
+		entry->relpages != (int32)num_pages)
+		entry->relpages = (int32)num_pages;
+
+	if (num_tuples >= 0 &&
+		num_tuples != (float4)entry->reltuples)
+		entry->reltuples = (float4)num_tuples;
+
+	/* only heap contain transaction information and relallvisible */
+	if (entry->relkind == RELKIND_RELATION)
+	{
+		if (entry->relallvisible >= 0 &&
+			entry->relallvisible != (int32)num_all_visible_pages)
+		{
+			entry->relallvisible = (int32)num_all_visible_pages;
+		}
+
+		if (TransactionIdIsNormal(relfrozenxid) &&
+			entry->relfrozenxid != relfrozenxid &&
+			(TransactionIdPrecedes(entry->relfrozenxid, relfrozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(), entry->relfrozenxid)))
+		{
+			remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+			entry->relfrozenxid = relfrozenxid;
+			insert_gtt_relfrozenxid_to_ordered_list(relfrozenxid);
+			set_gtt_session_relfrozenxid();
+		}
+
+		if (MultiXactIdIsValid(relminmxid) &&
+			entry->relminmxid != relminmxid &&
+			(MultiXactIdPrecedes(entry->relminmxid, relminmxid) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), entry->relminmxid)))
+		{
+			entry->relminmxid = relminmxid;
+		}
+	}
+
+	return;
+}
+
+/*
+ * Search global temp table relstats(relpage/reltuple/relallvisible) 
+ * from local hashtable.
+ */
+bool
+get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+				BlockNumber *relallvisible, TransactionId *relfrozenxid,
+				TransactionId *relminmxid)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	if (gtt_storage_local_hash == NULL)
+		return false;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return false;
+
+	Assert(entry->relid == relid);
+
+	if (relpages)
+		*relpages = entry->relpages;
+
+	if (reltuples)
+		*reltuples = entry->reltuples;
+
+	if (relallvisible)
+		*relallvisible = entry->relallvisible;
+
+	if (relfrozenxid)
+		*relfrozenxid = entry->relfrozenxid;
+
+	if (relminmxid)
+		*relminmxid = entry->relminmxid;
+
+	return true;
+}
+
+/*
+ * Update global temp table statistic info(definition is same as pg_statistic)
+ * to local hashtable where ananyze global temp table
+ */
+void
+up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+					TupleDesc tupleDescriptor, Datum *values, bool *isnull)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	MemoryContext			oldcontext;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	if (entry->relkind != RELKIND_RELATION)
+	{
+		elog(WARNING, "oid %u not a relation", reloid);
+		return;
+	}
+
+	/* todo */
+	if (entry->natts < natts)
+	{
+		elog(WARNING, "reloid %u not support update attstat after add colunm", reloid);
+		return;
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	Assert(entry->relid == reloid);
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == 0)
+		{
+			entry->attnum[i] = attnum;
+			break;
+		}
+		else if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			heap_freetuple(entry->att_stat_tups[i]);
+			entry->att_stat_tups[i] = NULL;
+			break;
+		}
+	}
+
+	Assert(i < entry->natts);
+	Assert(entry->att_stat_tups[i] == NULL);
+	entry->att_stat_tups[i] = heap_form_tuple(tupleDescriptor, values, isnull);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+/*
+ * Search global temp table statistic info(definition is same as pg_statistic)
+ * from local hashtable.
+ */
+HeapTuple
+get_gtt_att_statistic(Oid reloid, int attnum, bool inh)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return NULL;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return NULL;
+
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			return entry->att_stat_tups[i];
+		}
+	}
+
+	return NULL;
+}
+
+void
+release_gtt_statistic_cache(HeapTuple tup)
+{
+	/* do nothing */
+	return;
+}
+
+static void
+insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid)
+{
+	MemoryContext	oldcontext;
+	ListCell	*cell;
+	int			i;
+
+	Assert(TransactionIdIsNormal(relfrozenxid));
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	/* Does the datum belong at the front? */
+	if (gtt_session_relfrozenxid_list == NIL ||
+		TransactionIdFollowsOrEquals(relfrozenxid,
+			linitial_oid(gtt_session_relfrozenxid_list)))
+	{
+		gtt_session_relfrozenxid_list =
+			lcons_oid(relfrozenxid, gtt_session_relfrozenxid_list);
+		MemoryContextSwitchTo(oldcontext);
+
+		return;
+	}
+
+	/* No, so find the entry it belongs after */
+	i = 0;
+	foreach (cell, gtt_session_relfrozenxid_list)
+	{
+		if (TransactionIdFollowsOrEquals(relfrozenxid, lfirst_oid(cell)))
+			break;
+
+		i++;
+	}
+	gtt_session_relfrozenxid_list =
+		list_insert_nth_oid(gtt_session_relfrozenxid_list, i, relfrozenxid);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+static void
+remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid)
+{
+	gtt_session_relfrozenxid_list =
+		list_delete_oid(gtt_session_relfrozenxid_list, relfrozenxid);
+}
+
+static void
+set_gtt_session_relfrozenxid(void)
+{
+	TransactionId gtt_frozenxid = InvalidTransactionId;
+
+	if (gtt_session_relfrozenxid_list)
+		gtt_frozenxid = llast_oid(gtt_session_relfrozenxid_list);
+
+	gtt_session_frozenxid = gtt_frozenxid;
+	if (MyProc->session_gtt_frozenxid != gtt_frozenxid)
+		MyProc->session_gtt_frozenxid = gtt_frozenxid;
+}
+
+Datum
+pg_get_gtt_statistics(PG_FUNCTION_ARGS)
+{
+	HeapTuple	tuple;
+	Relation	rel = NULL;
+	int		attnum = PG_GETARG_INT32(1);
+	Oid		reloid = PG_GETARG_OID(0);
+	char		rel_persistence;
+	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	  tupdesc;
+	MemoryContext oldcontext;
+	Tuplestorestate *tupstore;
+	Relation		pg_tatistic = NULL;
+	TupleDesc		sd;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("set-valued function called in context that cannot accept a set")));
+
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("materialize mode required, but it is not " \
+				"allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+				rsinfo->econtext->ecxt_per_query_memory);
+
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	pg_tatistic = table_open(StatisticRelationId, AccessShareLock);
+	sd = RelationGetDescr(pg_tatistic);
+
+	tuple = get_gtt_att_statistic(reloid, attnum, false);
+	if (tuple)
+	{
+		Datum	values[31];
+		bool	isnull[31];
+		HeapTuple	res = NULL;
+
+		memset(&values, 0, sizeof(values));
+		memset(&isnull, 0, sizeof(isnull));
+		heap_deform_tuple(tuple, sd, values, isnull);
+		res = heap_form_tuple(tupdesc, values, isnull);
+		tuplestore_puttuple(tupstore, res);
+	}
+
+	table_close(rel, NoLock);
+	table_close(pg_tatistic, AccessShareLock);
+	tuplestore_donestoring(tupstore);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_get_gtt_relstats(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc		tupdesc;
+	Tuplestorestate	*tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	Oid		reloid = PG_GETARG_OID(0);
+	char	rel_persistence;
+	BlockNumber	relpages = 0;
+	double		reltuples = 0;
+	BlockNumber	relallvisible = 0;
+	uint32		relfrozenxid = 0;
+	uint32		relminmxid = 0;
+	Relation	rel = NULL;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	if (get_gtt_relstats(reloid,
+						&relpages, &reltuples, &relallvisible,
+						&relfrozenxid, &relminmxid))
+	{
+		Datum	values[5];
+		bool	isnull[5];
+
+		memset(isnull, 0, sizeof(isnull));
+		memset(values, 0, sizeof(values));
+		values[0] = Int32GetDatum(relpages);
+		values[1] = Float4GetDatum((float4)reltuples);
+		values[2] = Int32GetDatum(relallvisible);
+		values[3] = UInt32GetDatum(relfrozenxid);
+		values[4] = UInt32GetDatum(relminmxid);
+		tuple = heap_form_tuple(tupdesc, values, isnull);
+		tuplestore_puttuple(tupstore, tuple);
+	}
+
+	tuplestore_donestoring(tupstore);
+	table_close(rel, NoLock);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_gtt_attached_pid(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	Oid		reloid = PG_GETARG_OID(0);
+	char	rel_persistence;
+	Relation	rel = NULL;
+	PGPROC		*proc = NULL;
+	Bitmapset	*map = NULL;
+	pid_t		pid = 0;
+	int			backendid = 0;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	map = copy_active_gtt_bitmap(rel->rd_node);
+	if (map)
+	{
+		backendid = bms_first_member(map);
+
+		do
+		{
+			proc = BackendIdGetProc(backendid);
+			pid = proc->pid;
+			if (pid > 0)
+			{
+				Datum	values[2];
+				bool	isnull[2];
+
+				memset(isnull, false, sizeof(isnull));
+				memset(values, 0, sizeof(values));
+				values[0] = UInt32GetDatum(reloid);
+				values[1] = Int32GetDatum(pid);
+				tuple = heap_form_tuple(tupdesc, values, isnull);
+				tuplestore_puttuple(tupstore, tuple);
+			}
+			backendid = bms_next_member(map, backendid);
+		} while (backendid > 0);
+
+		pfree(map);
+	}
+
+	tuplestore_donestoring(tupstore);
+	table_close(rel, NoLock);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	int			num_xid = MaxBackends + 1;
+	int			*pids = NULL;
+	uint32		*xids = NULL;
+	int			i = 0;
+	int			j = 0;
+	uint32		oldest = 0;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (max_active_gtt <= 0)
+		return (Datum) 0;
+
+	if (RecoveryInProgress())
+		return (Datum) 0;
+
+	pids = palloc0(sizeof(int) * num_xid);
+	xids = palloc0(sizeof(int) * num_xid);
+	oldest = list_all_session_gtt_frozenxids(num_xid, pids, xids, &i);
+	if (i > 0)
+	{
+		if (i > 0)
+		{
+			pids[i] = 0;
+			xids[i] = oldest;
+			i++;
+		}
+
+		for(j = 0; j < i; j++)
+		{
+			Datum	values[2];
+			bool	isnull[2];
+
+			memset(isnull, false, sizeof(isnull));
+			memset(values, 0, sizeof(values));
+			values[0] = Int32GetDatum(pids[j]);
+			values[1] = UInt32GetDatum(xids[j]);
+			tuple = heap_form_tuple(tupdesc, values, isnull);
+			tuplestore_puttuple(tupstore, tuple);
+		}
+	}
+	tuplestore_donestoring(tupstore);
+	pfree(pids);
+	pfree(xids);
+
+	return (Datum) 0;
+}
+
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index c9e75f4..2adde62 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -186,6 +186,91 @@ CREATE OR REPLACE VIEW pg_sequences AS
     WHERE NOT pg_is_other_temp_schema(N.oid)
           AND relkind = 'S';
 
+-- For global temporary table
+CREATE VIEW pg_gtt_relstats WITH (security_barrier) AS
+ SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.*
+ FROM
+     pg_class c
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_get_gtt_relstats(c.oid) as s
+ WHERE c.relpersistence='g' AND c.relkind in('r','p') AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
+CREATE VIEW pg_gtt_attached_pids WITH (security_barrier) AS
+ SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.*
+ FROM
+     pg_class c
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_gtt_attached_pid(c.oid) as s
+ WHERE c.relpersistence='g' AND c.relkind in('r','p') AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
+CREATE VIEW pg_gtt_stats WITH (security_barrier) AS
+SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    a.attname,
+    s.stainherit AS inherited,
+    s.stanullfrac AS null_frac,
+    s.stawidth AS avg_width,
+    s.stadistinct AS n_distinct,
+        CASE
+            WHEN s.stakind1 = 1 THEN s.stavalues1
+            WHEN s.stakind2 = 1 THEN s.stavalues2
+            WHEN s.stakind3 = 1 THEN s.stavalues3
+            WHEN s.stakind4 = 1 THEN s.stavalues4
+            WHEN s.stakind5 = 1 THEN s.stavalues5
+        END AS most_common_vals,
+        CASE
+            WHEN s.stakind1 = 1 THEN s.stanumbers1
+            WHEN s.stakind2 = 1 THEN s.stanumbers2
+            WHEN s.stakind3 = 1 THEN s.stanumbers3
+            WHEN s.stakind4 = 1 THEN s.stanumbers4
+            WHEN s.stakind5 = 1 THEN s.stanumbers5
+        END AS most_common_freqs,
+        CASE
+            WHEN s.stakind1 = 2 THEN s.stavalues1
+            WHEN s.stakind2 = 2 THEN s.stavalues2
+            WHEN s.stakind3 = 2 THEN s.stavalues3
+            WHEN s.stakind4 = 2 THEN s.stavalues4
+            WHEN s.stakind5 = 2 THEN s.stavalues5
+        END AS histogram_bounds,
+        CASE
+            WHEN s.stakind1 = 3 THEN s.stanumbers1[1]
+            WHEN s.stakind2 = 3 THEN s.stanumbers2[1]
+            WHEN s.stakind3 = 3 THEN s.stanumbers3[1]
+            WHEN s.stakind4 = 3 THEN s.stanumbers4[1]
+            WHEN s.stakind5 = 3 THEN s.stanumbers5[1]
+        END AS correlation,
+        CASE
+            WHEN s.stakind1 = 4 THEN s.stavalues1
+            WHEN s.stakind2 = 4 THEN s.stavalues2
+            WHEN s.stakind3 = 4 THEN s.stavalues3
+            WHEN s.stakind4 = 4 THEN s.stavalues4
+            WHEN s.stakind5 = 4 THEN s.stavalues5
+        END AS most_common_elems,
+        CASE
+            WHEN s.stakind1 = 4 THEN s.stanumbers1
+            WHEN s.stakind2 = 4 THEN s.stanumbers2
+            WHEN s.stakind3 = 4 THEN s.stanumbers3
+            WHEN s.stakind4 = 4 THEN s.stanumbers4
+            WHEN s.stakind5 = 4 THEN s.stanumbers5
+        END AS most_common_elem_freqs,
+        CASE
+            WHEN s.stakind1 = 5 THEN s.stanumbers1
+            WHEN s.stakind2 = 5 THEN s.stanumbers2
+            WHEN s.stakind3 = 5 THEN s.stanumbers3
+            WHEN s.stakind4 = 5 THEN s.stanumbers4
+            WHEN s.stakind5 = 5 THEN s.stanumbers5
+        END AS elem_count_histogram
+   FROM 
+     pg_class c
+     JOIN pg_attribute a ON c.oid = a.attrelid
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_get_gtt_statistics(c.oid, a.attnum, ''::text) as s
+  WHERE c.relpersistence='g' AND c.relkind in('r','p') and NOT a.attisdropped AND has_column_privilege(c.oid, a.attnum, 'select'::text) AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
 CREATE VIEW pg_stats WITH (security_barrier) AS
     SELECT
         nspname AS schemaname,
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index c4420dd..a789718 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -66,6 +66,7 @@
 #include "utils/syscache.h"
 #include "utils/timestamp.h"
 
+#include "catalog/storage_gtt.h"
 
 /* Per-index data for ANALYZE */
 typedef struct AnlIndexData
@@ -103,7 +104,7 @@ static int	acquire_inherited_sample_rows(Relation onerel, int elevel,
 										  HeapTuple *rows, int targrows,
 										  double *totalrows, double *totaldeadrows);
 static void update_attstats(Oid relid, bool inh,
-							int natts, VacAttrStats **vacattrstats);
+							int natts, VacAttrStats **vacattrstats, char relpersistence);
 static Datum std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 static Datum ind_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 
@@ -586,14 +587,15 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 		 * pg_statistic for columns we didn't process, we leave them alone.)
 		 */
 		update_attstats(RelationGetRelid(onerel), inh,
-						attr_cnt, vacattrstats);
+						attr_cnt, vacattrstats, RelationGetRelPersistence(onerel));
 
 		for (ind = 0; ind < nindexes; ind++)
 		{
 			AnlIndexData *thisdata = &indexdata[ind];
 
 			update_attstats(RelationGetRelid(Irel[ind]), false,
-							thisdata->attr_cnt, thisdata->vacattrstats);
+							thisdata->attr_cnt, thisdata->vacattrstats,
+							RelationGetRelPersistence(Irel[ind]));
 		}
 
 		/*
@@ -673,11 +675,20 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 			IndexBulkDeleteResult *stats;
 			IndexVacuumInfo ivinfo;
 
+			memset(&ivinfo, 0, sizeof(IndexVacuumInfo));
 			ivinfo.index = Irel[ind];
 			ivinfo.analyze_only = true;
 			ivinfo.estimated_count = true;
 			ivinfo.message_level = elevel;
-			ivinfo.num_heap_tuples = onerel->rd_rel->reltuples;
+			/* get global temp relstats from localhash, not catalog */
+			if (RELATION_IS_GLOBAL_TEMP(onerel))
+			{
+				get_gtt_relstats(RelationGetRelid(onerel),
+								NULL, &ivinfo.num_heap_tuples, NULL,
+								NULL, NULL);
+			}
+			else
+				ivinfo.num_heap_tuples = onerel->rd_rel->reltuples;
 			ivinfo.strategy = vac_strategy;
 
 			stats = index_vacuum_cleanup(&ivinfo, NULL);
@@ -1456,7 +1467,7 @@ acquire_inherited_sample_rows(Relation onerel, int elevel,
  *		by taking a self-exclusive lock on the relation in analyze_rel().
  */
 static void
-update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
+update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats, char relpersistence)
 {
 	Relation	sd;
 	int			attno;
@@ -1558,31 +1569,45 @@ update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
 			}
 		}
 
-		/* Is there already a pg_statistic tuple for this attribute? */
-		oldtup = SearchSysCache3(STATRELATTINH,
-								 ObjectIdGetDatum(relid),
-								 Int16GetDatum(stats->attr->attnum),
-								 BoolGetDatum(inh));
-
-		if (HeapTupleIsValid(oldtup))
+		/* Update column statistic to localhash, not catalog */
+		if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		{
-			/* Yes, replace it */
-			stup = heap_modify_tuple(oldtup,
-									 RelationGetDescr(sd),
-									 values,
-									 nulls,
-									 replaces);
-			ReleaseSysCache(oldtup);
-			CatalogTupleUpdate(sd, &stup->t_self, stup);
+			up_gtt_att_statistic(relid,
+								stats->attr->attnum,
+								inh,
+								natts,
+								RelationGetDescr(sd),
+								values,
+								nulls);
 		}
 		else
 		{
-			/* No, insert new tuple */
-			stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
-			CatalogTupleInsert(sd, stup);
-		}
+			/* Is there already a pg_statistic tuple for this attribute? */
+			oldtup = SearchSysCache3(STATRELATTINH,
+									 ObjectIdGetDatum(relid),
+									 Int16GetDatum(stats->attr->attnum),
+									 BoolGetDatum(inh));
+
+			if (HeapTupleIsValid(oldtup))
+			{
+				/* Yes, replace it */
+				stup = heap_modify_tuple(oldtup,
+										 RelationGetDescr(sd),
+										 values,
+										 nulls,
+										 replaces);
+				ReleaseSysCache(oldtup);
+				CatalogTupleUpdate(sd, &stup->t_self, stup);
+			}
+			else
+			{
+				/* No, insert new tuple */
+				stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
+				CatalogTupleInsert(sd, stup);
+			}
 
-		heap_freetuple(stup);
+			heap_freetuple(stup);
+		}
 	}
 
 	table_close(sd, RowExclusiveLock);
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index e9d7a7f..3088e26 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -391,6 +391,12 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 					 errmsg("cannot vacuum temporary tables of other sessions")));
 	}
 
+	/* not support cluster global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(OldHeap))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support cluster global temporary tables yet")));
+
 	/*
 	 * Also check for active uses of the relation in the current transaction,
 	 * including open scans and pending AFTER trigger events.
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 52ce02f..3d3f7dc 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -2583,6 +2583,16 @@ ReindexMultipleTables(const char *objectName, ReindexObjectType objectKind,
 			!isTempNamespace(classtuple->relnamespace))
 			continue;
 
+		/* not support reindex on global temp table, so skip it */
+		if (classtuple->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			ereport(WARNING,
+				(errmsg("global temp table \"%s.%s\" skip reindexed",
+					get_namespace_name(get_rel_namespace(relid)),
+					get_rel_name(relid))));
+			continue;
+		}
+
 		/* Check user/system classification, and optionally skip */
 		if (objectKind == REINDEX_OBJECT_SYSTEM &&
 			!IsSystemClass(relid, classtuple))
diff --git a/src/backend/commands/lockcmds.c b/src/backend/commands/lockcmds.c
index 329ab84..dfa257c 100644
--- a/src/backend/commands/lockcmds.c
+++ b/src/backend/commands/lockcmds.c
@@ -96,7 +96,8 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
 	 * transaction.
 	 */
 	relpersistence = get_rel_persistence(relid);
-	if (relpersistence == RELPERSISTENCE_TEMP)
+	if (relpersistence == RELPERSISTENCE_TEMP ||
+		relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		MyXactFlags |= XACT_FLAGS_ACCESSEDTEMPNAMESPACE;
 
 	/* Check permissions. */
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index 6aab73b..44f350d 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -94,7 +94,7 @@ static HTAB *seqhashtab = NULL; /* hash table for SeqTable items */
  */
 static SeqTableData *last_used_seq = NULL;
 
-static void fill_seq_with_data(Relation rel, HeapTuple tuple);
+static void fill_seq_with_data(Relation rel, HeapTuple tuple, Buffer buf);
 static Relation lock_and_open_sequence(SeqTable seq);
 static void create_seq_hashtable(void);
 static void init_sequence(Oid relid, SeqTable *p_elm, Relation *p_rel);
@@ -108,6 +108,7 @@ static void init_params(ParseState *pstate, List *options, bool for_identity,
 						List **owned_by);
 static void do_setval(Oid relid, int64 next, bool iscalled);
 static void process_owned_by(Relation seqrel, List *owned_by, bool for_identity);
+int64 get_seqence_start_value(Oid seqid);
 
 
 /*
@@ -222,7 +223,7 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 
 	/* now initialize the sequence's data */
 	tuple = heap_form_tuple(tupDesc, value, null);
-	fill_seq_with_data(rel, tuple);
+	fill_seq_with_data(rel, tuple, InvalidBuffer);
 
 	/* process OWNED BY if given */
 	if (owned_by)
@@ -327,7 +328,7 @@ ResetSequence(Oid seq_relid)
 	/*
 	 * Insert the modified tuple into the new storage file.
 	 */
-	fill_seq_with_data(seq_rel, tuple);
+	fill_seq_with_data(seq_rel, tuple, InvalidBuffer);
 
 	/* Clear local cache so that we don't think we have cached numbers */
 	/* Note that we do not change the currval() state */
@@ -340,17 +341,21 @@ ResetSequence(Oid seq_relid)
  * Initialize a sequence's relation with the specified tuple as content
  */
 static void
-fill_seq_with_data(Relation rel, HeapTuple tuple)
+fill_seq_with_data(Relation rel, HeapTuple tuple, Buffer buf)
 {
-	Buffer		buf;
 	Page		page;
 	sequence_magic *sm;
 	OffsetNumber offnum;
+	bool lockBuffer = false;
 
 	/* Initialize first page of relation with special magic number */
 
-	buf = ReadBuffer(rel, P_NEW);
-	Assert(BufferGetBlockNumber(buf) == 0);
+	if (buf == InvalidBuffer)
+	{
+		buf = ReadBuffer(rel, P_NEW);
+		Assert(BufferGetBlockNumber(buf) == 0);
+		lockBuffer = true;
+	}
 
 	page = BufferGetPage(buf);
 
@@ -360,7 +365,8 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	/* Now insert sequence tuple */
 
-	LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
+	if (lockBuffer)
+		LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 
 	/*
 	 * Since VACUUM does not process sequences, we have to force the tuple to
@@ -410,7 +416,8 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	END_CRIT_SECTION();
 
-	UnlockReleaseBuffer(buf);
+	if (lockBuffer)
+		UnlockReleaseBuffer(buf);
 }
 
 /*
@@ -502,7 +509,7 @@ AlterSequence(ParseState *pstate, AlterSeqStmt *stmt)
 		/*
 		 * Insert the modified tuple into the new storage file.
 		 */
-		fill_seq_with_data(seqrel, newdatatuple);
+		fill_seq_with_data(seqrel, newdatatuple, InvalidBuffer);
 	}
 
 	/* process OWNED BY if given */
@@ -1178,6 +1185,25 @@ read_seq_tuple(Relation rel, Buffer *buf, HeapTuple seqdatatuple)
 	LockBuffer(*buf, BUFFER_LOCK_EXCLUSIVE);
 
 	page = BufferGetPage(*buf);
+	if (GlobalTempRelationPageIsNotInitialized(rel, page))
+	{
+		/* Initialize sequence for global temporary tables */
+		Datum		value[SEQ_COL_LASTCOL] = {0};
+		bool		null[SEQ_COL_LASTCOL] = {false};
+		HeapTuple	tuple;
+		int64		startv = get_seqence_start_value(RelationGetRelid(rel));
+
+		/*
+		 * last_value from pg_sequence.seqstart
+		 * log_cnt = 0
+		 * is_called = false
+		 */
+		value[SEQ_COL_LASTVAL-1] = Int64GetDatumFast(startv); /* start sequence with 1 */
+
+		tuple = heap_form_tuple(RelationGetDescr(rel), value, null);
+		fill_seq_with_data(rel, tuple, *buf);
+		heap_freetuple(tuple);
+	}
 	sm = (sequence_magic *) PageGetSpecialPointer(page);
 
 	if (sm->magic != SEQ_MAGIC)
@@ -1954,3 +1980,23 @@ seq_mask(char *page, BlockNumber blkno)
 
 	mask_unused_space(page);
 }
+
+int64
+get_seqence_start_value(Oid seqid)
+{
+	HeapTuple	seqtuple;
+	Form_pg_sequence	seqform;
+	int64		start;
+
+	seqtuple = SearchSysCache1(SEQRELID, ObjectIdGetDatum(seqid));
+	if (!HeapTupleIsValid(seqtuple))
+		elog(ERROR, "cache lookup failed for sequence %u",
+			 seqid);
+
+	seqform = (Form_pg_sequence) GETSTRUCT(seqtuple);
+	start = seqform->seqstart;
+	ReleaseSysCache(seqtuple);
+
+	return start;
+}
+
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 30b72b6..6db8c31 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -47,6 +47,7 @@
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
 #include "catalog/toasting.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/defrem.h"
@@ -552,6 +553,7 @@ static void refuseDupeIndexAttach(Relation parentIdx, Relation partIdx,
 								  Relation partitionTbl);
 static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
+static bool has_oncommit_option(List *options);
 
 
 /* ----------------------------------------------------------------
@@ -597,6 +599,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	LOCKMODE	parentLockmode;
 	const char *accessMethod = NULL;
 	Oid			accessMethodId = InvalidOid;
+	bool		has_oncommit_clause = false;
 
 	/*
 	 * Truncate relname to appropriate length (probably a waste of time, as
@@ -607,8 +610,10 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Check consistency of arguments
 	 */
+	/* global temp table same as local temp table */
 	if (stmt->oncommit != ONCOMMIT_NOOP
-		&& stmt->relation->relpersistence != RELPERSISTENCE_TEMP)
+		&& !(stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+			 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 				 errmsg("ON COMMIT can only be used on temporary tables")));
@@ -638,7 +643,9 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	 * code.  This is needed because calling code might not expect untrusted
 	 * tables to appear in pg_temp at the front of its search path.
 	 */
-	if (stmt->relation->relpersistence == RELPERSISTENCE_TEMP
+	/* global temp table same as local temp table */
+	if ((stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+		 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		&& InSecurityRestrictedOperation())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -739,6 +746,57 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Parse and validate reloptions, if any.
 	 */
+	/* global temp table */
+	has_oncommit_clause = has_oncommit_option(stmt->options);
+	if (stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP &&
+		(relkind == RELKIND_RELATION || relkind == RELKIND_PARTITIONED_TABLE))
+	{
+		/* inherit table or parition table inherit on commit property from parent table*/
+		if (inheritOids && stmt->oncommit == ONCOMMIT_NOOP && !has_oncommit_clause)
+		{
+			Oid			parent = linitial_oid(inheritOids);
+			Relation	relation = table_open(parent, NoLock);
+
+			if (!RELATION_IS_GLOBAL_TEMP(relation))
+				elog(ERROR, "The parent table must be global temporary table");
+
+			if (RELATION_GTT_ON_COMMIT_DELETE(relation))
+				stmt->oncommit = ONCOMMIT_DELETE_ROWS;
+			else
+				stmt->oncommit = ONCOMMIT_PRESERVE_ROWS;
+			table_close(relation, NoLock);
+		}
+
+		if (has_oncommit_clause)
+		{
+			if (stmt->oncommit != ONCOMMIT_NOOP)
+				elog(ERROR, "can not defeine global temp table with on commit and with clause at same time");
+		}
+		else
+		{
+			DefElem *opt = makeNode(DefElem);
+
+			opt->type = T_DefElem;
+			opt->defnamespace = NULL;
+			opt->defname = "on_commit_delete_rows";
+			opt->defaction = DEFELEM_UNSPEC;
+
+			/* use reloptions to remember on commit clause */
+			if (stmt->oncommit == ONCOMMIT_DELETE_ROWS)
+				opt->arg  = (Node *)makeString("true");
+			else if (stmt->oncommit == ONCOMMIT_PRESERVE_ROWS)
+				opt->arg  = (Node *)makeString("false");
+			else if (stmt->oncommit == ONCOMMIT_NOOP)
+				opt->arg  = (Node *)makeString("true");
+			else
+				elog(ERROR, "global temp table not support on commit drop clause");
+
+			stmt->options = lappend(stmt->options, opt);
+		}
+	}
+	else if (has_oncommit_clause)
+		elog(ERROR, "regular table cannot specifie on_commit_delete_rows");
+
 	reloptions = transformRelOptions((Datum) 0, stmt->options, NULL, validnsps,
 									 true, false);
 
@@ -1800,7 +1858,8 @@ ExecuteTruncateGuts(List *explicit_rels, List *relids, List *relids_logged,
 		 * table or the current physical file to be thrown away anyway.
 		 */
 		if (rel->rd_createSubid == mySubid ||
-			rel->rd_newRelfilenodeSubid == mySubid)
+			rel->rd_newRelfilenodeSubid == mySubid ||
+			RELATION_IS_GLOBAL_TEMP(rel))
 		{
 			/* Immediate, non-rollbackable truncation is OK */
 			heap_truncate_one_rel(rel);
@@ -3359,6 +3418,13 @@ RenameRelationInternal(Oid myrelid, const char *newrelname, bool is_internal, bo
 	 * specially.
 	 */
 	targetrelation = relation_open(myrelid, is_index ? ShareUpdateExclusiveLock : AccessExclusiveLock);
+
+	if (RELATION_IS_GLOBAL_TEMP(targetrelation))
+	{
+		if (is_other_backend_use_gtt(targetrelation->rd_node))
+			elog(ERROR, "can not rename relation when other backend attached this global temp table");
+	}
+
 	namespaceId = RelationGetNamespace(targetrelation);
 
 	/*
@@ -3534,6 +3600,13 @@ AlterTable(AlterTableStmt *stmt, LOCKMODE lockmode,
 	/* Caller is required to provide an adequate lock. */
 	rel = relation_open(context->relid, NoLock);
 
+	/* We allow to alter global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (is_other_backend_use_gtt(rel->rd_node))
+			elog(ERROR, "can not alter relation when other backend attached this global temp table");
+	}
+
 	CheckTableNotInUse(rel, "ALTER TABLE");
 
 	ATController(stmt, rel, stmt->cmds, stmt->relation->inh, lockmode, context);
@@ -8099,6 +8172,13 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 				 errmsg("referenced relation \"%s\" is not a table",
 						RelationGetRelationName(pkrel))));
 
+	/* global temp table not support foreign key constraint yet */
+	if (RELATION_IS_GLOBAL_TEMP(pkrel))
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("referenced relation \"%s\" is not a global temp table",
+						RelationGetRelationName(pkrel))));
+
 	if (!allowSystemTableMods && IsSystemRelation(pkrel))
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -8138,6 +8218,12 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 						 errmsg("constraints on temporary tables must involve temporary tables of this session")));
 			break;
+		/* global temp table not support foreign key constraint yet */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					 errmsg("not support foreign key constraints on global temp table yet")));
+			break;
 	}
 
 	/*
@@ -13174,7 +13260,7 @@ index_copy_data(Relation rel, RelFileNode newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
@@ -14581,7 +14667,9 @@ ATPrepChangePersistence(Relation rel, bool toLogged)
 	 */
 	switch (rel->rd_rel->relpersistence)
 	{
+		/* global temp table same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("cannot change logged status of table \"%s\" because it is temporary",
@@ -17221,3 +17309,20 @@ ATDetachCheckNoForeignKeyRefs(Relation partition)
 		table_close(rel, NoLock);
 	}
 }
+
+static bool
+has_oncommit_option(List *options)
+{
+	ListCell   *listptr;
+
+	foreach(listptr, options)
+	{
+		DefElem    *def = (DefElem *) lfirst(listptr);
+
+		if (pg_strcasecmp(def->defname, "on_commit_delete_rows") == 0)
+			return true;
+	}
+
+	return false;
+}
+
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index d625d17..db966e8 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -35,6 +35,7 @@
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
 #include "catalog/pg_namespace.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
 #include "commands/vacuum.h"
@@ -1125,12 +1126,25 @@ vac_estimate_reltuples(Relation relation,
 					   BlockNumber scanned_pages,
 					   double scanned_tuples)
 {
-	BlockNumber old_rel_pages = relation->rd_rel->relpages;
-	double		old_rel_tuples = relation->rd_rel->reltuples;
+	BlockNumber old_rel_pages = 0;
+	double		old_rel_tuples = 0;
 	double		old_density;
 	double		unscanned_pages;
 	double		total_tuples;
 
+	/* get relstat from gtt local hash */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+	{
+		get_gtt_relstats(RelationGetRelid(relation),
+						&old_rel_pages, &old_rel_tuples, NULL,
+						NULL, NULL);
+	}
+	else
+	{
+		old_rel_pages = relation->rd_rel->relpages;
+		old_rel_tuples = relation->rd_rel->reltuples;
+	}
+
 	/* If we did scan the whole table, just use the count as-is */
 	if (scanned_pages >= total_pages)
 		return scanned_tuples;
@@ -1230,24 +1244,8 @@ vac_update_relstats(Relation relation,
 	/* Apply statistical updates, if any, to copied tuple */
 
 	dirty = false;
-	if (pgcform->relpages != (int32) num_pages)
-	{
-		pgcform->relpages = (int32) num_pages;
-		dirty = true;
-	}
-	if (pgcform->reltuples != (float4) num_tuples)
-	{
-		pgcform->reltuples = (float4) num_tuples;
-		dirty = true;
-	}
-	if (pgcform->relallvisible != (int32) num_all_visible_pages)
-	{
-		pgcform->relallvisible = (int32) num_all_visible_pages;
-		dirty = true;
-	}
 
 	/* Apply DDL updates, but not inside an outer transaction (see above) */
-
 	if (!in_outer_xact)
 	{
 		/*
@@ -1272,37 +1270,64 @@ vac_update_relstats(Relation relation,
 		}
 	}
 
-	/*
-	 * Update relfrozenxid, unless caller passed InvalidTransactionId
-	 * indicating it has no new data.
-	 *
-	 * Ordinarily, we don't let relfrozenxid go backwards: if things are
-	 * working correctly, the only way the new frozenxid could be older would
-	 * be if a previous VACUUM was done with a tighter freeze_min_age, in
-	 * which case we don't want to forget the work it already did.  However,
-	 * if the stored relfrozenxid is "in the future", then it must be corrupt
-	 * and it seems best to overwrite it with the cutoff we used this time.
-	 * This should match vac_update_datfrozenxid() concerning what we consider
-	 * to be "in the future".
-	 */
-	if (TransactionIdIsNormal(frozenxid) &&
-		pgcform->relfrozenxid != frozenxid &&
-		(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
-		 TransactionIdPrecedes(ReadNewTransactionId(),
-							   pgcform->relfrozenxid)))
+	/* global temp table remember relstats to localhash not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
 	{
-		pgcform->relfrozenxid = frozenxid;
-		dirty = true;
+		up_gtt_relstats(relation,
+						num_pages, num_tuples,
+						num_all_visible_pages,
+						frozenxid, minmulti);
 	}
-
-	/* Similarly for relminmxid */
-	if (MultiXactIdIsValid(minmulti) &&
-		pgcform->relminmxid != minmulti &&
-		(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
-		 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
+	else
 	{
-		pgcform->relminmxid = minmulti;
-		dirty = true;
+		if (pgcform->relpages != (int32) num_pages)
+		{
+			pgcform->relpages = (int32) num_pages;
+			dirty = true;
+		}
+		if (pgcform->reltuples != (float4) num_tuples)
+		{
+			pgcform->reltuples = (float4) num_tuples;
+			dirty = true;
+		}
+		if (pgcform->relallvisible != (int32) num_all_visible_pages)
+		{
+			pgcform->relallvisible = (int32) num_all_visible_pages;
+			dirty = true;
+		}
+
+		/*
+		 * Update relfrozenxid, unless caller passed InvalidTransactionId
+		 * indicating it has no new data.
+		 *
+		 * Ordinarily, we don't let relfrozenxid go backwards: if things are
+		 * working correctly, the only way the new frozenxid could be older would
+		 * be if a previous VACUUM was done with a tighter freeze_min_age, in
+		 * which case we don't want to forget the work it already did.  However,
+		 * if the stored relfrozenxid is "in the future", then it must be corrupt
+		 * and it seems best to overwrite it with the cutoff we used this time.
+		 * This should match vac_update_datfrozenxid() concerning what we consider
+		 * to be "in the future".
+		 */
+		if (TransactionIdIsNormal(frozenxid) &&
+			pgcform->relfrozenxid != frozenxid &&
+			(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(),
+								   pgcform->relfrozenxid)))
+		{
+			pgcform->relfrozenxid = frozenxid;
+			dirty = true;
+		}
+
+		/* Similarly for relminmxid */
+		if (MultiXactIdIsValid(minmulti) &&
+			pgcform->relminmxid != minmulti &&
+			(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
+		{
+			pgcform->relminmxid = minmulti;
+			dirty = true;
+		}
 	}
 
 	/* If anything changed, write out the tuple. */
@@ -1394,6 +1419,10 @@ vac_update_datfrozenxid(void)
 			continue;
 		}
 
+		/* global temp table relstats not in pg_class */
+		if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			continue;
+
 		/*
 		 * Some table AMs might not need per-relation xid / multixid horizons.
 		 * It therefore seems reasonable to allow relfrozenxid and relminmxid
@@ -1451,6 +1480,25 @@ vac_update_datfrozenxid(void)
 	Assert(TransactionIdIsNormal(newFrozenXid));
 	Assert(MultiXactIdIsValid(newMinMulti));
 
+	/*
+	 * Global temp table get frozenxid from MyProc
+	 * to avoid the vacuum truncate clog that gtt need.
+	 */
+	if (max_active_gtt > 0)
+	{
+		TransactionId oldest_gtt_frozenxid =
+			list_all_session_gtt_frozenxids(0, NULL, NULL, NULL);
+
+		if (TransactionIdIsNormal(oldest_gtt_frozenxid) &&
+			TransactionIdPrecedes(oldest_gtt_frozenxid, newFrozenXid))
+		{
+			ereport(WARNING,
+				(errmsg("global temp table oldest FrozenXid is far in the past"),
+				 errhint("please truncate them or kill those sessions that use them.")));
+			newFrozenXid = oldest_gtt_frozenxid;
+		}
+	}
+
 	/* Now fetch the pg_database tuple we need to update. */
 	relation = table_open(DatabaseRelationId, RowExclusiveLock);
 
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 8286d9c..c3992a4 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -591,6 +591,8 @@ static void
 set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 						  RangeTblEntry *rte)
 {
+	char relpersistence;
+
 	/*
 	 * The flag has previously been initialized to false, so we can just
 	 * return if it becomes clear that we can't safely set it.
@@ -618,7 +620,11 @@ set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 			 * the rest of the necessary infrastructure right now anyway.  So
 			 * for now, bail out if we see a temporary table.
 			 */
-			if (get_rel_persistence(rte->relid) == RELPERSISTENCE_TEMP)
+			/* global temp table is same as local temp table */
+			relpersistence = get_rel_persistence(rte->relid);
+
+			if (relpersistence == RELPERSISTENCE_TEMP ||
+				relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 				return;
 
 			/*
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index d6f2153..310a9e2 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -6312,7 +6312,9 @@ plan_create_index_workers(Oid tableOid, Oid indexOid)
 	 * Furthermore, any index predicate or index expressions must be parallel
 	 * safe.
 	 */
+	/* global temp table is same as local temp table */
 	if (heap->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		heap->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexExpressions(index)) ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexPredicate(index)))
 	{
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index d82fc5a..189286b 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -31,6 +31,7 @@
 #include "catalog/pg_am.h"
 #include "catalog/pg_proc.h"
 #include "catalog/pg_statistic_ext.h"
+#include "catalog/storage_gtt.h"
 #include "foreign/fdwapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
@@ -53,6 +54,7 @@
 #include "utils/snapmgr.h"
 #include "utils/syscache.h"
 
+
 /* GUC parameter */
 int			constraint_exclusion = CONSTRAINT_EXCLUSION_PARTITION;
 
@@ -946,10 +948,10 @@ void
 estimate_rel_size(Relation rel, int32 *attr_widths,
 				  BlockNumber *pages, double *tuples, double *allvisfrac)
 {
-	BlockNumber curpages;
-	BlockNumber relpages;
-	double		reltuples;
-	BlockNumber relallvisible;
+	BlockNumber curpages = 0;
+	BlockNumber relpages = 0;
+	double		reltuples = 0;
+	BlockNumber relallvisible = 0;
 	double		density;
 
 	switch (rel->rd_rel->relkind)
@@ -963,6 +965,21 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 
 		case RELKIND_INDEX:
 
+			/* global temp table get relstats from localhash */
+			if (RELATION_IS_GLOBAL_TEMP(rel))
+			{
+				get_gtt_relstats(RelationGetRelid(rel),
+								&relpages, &reltuples, &relallvisible,
+								NULL, NULL);
+			}
+			else
+			{
+				/* coerce values in pg_class to more desirable types */
+				relpages = (BlockNumber) rel->rd_rel->relpages;
+				reltuples = (double) rel->rd_rel->reltuples;
+				relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
+			}
+
 			/*
 			 * XXX: It'd probably be good to move this into a callback,
 			 * individual index types e.g. know if they have a metapage.
@@ -971,11 +988,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 			/* it has storage, ok to call the smgr */
 			curpages = RelationGetNumberOfBlocks(rel);
 
-			/* coerce values in pg_class to more desirable types */
-			relpages = (BlockNumber) rel->rd_rel->relpages;
-			reltuples = (double) rel->rd_rel->reltuples;
-			relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
-
 			/* report estimated # pages */
 			*pages = curpages;
 			/* quick exit if rel is clearly empty */
@@ -985,10 +997,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 				*allvisfrac = 0;
 				break;
 			}
-			/* coerce values in pg_class to more desirable types */
-			relpages = (BlockNumber) rel->rd_rel->relpages;
-			reltuples = (double) rel->rd_rel->reltuples;
-			relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
 
 			/*
 			 * Discount the metapage while estimating the number of tuples.
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 748bebf..a5ddbcd 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -2579,6 +2579,11 @@ transformCreateTableAsStmt(ParseState *pstate, CreateTableAsStmt *stmt)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("materialized views must not use temporary tables or views")));
 
+		if (is_query_using_gtt(query))
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("materialized views must not use global temporary tables or views")));
+
 		/*
 		 * A materialized view would either need to save parameters for use in
 		 * maintaining/loading the data or prohibit them entirely.  The latter
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index ba5916b..0ee6931 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3290,17 +3290,11 @@ OptTemp:	TEMPORARY					{ $$ = RELPERSISTENCE_TEMP; }
 			| LOCAL TEMP				{ $$ = RELPERSISTENCE_TEMP; }
 			| GLOBAL TEMPORARY
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED					{ $$ = RELPERSISTENCE_UNLOGGED; }
 			| /*EMPTY*/					{ $$ = RELPERSISTENCE_PERMANENT; }
@@ -11588,19 +11582,13 @@ OptTempTableName:
 				}
 			| GLOBAL TEMPORARY opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED opt_table qualified_name
 				{
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index b875a50..123945b 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -81,6 +81,7 @@ static void expandTupleDesc(TupleDesc tupdesc, Alias *eref,
 							List **colnames, List **colvars);
 static int	specialAttNum(const char *attname);
 static bool isQueryUsingTempRelation_walker(Node *node, void *context);
+static bool is_query_using_gtt_walker(Node *node, void *context);
 
 
 /*
@@ -3579,3 +3580,49 @@ isQueryUsingTempRelation_walker(Node *node, void *context)
 								  isQueryUsingTempRelation_walker,
 								  context);
 }
+
+/* check if the query uses global temp table */
+static bool
+is_query_using_gtt_walker(Node *node, void *context)
+{
+	if (node == NULL)
+		return false;
+
+	if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+		ListCell   *rtable;
+
+		foreach(rtable, query->rtable)
+		{
+			RangeTblEntry *rte = lfirst(rtable);
+
+			if (rte->rtekind == RTE_RELATION)
+			{
+				Relation	rel = relation_open(rte->relid, AccessShareLock);
+				char		relpersistence = rel->rd_rel->relpersistence;
+
+				relation_close(rel, AccessShareLock);
+				if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+					return true;
+			}
+		}
+
+		return query_tree_walker(query,
+								 is_query_using_gtt_walker,
+								 context,
+								 QTW_IGNORE_JOINALIASES);
+	}
+
+	return expression_tree_walker(node,
+								  is_query_using_gtt_walker,
+								  context);
+}
+
+/* check if the query uses global temp table */
+bool
+is_query_using_gtt(Query *query)
+{
+	return is_query_using_gtt_walker((Node *) query, NULL);
+}
+
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index ee2d2b5..9c9abaa 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -437,6 +437,9 @@ generateSerialExtraStmts(CreateStmtContext *cxt, ColumnDef *column,
 	seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
 	seqstmt->options = seqoptions;
 
+	if (cxt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		seqstmt->sequence->relpersistence = cxt->relation->relpersistence;
+
 	/*
 	 * If a sequence data type was specified, add it to the options.  Prepend
 	 * to the list rather than append; in case a user supplied their own AS
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 6d1f28c..ed837d1 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -2086,6 +2086,11 @@ do_autovacuum(void)
 			}
 			continue;
 		}
+		else if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			/* autovacuum skip vacuum global temp table */
+			continue;
+		}
 
 		/* Fetch reloptions and the pgstat entry for this table */
 		relopts = extract_autovac_opts(tuple, pg_class_desc);
@@ -2152,7 +2157,9 @@ do_autovacuum(void)
 		/*
 		 * We cannot safely process other backends' temp tables, so skip 'em.
 		 */
-		if (classForm->relpersistence == RELPERSISTENCE_TEMP)
+		/* autovacuum skip vacuum global temp table */
+		if (classForm->relpersistence == RELPERSISTENCE_TEMP || 
+			classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 			continue;
 
 		relid = classForm->oid;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index aba3960..68adcd5 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -53,6 +53,8 @@
 #include "utils/resowner_private.h"
 #include "utils/timestamp.h"
 
+#include "utils/guc.h"
+#include "catalog/storage_gtt.h"
 
 /* Note: these two macros only work on shared buffers, not local ones! */
 #define BufHdrGetBlock(bufHdr)	((Block) (BufferBlocks + ((Size) (bufHdr)->buf_id) * BLCKSZ))
@@ -432,7 +434,7 @@ ForgetPrivateRefCountEntry(PrivateRefCountEntry *ref)
 static Buffer ReadBuffer_common(SMgrRelation reln, char relpersistence,
 								ForkNumber forkNum, BlockNumber blockNum,
 								ReadBufferMode mode, BufferAccessStrategy strategy,
-								bool *hit);
+								bool *hit, Relation rel);
 static bool PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy);
 static void PinBuffer_Locked(BufferDesc *buf);
 static void UnpinBuffer(BufferDesc *buf, bool fixOwner);
@@ -664,7 +666,8 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
 	 */
 	pgstat_count_buffer_read(reln);
 	buf = ReadBuffer_common(reln->rd_smgr, reln->rd_rel->relpersistence,
-							forkNum, blockNum, mode, strategy, &hit);
+							forkNum, blockNum, mode, strategy, &hit,
+							reln);
 	if (hit)
 		pgstat_count_buffer_hit(reln);
 	return buf;
@@ -692,7 +695,7 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 	Assert(InRecovery);
 
 	return ReadBuffer_common(smgr, RELPERSISTENCE_PERMANENT, forkNum, blockNum,
-							 mode, strategy, &hit);
+							 mode, strategy, &hit, NULL);
 }
 
 
@@ -704,7 +707,8 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 static Buffer
 ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 				  BlockNumber blockNum, ReadBufferMode mode,
-				  BufferAccessStrategy strategy, bool *hit)
+				  BufferAccessStrategy strategy, bool *hit,
+				  Relation rel)
 {
 	BufferDesc *bufHdr;
 	Block		bufBlock;
@@ -719,6 +723,15 @@ ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 
 	isExtend = (blockNum == P_NEW);
 
+	/* create storage when first read data page for gtt */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP &&
+		(isExtend || blockNum == 0) &&
+		forkNum == MAIN_FORKNUM &&
+		!gtt_storage_attached(smgr->smgr_rnode.node.relNode))
+	{
+		RelationCreateStorage(smgr->smgr_rnode.node, relpersistence, rel);
+	}
+
 	TRACE_POSTGRESQL_BUFFER_READ_START(forkNum, blockNum,
 									   smgr->smgr_rnode.node.spcNode,
 									   smgr->smgr_rnode.node.dbNode,
@@ -2809,6 +2822,16 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln)
 BlockNumber
 RelationGetNumberOfBlocksInFork(Relation relation, ForkNumber forkNum)
 {
+	/*
+	 * When this backend not init gtt storage
+	 * return 0
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(relation) &&
+		!gtt_storage_attached(relation->rd_node.relNode))
+	{
+		return 0;
+	}
+
 	switch (relation->rd_rel->relkind)
 	{
 		case RELKIND_SEQUENCE:
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 427b0d5..7adb969 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -21,6 +21,7 @@
 #include "access/nbtree.h"
 #include "access/subtrans.h"
 #include "access/twophase.h"
+#include "catalog/storage_gtt.h"
 #include "commands/async.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -147,6 +148,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, BTreeShmemSize());
 		size = add_size(size, SyncScanShmemSize());
 		size = add_size(size, AsyncShmemSize());
+		size = add_size(size, active_gtt_shared_hash_size());
 #ifdef EXEC_BACKEND
 		size = add_size(size, ShmemBackendArraySize());
 #endif
@@ -217,6 +219,8 @@ CreateSharedMemoryAndSemaphores(void)
 	SUBTRANSShmemInit();
 	MultiXactShmemInit();
 	InitBufferPool();
+	/* global temporary table */
+	active_gtt_shared_hash_init();
 
 	/*
 	 * Set up lock manager
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index c3adb2e..eb95e5f 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -62,6 +62,7 @@
 #include "utils/builtins.h"
 #include "utils/rel.h"
 #include "utils/snapmgr.h"
+#include "utils/guc.h"
 
 #define UINT32_ACCESS_ONCE(var)		 ((uint32)(*((volatile uint32 *)&(var))))
 
@@ -4087,3 +4088,77 @@ KnownAssignedXidsReset(void)
 
 	LWLockRelease(ProcArrayLock);
 }
+
+/*
+ * search all active backend to get oldest frozenxid
+ * for global temp table.
+ */
+int
+list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n)
+{
+	ProcArrayStruct *arrayP = procArray;
+	TransactionId result = InvalidTransactionId;
+	int			index;
+	int			flags = 0;
+	int			i = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	if (max_size > 0)
+	{
+		Assert(pids);
+		Assert(xids);
+		Assert(n);
+		*n = 0;
+	}
+
+	if (max_active_gtt <= 0)
+		return InvalidTransactionId;
+
+	if (RecoveryInProgress())
+		return InvalidTransactionId;
+
+	flags |= PROC_IS_AUTOVACUUM;
+	flags |= PROC_IN_LOGICAL_DECODING;
+
+	LWLockAcquire(ProcArrayLock, LW_SHARED);
+	if (max_size > 0 && max_size < arrayP->numProcs)
+	{
+		LWLockRelease(ProcArrayLock);
+		elog(ERROR, "list_all_gtt_frozenxids require more array");
+	}
+
+	for (index = 0; index < arrayP->numProcs; index++)
+	{
+		int			pgprocno = arrayP->pgprocnos[index];
+		volatile PGPROC *proc = &allProcs[pgprocno];
+		volatile PGXACT *pgxact = &allPgXact[pgprocno];
+
+		if (pgxact->vacuumFlags & flags)
+			continue;
+
+		if (proc->databaseId == MyDatabaseId &&
+			TransactionIdIsNormal(proc->session_gtt_frozenxid))
+		{
+			if (result == InvalidTransactionId)
+				result = proc->session_gtt_frozenxid;
+			else if (TransactionIdPrecedes(proc->session_gtt_frozenxid, result))
+				result = proc->session_gtt_frozenxid;
+
+			if (max_size > 0)
+			{
+				pids[i] = proc->pid;
+				xids[i] = proc->session_gtt_frozenxid;
+				i++;
+			}
+		}
+	}
+	LWLockRelease(ProcArrayLock);
+
+	if (max_size > 0)
+		*n = i;
+
+	return result;
+}
+
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 32df8c8..e4e1125 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -395,6 +395,7 @@ InitProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
@@ -577,6 +578,7 @@ InitAuxiliaryProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 85b7115..f5eae8c 100644
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -646,6 +646,12 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 		 */
 		if (zero_damaged_pages || InRecovery)
 			MemSet(buffer, 0, BLCKSZ);
+		else if(SmgrIsTemp(reln) && blocknum == 0 && forknum == MAIN_FORKNUM)
+		{
+			/* global temp table init btree meta page */
+			MemSet(buffer, 0, BLCKSZ);
+			mdwrite(reln, forknum, blocknum, buffer, true);
+		}
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_DATA_CORRUPTED),
diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c
index 8406644..92f028e 100644
--- a/src/backend/utils/adt/dbsize.c
+++ b/src/backend/utils/adt/dbsize.c
@@ -19,6 +19,8 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_authid.h"
 #include "catalog/pg_tablespace.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/index.h"
 #include "commands/dbcommands.h"
 #include "commands/tablespace.h"
 #include "miscadmin.h"
@@ -262,7 +264,6 @@ pg_tablespace_size_name(PG_FUNCTION_ARGS)
 	PG_RETURN_INT64(size);
 }
 
-
 /*
  * calculate size of (one fork of) a relation
  *
@@ -307,6 +308,41 @@ calculate_relation_size(RelFileNode *rfn, BackendId backend, ForkNumber forknum)
 	return totalsize;
 }
 
+static int64
+calculate_relation_size_all_file(Relation rel, const Bitmapset *gtt_map)
+{
+	int64		size = 0;
+	ForkNumber	forkNum;
+	BackendId	backendid;
+
+	/* For global temp table */
+	if (gtt_map)
+	{
+		Bitmapset *map_copy = bms_copy(gtt_map);
+
+		backendid = bms_first_member(map_copy);
+
+		do
+		{
+			for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
+				size += calculate_relation_size(&(rel->rd_node),
+										backendid,
+										forkNum);
+			backendid = bms_next_member(map_copy, backendid);
+		} while (backendid > 0);
+
+		pfree(map_copy);
+	}
+	else
+	{
+		for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
+			size += calculate_relation_size(&(rel->rd_node),
+											rel->rd_backend, forkNum);
+	}
+
+	return size;
+}
+
 Datum
 pg_relation_size(PG_FUNCTION_ARGS)
 {
@@ -340,20 +376,17 @@ pg_relation_size(PG_FUNCTION_ARGS)
  * Must not be applied to non-TOAST relations.
  */
 static int64
-calculate_toast_table_size(Oid toastrelid)
+calculate_toast_table_size(Oid toastrelid, Bitmapset *gtt_map)
 {
 	int64		size = 0;
 	Relation	toastRel;
-	ForkNumber	forkNum;
 	ListCell   *lc;
 	List	   *indexlist;
 
 	toastRel = relation_open(toastrelid, AccessShareLock);
 
 	/* toast heap size, including FSM and VM size */
-	for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-		size += calculate_relation_size(&(toastRel->rd_node),
-										toastRel->rd_backend, forkNum);
+	size += calculate_relation_size_all_file(toastRel, gtt_map);
 
 	/* toast index size, including FSM and VM size */
 	indexlist = RelationGetIndexList(toastRel);
@@ -365,9 +398,8 @@ calculate_toast_table_size(Oid toastrelid)
 
 		toastIdxRel = relation_open(lfirst_oid(lc),
 									AccessShareLock);
-		for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-			size += calculate_relation_size(&(toastIdxRel->rd_node),
-											toastIdxRel->rd_backend, forkNum);
+
+		size += calculate_relation_size_all_file(toastIdxRel, gtt_map);
 
 		relation_close(toastIdxRel, AccessShareLock);
 	}
@@ -386,23 +418,20 @@ calculate_toast_table_size(Oid toastrelid)
  * those won't have attached toast tables, but they can have multiple forks.
  */
 static int64
-calculate_table_size(Relation rel)
+calculate_table_size(Relation rel, Bitmapset *gtt_map)
 {
 	int64		size = 0;
-	ForkNumber	forkNum;
 
 	/*
 	 * heap size, including FSM and VM
 	 */
-	for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-		size += calculate_relation_size(&(rel->rd_node), rel->rd_backend,
-										forkNum);
+	size += calculate_relation_size_all_file(rel, gtt_map);
 
 	/*
 	 * Size of toast relation
 	 */
 	if (OidIsValid(rel->rd_rel->reltoastrelid))
-		size += calculate_toast_table_size(rel->rd_rel->reltoastrelid);
+		size += calculate_toast_table_size(rel->rd_rel->reltoastrelid, gtt_map);
 
 	return size;
 }
@@ -413,7 +442,7 @@ calculate_table_size(Relation rel)
  * Can be applied safely to an index, but you'll just get zero.
  */
 static int64
-calculate_indexes_size(Relation rel)
+calculate_indexes_size(Relation rel, Bitmapset *gtt_map)
 {
 	int64		size = 0;
 
@@ -429,14 +458,10 @@ calculate_indexes_size(Relation rel)
 		{
 			Oid			idxOid = lfirst_oid(cell);
 			Relation	idxRel;
-			ForkNumber	forkNum;
 
 			idxRel = relation_open(idxOid, AccessShareLock);
 
-			for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-				size += calculate_relation_size(&(idxRel->rd_node),
-												idxRel->rd_backend,
-												forkNum);
+			size += calculate_relation_size_all_file(idxRel, gtt_map);
 
 			relation_close(idxRel, AccessShareLock);
 		}
@@ -453,16 +478,40 @@ pg_table_size(PG_FUNCTION_ARGS)
 	Oid			relOid = PG_GETARG_OID(0);
 	Relation	rel;
 	int64		size;
+	Bitmapset	*gtt_map = NULL;
 
 	rel = try_relation_open(relOid, AccessShareLock);
 
 	if (rel == NULL)
 		PG_RETURN_NULL();
 
-	size = calculate_table_size(rel);
+	/* For GTT, calculate the size of the data file in the session where the GTT has been initialized */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (rel->rd_rel->relkind == RELKIND_INDEX)
+		{
+			Relation	relation;
+			Oid			relid;
+
+			relid = IndexGetRelation(RelationGetRelid(rel), false);
+			relation = try_relation_open(relid, AccessShareLock);
+			if (relation)
+			{
+				gtt_map = copy_active_gtt_bitmap(relation->rd_node);
+				relation_close(relation, AccessShareLock);
+			}
+		}
+		else
+			gtt_map = copy_active_gtt_bitmap(rel->rd_node);
+	}
+
+	size = calculate_table_size(rel, gtt_map);
 
 	relation_close(rel, AccessShareLock);
 
+	if(gtt_map)
+		pfree(gtt_map);
+
 	PG_RETURN_INT64(size);
 }
 
@@ -472,16 +521,24 @@ pg_indexes_size(PG_FUNCTION_ARGS)
 	Oid			relOid = PG_GETARG_OID(0);
 	Relation	rel;
 	int64		size;
+	Bitmapset	*gtt_map = NULL;
 
 	rel = try_relation_open(relOid, AccessShareLock);
 
 	if (rel == NULL)
 		PG_RETURN_NULL();
 
-	size = calculate_indexes_size(rel);
+	/* For GTT, calculate the size of the data file in the session where the GTT has been initialized */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		gtt_map = copy_active_gtt_bitmap(rel->rd_node);
+
+	size = calculate_indexes_size(rel, gtt_map);
 
 	relation_close(rel, AccessShareLock);
 
+	if (gtt_map)
+		pfree(gtt_map);
+
 	PG_RETURN_INT64(size);
 }
 
@@ -493,17 +550,25 @@ static int64
 calculate_total_relation_size(Relation rel)
 {
 	int64		size;
+	Bitmapset	*gtt_map = NULL;
+
+	/* For GTT, calculate the size of the data file in the session where the GTT has been initialized */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		gtt_map = copy_active_gtt_bitmap(rel->rd_node);
 
 	/*
 	 * Aggregate the table size, this includes size of the heap, toast and
 	 * toast index with free space and visibility map
 	 */
-	size = calculate_table_size(rel);
+	size = calculate_table_size(rel, gtt_map);
 
 	/*
 	 * Add size of all attached indexes as well
 	 */
-	size += calculate_indexes_size(rel);
+	size += calculate_indexes_size(rel, gtt_map);
+
+	if (gtt_map)
+		pfree(gtt_map);
 
 	return size;
 }
@@ -1008,6 +1073,10 @@ pg_relation_filepath(PG_FUNCTION_ARGS)
 				Assert(backend != InvalidBackendId);
 			}
 			break;
+		/* For global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			backend = BackendIdForTempRelations();
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relform->relpersistence);
 			backend = InvalidBackendId; /* placate compiler */
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 7c6f057..589bd38 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -142,6 +142,7 @@
 #include "utils/timestamp.h"
 #include "utils/typcache.h"
 
+#include "catalog/storage_gtt.h"
 
 /* Hooks for plugins to get control when we ask for stats */
 get_relation_stats_hook_type get_relation_stats_hook = NULL;
@@ -4578,12 +4579,25 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
 						}
 						else if (index->indpred == NIL)
 						{
-							vardata->statsTuple =
-								SearchSysCache3(STATRELATTINH,
-												ObjectIdGetDatum(index->indexoid),
-												Int16GetDatum(pos + 1),
-												BoolGetDatum(false));
-							vardata->freefunc = ReleaseSysCache;
+							char rel_persistence = get_rel_persistence(index->indexoid);
+
+							if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+							{
+								vardata->statsTuple =
+									get_gtt_att_statistic(index->indexoid,
+														Int16GetDatum(pos + 1),
+														false);
+								vardata->freefunc = release_gtt_statistic_cache;
+							}
+							else
+							{
+								vardata->statsTuple =
+									SearchSysCache3(STATRELATTINH,
+													ObjectIdGetDatum(index->indexoid),
+													Int16GetDatum(pos + 1),
+													BoolGetDatum(false));
+								vardata->freefunc = ReleaseSysCache;
+							}
 
 							if (HeapTupleIsValid(vardata->statsTuple))
 							{
@@ -4708,15 +4722,27 @@ examine_simple_variable(PlannerInfo *root, Var *var,
 	}
 	else if (rte->rtekind == RTE_RELATION)
 	{
-		/*
-		 * Plain table or parent of an inheritance appendrel, so look up the
-		 * column in pg_statistic
-		 */
-		vardata->statsTuple = SearchSysCache3(STATRELATTINH,
-											  ObjectIdGetDatum(rte->relid),
-											  Int16GetDatum(var->varattno),
-											  BoolGetDatum(rte->inh));
-		vardata->freefunc = ReleaseSysCache;
+		char rel_persistence = get_rel_persistence(rte->relid);
+
+		if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata->statsTuple = get_gtt_att_statistic(rte->relid,
+														var->varattno,
+														rte->inh);
+			vardata->freefunc = release_gtt_statistic_cache;
+		}
+		else
+		{
+			/*
+			 * Plain table or parent of an inheritance appendrel, so look up the
+			 * column in pg_statistic
+			 */
+			vardata->statsTuple = SearchSysCache3(STATRELATTINH,
+												  ObjectIdGetDatum(rte->relid),
+												  Int16GetDatum(var->varattno),
+												  BoolGetDatum(rte->inh));
+			vardata->freefunc = ReleaseSysCache;
+		}
 
 		if (HeapTupleIsValid(vardata->statsTuple))
 		{
@@ -6098,6 +6124,7 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	{
 		/* Simple variable --- look to stats for the underlying table */
 		RangeTblEntry *rte = planner_rt_fetch(index->rel->relid, root);
+		char	rel_persistence = get_rel_persistence(rte->relid);
 
 		Assert(rte->rtekind == RTE_RELATION);
 		relid = rte->relid;
@@ -6115,6 +6142,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													rte->inh);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -6126,6 +6160,8 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	}
 	else
 	{
+		char	rel_persistence = get_rel_persistence(index->indexoid);
+
 		/* Expression --- maybe there are stats for the index itself */
 		relid = index->indexoid;
 		colnum = 1;
@@ -6141,6 +6177,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													false);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -7054,6 +7097,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		/* attempt to lookup stats in relation for this index column */
 		if (attnum != 0)
 		{
+			char	rel_persistence = get_rel_persistence(rte->relid);
+
 			/* Simple variable -- look to stats for the underlying table */
 			if (get_relation_stats_hook &&
 				(*get_relation_stats_hook) (root, rte, attnum, &vardata))
@@ -7066,6 +7111,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					elog(ERROR,
 						 "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(rte->relid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple =
@@ -7078,6 +7131,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		}
 		else
 		{
+			char	rel_persistence = get_rel_persistence(index->indexoid);
+
 			/*
 			 * Looks like we've found an expression column in the index. Let's
 			 * see if there's any stats for it.
@@ -7097,6 +7152,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					!vardata.freefunc)
 					elog(ERROR, "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(index->indexoid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple = SearchSysCache3(STATRELATTINH,
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 1e3e6d3..44686ce 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -34,6 +34,7 @@
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_transform.h"
 #include "catalog/pg_type.h"
+#include "catalog/storage_gtt.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "utils/array.h"
@@ -46,6 +47,7 @@
 #include "utils/syscache.h"
 #include "utils/typcache.h"
 
+
 /* Hook for plugins to get control in get_attavgwidth() */
 get_attavgwidth_hook_type get_attavgwidth_hook = NULL;
 
@@ -2878,6 +2880,18 @@ get_attavgwidth(Oid relid, AttrNumber attnum)
 		if (stawidth > 0)
 			return stawidth;
 	}
+	if (get_rel_persistence(relid) == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		tp = get_gtt_att_statistic(relid, attnum, false);
+		if (!HeapTupleIsValid(tp))
+			return 0;
+
+		stawidth = ((Form_pg_statistic) GETSTRUCT(tp))->stawidth;
+		if (stawidth > 0)
+			return stawidth;
+		else
+			return 0;
+	}
 	tp = SearchSysCache3(STATRELATTINH,
 						 ObjectIdGetDatum(relid),
 						 Int16GetDatum(attnum),
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index df025a5..1c30d86 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -1124,6 +1124,16 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
 				relation->rd_islocaltemp = false;
 			}
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			{
+				relation->rd_backend = BackendIdForTempRelations();
+				/*
+				 * For global temp table, all backend can use
+				 * this relation, so rd_islocaltemp always true.
+				 */
+				relation->rd_islocaltemp = true;
+			}
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c",
 				 relation->rd_rel->relpersistence);
@@ -3313,6 +3323,10 @@ RelationBuildLocalRelation(const char *relname,
 			rel->rd_backend = BackendIdForTempRelations();
 			rel->rd_islocaltemp = true;
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			rel->rd_backend = BackendIdForTempRelations();
+			rel->rd_islocaltemp = true;
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relpersistence);
 			break;
@@ -3427,6 +3441,9 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 	TransactionId freezeXid = InvalidTransactionId;
 	RelFileNode newrnode;
 
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+		elog(ERROR, "global temp table does not allow setting new relfilenode");
+
 	/* Allocate a new relfilenode */
 	newrelfilenode = GetNewRelFileNode(relation->rd_rel->reltablespace, NULL,
 									   persistence);
@@ -3467,7 +3484,7 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 				/* handle these directly, at least for now */
 				SMgrRelation srel;
 
-				srel = RelationCreateStorage(newrnode, persistence);
+				srel = RelationCreateStorage(newrnode, persistence, relation);
 				smgrclose(srel);
 			}
 			break;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index e44f71e..44c86c8 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -139,6 +139,18 @@ char	   *GUC_check_errmsg_string;
 char	   *GUC_check_errdetail_string;
 char	   *GUC_check_errhint_string;
 
+/*
+ * num = 0 means disable global temp table feature.
+ * global temp table define can still storage in catalog
+ * just can not use.
+ * num > 0 means database can management num active global temp table.
+ */
+#define	MIN_NUM_ACTIVE_GTT			0
+#define	DEFAULT_NUM_ACTIVE_GTT			1000
+#define	MAX_NUM_ACTIVE_GTT			1000000
+
+int		max_active_gtt = MIN_NUM_ACTIVE_GTT;
+
 static void do_serialize(char **destptr, Size *maxbytes, const char *fmt,...) pg_attribute_printf(3, 4);
 
 static void set_config_sourcefile(const char *name, char *sourcefile,
@@ -1992,6 +2004,15 @@ static struct config_bool ConfigureNamesBool[] =
 static struct config_int ConfigureNamesInt[] =
 {
 	{
+		{"max_active_global_temporary_table", PGC_POSTMASTER, UNGROUPED,
+			gettext_noop("max active global temporary table."),
+			NULL
+		},
+		&max_active_gtt,
+		DEFAULT_NUM_ACTIVE_GTT, MIN_NUM_ACTIVE_GTT, MAX_NUM_ACTIVE_GTT,
+		NULL, NULL, NULL
+	},
+	{
 		{"archive_timeout", PGC_SIGHUP, WAL_ARCHIVING,
 			gettext_noop("Forces a switch to the next WAL file if a "
 						 "new file has not been started within N seconds."),
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 799b698..b98d396 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15583,6 +15583,7 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 	{
 		char	   *ftoptions = NULL;
 		char	   *srvname = NULL;
+		char		*table_type = NULL;
 
 		switch (tbinfo->relkind)
 		{
@@ -15634,9 +15635,15 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 			binary_upgrade_set_pg_class_oids(fout, q,
 											 tbinfo->dobj.catId.oid, false);
 
+		if (tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED)
+			table_type = "UNLOGGED ";
+		else if (tbinfo->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			table_type = "GLOBAL TEMPORARY ";
+		else
+			table_type = "";
+
 		appendPQExpBuffer(q, "CREATE %s%s %s",
-						  tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED ?
-						  "UNLOGGED " : "",
+						  table_type,
 						  reltypename,
 						  qualrelname);
 
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index f3c7eb9..28134e2 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3723,7 +3723,8 @@ listTables(const char *tabtypes, const char *pattern, bool verbose, bool showSys
 		if (pset.sversion >= 90100)
 		{
 			appendPQExpBuffer(&buf,
-							  ",\n  CASE c.relpersistence WHEN 'p' THEN '%s' WHEN 't' THEN '%s' WHEN 'u' THEN '%s' END as \"%s\"",
+							  ",\n  CASE c.relpersistence WHEN 'g' THEN '%s' WHEN 'p' THEN '%s' WHEN 't' THEN '%s' WHEN 'u' THEN '%s' END as \"%s\"",
+							  gettext_noop("session"),
 							  gettext_noop("permanent"),
 							  gettext_noop("temporary"),
 							  gettext_noop("unlogged"),
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index a12fc1f..78958e4 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -165,6 +165,7 @@ typedef FormData_pg_class *Form_pg_class;
 #define		  RELPERSISTENCE_PERMANENT	'p' /* regular table */
 #define		  RELPERSISTENCE_UNLOGGED	'u' /* unlogged permanent table */
 #define		  RELPERSISTENCE_TEMP		't' /* temporary table */
+#define		  RELPERSISTENCE_GLOBAL_TEMP	'g' /* global temporary table */
 
 /* default selection for replica identity (primary key or nothing) */
 #define		  REPLICA_IDENTITY_DEFAULT	'd'
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index fcf2a12..ba0bd5f 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -5484,6 +5484,40 @@
   proparallel => 'r', prorettype => 'float8', proargtypes => 'oid',
   prosrc => 'pg_stat_get_xact_function_self_time' },
 
+# For global temporary table
+{ oid => '4191',
+  descr => 'List local statistics for global temporary table',
+  proname => 'pg_get_gtt_statistics', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid int4 anyelement',
+  proallargtypes => '{oid,int4,anyelement,oid,int2,bool,float4,int4,float4,int2,int2,int2,int2,int2,oid,oid,oid,oid,oid,oid,oid,oid,oid,oid,_float4,_float4,_float4,_float4,_float4,anyarray,anyarray,anyarray,anyarray,anyarray}',
+  proargmodes => '{i,i,i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
+  proargnames => '{relid,att,x,starelid,staattnum,stainherit,stanullfrac,stawidth,stadistinct,stakind1,stakind2,stakind3,stakind4,stakind5,staop1,staop2,staop3,staop4,staop5,stacoll1,stacoll2,stacoll3,stacoll4,stacoll5,stanumbers1,stanumbers2,stanumbers3,stanumbers4,stanumbers5,stavalues1,stavalues2,stavalues3,stavalues4,stavalues5}',
+  prosrc => 'pg_get_gtt_statistics' },
+{ oid => '4192',
+  descr => 'List local relstats for global temporary table',
+  proname => 'pg_get_gtt_relstats', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid',
+  proallargtypes => '{oid,int4,float4,int4,xid,xid}',
+  proargmodes => '{i,o,o,o,o,o}',
+  proargnames => '{relid,relpages,reltuples,relallvisible,relfrozenxid,relminmxid}',
+  prosrc => 'pg_get_gtt_relstats' },
+{ oid => '4193',
+  descr => 'List attached pid for one global temporary table',
+  proname => 'pg_gtt_attached_pid', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid',
+  proallargtypes => '{oid,oid,int4}',
+  proargmodes => '{i,o,o}',
+  proargnames => '{relid,relid,pid}',
+  prosrc => 'pg_gtt_attached_pid' },
+{ oid => '4194',
+  descr => 'List those backends that have used global temporary table',
+  proname => 'pg_list_gtt_relfrozenxids', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => '',
+  proallargtypes => '{int4,xid}',
+  proargmodes => '{o,o}',
+  proargnames => '{pid,relfrozenxid}',
+  prosrc => 'pg_list_gtt_relfrozenxids' },
+
 { oid => '3788',
   descr => 'statistics: timestamp of the current statistics snapshot',
   proname => 'pg_stat_get_snapshot_timestamp', provolatile => 's',
diff --git a/src/include/catalog/storage.h b/src/include/catalog/storage.h
index 048003c..af48cdf 100644
--- a/src/include/catalog/storage.h
+++ b/src/include/catalog/storage.h
@@ -19,7 +19,7 @@
 #include "storage/smgr.h"
 #include "utils/relcache.h"
 
-extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence);
+extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel);
 extern void RelationDropStorage(Relation rel);
 extern void RelationPreserveStorage(RelFileNode rnode, bool atCommit);
 extern void RelationTruncate(Relation rel, BlockNumber nblocks);
diff --git a/src/include/catalog/storage_gtt.h b/src/include/catalog/storage_gtt.h
new file mode 100644
index 0000000..eacc214
--- /dev/null
+++ b/src/include/catalog/storage_gtt.h
@@ -0,0 +1,39 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.h
+ *	  prototypes for functions in backend/catalog/storage_gtt.c
+ *
+ * src/include/catalog/storage_gtt.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef STORAGE_GTT_H
+#define STORAGE_GTT_H
+
+#include "access/htup.h"
+#include "storage/block.h"
+#include "storage/relfilenode.h"
+#include "utils/relcache.h"
+
+extern Size active_gtt_shared_hash_size(void);
+extern void active_gtt_shared_hash_init(void);
+extern void remember_gtt_storage_info(RelFileNode rnode, Relation rel);
+extern void forget_gtt_storage_info(Oid relid);
+extern bool is_other_backend_use_gtt(RelFileNode node);
+extern bool gtt_storage_attached(Oid relid);
+extern Bitmapset *copy_active_gtt_bitmap(RelFileNode node);
+extern void up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+								TupleDesc tupleDescriptor, Datum *values, bool *isnull);
+extern HeapTuple get_gtt_att_statistic(Oid reloid, int attnum, bool inh);
+extern void release_gtt_statistic_cache(HeapTuple tup);
+extern void up_gtt_relstats(Relation relation,
+							BlockNumber num_pages,
+							double num_tuples,
+							BlockNumber num_all_visible_pages,
+							TransactionId relfrozenxid,
+							TransactionId relminmxid);
+extern bool get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+							BlockNumber *relallvisible, TransactionId *relfrozenxid,
+							TransactionId *relminmxid);
+
+#endif							/* STORAGE_H */
diff --git a/src/include/parser/parse_relation.h b/src/include/parser/parse_relation.h
index 93f9446..14cafae 100644
--- a/src/include/parser/parse_relation.h
+++ b/src/include/parser/parse_relation.h
@@ -120,4 +120,7 @@ extern Oid	attnumTypeId(Relation rd, int attid);
 extern Oid	attnumCollationId(Relation rd, int attid);
 extern bool isQueryUsingTempRelation(Query *query);
 
+/* global temp table check */
+extern bool is_query_using_gtt(Query *query);
+
 #endif							/* PARSE_RELATION_H */
diff --git a/src/include/storage/bufpage.h b/src/include/storage/bufpage.h
index 870ecb5..92c590e 100644
--- a/src/include/storage/bufpage.h
+++ b/src/include/storage/bufpage.h
@@ -405,6 +405,8 @@ do { \
 #define PageClearPrunable(page) \
 	(((PageHeader) (page))->pd_prune_xid = InvalidTransactionId)
 
+#define GlobalTempRelationPageIsNotInitialized(rel, page) \
+	((rel)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP && PageIsNew(page))
 
 /* ----------------------------------------------------------------
  *		extern declarations
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 8fda8e4..172eae9 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -220,6 +220,7 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_TBM,
 	LWTRANCHE_PARALLEL_APPEND,
 	LWTRANCHE_SXACT,
+	LWTRANCHE_GTT_CTL,
 	LWTRANCHE_FIRST_USER_DEFINED
 }			BuiltinTrancheIds;
 
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 5b407e6..f13250a 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -117,6 +117,8 @@ struct PGPROC
 	Oid			tempNamespaceId;	/* OID of temp schema this backend is
 									 * using */
 
+	TransactionId session_gtt_frozenxid;	/* session level global temp table relfrozenxid */
+
 	bool		isBackgroundWorker; /* true if background worker. */
 
 	/*
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index a5c7d0c..a86f61f 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -125,4 +125,6 @@ extern void ProcArraySetReplicationSlotXmin(TransactionId xmin,
 extern void ProcArrayGetReplicationSlotXmin(TransactionId *xmin,
 											TransactionId *catalog_xmin);
 
+extern int list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n);
+
 #endif							/* PROCARRAY_H */
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index ce93ace..0f7262e 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -281,6 +281,10 @@ extern int	tcp_user_timeout;
 extern bool trace_sort;
 #endif
 
+/* global temporary table */
+extern int	max_active_gtt;
+/* end */
+
 /*
  * Functions exported by guc.c
  */
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 44ed04d..3f9720d 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -277,6 +277,7 @@ typedef struct StdRdOptions
 	int			parallel_workers;	/* max number of parallel workers */
 	bool		vacuum_index_cleanup;	/* enables index vacuuming and cleanup */
 	bool		vacuum_truncate;	/* enables vacuum to truncate a relation */
+	bool		on_commit_delete_rows;	/* global temp table */
 } StdRdOptions;
 
 #define HEAP_MIN_FILLFACTOR			10
@@ -535,7 +536,8 @@ typedef struct ViewOptions
  *		True if relation's pages are stored in local buffers.
  */
 #define RelationUsesLocalBuffers(relation) \
-	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP || \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 
 /*
  * RELATION_IS_LOCAL
@@ -602,6 +604,17 @@ typedef struct ViewOptions
 	 RelationNeedsWAL(relation) && \
 	 !IsCatalogRelation(relation))
 
+/* global temp table implementations */
+#define RELATION_IS_GLOBAL_TEMP(relation)	((relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+
+#define RELATION_GTT_ON_COMMIT_DELETE(relation)	\
+	((relation)->rd_options && \
+	 ((relation)->rd_rel->relkind == RELKIND_RELATION || (relation)->rd_rel->relkind == RELKIND_PARTITIONED_TABLE) && \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ? \
+	 ((StdRdOptions *) (relation)->rd_options)->on_commit_delete_rows : false)
+
+#define RelationGetRelPersistence(relation) ((relation)->rd_rel->relpersistence)
+
 /* routines in utils/cache/relcache.c */
 extern void RelationIncrementReferenceCount(Relation rel);
 extern void RelationDecrementReferenceCount(Relation rel);
diff --git a/src/test/regress/expected/gtt_clean.out b/src/test/regress/expected/gtt_clean.out
new file mode 100644
index 0000000..50ca9ac
--- /dev/null
+++ b/src/test/regress/expected/gtt_clean.out
@@ -0,0 +1,7 @@
+reset search_path;
+drop schema gtt cascade;
+NOTICE:  drop cascades to 4 other objects
+DETAIL:  drop cascades to table gtt.gtt1
+drop cascades to table gtt.gtt2
+drop cascades to table gtt.gtt3
+drop cascades to table gtt.gtt_t_kenyon
diff --git a/src/test/regress/expected/gtt_function.out b/src/test/regress/expected/gtt_function.out
new file mode 100644
index 0000000..2c69f14
--- /dev/null
+++ b/src/test/regress/expected/gtt_function.out
@@ -0,0 +1,197 @@
+CREATE SCHEMA IF NOT EXISTS gtt_function;
+set search_path=gtt_function,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt_test_rename(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+ERROR:  cannot create indexes on global temporary tables using concurrent mode
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+ERROR:  not support cluster global temporary tables yet
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+ERROR:  ON COMMIT can only be used on temporary tables
+-- ok
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+ERROR:  regular table cannot specifie on_commit_delete_rows
+-- ok
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+--ok
+CREATE global temp TABLE p_table01 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+);
+ 
+CREATE global temp TABLE p_table01_2018
+PARTITION OF p_table01
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+ 
+CREATE global temp TABLE p_table01_2017
+PARTITION OF p_table01
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+begin;
+insert into p_table01 values(1,'2018-01-02 00:00:00','test1');
+insert into p_table01 values(1,'2018-01-02 00:00:00','test2');
+select count(*) from p_table01;
+ count 
+-------
+     2
+(1 row)
+
+commit;
+select count(*) from p_table01;
+ count 
+-------
+     0
+(1 row)
+
+--ok
+CREATE global temp TABLE p_table02 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)
+on commit PRESERVE rows;
+CREATE global temp TABLE p_table02_2018
+PARTITION OF p_table02
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+CREATE global temp TABLE p_table02_2017
+PARTITION OF p_table02
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+-- ok
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+ERROR:  The parent table must be global temporary table
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent_global_temp);
+select relname ,relkind, relpersistence, reloptions from pg_class where relname like 'p_table0%' or  relname like 'tbl_inherits%' order by relname;
+             relname             | relkind | relpersistence |          reloptions           
+---------------------------------+---------+----------------+-------------------------------
+ p_table01                       | p       | g              | {on_commit_delete_rows=true}
+ p_table01_2017                  | r       | g              | {on_commit_delete_rows=true}
+ p_table01_2018                  | r       | g              | {on_commit_delete_rows=true}
+ p_table01_id_seq                | S       | g              | 
+ p_table02                       | p       | g              | {on_commit_delete_rows=false}
+ p_table02_2017                  | r       | g              | {on_commit_delete_rows=false}
+ p_table02_2018                  | r       | g              | {on_commit_delete_rows=false}
+ p_table02_id_seq                | S       | g              | 
+ tbl_inherits_parent             | r       | p              | 
+ tbl_inherits_parent_global_temp | r       | g              | {on_commit_delete_rows=true}
+ tbl_inherits_partition          | r       | g              | {on_commit_delete_rows=true}
+(11 rows)
+
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+ERROR:  global temp table not support on commit drop clause
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+ERROR:  can not defeine global temp table with on commit and with clause at same time
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+--ok
+alter table gtt_test_rename rename to gtt_test;
+-- ok
+ALTER TABLE gtt_test ADD COLUMN address varchar(30);
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  referenced relation "products" is not a global temp table
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  referenced relation "products" is not a global temp table
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+-- ok
+create global temp table gtt_seq(id int GENERATED ALWAYS AS IDENTITY (START WITH 2) primary key, a int)  on commit PRESERVE rows;
+insert into gtt_seq (a) values(1);
+insert into gtt_seq (a) values(2);
+select * from gtt_seq order by id;
+ id | a 
+----+---
+  2 | 1
+  3 | 2
+(2 rows)
+
+truncate gtt_seq;
+select * from gtt_seq order by id;
+ id | a 
+----+---
+(0 rows)
+
+insert into gtt_seq (a) values(3);
+select * from gtt_seq order by id;
+ id | a 
+----+---
+  4 | 3
+(1 row)
+
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+ERROR:  materialized views must not use global temporary tables or views
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+ERROR:  only support btree index on global temp table
+create index idx_err on gtt1 using gist (a);
+ERROR:  data type integer has no default operator class for access method "gist"
+HINT:  You must specify an operator class for the index or define a default operator class for the data type.
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+ERROR:  only support btree index on global temp table
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+ERROR:  only support btree index on global temp table
+reset search_path;
+drop schema gtt_function cascade;
+NOTICE:  drop cascades to 15 other objects
+DETAIL:  drop cascades to table gtt_function.gtt1
+drop cascades to table gtt_function.gtt_test
+drop cascades to table gtt_function.gtt2
+drop cascades to table gtt_function.gtt3
+drop cascades to table gtt_function.tmp_t0
+drop cascades to table gtt_function.tbl_inherits_parent
+drop cascades to table gtt_function.tbl_inherits_parent_global_temp
+drop cascades to table gtt_function.products
+drop cascades to table gtt_function.measurement
+drop cascades to table gtt_function.p_table01
+drop cascades to table gtt_function.p_table02
+drop cascades to table gtt_function.tbl_inherits_partition
+drop cascades to table gtt_function.gtt5
+drop cascades to table gtt_function.mytable
+drop cascades to table gtt_function.gtt_seq
diff --git a/src/test/regress/expected/gtt_parallel_1.out b/src/test/regress/expected/gtt_parallel_1.out
new file mode 100644
index 0000000..30d8a7b
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_1.out
@@ -0,0 +1,84 @@
+set search_path=gtt,sys;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_parallel_2.out b/src/test/regress/expected/gtt_parallel_2.out
new file mode 100644
index 0000000..850ef3e
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_2.out
@@ -0,0 +1,161 @@
+set search_path=gtt,sys;
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+ 3 | test1
+(3 rows)
+
+rollback;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test2
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 3 | test3
+(1 row)
+
+rollback;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 5 | test5
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 6 | test6
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+ count  
+--------
+ 100000
+(1 row)
+
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+             QUERY PLAN             
+------------------------------------
+ Index Scan using gtt3_pkey on gtt3
+   Index Cond: (a = 300)
+(2 rows)
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid),pg_table_size(oid),pg_indexes_size(oid),pg_total_relation_size(oid) from pg_class where relname = 'gtt_t_kenyon';
+   relname    | pg_relation_size | pg_relation_size | pg_table_size | pg_indexes_size | pg_total_relation_size 
+--------------+------------------+------------------+---------------+-----------------+------------------------
+ gtt_t_kenyon |           450560 |             8192 |        499712 |          475136 |                 974848
+(1 row)
+
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+   relname    
+--------------
+ gtt_t_kenyon
+(1 row)
+
+select
+c.relname, pg_relation_size(c.oid),pg_table_size(c.oid),pg_total_relation_size(c.oid)
+from
+pg_class c
+where
+c.oid in
+(
+select
+i.indexrelid as indexrelid
+from 
+pg_index i ,pg_class cc
+where cc.relname = 'gtt_t_kenyon' and cc.oid = i.indrelid
+)
+order by c.relname;
+      relname       | pg_relation_size | pg_table_size | pg_total_relation_size 
+--------------------+------------------+---------------+------------------------
+ idx_gtt_t_kenyon_1 |            65536 |         65536 |                  65536
+ idx_gtt_t_kenyon_2 |           409600 |        409600 |                 409600
+(2 rows)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_prepare.out b/src/test/regress/expected/gtt_prepare.out
new file mode 100644
index 0000000..9735a93
--- /dev/null
+++ b/src/test/regress/expected/gtt_prepare.out
@@ -0,0 +1,9 @@
+CREATE SCHEMA IF NOT EXISTS gtt;
+set search_path=gtt,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+create index idx_gtt_t_kenyon_1 on gtt_t_kenyon(id);
+create index idx_gtt_t_kenyon_2 on gtt_t_kenyon(remark);
+reset search_path;
diff --git a/src/test/regress/expected/gtt_stats.out b/src/test/regress/expected/gtt_stats.out
new file mode 100644
index 0000000..b258b7c
--- /dev/null
+++ b/src/test/regress/expected/gtt_stats.out
@@ -0,0 +1,76 @@
+CREATE SCHEMA IF NOT EXISTS gtt_stats;
+set search_path=gtt_stats,sys;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     0
+(1 row)
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     0
+(1 row)
+
+create global temp table gtt(a int primary key, b text) on commit PRESERVE rows;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     0
+(1 row)
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     0
+(1 row)
+
+insert into gtt values(generate_series(1,10000),'test');
+-- expect 1
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     1
+(1 row)
+
+-- expect 2
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     2
+(1 row)
+
+-- expect 0
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+ schemaname | tablename | relpages | reltuples | relallvisible 
+------------+-----------+----------+-----------+---------------
+ gtt_stats  | gtt       |        0 |         0 |             0
+(1 row)
+
+-- expect 0
+select * from pg_gtt_stats order by tablename;
+ schemaname | tablename | attname | inherited | null_frac | avg_width | n_distinct | most_common_vals | most_common_freqs | histogram_bounds | correlation | most_common_elems | most_common_elem_freqs | elem_count_histogram 
+------------+-----------+---------+-----------+-----------+-----------+------------+------------------+-------------------+------------------+-------------+-------------------+------------------------+----------------------
+(0 rows)
+
+analyze gtt;
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+ schemaname | tablename | relpages | reltuples | relallvisible 
+------------+-----------+----------+-----------+---------------
+ gtt_stats  | gtt       |       55 |     10000 |             0
+(1 row)
+
+select * from pg_gtt_stats order by tablename;
+ schemaname | tablename | attname | inherited | null_frac | avg_width | n_distinct | most_common_vals | most_common_freqs |                                                                                                                                                                                                                                                histogram_bounds                                                                                                                                                                                                                                                 | correlation | most_common_elems | most_common_elem_freqs | elem_count_histogram 
+------------+-----------+---------+-----------+-----------+-----------+------------+------------------+-------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+-------------------+------------------------+----------------------
+ gtt_stats  | gtt       | a       | f         |         0 |         4 |         -1 |                  |                   | {1,100,200,300,400,500,600,700,800,900,1000,1100,1200,1300,1400,1500,1600,1700,1800,1900,2000,2100,2200,2300,2400,2500,2600,2700,2800,2900,3000,3100,3200,3300,3400,3500,3600,3700,3800,3900,4000,4100,4200,4300,4400,4500,4600,4700,4800,4900,5000,5100,5200,5300,5400,5500,5600,5700,5800,5900,6000,6100,6200,6300,6400,6500,6600,6700,6800,6900,7000,7100,7200,7300,7400,7500,7600,7700,7800,7900,8000,8100,8200,8300,8400,8500,8600,8700,8800,8900,9000,9100,9200,9300,9400,9500,9600,9700,9800,9900,10000} |           1 |                   |                        | 
+ gtt_stats  | gtt       | b       | f         |         0 |         5 |          1 | {test}           | {1}               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |           1 |                   |                        | 
+(2 rows)
+
+reset search_path;
+drop schema gtt_stats cascade;
+NOTICE:  drop cascades to table gtt_stats.gtt
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index 70e1e2f..30cf4bd 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1348,6 +1348,93 @@ pg_group| SELECT pg_authid.rolname AS groname,
           WHERE (pg_auth_members.roleid = pg_authid.oid)) AS grolist
    FROM pg_authid
   WHERE (NOT pg_authid.rolcanlogin);
+pg_gtt_attached_pids| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.relid,
+    s.pid
+   FROM (pg_class c
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_gtt_attached_pid(c.oid) s(relid, pid)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
+pg_gtt_relstats| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.relpages,
+    s.reltuples,
+    s.relallvisible,
+    s.relfrozenxid,
+    s.relminmxid
+   FROM (pg_class c
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_get_gtt_relstats(c.oid) s(relpages, reltuples, relallvisible, relfrozenxid, relminmxid)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
+pg_gtt_stats| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    a.attname,
+    s.stainherit AS inherited,
+    s.stanullfrac AS null_frac,
+    s.stawidth AS avg_width,
+    s.stadistinct AS n_distinct,
+        CASE
+            WHEN (s.stakind1 = 1) THEN s.stavalues1
+            WHEN (s.stakind2 = 1) THEN s.stavalues2
+            WHEN (s.stakind3 = 1) THEN s.stavalues3
+            WHEN (s.stakind4 = 1) THEN s.stavalues4
+            WHEN (s.stakind5 = 1) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS most_common_vals,
+        CASE
+            WHEN (s.stakind1 = 1) THEN s.stanumbers1
+            WHEN (s.stakind2 = 1) THEN s.stanumbers2
+            WHEN (s.stakind3 = 1) THEN s.stanumbers3
+            WHEN (s.stakind4 = 1) THEN s.stanumbers4
+            WHEN (s.stakind5 = 1) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS most_common_freqs,
+        CASE
+            WHEN (s.stakind1 = 2) THEN s.stavalues1
+            WHEN (s.stakind2 = 2) THEN s.stavalues2
+            WHEN (s.stakind3 = 2) THEN s.stavalues3
+            WHEN (s.stakind4 = 2) THEN s.stavalues4
+            WHEN (s.stakind5 = 2) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS histogram_bounds,
+        CASE
+            WHEN (s.stakind1 = 3) THEN s.stanumbers1[1]
+            WHEN (s.stakind2 = 3) THEN s.stanumbers2[1]
+            WHEN (s.stakind3 = 3) THEN s.stanumbers3[1]
+            WHEN (s.stakind4 = 3) THEN s.stanumbers4[1]
+            WHEN (s.stakind5 = 3) THEN s.stanumbers5[1]
+            ELSE NULL::real
+        END AS correlation,
+        CASE
+            WHEN (s.stakind1 = 4) THEN s.stavalues1
+            WHEN (s.stakind2 = 4) THEN s.stavalues2
+            WHEN (s.stakind3 = 4) THEN s.stavalues3
+            WHEN (s.stakind4 = 4) THEN s.stavalues4
+            WHEN (s.stakind5 = 4) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS most_common_elems,
+        CASE
+            WHEN (s.stakind1 = 4) THEN s.stanumbers1
+            WHEN (s.stakind2 = 4) THEN s.stanumbers2
+            WHEN (s.stakind3 = 4) THEN s.stanumbers3
+            WHEN (s.stakind4 = 4) THEN s.stanumbers4
+            WHEN (s.stakind5 = 4) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS most_common_elem_freqs,
+        CASE
+            WHEN (s.stakind1 = 5) THEN s.stanumbers1
+            WHEN (s.stakind2 = 5) THEN s.stanumbers2
+            WHEN (s.stakind3 = 5) THEN s.stanumbers3
+            WHEN (s.stakind4 = 5) THEN s.stanumbers4
+            WHEN (s.stakind5 = 5) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS elem_count_histogram
+   FROM ((pg_class c
+     JOIN pg_attribute a ON ((c.oid = a.attrelid)))
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_get_gtt_statistics(c.oid, (a.attnum)::integer, ''::text) s(starelid, staattnum, stainherit, stanullfrac, stawidth, stadistinct, stakind1, stakind2, stakind3, stakind4, stakind5, staop1, staop2, staop3, staop4, staop5, stacoll1, stacoll2, stacoll3, stacoll4, stacoll5, stanumbers1, stanumbers2, stanumbers3, stanumbers4, stanumbers5, stavalues1, stavalues2, stavalues3, stavalues4, stavalues5)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND (NOT a.attisdropped) AND has_column_privilege(c.oid, a.attnum, 'select'::text) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
 pg_hba_file_rules| SELECT a.line_number,
     a.type,
     a.database,
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index d33a4e1..643afe4 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -121,3 +121,10 @@ test: fast_default
 
 # run stats by itself because its delay may be insufficient under heavy load
 test: stats
+
+# global temp table test
+test: gtt_stats
+test: gtt_function
+test: gtt_prepare
+test: gtt_parallel_1 gtt_parallel_2
+test: gtt_clean
diff --git a/src/test/regress/sql/gtt_clean.sql b/src/test/regress/sql/gtt_clean.sql
new file mode 100644
index 0000000..f3cf710
--- /dev/null
+++ b/src/test/regress/sql/gtt_clean.sql
@@ -0,0 +1,6 @@
+
+
+reset search_path;
+
+drop schema gtt cascade;
+
diff --git a/src/test/regress/sql/gtt_function.sql b/src/test/regress/sql/gtt_function.sql
new file mode 100644
index 0000000..49c3f11
--- /dev/null
+++ b/src/test/regress/sql/gtt_function.sql
@@ -0,0 +1,163 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt_function;
+
+set search_path=gtt_function,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt_test_rename(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+
+-- ok
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+
+-- ok
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+
+--ok
+CREATE global temp TABLE p_table01 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+);
+ 
+CREATE global temp TABLE p_table01_2018
+PARTITION OF p_table01
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+ 
+CREATE global temp TABLE p_table01_2017
+PARTITION OF p_table01
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+
+begin;
+insert into p_table01 values(1,'2018-01-02 00:00:00','test1');
+insert into p_table01 values(1,'2018-01-02 00:00:00','test2');
+select count(*) from p_table01;
+commit;
+
+select count(*) from p_table01;
+
+--ok
+CREATE global temp TABLE p_table02 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)
+on commit PRESERVE rows;
+
+CREATE global temp TABLE p_table02_2018
+PARTITION OF p_table02
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+
+CREATE global temp TABLE p_table02_2017
+PARTITION OF p_table02
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+
+-- ok
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent_global_temp);
+
+select relname ,relkind, relpersistence, reloptions from pg_class where relname like 'p_table0%' or  relname like 'tbl_inherits%' order by relname;
+
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+
+--ok
+alter table gtt_test_rename rename to gtt_test;
+
+-- ok
+ALTER TABLE gtt_test ADD COLUMN address varchar(30);
+
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+
+-- ok
+create global temp table gtt_seq(id int GENERATED ALWAYS AS IDENTITY (START WITH 2) primary key, a int)  on commit PRESERVE rows;
+insert into gtt_seq (a) values(1);
+insert into gtt_seq (a) values(2);
+select * from gtt_seq order by id;
+truncate gtt_seq;
+select * from gtt_seq order by id;
+insert into gtt_seq (a) values(3);
+select * from gtt_seq order by id;
+
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+create index idx_err on gtt1 using gist (a);
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+
+reset search_path;
+
+drop schema gtt_function cascade;
+
diff --git a/src/test/regress/sql/gtt_parallel_1.sql b/src/test/regress/sql/gtt_parallel_1.sql
new file mode 100644
index 0000000..d7d81de
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_1.sql
@@ -0,0 +1,42 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+commit;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+rollback;
+select * from gtt1 order by a;
+
+truncate gtt1;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+select * from gtt1 order by a;
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+
+begin;
+select * from gtt1 order by a;
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_parallel_2.sql b/src/test/regress/sql/gtt_parallel_2.sql
new file mode 100644
index 0000000..5203c2b
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_2.sql
@@ -0,0 +1,76 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+commit;
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+truncate gtt3;
+select * from gtt3 order by a;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+truncate gtt3;
+select * from gtt3 order by a;
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+begin;
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid),pg_table_size(oid),pg_indexes_size(oid),pg_total_relation_size(oid) from pg_class where relname = 'gtt_t_kenyon';
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+
+select
+c.relname, pg_relation_size(c.oid),pg_table_size(c.oid),pg_total_relation_size(c.oid)
+from
+pg_class c
+where
+c.oid in
+(
+select
+i.indexrelid as indexrelid
+from 
+pg_index i ,pg_class cc
+where cc.relname = 'gtt_t_kenyon' and cc.oid = i.indrelid
+)
+order by c.relname;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_prepare.sql b/src/test/regress/sql/gtt_prepare.sql
new file mode 100644
index 0000000..1e4cf27
--- /dev/null
+++ b/src/test/regress/sql/gtt_prepare.sql
@@ -0,0 +1,16 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt;
+
+set search_path=gtt,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+create index idx_gtt_t_kenyon_1 on gtt_t_kenyon(id);
+create index idx_gtt_t_kenyon_2 on gtt_t_kenyon(remark);
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_stats.sql b/src/test/regress/sql/gtt_stats.sql
new file mode 100644
index 0000000..f041892
--- /dev/null
+++ b/src/test/regress/sql/gtt_stats.sql
@@ -0,0 +1,42 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt_stats;
+
+set search_path=gtt_stats,sys;
+
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+
+create global temp table gtt(a int primary key, b text) on commit PRESERVE rows;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+
+insert into gtt values(generate_series(1,10000),'test');
+
+-- expect 1
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 2
+select count(*) from pg_list_gtt_relfrozenxids();
+
+-- expect 0
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+
+-- expect 0
+select * from pg_gtt_stats order by tablename;
+
+analyze gtt;
+
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+
+select * from pg_gtt_stats order by tablename;
+
+reset search_path;
+
+drop schema gtt_stats cascade;
+

diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c
index 79430d2..b7173c7 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -158,6 +158,19 @@ static relopt_bool boolRelOpts[] =
 		},
 		true
 	},
+	/*
+	 * For global temp table only
+	 * use AccessExclusiveLock for ensure safety
+	 */
+	{
+		{
+			"on_commit_delete_rows",
+			"global temp table on commit options",
+			RELOPT_KIND_HEAP | RELOPT_KIND_PARTITIONED,
+			ShareUpdateExclusiveLock
+		},
+		true
+	},	
 	/* list terminator */
 	{{NULL}}
 };
@@ -1486,6 +1499,8 @@ bytea *
 default_reloptions(Datum reloptions, bool validate, relopt_kind kind)
 {
 	static const relopt_parse_elt tab[] = {
+		{"on_commit_delete_rows", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, on_commit_delete_rows)},
 		{"fillfactor", RELOPT_TYPE_INT, offsetof(StdRdOptions, fillfactor)},
 		{"autovacuum_enabled", RELOPT_TYPE_BOOL,
 		offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, enabled)},
@@ -1586,13 +1601,18 @@ build_reloptions(Datum reloptions, bool validate,
 bytea *
 partitioned_table_reloptions(Datum reloptions, bool validate)
 {
+	static const relopt_parse_elt tab[] = {
+		{"on_commit_delete_rows", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, on_commit_delete_rows)}
+	};
+
 	/*
 	 * There are no options for partitioned tables yet, but this is able to do
 	 * some validation.
 	 */
 	return (bytea *) build_reloptions(reloptions, validate,
 									  RELOPT_KIND_PARTITIONED,
-									  0, NULL, 0);
+									  sizeof(StdRdOptions), tab, lengthof(tab));
 }
 
 /*
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index dd975b1..1610e7d 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -1013,7 +1013,9 @@ gistGetFakeLSN(Relation rel)
 {
 	static XLogRecPtr counter = FirstNormalUnloggedLSN;
 
-	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	/* global temp is same as local temp table */
+	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		rel->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 	{
 		/*
 		 * Temporary relations are only accessible in our session, so a simple
diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index 4871b7f..16b00c9 100644
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -149,7 +149,9 @@ hashbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	 * metapage, nor the first bitmap page.
 	 */
 	sort_threshold = (maintenance_work_mem * 1024L) / BLCKSZ;
-	if (index->rd_rel->relpersistence != RELPERSISTENCE_TEMP)
+	/* global temp table is same as local temp table */
+	if (!(index->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		index->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		sort_threshold = Min(sort_threshold, NBuffers);
 	else
 		sort_threshold = Min(sort_threshold, NLocBuffer);
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 1f6f6d0..5727ccd 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -598,7 +598,7 @@ heapam_relation_set_new_filenode(Relation rel,
 	 */
 	*minmulti = GetOldestMultiXactId();
 
-	srel = RelationCreateStorage(*newrnode, persistence);
+	srel = RelationCreateStorage(*newrnode, persistence, rel);
 
 	/*
 	 * If required, set up an init fork for an unlogged table so that it can
@@ -651,7 +651,7 @@ heapam_relation_copy_data(Relation rel, const RelFileNode *newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index b331f4c..5bd681f 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -79,6 +79,7 @@
 #include "utils/pg_rusage.h"
 #include "utils/timestamp.h"
 
+#include "catalog/storage_gtt.h"
 
 /*
  * Space/time tradeoff parameters: do these need to be user-tunable?
@@ -397,8 +398,10 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 	Assert(params->truncate != VACOPT_TERNARY_DEFAULT);
 
 	/* not every AM requires these to be valid, but heap does */
-	Assert(TransactionIdIsNormal(onerel->rd_rel->relfrozenxid));
-	Assert(MultiXactIdIsValid(onerel->rd_rel->relminmxid));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relfrozenxid == InvalidTransactionId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && TransactionIdIsNormal(onerel->rd_rel->relfrozenxid)));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relminmxid == InvalidMultiXactId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && MultiXactIdIsValid(onerel->rd_rel->relminmxid)));
 
 	/* measure elapsed time iff autovacuum logging requires it */
 	if (IsAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
@@ -457,8 +460,19 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 
 	vacrelstats = (LVRelStats *) palloc0(sizeof(LVRelStats));
 
-	vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
-	vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
+	/* get relstat from gtt localhash */
+	if (RELATION_IS_GLOBAL_TEMP(onerel))
+	{
+		get_gtt_relstats(RelationGetRelid(onerel),
+						&vacrelstats->old_rel_pages,
+						&vacrelstats->old_live_tuples,
+						NULL, NULL, NULL);
+	}
+	else
+	{
+		vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
+		vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
+	}
 	vacrelstats->num_index_scans = 0;
 	vacrelstats->pages_removed = 0;
 	vacrelstats->lock_waiter_detected = false;
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index f05cbe7..946c9d2 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -763,7 +763,14 @@ _bt_getbuf(Relation rel, BlockNumber blkno, int access)
 		/* Read an existing block of the relation */
 		buf = ReadBuffer(rel, blkno);
 		LockBuffer(buf, access);
-		_bt_checkpage(rel, buf);
+
+		/* global temp table may be not yet initialized for this backend. */
+		if (RELATION_IS_GLOBAL_TEMP(rel) &&
+			blkno == BTREE_METAPAGE &&
+			PageIsNew(BufferGetPage(buf)))
+			_bt_initmetapage(BufferGetPage(buf), P_NONE, 0);
+		else
+			_bt_checkpage(rel, buf);
 	}
 	else
 	{
diff --git a/src/backend/access/table/tableam.c b/src/backend/access/table/tableam.c
index c814733..ff51840 100644
--- a/src/backend/access/table/tableam.c
+++ b/src/backend/access/table/tableam.c
@@ -24,6 +24,7 @@
 #include "access/heapam.h"		/* for ss_* */
 #include "access/tableam.h"
 #include "access/xact.h"
+#include "catalog/storage_gtt.h"
 #include "optimizer/plancat.h"
 #include "storage/bufmgr.h"
 #include "storage/shmem.h"
@@ -560,10 +561,20 @@ table_block_relation_estimate_size(Relation rel, int32 *attr_widths,
 	/* it should have storage, so we can call the smgr */
 	curpages = RelationGetNumberOfBlocks(rel);
 
-	/* coerce values in pg_class to more desirable types */
-	relpages = (BlockNumber) rel->rd_rel->relpages;
-	reltuples = (double) rel->rd_rel->reltuples;
-	relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
+	/* global temp table get relstats from localhash */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		get_gtt_relstats(RelationGetRelid(rel),
+						&relpages, &reltuples, &relallvisible,
+						NULL, NULL);
+	}
+	else
+	{
+		/* coerce values in pg_class to more desirable types */
+		relpages = (BlockNumber) rel->rd_rel->relpages;
+		reltuples = (double) rel->rd_rel->reltuples;
+		relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
+	}
 
 	/*
 	 * HACK: if the relation has never yet been vacuumed, use a minimum size
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 7f4f784..aba8a9f 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6327,6 +6327,10 @@ StartupXLOG(void)
 	else
 		recoveryTargetTLI = ControlFile->checkPointCopy.ThisTimeLineID;
 
+	/* clean temp relation files */
+	if (max_active_gtt > 0)
+		RemovePgTempFiles();
+
 	/*
 	 * Check for signal files, and if so set up state for offline recovery
 	 */
diff --git a/src/backend/catalog/Makefile b/src/backend/catalog/Makefile
index d5da81c..c753b0e 100644
--- a/src/backend/catalog/Makefile
+++ b/src/backend/catalog/Makefile
@@ -42,6 +42,7 @@ OBJS = \
 	pg_subscription.o \
 	pg_type.o \
 	storage.o \
+	storage_gtt.o \
 	toasting.o
 
 include $(top_srcdir)/src/backend/common.mk
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index 16cb6d8..f28f2c2 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -398,7 +398,9 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class, char relpersistence)
 
 	switch (relpersistence)
 	{
+		/* global temp table is same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			break;
 		case RELPERSISTENCE_UNLOGGED:
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 0fdff29..54a5243 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -61,6 +61,7 @@
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "commands/tablecmds.h"
 #include "commands/typecmds.h"
 #include "executor/executor.h"
@@ -99,6 +100,7 @@ static void AddNewRelationTuple(Relation pg_class_desc,
 								Oid reloftype,
 								Oid relowner,
 								char relkind,
+								char relpersistence,
 								TransactionId relfrozenxid,
 								TransactionId relminmxid,
 								Datum relacl,
@@ -404,6 +406,10 @@ heap_create(const char *relname,
 									 relpersistence,
 									 relkind);
 
+	/* global temp table not create storage file when catalog create */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		create_storage = false;
+
 	/*
 	 * Have the storage manager create the relation's disk file, if needed.
 	 *
@@ -427,7 +433,7 @@ heap_create(const char *relname,
 
 			case RELKIND_INDEX:
 			case RELKIND_SEQUENCE:
-				RelationCreateStorage(rel->rd_node, relpersistence);
+				RelationCreateStorage(rel->rd_node, relpersistence, rel);
 				break;
 
 			case RELKIND_RELATION:
@@ -956,6 +962,7 @@ AddNewRelationTuple(Relation pg_class_desc,
 					Oid reloftype,
 					Oid relowner,
 					char relkind,
+					char relpersistence,
 					TransactionId relfrozenxid,
 					TransactionId relminmxid,
 					Datum relacl,
@@ -994,8 +1001,18 @@ AddNewRelationTuple(Relation pg_class_desc,
 			break;
 	}
 
-	new_rel_reltup->relfrozenxid = relfrozenxid;
-	new_rel_reltup->relminmxid = relminmxid;
+	/* global temp table not remember transaction info in catalog */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		new_rel_reltup->relfrozenxid = InvalidTransactionId;
+		new_rel_reltup->relminmxid = InvalidMultiXactId;
+	}
+	else
+	{
+		new_rel_reltup->relfrozenxid = relfrozenxid;
+		new_rel_reltup->relminmxid = relminmxid;
+	}
+
 	new_rel_reltup->relowner = relowner;
 	new_rel_reltup->reltype = new_type_oid;
 	new_rel_reltup->reloftype = reloftype;
@@ -1357,6 +1374,7 @@ heap_create_with_catalog(const char *relname,
 						reloftypeid,
 						ownerid,
 						relkind,
+						relpersistence,
 						relfrozenxid,
 						relminmxid,
 						PointerGetDatum(relacl),
@@ -1441,11 +1459,15 @@ heap_create_with_catalog(const char *relname,
 	 */
 	StoreConstraints(new_rel_desc, cooked_constraints, is_internal);
 
-	/*
-	 * If there's a special on-commit action, remember it
-	 */
-	if (oncommit != ONCOMMIT_NOOP)
-		register_on_commit_action(relid, oncommit);
+	/* global temp table register action when storage init */
+	if (relpersistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		/*
+		 * If there's a special on-commit action, remember it
+		 */
+		if (oncommit != ONCOMMIT_NOOP)
+			register_on_commit_action(relid, oncommit);
+	}
 
 	/*
 	 * ok, the relation has been cataloged, so close our relations and return
@@ -1937,6 +1959,13 @@ heap_drop_with_catalog(Oid relid)
 	if (relid == defaultPartOid)
 		update_default_partition_oid(parentOid, InvalidOid);
 
+	/* We allow to drop global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (is_other_backend_use_gtt(rel->rd_node))
+			elog(ERROR, "can not drop relation when other backend attached this global temp table");
+	}
+
 	/*
 	 * Schedule unlinking of the relation's physical files at commit.
 	 */
@@ -3163,9 +3192,10 @@ RemoveStatistics(Oid relid, AttrNumber attnum)
  *
  * The routine will truncate and then reconstruct the indexes on
  * the specified relation.  Caller must hold exclusive lock on rel.
+ *
  */
 static void
-RelationTruncateIndexes(Relation heapRelation)
+RelationTruncateIndexes(Relation heapRelation, LOCKMODE lockmode)
 {
 	ListCell   *indlist;
 
@@ -3177,7 +3207,7 @@ RelationTruncateIndexes(Relation heapRelation)
 		IndexInfo  *indexInfo;
 
 		/* Open the index relation; use exclusive lock, just to be sure */
-		currentIndex = index_open(indexId, AccessExclusiveLock);
+		currentIndex = index_open(indexId, lockmode);
 
 		/*
 		 * Fetch info needed for index_build.  Since we know there are no
@@ -3223,8 +3253,13 @@ heap_truncate(List *relids)
 	{
 		Oid			rid = lfirst_oid(cell);
 		Relation	rel;
+		LOCKMODE	lockmode = AccessExclusiveLock;
 
-		rel = table_open(rid, AccessExclusiveLock);
+		/* truncate global temp table only need RowExclusiveLock */
+		if (get_rel_persistence(rid) == RELPERSISTENCE_GLOBAL_TEMP)
+			lockmode = RowExclusiveLock;
+
+		rel = table_open(rid, lockmode);
 		relations = lappend(relations, rel);
 	}
 
@@ -3257,6 +3292,8 @@ void
 heap_truncate_one_rel(Relation rel)
 {
 	Oid			toastrelid;
+	LOCKMODE	lockmode = AccessExclusiveLock;
+	bool		truncate_toastrel = false;
 
 	/*
 	 * Truncate the relation.  Partitioned tables have no storage, so there is
@@ -3265,23 +3302,40 @@ heap_truncate_one_rel(Relation rel)
 	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 		return;
 
+	toastrelid = rel->rd_rel->reltoastrelid;
+
+	/*
+	 * Truncate global temp table only need RowExclusiveLock
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		lockmode = RowExclusiveLock;
+		if (OidIsValid(toastrelid) &&
+			gtt_storage_attached(toastrelid))
+			truncate_toastrel = true;
+	}
+	else if (OidIsValid(toastrelid))
+		truncate_toastrel = true;
+
 	/* Truncate the underlying relation */
 	table_relation_nontransactional_truncate(rel);
 
 	/* If the relation has indexes, truncate the indexes too */
-	RelationTruncateIndexes(rel);
+	RelationTruncateIndexes(rel, lockmode);
 
 	/* If there is a toast table, truncate that too */
-	toastrelid = rel->rd_rel->reltoastrelid;
-	if (OidIsValid(toastrelid))
+	if (truncate_toastrel)
 	{
-		Relation	toastrel = table_open(toastrelid, AccessExclusiveLock);
+		Relation	toastrel = table_open(toastrelid, lockmode);
 
 		table_relation_nontransactional_truncate(toastrel);
-		RelationTruncateIndexes(toastrel);
+		RelationTruncateIndexes(toastrel, lockmode);
 		/* keep the lock... */
 		table_close(toastrel, NoLock);
 	}
+
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		up_gtt_relstats(rel, 0, 0, 0, RecentXmin, InvalidMultiXactId);
 }
 
 /*
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 3e59e64..9867d6f 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -52,6 +52,7 @@
 #include "catalog/pg_trigger.h"
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
+#include "catalog/storage_gtt.h"
 #include "commands/event_trigger.h"
 #include "commands/progress.h"
 #include "commands/tablecmds.h"
@@ -877,6 +878,26 @@ index_create(Relation heapRelation,
 						indexRelationName, RelationGetRelationName(heapRelation))));
 	}
 
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		if (accessMethodObjectId != BTREE_AM_OID)
+			elog(ERROR, "only support btree index on global temp table");
+
+		/* We allow to create index on global temp table only this session use it */
+		if (is_other_backend_use_gtt(heapRelation->rd_node))
+			elog(ERROR, "can not create index when have other backend attached this global temp table");
+
+		/* No support create index on global temp table use concurrent mode yet */
+		if (concurrent)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("cannot create indexes on global temporary tables using concurrent mode")));
+
+		/* if global temp table not init storage, then skip build index */
+		if (!gtt_storage_attached(heapRelation->rd_node.relNode))
+			flags |= INDEX_CREATE_SKIP_BUILD;
+	}
+
 	/*
 	 * construct tuple descriptor for index tuples
 	 */
@@ -2045,6 +2066,13 @@ index_drop(Oid indexId, bool concurrent, bool concurrent_lock_mode)
 	 */
 	CheckTableNotInUse(userIndexRelation, "DROP INDEX");
 
+	/* We allow to drop index on global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(userHeapRelation))
+	{
+		if (is_other_backend_use_gtt(userHeapRelation->rd_node))
+			elog(ERROR, "can not drop index when other backend attached this global temp table");
+	}
+
 	/*
 	 * Drop Index Concurrently is more or less the reverse process of Create
 	 * Index Concurrently.
@@ -2736,20 +2764,29 @@ index_update_stats(Relation rel,
 		else					/* don't bother for indexes */
 			relallvisible = 0;
 
-		if (rd_rel->relpages != (int32) relpages)
+		/* update index stats into localhash for global temp table */
+		if (RELATION_IS_GLOBAL_TEMP(rel))
 		{
-			rd_rel->relpages = (int32) relpages;
-			dirty = true;
+			up_gtt_relstats(rel, relpages, reltuples, relallvisible,
+							InvalidTransactionId, InvalidMultiXactId);
 		}
-		if (rd_rel->reltuples != (float4) reltuples)
-		{
-			rd_rel->reltuples = (float4) reltuples;
-			dirty = true;
-		}
-		if (rd_rel->relallvisible != (int32) relallvisible)
+		else
 		{
-			rd_rel->relallvisible = (int32) relallvisible;
-			dirty = true;
+			if (rd_rel->relpages != (int32) relpages)
+			{
+				rd_rel->relpages = (int32) relpages;
+				dirty = true;
+			}
+			if (rd_rel->reltuples != (float4) reltuples)
+			{
+				rd_rel->reltuples = (float4) reltuples;
+				dirty = true;
+			}
+			if (rd_rel->relallvisible != (int32) relallvisible)
+			{
+				rd_rel->relallvisible = (int32) relallvisible;
+				dirty = true;
+			}
 		}
 	}
 
@@ -2864,6 +2901,12 @@ index_build(Relation heapRelation,
 		pgstat_progress_update_multi_param(6, index, val);
 	}
 
+	if (RELATION_IS_GLOBAL_TEMP(indexRelation))
+	{
+		if (!gtt_storage_attached(indexRelation->rd_node.relNode))
+			RelationCreateStorage(indexRelation->rd_node, RELPERSISTENCE_GLOBAL_TEMP, indexRelation);
+	}
+
 	/*
 	 * Call the access method's build procedure
 	 */
@@ -3196,12 +3239,22 @@ validate_index(Oid heapId, Oid indexId, Snapshot snapshot)
 	/*
 	 * Scan the index and gather up all the TIDs into a tuplesort object.
 	 */
+	memset(&ivinfo, 0, sizeof(IndexVacuumInfo));
 	ivinfo.index = indexRelation;
 	ivinfo.analyze_only = false;
 	ivinfo.report_progress = true;
 	ivinfo.estimated_count = true;
 	ivinfo.message_level = DEBUG2;
-	ivinfo.num_heap_tuples = heapRelation->rd_rel->reltuples;
+
+	/* get relstats abort global temp table from hashtable, not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		get_gtt_relstats(RelationGetRelid(heapRelation),
+						NULL, &ivinfo.num_heap_tuples, NULL,
+						NULL, NULL);
+	}
+	else
+		ivinfo.num_heap_tuples = heapRelation->rd_rel->reltuples;
 	ivinfo.strategy = NULL;
 
 	/*
@@ -3459,6 +3512,15 @@ reindex_index(Oid indexId, bool skip_constraint_checks, char persistence,
 				 errmsg("cannot reindex temporary tables of other sessions")));
 
 	/*
+	 * Because global temp table cannot change relfilenode
+	 * no support reindex on global temp table yet.
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(iRel))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot reindex global temporary tables")));
+
+	/*
 	 * Also check for active uses of the index in the current transaction; we
 	 * don't want to reindex underneath an open indexscan.
 	 */
diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index e70243a..301da79 100644
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -647,6 +647,13 @@ RangeVarAdjustRelationPersistence(RangeVar *newRelation, Oid nspid)
 							 errmsg("cannot create temporary relation in non-temporary schema")));
 			}
 			break;
+		/* global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			if (isAnyTempNamespace(nspid))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+						 errmsg("cannot create global temp relations in temporary schemas")));
+			break;
 		case RELPERSISTENCE_PERMANENT:
 			if (isTempOrTempToastNamespace(nspid))
 				newRelation->relpersistence = RELPERSISTENCE_TEMP;
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index fddfbf1..03806ae 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -26,6 +26,7 @@
 #include "access/xlogutils.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "miscadmin.h"
 #include "storage/freespace.h"
 #include "storage/smgr.h"
@@ -73,9 +74,10 @@ static PendingRelDelete *pendingDeletes = NULL; /* head of linked list */
  *
  * This function is transactional. The creation is WAL-logged, and if the
  * transaction aborts later on, the storage will be destroyed.
+ *
  */
 SMgrRelation
-RelationCreateStorage(RelFileNode rnode, char relpersistence)
+RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel)
 {
 	PendingRelDelete *pending;
 	SMgrRelation srel;
@@ -85,6 +87,8 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	switch (relpersistence)
 	{
 		case RELPERSISTENCE_TEMP:
+		/* global temp table use same storage strategy as local temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			needs_wal = false;
 			break;
@@ -117,6 +121,10 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	pending->next = pendingDeletes;
 	pendingDeletes = pending;
 
+	/* remember global temp table storage info to localhash */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP && rel)
+		remember_gtt_storage_info(rnode, rel);
+
 	return srel;
 }
 
@@ -486,8 +494,15 @@ smgrDoPendingDeletes(bool isCommit)
 		smgrdounlinkall(srels, nrels, false);
 
 		for (i = 0; i < nrels; i++)
+		{
 			smgrclose(srels[i]);
 
+			/* clean global temp table flags when transaction commit or rollback */
+			if (SmgrIsTemp(srels[i]) && 
+				gtt_storage_attached(srels[i]->smgr_rnode.node.relNode))
+				forget_gtt_storage_info(srels[i]->smgr_rnode.node.relNode);
+		}
+
 		pfree(srels);
 	}
 }
diff --git a/src/backend/catalog/storage_gtt.c b/src/backend/catalog/storage_gtt.c
new file mode 100644
index 0000000..f489cd3
--- /dev/null
+++ b/src/backend/catalog/storage_gtt.c
@@ -0,0 +1,1129 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.c
+ *	  code to create and destroy physical storage for global temparary table
+ *
+ * IDENTIFICATION
+ *	  src/backend/catalog/storage_gtt.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/table.h"
+#include "access/visibilitymap.h"
+#include "access/xact.h"
+#include "access/xlog.h"
+#include "access/xloginsert.h"
+#include "access/xlogutils.h"
+#include "access/htup_details.h"
+#include "access/multixact.h"
+#include "catalog/storage.h"
+#include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/heap.h"
+#include "catalog/namespace.h"
+#include "catalog/pg_type.h"
+#include "catalog/pg_statistic.h"
+#include "commands/tablecmds.h"
+#include "funcapi.h"
+#include "nodes/primnodes.h"
+#include "nodes/pg_list.h"
+#include "nodes/execnodes.h"
+#include "miscadmin.h"
+#include "storage/freespace.h"
+#include "storage/smgr.h"
+#include "storage/ipc.h"
+#include "storage/proc.h"
+#include "storage/procarray.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "storage/sinvaladt.h"
+#include "utils/memutils.h"
+#include "utils/rel.h"
+#include "utils/hsearch.h"
+#include "utils/catcache.h"
+#include "utils/lsyscache.h"
+#include <utils/relcache.h>
+#include "utils/inval.h"
+#include "utils/guc.h"
+
+
+/* Copy from bitmapset.c, because gtt used the function in bitmapset.c */
+#define WORDNUM(x)	((x) / BITS_PER_BITMAPWORD)
+#define BITNUM(x)	((x) % BITS_PER_BITMAPWORD)
+
+#define BITMAPSET_SIZE(nwords)	\
+	(offsetof(Bitmapset, words) + (nwords) * sizeof(bitmapword))
+
+static bool gtt_cleaner_exit_registered = false;
+static HTAB *gtt_storage_local_hash = NULL;
+static HTAB *active_gtt_shared_hash = NULL;
+static MemoryContext gtt_relstats_context = NULL;
+
+/* relfrozenxid of all gtts in the current session */
+static List *gtt_session_relfrozenxid_list = NIL;
+static TransactionId gtt_session_frozenxid = InvalidTransactionId;
+
+typedef struct gtt_ctl_data
+{
+	LWLock			lock;
+	int			max_entry;
+	int			entry_size;
+}gtt_ctl_data;
+
+static gtt_ctl_data *gtt_shared_ctl = NULL;
+
+typedef struct
+{
+	RelFileNode	rnode;
+	Bitmapset	*map;
+	/* bitmap data */
+} gtt_shared_hash_entry;
+
+typedef struct
+{
+	Oid			relid;
+
+	Oid			spcnode;
+	/* pg_class stat */
+	int32		relpages;
+	float4		reltuples;
+	int32		relallvisible;
+	TransactionId relfrozenxid;
+	TransactionId relminmxid;
+	char		relkind;
+	bool		on_commit_delete;
+
+	/* pg_statistic */
+	int			natts;
+	int			*attnum;
+	HeapTuple	*att_stat_tups;
+} gtt_local_hash_entry;
+
+static Size action_gtt_shared_hash_entry_size(void);
+static void gtt_storage_checkin(RelFileNode rnode);
+static void gtt_storage_checkout(RelFileNode rnode, bool skiplock);
+static void gtt_storage_removeall(int code, Datum arg);
+static void insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid);
+static void remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid);
+static void set_gtt_session_relfrozenxid(void);
+
+Datum pg_get_gtt_statistics(PG_FUNCTION_ARGS);
+Datum pg_get_gtt_relstats(PG_FUNCTION_ARGS);
+Datum pg_gtt_attached_pid(PG_FUNCTION_ARGS);
+Datum pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS);
+
+
+static Size
+action_gtt_shared_hash_entry_size(void)
+{
+	int 	wordnum;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	wordnum = WORDNUM(MaxBackends + 1);
+	hash_entry_size += MAXALIGN(sizeof(gtt_shared_hash_entry));
+	hash_entry_size += MAXALIGN(BITMAPSET_SIZE(wordnum + 1));
+
+	return hash_entry_size;
+}
+
+Size
+active_gtt_shared_hash_size(void)
+{
+	Size	size = 0;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	size = MAXALIGN(sizeof(gtt_ctl_data));
+	hash_entry_size = action_gtt_shared_hash_entry_size();
+	size += hash_estimate_size(max_active_gtt, hash_entry_size);
+
+	return size;
+}
+
+void
+active_gtt_shared_hash_init(void)
+{
+	HASHCTL info;
+	bool	found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	gtt_shared_ctl =
+		ShmemInitStruct("gtt_shared_ctl",
+						sizeof(gtt_ctl_data),
+						&found);
+
+	if (!found)
+	{
+		LWLockRegisterTranche(LWTRANCHE_GTT_CTL, "gtt_shared_ctl");
+		LWLockInitialize(&gtt_shared_ctl->lock, LWTRANCHE_GTT_CTL);
+		gtt_shared_ctl->max_entry = max_active_gtt;
+		gtt_shared_ctl->entry_size = action_gtt_shared_hash_entry_size();
+	}
+
+	info.keysize = sizeof(RelFileNode);
+	info.entrysize = gtt_shared_ctl->entry_size;
+	active_gtt_shared_hash =
+		ShmemInitHash("active gtt shared hash",
+						gtt_shared_ctl->max_entry,
+						gtt_shared_ctl->max_entry,
+						&info, HASH_ELEM | HASH_BLOBS | HASH_FIXED_SIZE);
+}
+
+static void
+gtt_storage_checkin(RelFileNode rnode)
+{
+	gtt_shared_hash_entry	*entry;
+	bool			found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+	entry = (gtt_shared_hash_entry *) hash_search(active_gtt_shared_hash,
+												&rnode, HASH_ENTER_NULL, &found);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		ereport(ERROR,
+				(errcode(ERRCODE_OUT_OF_MEMORY),
+				 errmsg("out of shared memory"),
+				 errhint("You might need to increase max_active_gtt.")));
+	}
+
+	if (found == false)
+	{
+		int			wordnum;
+
+		entry->map = (Bitmapset *)((char *)entry + MAXALIGN(sizeof(gtt_shared_hash_entry)));
+		wordnum = WORDNUM(MaxBackends + 1);
+		memset(entry->map, 0, BITMAPSET_SIZE(wordnum + 1));
+		entry->map->nwords = wordnum + 1;
+	}
+
+	bms_add_member(entry->map, MyBackendId);
+	LWLockRelease(&gtt_shared_ctl->lock);
+}
+
+static void
+gtt_storage_checkout(RelFileNode rnode, bool skiplock)
+{
+	gtt_shared_hash_entry	*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (!skiplock)
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(rnode), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		if (!skiplock)
+			LWLockRelease(&gtt_shared_ctl->lock);
+
+		elog(WARNING, "relfilenode %u/%u/%u not exist in gtt shared hash when forget",
+						rnode.dbNode, rnode.spcNode, rnode.relNode);
+		return;
+	}
+
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+	bms_del_member(entry->map, MyBackendId);
+
+	if (bms_is_empty(entry->map))
+	{
+		if (!hash_search(active_gtt_shared_hash, &rnode, HASH_REMOVE, NULL))
+			elog(PANIC, "gtt shared hash table corrupted");
+	}
+
+	if (!skiplock)
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+	return;
+}
+
+Bitmapset *
+copy_active_gtt_bitmap(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	Bitmapset	*map_copy = NULL;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return NULL;
+	}
+
+	Assert(entry->map);
+	if (!bms_is_empty(entry->map))
+		map_copy = bms_copy(entry->map);
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return map_copy;
+}
+
+bool
+is_other_backend_use_gtt(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	bool		in_use = false;
+	int			num_use = 0;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return false;
+	}
+
+	Assert(entry->map);
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+
+	num_use = bms_num_members(entry->map);
+	if (num_use == 0)
+		in_use = false;
+	else if (num_use == 1)
+	{
+		if(bms_is_member(MyBackendId, entry->map))
+			in_use = false;
+		else
+			in_use = true;
+	}
+	else
+		in_use = true;
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return in_use;
+}
+
+void
+remember_gtt_storage_info(RelFileNode rnode, Relation rel)
+{
+	gtt_local_hash_entry	*entry;
+	MemoryContext			oldcontext;
+	Oid			relid = rnode.relNode;
+	bool		found;
+
+	if (max_active_gtt <= 0)
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("Global temporary table feature is disable"),
+			 errhint("You might need to increase max_active_gtt to enable this feature.")));
+
+	if (RecoveryInProgress())
+		elog(ERROR, "readonly mode not support access global temp table yet");
+
+	if (gtt_storage_local_hash == NULL)
+	{
+#define GTT_LOCAL_HASH_SIZE		1024
+		/* First time through: initialize the hash table */
+		HASHCTL		ctl;
+
+		MemSet(&ctl, 0, sizeof(ctl));
+		ctl.keysize = sizeof(Oid);
+		ctl.entrysize = sizeof(gtt_local_hash_entry);
+		gtt_storage_local_hash =
+			hash_create("global temp relation table",
+						GTT_LOCAL_HASH_SIZE,
+						&ctl, HASH_ELEM | HASH_BLOBS);
+
+		if (!CacheMemoryContext)
+			CreateCacheMemoryContext();
+
+		gtt_relstats_context =
+			AllocSetContextCreate(CacheMemoryContext,
+							"gtt relstats context",
+							ALLOCSET_DEFAULT_SIZES);
+	}
+
+	/* Look up or create an entry */
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_ENTER, &found);
+
+	if (found)
+	{
+		elog(ERROR, "backend %d relid %u already exists in global temp table local hash",
+					MyBackendId, relid);
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+
+	entry->spcnode = rnode.spcNode;
+	entry->relpages = 0;
+	entry->reltuples = 0;
+	entry->relallvisible = 0;
+	entry->relkind = rel->rd_rel->relkind;
+	/* only heap contain transaction information */
+	if (entry->relkind == RELKIND_RELATION || entry->relkind == RELKIND_PARTITIONED_TABLE)
+	{
+		int natts = RelationGetNumberOfAttributes(rel);
+		entry->natts = natts;
+		entry->attnum = palloc0(sizeof(int) * natts);
+		entry->att_stat_tups = palloc0(sizeof(HeapTuple) * natts);
+
+		if (RELATION_GTT_ON_COMMIT_DELETE(rel))
+		{
+			entry->on_commit_delete = true;
+			register_on_commit_action(rel->rd_node.relNode, ONCOMMIT_DELETE_ROWS);
+		}
+
+		entry->relfrozenxid = RecentXmin;
+		entry->relminmxid = GetOldestMultiXactId();
+		insert_gtt_relfrozenxid_to_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+		gtt_storage_checkin(rnode);
+	}
+	else
+	{
+		entry->natts = 0;
+		entry->attnum = 0;
+		entry->att_stat_tups = NULL;
+		entry->on_commit_delete = false;
+		entry->relfrozenxid = 0;
+		entry->relminmxid = 0;
+	}
+
+	MemoryContextSwitchTo(oldcontext);
+
+	if (!gtt_cleaner_exit_registered)
+	{
+		before_shmem_exit(gtt_storage_removeall, 0);
+		gtt_cleaner_exit_registered = true;
+	}
+
+	return;
+}
+
+void
+forget_gtt_storage_info(Oid relid)
+{
+	gtt_local_hash_entry		*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+				(void *) &(relid), HASH_FIND, NULL);
+
+	if (entry && entry->relkind == RELKIND_RELATION)
+	{
+		RelFileNode rnode;
+		int			i;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		gtt_storage_checkout(rnode, false);
+
+		Assert(TransactionIdIsNormal(entry->relfrozenxid));
+		remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+
+		for (i = 0; i < entry->natts; i++)
+		{
+			if (entry->att_stat_tups[i])
+			{
+				heap_freetuple(entry->att_stat_tups[i]);
+				entry->att_stat_tups[i] = NULL;
+			}
+		}
+	}
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_REMOVE, NULL);
+
+	return;
+}
+
+/* is the storage file was created in this backend */
+bool
+gtt_storage_attached(Oid relid)
+{
+	bool found;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	if (gtt_storage_local_hash == NULL)
+		return false;
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_FIND, &found);
+
+	return found;
+}
+
+static void
+gtt_storage_removeall(int code, Datum arg)
+{
+	HASH_SEQ_STATUS				status;
+	gtt_local_hash_entry		*entry;
+	int			nrels = 0,
+				maxrels = 0;
+	SMgrRelation	*srels = NULL;
+	RelFileNode		*rnodes = NULL;
+	char			*relkinds = NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	hash_seq_init(&status, gtt_storage_local_hash);
+	while ((entry = (gtt_local_hash_entry *) hash_seq_search(&status)) != NULL)
+	{
+		SMgrRelation srel;
+		RelFileNode rnode;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		srel = smgropen(rnode, MyBackendId);
+
+		/* allocate the initial array, or extend it, if needed */
+		if (maxrels == 0)
+		{
+			maxrels = 32;
+			srels = palloc(sizeof(SMgrRelation) * maxrels);
+			rnodes = palloc(sizeof(RelFileNode) * maxrels);
+			relkinds = palloc(sizeof(char) * maxrels);
+		}
+		else if (maxrels <= nrels)
+		{
+			maxrels *= 2;
+			srels = repalloc(srels, sizeof(SMgrRelation) * maxrels);
+			rnodes = repalloc(rnodes, sizeof(RelFileNode) * maxrels);
+			relkinds = repalloc(relkinds, sizeof(char) * maxrels);
+		}
+
+		srels[nrels] = srel;
+		rnodes[nrels] = rnode;
+		relkinds[nrels] = entry->relkind;
+		nrels++;
+	}
+
+	if (nrels > 0)
+	{
+		int i;
+
+		smgrdounlinkall(srels, nrels, false);
+
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+		for (i = 0; i < nrels; i++)
+		{
+			smgrclose(srels[i]);
+			if (relkinds[i] == RELKIND_RELATION)
+				gtt_storage_checkout(rnodes[i], true);
+		}
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+		pfree(srels);
+		pfree(rnodes);
+		pfree(relkinds);
+	}
+
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;
+
+	return;
+}
+
+/*
+ * Update global temp table relstats(relpage/reltuple/relallvisible) 
+ * to local hashtable
+ */
+void
+up_gtt_relstats(Relation relation,
+					BlockNumber num_pages,
+					double num_tuples,
+					BlockNumber num_all_visible_pages,
+					TransactionId relfrozenxid,
+					TransactionId relminmxid)
+{
+	Oid		relid = RelationGetRelid(relation);
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	Assert(entry->spcnode);
+
+	if (num_pages >= 0 &&
+		entry->relpages != (int32)num_pages)
+		entry->relpages = (int32)num_pages;
+
+	if (num_tuples >= 0 &&
+		num_tuples != (float4)entry->reltuples)
+		entry->reltuples = (float4)num_tuples;
+
+	/* only heap contain transaction information and relallvisible */
+	if (entry->relkind == RELKIND_RELATION)
+	{
+		if (entry->relallvisible >= 0 &&
+			entry->relallvisible != (int32)num_all_visible_pages)
+		{
+			entry->relallvisible = (int32)num_all_visible_pages;
+		}
+
+		if (TransactionIdIsNormal(relfrozenxid) &&
+			entry->relfrozenxid != relfrozenxid &&
+			(TransactionIdPrecedes(entry->relfrozenxid, relfrozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(), entry->relfrozenxid)))
+		{
+			remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+			entry->relfrozenxid = relfrozenxid;
+			insert_gtt_relfrozenxid_to_ordered_list(relfrozenxid);
+			set_gtt_session_relfrozenxid();
+		}
+
+		if (MultiXactIdIsValid(relminmxid) &&
+			entry->relminmxid != relminmxid &&
+			(MultiXactIdPrecedes(entry->relminmxid, relminmxid) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), entry->relminmxid)))
+		{
+			entry->relminmxid = relminmxid;
+		}
+	}
+
+	return;
+}
+
+/*
+ * Search global temp table relstats(relpage/reltuple/relallvisible) 
+ * from local hashtable.
+ */
+bool
+get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+				BlockNumber *relallvisible, TransactionId *relfrozenxid,
+				TransactionId *relminmxid)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	if (gtt_storage_local_hash == NULL)
+		return false;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return false;
+
+	Assert(entry->relid == relid);
+
+	if (relpages)
+		*relpages = entry->relpages;
+
+	if (reltuples)
+		*reltuples = entry->reltuples;
+
+	if (relallvisible)
+		*relallvisible = entry->relallvisible;
+
+	if (relfrozenxid)
+		*relfrozenxid = entry->relfrozenxid;
+
+	if (relminmxid)
+		*relminmxid = entry->relminmxid;
+
+	return true;
+}
+
+/*
+ * Update global temp table statistic info(definition is same as pg_statistic)
+ * to local hashtable where ananyze global temp table
+ */
+void
+up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+					TupleDesc tupleDescriptor, Datum *values, bool *isnull)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	MemoryContext			oldcontext;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	if (entry->relkind != RELKIND_RELATION)
+	{
+		elog(WARNING, "oid %u not a relation", reloid);
+		return;
+	}
+
+	/* todo */
+	if (entry->natts < natts)
+	{
+		elog(WARNING, "reloid %u not support update attstat after add colunm", reloid);
+		return;
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	Assert(entry->relid == reloid);
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == 0)
+		{
+			entry->attnum[i] = attnum;
+			break;
+		}
+		else if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			heap_freetuple(entry->att_stat_tups[i]);
+			entry->att_stat_tups[i] = NULL;
+			break;
+		}
+	}
+
+	Assert(i < entry->natts);
+	Assert(entry->att_stat_tups[i] == NULL);
+	entry->att_stat_tups[i] = heap_form_tuple(tupleDescriptor, values, isnull);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+/*
+ * Search global temp table statistic info(definition is same as pg_statistic)
+ * from local hashtable.
+ */
+HeapTuple
+get_gtt_att_statistic(Oid reloid, int attnum, bool inh)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return NULL;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return NULL;
+
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			return entry->att_stat_tups[i];
+		}
+	}
+
+	return NULL;
+}
+
+void
+release_gtt_statistic_cache(HeapTuple tup)
+{
+	/* do nothing */
+	return;
+}
+
+static void
+insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid)
+{
+	MemoryContext	oldcontext;
+	ListCell	*cell;
+	int			i;
+
+	Assert(TransactionIdIsNormal(relfrozenxid));
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	/* Does the datum belong at the front? */
+	if (gtt_session_relfrozenxid_list == NIL ||
+		TransactionIdFollowsOrEquals(relfrozenxid,
+			linitial_oid(gtt_session_relfrozenxid_list)))
+	{
+		gtt_session_relfrozenxid_list =
+			lcons_oid(relfrozenxid, gtt_session_relfrozenxid_list);
+		MemoryContextSwitchTo(oldcontext);
+
+		return;
+	}
+
+	/* No, so find the entry it belongs after */
+	i = 0;
+	foreach (cell, gtt_session_relfrozenxid_list)
+	{
+		if (TransactionIdFollowsOrEquals(relfrozenxid, lfirst_oid(cell)))
+			break;
+
+		i++;
+	}
+	gtt_session_relfrozenxid_list =
+		list_insert_nth_oid(gtt_session_relfrozenxid_list, i, relfrozenxid);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+static void
+remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid)
+{
+	gtt_session_relfrozenxid_list =
+		list_delete_oid(gtt_session_relfrozenxid_list, relfrozenxid);
+}
+
+static void
+set_gtt_session_relfrozenxid(void)
+{
+	TransactionId gtt_frozenxid = InvalidTransactionId;
+
+	if (gtt_session_relfrozenxid_list)
+		gtt_frozenxid = llast_oid(gtt_session_relfrozenxid_list);
+
+	gtt_session_frozenxid = gtt_frozenxid;
+	if (MyProc->session_gtt_frozenxid != gtt_frozenxid)
+		MyProc->session_gtt_frozenxid = gtt_frozenxid;
+}
+
+Datum
+pg_get_gtt_statistics(PG_FUNCTION_ARGS)
+{
+	HeapTuple	tuple;
+	Relation	rel = NULL;
+	int		attnum = PG_GETARG_INT32(1);
+	Oid		reloid = PG_GETARG_OID(0);
+	char		rel_persistence;
+	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	  tupdesc;
+	MemoryContext oldcontext;
+	Tuplestorestate *tupstore;
+	Relation		pg_tatistic = NULL;
+	TupleDesc		sd;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("set-valued function called in context that cannot accept a set")));
+
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("materialize mode required, but it is not " \
+				"allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+				rsinfo->econtext->ecxt_per_query_memory);
+
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	pg_tatistic = table_open(StatisticRelationId, AccessShareLock);
+	sd = RelationGetDescr(pg_tatistic);
+
+	tuple = get_gtt_att_statistic(reloid, attnum, false);
+	if (tuple)
+	{
+		Datum	values[31];
+		bool	isnull[31];
+		HeapTuple	res = NULL;
+
+		memset(&values, 0, sizeof(values));
+		memset(&isnull, 0, sizeof(isnull));
+		heap_deform_tuple(tuple, sd, values, isnull);
+		res = heap_form_tuple(tupdesc, values, isnull);
+		tuplestore_puttuple(tupstore, res);
+	}
+
+	table_close(rel, NoLock);
+	table_close(pg_tatistic, AccessShareLock);
+	tuplestore_donestoring(tupstore);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_get_gtt_relstats(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc		tupdesc;
+	Tuplestorestate	*tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	Oid		reloid = PG_GETARG_OID(0);
+	char	rel_persistence;
+	BlockNumber	relpages = 0;
+	double		reltuples = 0;
+	BlockNumber	relallvisible = 0;
+	uint32		relfrozenxid = 0;
+	uint32		relminmxid = 0;
+	Relation	rel = NULL;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	if (get_gtt_relstats(reloid,
+						&relpages, &reltuples, &relallvisible,
+						&relfrozenxid, &relminmxid))
+	{
+		Datum	values[5];
+		bool	isnull[5];
+
+		memset(isnull, 0, sizeof(isnull));
+		memset(values, 0, sizeof(values));
+		values[0] = Int32GetDatum(relpages);
+		values[1] = Float4GetDatum((float4)reltuples);
+		values[2] = Int32GetDatum(relallvisible);
+		values[3] = UInt32GetDatum(relfrozenxid);
+		values[4] = UInt32GetDatum(relminmxid);
+		tuple = heap_form_tuple(tupdesc, values, isnull);
+		tuplestore_puttuple(tupstore, tuple);
+	}
+
+	tuplestore_donestoring(tupstore);
+	table_close(rel, NoLock);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_gtt_attached_pid(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	Oid		reloid = PG_GETARG_OID(0);
+	char	rel_persistence;
+	Relation	rel = NULL;
+	PGPROC		*proc = NULL;
+	Bitmapset	*map = NULL;
+	pid_t		pid = 0;
+	int			backendid = 0;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	map = copy_active_gtt_bitmap(rel->rd_node);
+	if (map)
+	{
+		backendid = bms_first_member(map);
+
+		do
+		{
+			proc = BackendIdGetProc(backendid);
+			pid = proc->pid;
+			if (pid > 0)
+			{
+				Datum	values[2];
+				bool	isnull[2];
+
+				memset(isnull, false, sizeof(isnull));
+				memset(values, 0, sizeof(values));
+				values[0] = UInt32GetDatum(reloid);
+				values[1] = Int32GetDatum(pid);
+				tuple = heap_form_tuple(tupdesc, values, isnull);
+				tuplestore_puttuple(tupstore, tuple);
+			}
+			backendid = bms_next_member(map, backendid);
+		} while (backendid > 0);
+
+		pfree(map);
+	}
+
+	tuplestore_donestoring(tupstore);
+	table_close(rel, NoLock);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	int			num_xid = MaxBackends + 1;
+	int			*pids = NULL;
+	uint32		*xids = NULL;
+	int			i = 0;
+	int			j = 0;
+	uint32		oldest = 0;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (max_active_gtt <= 0)
+		return (Datum) 0;
+
+	if (RecoveryInProgress())
+		return (Datum) 0;
+
+	pids = palloc0(sizeof(int) * num_xid);
+	xids = palloc0(sizeof(int) * num_xid);
+	oldest = list_all_session_gtt_frozenxids(num_xid, pids, xids, &i);
+	if (i > 0)
+	{
+		if (i > 0)
+		{
+			pids[i] = 0;
+			xids[i] = oldest;
+			i++;
+		}
+
+		for(j = 0; j < i; j++)
+		{
+			Datum	values[2];
+			bool	isnull[2];
+
+			memset(isnull, false, sizeof(isnull));
+			memset(values, 0, sizeof(values));
+			values[0] = Int32GetDatum(pids[j]);
+			values[1] = UInt32GetDatum(xids[j]);
+			tuple = heap_form_tuple(tupdesc, values, isnull);
+			tuplestore_puttuple(tupstore, tuple);
+		}
+	}
+	tuplestore_donestoring(tupstore);
+	pfree(pids);
+	pfree(xids);
+
+	return (Datum) 0;
+}
+
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index c9e75f4..2adde62 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -186,6 +186,91 @@ CREATE OR REPLACE VIEW pg_sequences AS
     WHERE NOT pg_is_other_temp_schema(N.oid)
           AND relkind = 'S';
 
+-- For global temporary table
+CREATE VIEW pg_gtt_relstats WITH (security_barrier) AS
+ SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.*
+ FROM
+     pg_class c
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_get_gtt_relstats(c.oid) as s
+ WHERE c.relpersistence='g' AND c.relkind in('r','p') AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
+CREATE VIEW pg_gtt_attached_pids WITH (security_barrier) AS
+ SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.*
+ FROM
+     pg_class c
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_gtt_attached_pid(c.oid) as s
+ WHERE c.relpersistence='g' AND c.relkind in('r','p') AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
+CREATE VIEW pg_gtt_stats WITH (security_barrier) AS
+SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    a.attname,
+    s.stainherit AS inherited,
+    s.stanullfrac AS null_frac,
+    s.stawidth AS avg_width,
+    s.stadistinct AS n_distinct,
+        CASE
+            WHEN s.stakind1 = 1 THEN s.stavalues1
+            WHEN s.stakind2 = 1 THEN s.stavalues2
+            WHEN s.stakind3 = 1 THEN s.stavalues3
+            WHEN s.stakind4 = 1 THEN s.stavalues4
+            WHEN s.stakind5 = 1 THEN s.stavalues5
+        END AS most_common_vals,
+        CASE
+            WHEN s.stakind1 = 1 THEN s.stanumbers1
+            WHEN s.stakind2 = 1 THEN s.stanumbers2
+            WHEN s.stakind3 = 1 THEN s.stanumbers3
+            WHEN s.stakind4 = 1 THEN s.stanumbers4
+            WHEN s.stakind5 = 1 THEN s.stanumbers5
+        END AS most_common_freqs,
+        CASE
+            WHEN s.stakind1 = 2 THEN s.stavalues1
+            WHEN s.stakind2 = 2 THEN s.stavalues2
+            WHEN s.stakind3 = 2 THEN s.stavalues3
+            WHEN s.stakind4 = 2 THEN s.stavalues4
+            WHEN s.stakind5 = 2 THEN s.stavalues5
+        END AS histogram_bounds,
+        CASE
+            WHEN s.stakind1 = 3 THEN s.stanumbers1[1]
+            WHEN s.stakind2 = 3 THEN s.stanumbers2[1]
+            WHEN s.stakind3 = 3 THEN s.stanumbers3[1]
+            WHEN s.stakind4 = 3 THEN s.stanumbers4[1]
+            WHEN s.stakind5 = 3 THEN s.stanumbers5[1]
+        END AS correlation,
+        CASE
+            WHEN s.stakind1 = 4 THEN s.stavalues1
+            WHEN s.stakind2 = 4 THEN s.stavalues2
+            WHEN s.stakind3 = 4 THEN s.stavalues3
+            WHEN s.stakind4 = 4 THEN s.stavalues4
+            WHEN s.stakind5 = 4 THEN s.stavalues5
+        END AS most_common_elems,
+        CASE
+            WHEN s.stakind1 = 4 THEN s.stanumbers1
+            WHEN s.stakind2 = 4 THEN s.stanumbers2
+            WHEN s.stakind3 = 4 THEN s.stanumbers3
+            WHEN s.stakind4 = 4 THEN s.stanumbers4
+            WHEN s.stakind5 = 4 THEN s.stanumbers5
+        END AS most_common_elem_freqs,
+        CASE
+            WHEN s.stakind1 = 5 THEN s.stanumbers1
+            WHEN s.stakind2 = 5 THEN s.stanumbers2
+            WHEN s.stakind3 = 5 THEN s.stanumbers3
+            WHEN s.stakind4 = 5 THEN s.stanumbers4
+            WHEN s.stakind5 = 5 THEN s.stanumbers5
+        END AS elem_count_histogram
+   FROM 
+     pg_class c
+     JOIN pg_attribute a ON c.oid = a.attrelid
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_get_gtt_statistics(c.oid, a.attnum, ''::text) as s
+  WHERE c.relpersistence='g' AND c.relkind in('r','p') and NOT a.attisdropped AND has_column_privilege(c.oid, a.attnum, 'select'::text) AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
 CREATE VIEW pg_stats WITH (security_barrier) AS
     SELECT
         nspname AS schemaname,
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index c4420dd..a789718 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -66,6 +66,7 @@
 #include "utils/syscache.h"
 #include "utils/timestamp.h"
 
+#include "catalog/storage_gtt.h"
 
 /* Per-index data for ANALYZE */
 typedef struct AnlIndexData
@@ -103,7 +104,7 @@ static int	acquire_inherited_sample_rows(Relation onerel, int elevel,
 										  HeapTuple *rows, int targrows,
 										  double *totalrows, double *totaldeadrows);
 static void update_attstats(Oid relid, bool inh,
-							int natts, VacAttrStats **vacattrstats);
+							int natts, VacAttrStats **vacattrstats, char relpersistence);
 static Datum std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 static Datum ind_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 
@@ -586,14 +587,15 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 		 * pg_statistic for columns we didn't process, we leave them alone.)
 		 */
 		update_attstats(RelationGetRelid(onerel), inh,
-						attr_cnt, vacattrstats);
+						attr_cnt, vacattrstats, RelationGetRelPersistence(onerel));
 
 		for (ind = 0; ind < nindexes; ind++)
 		{
 			AnlIndexData *thisdata = &indexdata[ind];
 
 			update_attstats(RelationGetRelid(Irel[ind]), false,
-							thisdata->attr_cnt, thisdata->vacattrstats);
+							thisdata->attr_cnt, thisdata->vacattrstats,
+							RelationGetRelPersistence(Irel[ind]));
 		}
 
 		/*
@@ -673,11 +675,20 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 			IndexBulkDeleteResult *stats;
 			IndexVacuumInfo ivinfo;
 
+			memset(&ivinfo, 0, sizeof(IndexVacuumInfo));
 			ivinfo.index = Irel[ind];
 			ivinfo.analyze_only = true;
 			ivinfo.estimated_count = true;
 			ivinfo.message_level = elevel;
-			ivinfo.num_heap_tuples = onerel->rd_rel->reltuples;
+			/* get global temp relstats from localhash, not catalog */
+			if (RELATION_IS_GLOBAL_TEMP(onerel))
+			{
+				get_gtt_relstats(RelationGetRelid(onerel),
+								NULL, &ivinfo.num_heap_tuples, NULL,
+								NULL, NULL);
+			}
+			else
+				ivinfo.num_heap_tuples = onerel->rd_rel->reltuples;
 			ivinfo.strategy = vac_strategy;
 
 			stats = index_vacuum_cleanup(&ivinfo, NULL);
@@ -1456,7 +1467,7 @@ acquire_inherited_sample_rows(Relation onerel, int elevel,
  *		by taking a self-exclusive lock on the relation in analyze_rel().
  */
 static void
-update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
+update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats, char relpersistence)
 {
 	Relation	sd;
 	int			attno;
@@ -1558,31 +1569,45 @@ update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
 			}
 		}
 
-		/* Is there already a pg_statistic tuple for this attribute? */
-		oldtup = SearchSysCache3(STATRELATTINH,
-								 ObjectIdGetDatum(relid),
-								 Int16GetDatum(stats->attr->attnum),
-								 BoolGetDatum(inh));
-
-		if (HeapTupleIsValid(oldtup))
+		/* Update column statistic to localhash, not catalog */
+		if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		{
-			/* Yes, replace it */
-			stup = heap_modify_tuple(oldtup,
-									 RelationGetDescr(sd),
-									 values,
-									 nulls,
-									 replaces);
-			ReleaseSysCache(oldtup);
-			CatalogTupleUpdate(sd, &stup->t_self, stup);
+			up_gtt_att_statistic(relid,
+								stats->attr->attnum,
+								inh,
+								natts,
+								RelationGetDescr(sd),
+								values,
+								nulls);
 		}
 		else
 		{
-			/* No, insert new tuple */
-			stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
-			CatalogTupleInsert(sd, stup);
-		}
+			/* Is there already a pg_statistic tuple for this attribute? */
+			oldtup = SearchSysCache3(STATRELATTINH,
+									 ObjectIdGetDatum(relid),
+									 Int16GetDatum(stats->attr->attnum),
+									 BoolGetDatum(inh));
+
+			if (HeapTupleIsValid(oldtup))
+			{
+				/* Yes, replace it */
+				stup = heap_modify_tuple(oldtup,
+										 RelationGetDescr(sd),
+										 values,
+										 nulls,
+										 replaces);
+				ReleaseSysCache(oldtup);
+				CatalogTupleUpdate(sd, &stup->t_self, stup);
+			}
+			else
+			{
+				/* No, insert new tuple */
+				stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
+				CatalogTupleInsert(sd, stup);
+			}
 
-		heap_freetuple(stup);
+			heap_freetuple(stup);
+		}
 	}
 
 	table_close(sd, RowExclusiveLock);
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index e9d7a7f..3088e26 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -391,6 +391,12 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 					 errmsg("cannot vacuum temporary tables of other sessions")));
 	}
 
+	/* not support cluster global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(OldHeap))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support cluster global temporary tables yet")));
+
 	/*
 	 * Also check for active uses of the relation in the current transaction,
 	 * including open scans and pending AFTER trigger events.
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 52ce02f..3d3f7dc 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -2583,6 +2583,16 @@ ReindexMultipleTables(const char *objectName, ReindexObjectType objectKind,
 			!isTempNamespace(classtuple->relnamespace))
 			continue;
 
+		/* not support reindex on global temp table, so skip it */
+		if (classtuple->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			ereport(WARNING,
+				(errmsg("global temp table \"%s.%s\" skip reindexed",
+					get_namespace_name(get_rel_namespace(relid)),
+					get_rel_name(relid))));
+			continue;
+		}
+
 		/* Check user/system classification, and optionally skip */
 		if (objectKind == REINDEX_OBJECT_SYSTEM &&
 			!IsSystemClass(relid, classtuple))
diff --git a/src/backend/commands/lockcmds.c b/src/backend/commands/lockcmds.c
index 329ab84..dfa257c 100644
--- a/src/backend/commands/lockcmds.c
+++ b/src/backend/commands/lockcmds.c
@@ -96,7 +96,8 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
 	 * transaction.
 	 */
 	relpersistence = get_rel_persistence(relid);
-	if (relpersistence == RELPERSISTENCE_TEMP)
+	if (relpersistence == RELPERSISTENCE_TEMP ||
+		relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		MyXactFlags |= XACT_FLAGS_ACCESSEDTEMPNAMESPACE;
 
 	/* Check permissions. */
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index 6aab73b..44f350d 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -94,7 +94,7 @@ static HTAB *seqhashtab = NULL; /* hash table for SeqTable items */
  */
 static SeqTableData *last_used_seq = NULL;
 
-static void fill_seq_with_data(Relation rel, HeapTuple tuple);
+static void fill_seq_with_data(Relation rel, HeapTuple tuple, Buffer buf);
 static Relation lock_and_open_sequence(SeqTable seq);
 static void create_seq_hashtable(void);
 static void init_sequence(Oid relid, SeqTable *p_elm, Relation *p_rel);
@@ -108,6 +108,7 @@ static void init_params(ParseState *pstate, List *options, bool for_identity,
 						List **owned_by);
 static void do_setval(Oid relid, int64 next, bool iscalled);
 static void process_owned_by(Relation seqrel, List *owned_by, bool for_identity);
+int64 get_seqence_start_value(Oid seqid);
 
 
 /*
@@ -222,7 +223,7 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 
 	/* now initialize the sequence's data */
 	tuple = heap_form_tuple(tupDesc, value, null);
-	fill_seq_with_data(rel, tuple);
+	fill_seq_with_data(rel, tuple, InvalidBuffer);
 
 	/* process OWNED BY if given */
 	if (owned_by)
@@ -327,7 +328,7 @@ ResetSequence(Oid seq_relid)
 	/*
 	 * Insert the modified tuple into the new storage file.
 	 */
-	fill_seq_with_data(seq_rel, tuple);
+	fill_seq_with_data(seq_rel, tuple, InvalidBuffer);
 
 	/* Clear local cache so that we don't think we have cached numbers */
 	/* Note that we do not change the currval() state */
@@ -340,17 +341,21 @@ ResetSequence(Oid seq_relid)
  * Initialize a sequence's relation with the specified tuple as content
  */
 static void
-fill_seq_with_data(Relation rel, HeapTuple tuple)
+fill_seq_with_data(Relation rel, HeapTuple tuple, Buffer buf)
 {
-	Buffer		buf;
 	Page		page;
 	sequence_magic *sm;
 	OffsetNumber offnum;
+	bool lockBuffer = false;
 
 	/* Initialize first page of relation with special magic number */
 
-	buf = ReadBuffer(rel, P_NEW);
-	Assert(BufferGetBlockNumber(buf) == 0);
+	if (buf == InvalidBuffer)
+	{
+		buf = ReadBuffer(rel, P_NEW);
+		Assert(BufferGetBlockNumber(buf) == 0);
+		lockBuffer = true;
+	}
 
 	page = BufferGetPage(buf);
 
@@ -360,7 +365,8 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	/* Now insert sequence tuple */
 
-	LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
+	if (lockBuffer)
+		LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 
 	/*
 	 * Since VACUUM does not process sequences, we have to force the tuple to
@@ -410,7 +416,8 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	END_CRIT_SECTION();
 
-	UnlockReleaseBuffer(buf);
+	if (lockBuffer)
+		UnlockReleaseBuffer(buf);
 }
 
 /*
@@ -502,7 +509,7 @@ AlterSequence(ParseState *pstate, AlterSeqStmt *stmt)
 		/*
 		 * Insert the modified tuple into the new storage file.
 		 */
-		fill_seq_with_data(seqrel, newdatatuple);
+		fill_seq_with_data(seqrel, newdatatuple, InvalidBuffer);
 	}
 
 	/* process OWNED BY if given */
@@ -1178,6 +1185,25 @@ read_seq_tuple(Relation rel, Buffer *buf, HeapTuple seqdatatuple)
 	LockBuffer(*buf, BUFFER_LOCK_EXCLUSIVE);
 
 	page = BufferGetPage(*buf);
+	if (GlobalTempRelationPageIsNotInitialized(rel, page))
+	{
+		/* Initialize sequence for global temporary tables */
+		Datum		value[SEQ_COL_LASTCOL] = {0};
+		bool		null[SEQ_COL_LASTCOL] = {false};
+		HeapTuple	tuple;
+		int64		startv = get_seqence_start_value(RelationGetRelid(rel));
+
+		/*
+		 * last_value from pg_sequence.seqstart
+		 * log_cnt = 0
+		 * is_called = false
+		 */
+		value[SEQ_COL_LASTVAL-1] = Int64GetDatumFast(startv); /* start sequence with 1 */
+
+		tuple = heap_form_tuple(RelationGetDescr(rel), value, null);
+		fill_seq_with_data(rel, tuple, *buf);
+		heap_freetuple(tuple);
+	}
 	sm = (sequence_magic *) PageGetSpecialPointer(page);
 
 	if (sm->magic != SEQ_MAGIC)
@@ -1954,3 +1980,23 @@ seq_mask(char *page, BlockNumber blkno)
 
 	mask_unused_space(page);
 }
+
+int64
+get_seqence_start_value(Oid seqid)
+{
+	HeapTuple	seqtuple;
+	Form_pg_sequence	seqform;
+	int64		start;
+
+	seqtuple = SearchSysCache1(SEQRELID, ObjectIdGetDatum(seqid));
+	if (!HeapTupleIsValid(seqtuple))
+		elog(ERROR, "cache lookup failed for sequence %u",
+			 seqid);
+
+	seqform = (Form_pg_sequence) GETSTRUCT(seqtuple);
+	start = seqform->seqstart;
+	ReleaseSysCache(seqtuple);
+
+	return start;
+}
+
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 30b72b6..cc5b991 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -47,6 +47,7 @@
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
 #include "catalog/toasting.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/defrem.h"
@@ -552,6 +553,7 @@ static void refuseDupeIndexAttach(Relation parentIdx, Relation partIdx,
 								  Relation partitionTbl);
 static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
+static bool has_oncommit_option(List *options);
 
 
 /* ----------------------------------------------------------------
@@ -597,6 +599,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	LOCKMODE	parentLockmode;
 	const char *accessMethod = NULL;
 	Oid			accessMethodId = InvalidOid;
+	bool		has_oncommit_clause = false;
 
 	/*
 	 * Truncate relname to appropriate length (probably a waste of time, as
@@ -607,8 +610,10 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Check consistency of arguments
 	 */
+	/* global temp table same as local temp table */
 	if (stmt->oncommit != ONCOMMIT_NOOP
-		&& stmt->relation->relpersistence != RELPERSISTENCE_TEMP)
+		&& !(stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+			 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 				 errmsg("ON COMMIT can only be used on temporary tables")));
@@ -638,7 +643,9 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	 * code.  This is needed because calling code might not expect untrusted
 	 * tables to appear in pg_temp at the front of its search path.
 	 */
-	if (stmt->relation->relpersistence == RELPERSISTENCE_TEMP
+	/* global temp table same as local temp table */
+	if ((stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+		 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		&& InSecurityRestrictedOperation())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -739,6 +746,57 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Parse and validate reloptions, if any.
 	 */
+	/* global temp table */
+	has_oncommit_clause = has_oncommit_option(stmt->options);
+	if (stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP &&
+		(relkind == RELKIND_RELATION || relkind == RELKIND_PARTITIONED_TABLE))
+	{
+		/* inherit table or parition table inherit on commit property from parent table*/
+		if (inheritOids && stmt->oncommit == ONCOMMIT_NOOP && !has_oncommit_clause)
+		{
+			Oid			parent = linitial_oid(inheritOids);
+			Relation	relation = table_open(parent, NoLock);
+
+			if (!RELATION_IS_GLOBAL_TEMP(relation))
+				elog(ERROR, "The parent table must be global temporary table");
+
+			if (RELATION_GTT_ON_COMMIT_DELETE(relation))
+				stmt->oncommit = ONCOMMIT_DELETE_ROWS;
+			else
+				stmt->oncommit = ONCOMMIT_PRESERVE_ROWS;
+			table_close(relation, NoLock);
+		}
+
+		if (has_oncommit_clause)
+		{
+			if (stmt->oncommit != ONCOMMIT_NOOP)
+				elog(ERROR, "can not defeine global temp table with on commit and with clause at same time");
+		}
+		else
+		{
+			DefElem *opt = makeNode(DefElem);
+
+			opt->type = T_DefElem;
+			opt->defnamespace = NULL;
+			opt->defname = "on_commit_delete_rows";
+			opt->defaction = DEFELEM_UNSPEC;
+
+			/* use reloptions to remember on commit clause */
+			if (stmt->oncommit == ONCOMMIT_DELETE_ROWS)
+				opt->arg  = (Node *)makeString("true");
+			else if (stmt->oncommit == ONCOMMIT_PRESERVE_ROWS)
+				opt->arg  = (Node *)makeString("false");
+			else if (stmt->oncommit == ONCOMMIT_NOOP)
+				opt->arg  = (Node *)makeString("false");
+			else
+				elog(ERROR, "global temp table not support on commit drop clause");
+
+			stmt->options = lappend(stmt->options, opt);
+		}
+	}
+	else if (has_oncommit_clause)
+		elog(ERROR, "regular table cannot specifie on_commit_delete_rows");
+
 	reloptions = transformRelOptions((Datum) 0, stmt->options, NULL, validnsps,
 									 true, false);
 
@@ -1800,7 +1858,8 @@ ExecuteTruncateGuts(List *explicit_rels, List *relids, List *relids_logged,
 		 * table or the current physical file to be thrown away anyway.
 		 */
 		if (rel->rd_createSubid == mySubid ||
-			rel->rd_newRelfilenodeSubid == mySubid)
+			rel->rd_newRelfilenodeSubid == mySubid ||
+			RELATION_IS_GLOBAL_TEMP(rel))
 		{
 			/* Immediate, non-rollbackable truncation is OK */
 			heap_truncate_one_rel(rel);
@@ -3359,6 +3418,13 @@ RenameRelationInternal(Oid myrelid, const char *newrelname, bool is_internal, bo
 	 * specially.
 	 */
 	targetrelation = relation_open(myrelid, is_index ? ShareUpdateExclusiveLock : AccessExclusiveLock);
+
+	if (RELATION_IS_GLOBAL_TEMP(targetrelation))
+	{
+		if (is_other_backend_use_gtt(targetrelation->rd_node))
+			elog(ERROR, "can not rename relation when other backend attached this global temp table");
+	}
+
 	namespaceId = RelationGetNamespace(targetrelation);
 
 	/*
@@ -3534,6 +3600,13 @@ AlterTable(AlterTableStmt *stmt, LOCKMODE lockmode,
 	/* Caller is required to provide an adequate lock. */
 	rel = relation_open(context->relid, NoLock);
 
+	/* We allow to alter global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (is_other_backend_use_gtt(rel->rd_node))
+			elog(ERROR, "can not alter relation when other backend attached this global temp table");
+	}
+
 	CheckTableNotInUse(rel, "ALTER TABLE");
 
 	ATController(stmt, rel, stmt->cmds, stmt->relation->inh, lockmode, context);
@@ -8099,6 +8172,13 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 				 errmsg("referenced relation \"%s\" is not a table",
 						RelationGetRelationName(pkrel))));
 
+	/* global temp table not support foreign key constraint yet */
+	if (RELATION_IS_GLOBAL_TEMP(pkrel))
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("referenced relation \"%s\" is not a global temp table",
+						RelationGetRelationName(pkrel))));
+
 	if (!allowSystemTableMods && IsSystemRelation(pkrel))
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -8138,6 +8218,12 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 						 errmsg("constraints on temporary tables must involve temporary tables of this session")));
 			break;
+		/* global temp table not support foreign key constraint yet */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					 errmsg("not support foreign key constraints on global temp table yet")));
+			break;
 	}
 
 	/*
@@ -13174,7 +13260,7 @@ index_copy_data(Relation rel, RelFileNode newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
@@ -14581,7 +14667,9 @@ ATPrepChangePersistence(Relation rel, bool toLogged)
 	 */
 	switch (rel->rd_rel->relpersistence)
 	{
+		/* global temp table same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("cannot change logged status of table \"%s\" because it is temporary",
@@ -17221,3 +17309,20 @@ ATDetachCheckNoForeignKeyRefs(Relation partition)
 		table_close(rel, NoLock);
 	}
 }
+
+static bool
+has_oncommit_option(List *options)
+{
+	ListCell   *listptr;
+
+	foreach(listptr, options)
+	{
+		DefElem    *def = (DefElem *) lfirst(listptr);
+
+		if (pg_strcasecmp(def->defname, "on_commit_delete_rows") == 0)
+			return true;
+	}
+
+	return false;
+}
+
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index d625d17..db966e8 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -35,6 +35,7 @@
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
 #include "catalog/pg_namespace.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
 #include "commands/vacuum.h"
@@ -1125,12 +1126,25 @@ vac_estimate_reltuples(Relation relation,
 					   BlockNumber scanned_pages,
 					   double scanned_tuples)
 {
-	BlockNumber old_rel_pages = relation->rd_rel->relpages;
-	double		old_rel_tuples = relation->rd_rel->reltuples;
+	BlockNumber old_rel_pages = 0;
+	double		old_rel_tuples = 0;
 	double		old_density;
 	double		unscanned_pages;
 	double		total_tuples;
 
+	/* get relstat from gtt local hash */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+	{
+		get_gtt_relstats(RelationGetRelid(relation),
+						&old_rel_pages, &old_rel_tuples, NULL,
+						NULL, NULL);
+	}
+	else
+	{
+		old_rel_pages = relation->rd_rel->relpages;
+		old_rel_tuples = relation->rd_rel->reltuples;
+	}
+
 	/* If we did scan the whole table, just use the count as-is */
 	if (scanned_pages >= total_pages)
 		return scanned_tuples;
@@ -1230,24 +1244,8 @@ vac_update_relstats(Relation relation,
 	/* Apply statistical updates, if any, to copied tuple */
 
 	dirty = false;
-	if (pgcform->relpages != (int32) num_pages)
-	{
-		pgcform->relpages = (int32) num_pages;
-		dirty = true;
-	}
-	if (pgcform->reltuples != (float4) num_tuples)
-	{
-		pgcform->reltuples = (float4) num_tuples;
-		dirty = true;
-	}
-	if (pgcform->relallvisible != (int32) num_all_visible_pages)
-	{
-		pgcform->relallvisible = (int32) num_all_visible_pages;
-		dirty = true;
-	}
 
 	/* Apply DDL updates, but not inside an outer transaction (see above) */
-
 	if (!in_outer_xact)
 	{
 		/*
@@ -1272,37 +1270,64 @@ vac_update_relstats(Relation relation,
 		}
 	}
 
-	/*
-	 * Update relfrozenxid, unless caller passed InvalidTransactionId
-	 * indicating it has no new data.
-	 *
-	 * Ordinarily, we don't let relfrozenxid go backwards: if things are
-	 * working correctly, the only way the new frozenxid could be older would
-	 * be if a previous VACUUM was done with a tighter freeze_min_age, in
-	 * which case we don't want to forget the work it already did.  However,
-	 * if the stored relfrozenxid is "in the future", then it must be corrupt
-	 * and it seems best to overwrite it with the cutoff we used this time.
-	 * This should match vac_update_datfrozenxid() concerning what we consider
-	 * to be "in the future".
-	 */
-	if (TransactionIdIsNormal(frozenxid) &&
-		pgcform->relfrozenxid != frozenxid &&
-		(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
-		 TransactionIdPrecedes(ReadNewTransactionId(),
-							   pgcform->relfrozenxid)))
+	/* global temp table remember relstats to localhash not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
 	{
-		pgcform->relfrozenxid = frozenxid;
-		dirty = true;
+		up_gtt_relstats(relation,
+						num_pages, num_tuples,
+						num_all_visible_pages,
+						frozenxid, minmulti);
 	}
-
-	/* Similarly for relminmxid */
-	if (MultiXactIdIsValid(minmulti) &&
-		pgcform->relminmxid != minmulti &&
-		(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
-		 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
+	else
 	{
-		pgcform->relminmxid = minmulti;
-		dirty = true;
+		if (pgcform->relpages != (int32) num_pages)
+		{
+			pgcform->relpages = (int32) num_pages;
+			dirty = true;
+		}
+		if (pgcform->reltuples != (float4) num_tuples)
+		{
+			pgcform->reltuples = (float4) num_tuples;
+			dirty = true;
+		}
+		if (pgcform->relallvisible != (int32) num_all_visible_pages)
+		{
+			pgcform->relallvisible = (int32) num_all_visible_pages;
+			dirty = true;
+		}
+
+		/*
+		 * Update relfrozenxid, unless caller passed InvalidTransactionId
+		 * indicating it has no new data.
+		 *
+		 * Ordinarily, we don't let relfrozenxid go backwards: if things are
+		 * working correctly, the only way the new frozenxid could be older would
+		 * be if a previous VACUUM was done with a tighter freeze_min_age, in
+		 * which case we don't want to forget the work it already did.  However,
+		 * if the stored relfrozenxid is "in the future", then it must be corrupt
+		 * and it seems best to overwrite it with the cutoff we used this time.
+		 * This should match vac_update_datfrozenxid() concerning what we consider
+		 * to be "in the future".
+		 */
+		if (TransactionIdIsNormal(frozenxid) &&
+			pgcform->relfrozenxid != frozenxid &&
+			(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(),
+								   pgcform->relfrozenxid)))
+		{
+			pgcform->relfrozenxid = frozenxid;
+			dirty = true;
+		}
+
+		/* Similarly for relminmxid */
+		if (MultiXactIdIsValid(minmulti) &&
+			pgcform->relminmxid != minmulti &&
+			(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
+		{
+			pgcform->relminmxid = minmulti;
+			dirty = true;
+		}
 	}
 
 	/* If anything changed, write out the tuple. */
@@ -1394,6 +1419,10 @@ vac_update_datfrozenxid(void)
 			continue;
 		}
 
+		/* global temp table relstats not in pg_class */
+		if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			continue;
+
 		/*
 		 * Some table AMs might not need per-relation xid / multixid horizons.
 		 * It therefore seems reasonable to allow relfrozenxid and relminmxid
@@ -1451,6 +1480,25 @@ vac_update_datfrozenxid(void)
 	Assert(TransactionIdIsNormal(newFrozenXid));
 	Assert(MultiXactIdIsValid(newMinMulti));
 
+	/*
+	 * Global temp table get frozenxid from MyProc
+	 * to avoid the vacuum truncate clog that gtt need.
+	 */
+	if (max_active_gtt > 0)
+	{
+		TransactionId oldest_gtt_frozenxid =
+			list_all_session_gtt_frozenxids(0, NULL, NULL, NULL);
+
+		if (TransactionIdIsNormal(oldest_gtt_frozenxid) &&
+			TransactionIdPrecedes(oldest_gtt_frozenxid, newFrozenXid))
+		{
+			ereport(WARNING,
+				(errmsg("global temp table oldest FrozenXid is far in the past"),
+				 errhint("please truncate them or kill those sessions that use them.")));
+			newFrozenXid = oldest_gtt_frozenxid;
+		}
+	}
+
 	/* Now fetch the pg_database tuple we need to update. */
 	relation = table_open(DatabaseRelationId, RowExclusiveLock);
 
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 8286d9c..c3992a4 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -591,6 +591,8 @@ static void
 set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 						  RangeTblEntry *rte)
 {
+	char relpersistence;
+
 	/*
 	 * The flag has previously been initialized to false, so we can just
 	 * return if it becomes clear that we can't safely set it.
@@ -618,7 +620,11 @@ set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 			 * the rest of the necessary infrastructure right now anyway.  So
 			 * for now, bail out if we see a temporary table.
 			 */
-			if (get_rel_persistence(rte->relid) == RELPERSISTENCE_TEMP)
+			/* global temp table is same as local temp table */
+			relpersistence = get_rel_persistence(rte->relid);
+
+			if (relpersistence == RELPERSISTENCE_TEMP ||
+				relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 				return;
 
 			/*
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index d6f2153..310a9e2 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -6312,7 +6312,9 @@ plan_create_index_workers(Oid tableOid, Oid indexOid)
 	 * Furthermore, any index predicate or index expressions must be parallel
 	 * safe.
 	 */
+	/* global temp table is same as local temp table */
 	if (heap->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		heap->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexExpressions(index)) ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexPredicate(index)))
 	{
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index d82fc5a..189286b 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -31,6 +31,7 @@
 #include "catalog/pg_am.h"
 #include "catalog/pg_proc.h"
 #include "catalog/pg_statistic_ext.h"
+#include "catalog/storage_gtt.h"
 #include "foreign/fdwapi.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
@@ -53,6 +54,7 @@
 #include "utils/snapmgr.h"
 #include "utils/syscache.h"
 
+
 /* GUC parameter */
 int			constraint_exclusion = CONSTRAINT_EXCLUSION_PARTITION;
 
@@ -946,10 +948,10 @@ void
 estimate_rel_size(Relation rel, int32 *attr_widths,
 				  BlockNumber *pages, double *tuples, double *allvisfrac)
 {
-	BlockNumber curpages;
-	BlockNumber relpages;
-	double		reltuples;
-	BlockNumber relallvisible;
+	BlockNumber curpages = 0;
+	BlockNumber relpages = 0;
+	double		reltuples = 0;
+	BlockNumber relallvisible = 0;
 	double		density;
 
 	switch (rel->rd_rel->relkind)
@@ -963,6 +965,21 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 
 		case RELKIND_INDEX:
 
+			/* global temp table get relstats from localhash */
+			if (RELATION_IS_GLOBAL_TEMP(rel))
+			{
+				get_gtt_relstats(RelationGetRelid(rel),
+								&relpages, &reltuples, &relallvisible,
+								NULL, NULL);
+			}
+			else
+			{
+				/* coerce values in pg_class to more desirable types */
+				relpages = (BlockNumber) rel->rd_rel->relpages;
+				reltuples = (double) rel->rd_rel->reltuples;
+				relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
+			}
+
 			/*
 			 * XXX: It'd probably be good to move this into a callback,
 			 * individual index types e.g. know if they have a metapage.
@@ -971,11 +988,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 			/* it has storage, ok to call the smgr */
 			curpages = RelationGetNumberOfBlocks(rel);
 
-			/* coerce values in pg_class to more desirable types */
-			relpages = (BlockNumber) rel->rd_rel->relpages;
-			reltuples = (double) rel->rd_rel->reltuples;
-			relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
-
 			/* report estimated # pages */
 			*pages = curpages;
 			/* quick exit if rel is clearly empty */
@@ -985,10 +997,6 @@ estimate_rel_size(Relation rel, int32 *attr_widths,
 				*allvisfrac = 0;
 				break;
 			}
-			/* coerce values in pg_class to more desirable types */
-			relpages = (BlockNumber) rel->rd_rel->relpages;
-			reltuples = (double) rel->rd_rel->reltuples;
-			relallvisible = (BlockNumber) rel->rd_rel->relallvisible;
 
 			/*
 			 * Discount the metapage while estimating the number of tuples.
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 748bebf..a5ddbcd 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -2579,6 +2579,11 @@ transformCreateTableAsStmt(ParseState *pstate, CreateTableAsStmt *stmt)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("materialized views must not use temporary tables or views")));
 
+		if (is_query_using_gtt(query))
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("materialized views must not use global temporary tables or views")));
+
 		/*
 		 * A materialized view would either need to save parameters for use in
 		 * maintaining/loading the data or prohibit them entirely.  The latter
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index ba5916b..0ee6931 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3290,17 +3290,11 @@ OptTemp:	TEMPORARY					{ $$ = RELPERSISTENCE_TEMP; }
 			| LOCAL TEMP				{ $$ = RELPERSISTENCE_TEMP; }
 			| GLOBAL TEMPORARY
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED					{ $$ = RELPERSISTENCE_UNLOGGED; }
 			| /*EMPTY*/					{ $$ = RELPERSISTENCE_PERMANENT; }
@@ -11588,19 +11582,13 @@ OptTempTableName:
 				}
 			| GLOBAL TEMPORARY opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED opt_table qualified_name
 				{
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index b875a50..123945b 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -81,6 +81,7 @@ static void expandTupleDesc(TupleDesc tupdesc, Alias *eref,
 							List **colnames, List **colvars);
 static int	specialAttNum(const char *attname);
 static bool isQueryUsingTempRelation_walker(Node *node, void *context);
+static bool is_query_using_gtt_walker(Node *node, void *context);
 
 
 /*
@@ -3579,3 +3580,49 @@ isQueryUsingTempRelation_walker(Node *node, void *context)
 								  isQueryUsingTempRelation_walker,
 								  context);
 }
+
+/* check if the query uses global temp table */
+static bool
+is_query_using_gtt_walker(Node *node, void *context)
+{
+	if (node == NULL)
+		return false;
+
+	if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+		ListCell   *rtable;
+
+		foreach(rtable, query->rtable)
+		{
+			RangeTblEntry *rte = lfirst(rtable);
+
+			if (rte->rtekind == RTE_RELATION)
+			{
+				Relation	rel = relation_open(rte->relid, AccessShareLock);
+				char		relpersistence = rel->rd_rel->relpersistence;
+
+				relation_close(rel, AccessShareLock);
+				if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+					return true;
+			}
+		}
+
+		return query_tree_walker(query,
+								 is_query_using_gtt_walker,
+								 context,
+								 QTW_IGNORE_JOINALIASES);
+	}
+
+	return expression_tree_walker(node,
+								  is_query_using_gtt_walker,
+								  context);
+}
+
+/* check if the query uses global temp table */
+bool
+is_query_using_gtt(Query *query)
+{
+	return is_query_using_gtt_walker((Node *) query, NULL);
+}
+
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index ee2d2b5..9c9abaa 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -437,6 +437,9 @@ generateSerialExtraStmts(CreateStmtContext *cxt, ColumnDef *column,
 	seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
 	seqstmt->options = seqoptions;
 
+	if (cxt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		seqstmt->sequence->relpersistence = cxt->relation->relpersistence;
+
 	/*
 	 * If a sequence data type was specified, add it to the options.  Prepend
 	 * to the list rather than append; in case a user supplied their own AS
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 6d1f28c..ed837d1 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -2086,6 +2086,11 @@ do_autovacuum(void)
 			}
 			continue;
 		}
+		else if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			/* autovacuum skip vacuum global temp table */
+			continue;
+		}
 
 		/* Fetch reloptions and the pgstat entry for this table */
 		relopts = extract_autovac_opts(tuple, pg_class_desc);
@@ -2152,7 +2157,9 @@ do_autovacuum(void)
 		/*
 		 * We cannot safely process other backends' temp tables, so skip 'em.
 		 */
-		if (classForm->relpersistence == RELPERSISTENCE_TEMP)
+		/* autovacuum skip vacuum global temp table */
+		if (classForm->relpersistence == RELPERSISTENCE_TEMP || 
+			classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 			continue;
 
 		relid = classForm->oid;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index aba3960..68adcd5 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -53,6 +53,8 @@
 #include "utils/resowner_private.h"
 #include "utils/timestamp.h"
 
+#include "utils/guc.h"
+#include "catalog/storage_gtt.h"
 
 /* Note: these two macros only work on shared buffers, not local ones! */
 #define BufHdrGetBlock(bufHdr)	((Block) (BufferBlocks + ((Size) (bufHdr)->buf_id) * BLCKSZ))
@@ -432,7 +434,7 @@ ForgetPrivateRefCountEntry(PrivateRefCountEntry *ref)
 static Buffer ReadBuffer_common(SMgrRelation reln, char relpersistence,
 								ForkNumber forkNum, BlockNumber blockNum,
 								ReadBufferMode mode, BufferAccessStrategy strategy,
-								bool *hit);
+								bool *hit, Relation rel);
 static bool PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy);
 static void PinBuffer_Locked(BufferDesc *buf);
 static void UnpinBuffer(BufferDesc *buf, bool fixOwner);
@@ -664,7 +666,8 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
 	 */
 	pgstat_count_buffer_read(reln);
 	buf = ReadBuffer_common(reln->rd_smgr, reln->rd_rel->relpersistence,
-							forkNum, blockNum, mode, strategy, &hit);
+							forkNum, blockNum, mode, strategy, &hit,
+							reln);
 	if (hit)
 		pgstat_count_buffer_hit(reln);
 	return buf;
@@ -692,7 +695,7 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 	Assert(InRecovery);
 
 	return ReadBuffer_common(smgr, RELPERSISTENCE_PERMANENT, forkNum, blockNum,
-							 mode, strategy, &hit);
+							 mode, strategy, &hit, NULL);
 }
 
 
@@ -704,7 +707,8 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 static Buffer
 ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 				  BlockNumber blockNum, ReadBufferMode mode,
-				  BufferAccessStrategy strategy, bool *hit)
+				  BufferAccessStrategy strategy, bool *hit,
+				  Relation rel)
 {
 	BufferDesc *bufHdr;
 	Block		bufBlock;
@@ -719,6 +723,15 @@ ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 
 	isExtend = (blockNum == P_NEW);
 
+	/* create storage when first read data page for gtt */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP &&
+		(isExtend || blockNum == 0) &&
+		forkNum == MAIN_FORKNUM &&
+		!gtt_storage_attached(smgr->smgr_rnode.node.relNode))
+	{
+		RelationCreateStorage(smgr->smgr_rnode.node, relpersistence, rel);
+	}
+
 	TRACE_POSTGRESQL_BUFFER_READ_START(forkNum, blockNum,
 									   smgr->smgr_rnode.node.spcNode,
 									   smgr->smgr_rnode.node.dbNode,
@@ -2809,6 +2822,16 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln)
 BlockNumber
 RelationGetNumberOfBlocksInFork(Relation relation, ForkNumber forkNum)
 {
+	/*
+	 * When this backend not init gtt storage
+	 * return 0
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(relation) &&
+		!gtt_storage_attached(relation->rd_node.relNode))
+	{
+		return 0;
+	}
+
 	switch (relation->rd_rel->relkind)
 	{
 		case RELKIND_SEQUENCE:
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 427b0d5..7adb969 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -21,6 +21,7 @@
 #include "access/nbtree.h"
 #include "access/subtrans.h"
 #include "access/twophase.h"
+#include "catalog/storage_gtt.h"
 #include "commands/async.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -147,6 +148,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, BTreeShmemSize());
 		size = add_size(size, SyncScanShmemSize());
 		size = add_size(size, AsyncShmemSize());
+		size = add_size(size, active_gtt_shared_hash_size());
 #ifdef EXEC_BACKEND
 		size = add_size(size, ShmemBackendArraySize());
 #endif
@@ -217,6 +219,8 @@ CreateSharedMemoryAndSemaphores(void)
 	SUBTRANSShmemInit();
 	MultiXactShmemInit();
 	InitBufferPool();
+	/* global temporary table */
+	active_gtt_shared_hash_init();
 
 	/*
 	 * Set up lock manager
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index c3adb2e..eb95e5f 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -62,6 +62,7 @@
 #include "utils/builtins.h"
 #include "utils/rel.h"
 #include "utils/snapmgr.h"
+#include "utils/guc.h"
 
 #define UINT32_ACCESS_ONCE(var)		 ((uint32)(*((volatile uint32 *)&(var))))
 
@@ -4087,3 +4088,77 @@ KnownAssignedXidsReset(void)
 
 	LWLockRelease(ProcArrayLock);
 }
+
+/*
+ * search all active backend to get oldest frozenxid
+ * for global temp table.
+ */
+int
+list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n)
+{
+	ProcArrayStruct *arrayP = procArray;
+	TransactionId result = InvalidTransactionId;
+	int			index;
+	int			flags = 0;
+	int			i = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	if (max_size > 0)
+	{
+		Assert(pids);
+		Assert(xids);
+		Assert(n);
+		*n = 0;
+	}
+
+	if (max_active_gtt <= 0)
+		return InvalidTransactionId;
+
+	if (RecoveryInProgress())
+		return InvalidTransactionId;
+
+	flags |= PROC_IS_AUTOVACUUM;
+	flags |= PROC_IN_LOGICAL_DECODING;
+
+	LWLockAcquire(ProcArrayLock, LW_SHARED);
+	if (max_size > 0 && max_size < arrayP->numProcs)
+	{
+		LWLockRelease(ProcArrayLock);
+		elog(ERROR, "list_all_gtt_frozenxids require more array");
+	}
+
+	for (index = 0; index < arrayP->numProcs; index++)
+	{
+		int			pgprocno = arrayP->pgprocnos[index];
+		volatile PGPROC *proc = &allProcs[pgprocno];
+		volatile PGXACT *pgxact = &allPgXact[pgprocno];
+
+		if (pgxact->vacuumFlags & flags)
+			continue;
+
+		if (proc->databaseId == MyDatabaseId &&
+			TransactionIdIsNormal(proc->session_gtt_frozenxid))
+		{
+			if (result == InvalidTransactionId)
+				result = proc->session_gtt_frozenxid;
+			else if (TransactionIdPrecedes(proc->session_gtt_frozenxid, result))
+				result = proc->session_gtt_frozenxid;
+
+			if (max_size > 0)
+			{
+				pids[i] = proc->pid;
+				xids[i] = proc->session_gtt_frozenxid;
+				i++;
+			}
+		}
+	}
+	LWLockRelease(ProcArrayLock);
+
+	if (max_size > 0)
+		*n = i;
+
+	return result;
+}
+
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 32df8c8..e4e1125 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -395,6 +395,7 @@ InitProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
@@ -577,6 +578,7 @@ InitAuxiliaryProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 85b7115..f5eae8c 100644
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -646,6 +646,12 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 		 */
 		if (zero_damaged_pages || InRecovery)
 			MemSet(buffer, 0, BLCKSZ);
+		else if(SmgrIsTemp(reln) && blocknum == 0 && forknum == MAIN_FORKNUM)
+		{
+			/* global temp table init btree meta page */
+			MemSet(buffer, 0, BLCKSZ);
+			mdwrite(reln, forknum, blocknum, buffer, true);
+		}
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_DATA_CORRUPTED),
diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c
index 8406644..92f028e 100644
--- a/src/backend/utils/adt/dbsize.c
+++ b/src/backend/utils/adt/dbsize.c
@@ -19,6 +19,8 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_authid.h"
 #include "catalog/pg_tablespace.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/index.h"
 #include "commands/dbcommands.h"
 #include "commands/tablespace.h"
 #include "miscadmin.h"
@@ -262,7 +264,6 @@ pg_tablespace_size_name(PG_FUNCTION_ARGS)
 	PG_RETURN_INT64(size);
 }
 
-
 /*
  * calculate size of (one fork of) a relation
  *
@@ -307,6 +308,41 @@ calculate_relation_size(RelFileNode *rfn, BackendId backend, ForkNumber forknum)
 	return totalsize;
 }
 
+static int64
+calculate_relation_size_all_file(Relation rel, const Bitmapset *gtt_map)
+{
+	int64		size = 0;
+	ForkNumber	forkNum;
+	BackendId	backendid;
+
+	/* For global temp table */
+	if (gtt_map)
+	{
+		Bitmapset *map_copy = bms_copy(gtt_map);
+
+		backendid = bms_first_member(map_copy);
+
+		do
+		{
+			for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
+				size += calculate_relation_size(&(rel->rd_node),
+										backendid,
+										forkNum);
+			backendid = bms_next_member(map_copy, backendid);
+		} while (backendid > 0);
+
+		pfree(map_copy);
+	}
+	else
+	{
+		for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
+			size += calculate_relation_size(&(rel->rd_node),
+											rel->rd_backend, forkNum);
+	}
+
+	return size;
+}
+
 Datum
 pg_relation_size(PG_FUNCTION_ARGS)
 {
@@ -340,20 +376,17 @@ pg_relation_size(PG_FUNCTION_ARGS)
  * Must not be applied to non-TOAST relations.
  */
 static int64
-calculate_toast_table_size(Oid toastrelid)
+calculate_toast_table_size(Oid toastrelid, Bitmapset *gtt_map)
 {
 	int64		size = 0;
 	Relation	toastRel;
-	ForkNumber	forkNum;
 	ListCell   *lc;
 	List	   *indexlist;
 
 	toastRel = relation_open(toastrelid, AccessShareLock);
 
 	/* toast heap size, including FSM and VM size */
-	for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-		size += calculate_relation_size(&(toastRel->rd_node),
-										toastRel->rd_backend, forkNum);
+	size += calculate_relation_size_all_file(toastRel, gtt_map);
 
 	/* toast index size, including FSM and VM size */
 	indexlist = RelationGetIndexList(toastRel);
@@ -365,9 +398,8 @@ calculate_toast_table_size(Oid toastrelid)
 
 		toastIdxRel = relation_open(lfirst_oid(lc),
 									AccessShareLock);
-		for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-			size += calculate_relation_size(&(toastIdxRel->rd_node),
-											toastIdxRel->rd_backend, forkNum);
+
+		size += calculate_relation_size_all_file(toastIdxRel, gtt_map);
 
 		relation_close(toastIdxRel, AccessShareLock);
 	}
@@ -386,23 +418,20 @@ calculate_toast_table_size(Oid toastrelid)
  * those won't have attached toast tables, but they can have multiple forks.
  */
 static int64
-calculate_table_size(Relation rel)
+calculate_table_size(Relation rel, Bitmapset *gtt_map)
 {
 	int64		size = 0;
-	ForkNumber	forkNum;
 
 	/*
 	 * heap size, including FSM and VM
 	 */
-	for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-		size += calculate_relation_size(&(rel->rd_node), rel->rd_backend,
-										forkNum);
+	size += calculate_relation_size_all_file(rel, gtt_map);
 
 	/*
 	 * Size of toast relation
 	 */
 	if (OidIsValid(rel->rd_rel->reltoastrelid))
-		size += calculate_toast_table_size(rel->rd_rel->reltoastrelid);
+		size += calculate_toast_table_size(rel->rd_rel->reltoastrelid, gtt_map);
 
 	return size;
 }
@@ -413,7 +442,7 @@ calculate_table_size(Relation rel)
  * Can be applied safely to an index, but you'll just get zero.
  */
 static int64
-calculate_indexes_size(Relation rel)
+calculate_indexes_size(Relation rel, Bitmapset *gtt_map)
 {
 	int64		size = 0;
 
@@ -429,14 +458,10 @@ calculate_indexes_size(Relation rel)
 		{
 			Oid			idxOid = lfirst_oid(cell);
 			Relation	idxRel;
-			ForkNumber	forkNum;
 
 			idxRel = relation_open(idxOid, AccessShareLock);
 
-			for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-				size += calculate_relation_size(&(idxRel->rd_node),
-												idxRel->rd_backend,
-												forkNum);
+			size += calculate_relation_size_all_file(idxRel, gtt_map);
 
 			relation_close(idxRel, AccessShareLock);
 		}
@@ -453,16 +478,40 @@ pg_table_size(PG_FUNCTION_ARGS)
 	Oid			relOid = PG_GETARG_OID(0);
 	Relation	rel;
 	int64		size;
+	Bitmapset	*gtt_map = NULL;
 
 	rel = try_relation_open(relOid, AccessShareLock);
 
 	if (rel == NULL)
 		PG_RETURN_NULL();
 
-	size = calculate_table_size(rel);
+	/* For GTT, calculate the size of the data file in the session where the GTT has been initialized */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (rel->rd_rel->relkind == RELKIND_INDEX)
+		{
+			Relation	relation;
+			Oid			relid;
+
+			relid = IndexGetRelation(RelationGetRelid(rel), false);
+			relation = try_relation_open(relid, AccessShareLock);
+			if (relation)
+			{
+				gtt_map = copy_active_gtt_bitmap(relation->rd_node);
+				relation_close(relation, AccessShareLock);
+			}
+		}
+		else
+			gtt_map = copy_active_gtt_bitmap(rel->rd_node);
+	}
+
+	size = calculate_table_size(rel, gtt_map);
 
 	relation_close(rel, AccessShareLock);
 
+	if(gtt_map)
+		pfree(gtt_map);
+
 	PG_RETURN_INT64(size);
 }
 
@@ -472,16 +521,24 @@ pg_indexes_size(PG_FUNCTION_ARGS)
 	Oid			relOid = PG_GETARG_OID(0);
 	Relation	rel;
 	int64		size;
+	Bitmapset	*gtt_map = NULL;
 
 	rel = try_relation_open(relOid, AccessShareLock);
 
 	if (rel == NULL)
 		PG_RETURN_NULL();
 
-	size = calculate_indexes_size(rel);
+	/* For GTT, calculate the size of the data file in the session where the GTT has been initialized */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		gtt_map = copy_active_gtt_bitmap(rel->rd_node);
+
+	size = calculate_indexes_size(rel, gtt_map);
 
 	relation_close(rel, AccessShareLock);
 
+	if (gtt_map)
+		pfree(gtt_map);
+
 	PG_RETURN_INT64(size);
 }
 
@@ -493,17 +550,25 @@ static int64
 calculate_total_relation_size(Relation rel)
 {
 	int64		size;
+	Bitmapset	*gtt_map = NULL;
+
+	/* For GTT, calculate the size of the data file in the session where the GTT has been initialized */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		gtt_map = copy_active_gtt_bitmap(rel->rd_node);
 
 	/*
 	 * Aggregate the table size, this includes size of the heap, toast and
 	 * toast index with free space and visibility map
 	 */
-	size = calculate_table_size(rel);
+	size = calculate_table_size(rel, gtt_map);
 
 	/*
 	 * Add size of all attached indexes as well
 	 */
-	size += calculate_indexes_size(rel);
+	size += calculate_indexes_size(rel, gtt_map);
+
+	if (gtt_map)
+		pfree(gtt_map);
 
 	return size;
 }
@@ -1008,6 +1073,10 @@ pg_relation_filepath(PG_FUNCTION_ARGS)
 				Assert(backend != InvalidBackendId);
 			}
 			break;
+		/* For global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			backend = BackendIdForTempRelations();
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relform->relpersistence);
 			backend = InvalidBackendId; /* placate compiler */
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 7c6f057..589bd38 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -142,6 +142,7 @@
 #include "utils/timestamp.h"
 #include "utils/typcache.h"
 
+#include "catalog/storage_gtt.h"
 
 /* Hooks for plugins to get control when we ask for stats */
 get_relation_stats_hook_type get_relation_stats_hook = NULL;
@@ -4578,12 +4579,25 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
 						}
 						else if (index->indpred == NIL)
 						{
-							vardata->statsTuple =
-								SearchSysCache3(STATRELATTINH,
-												ObjectIdGetDatum(index->indexoid),
-												Int16GetDatum(pos + 1),
-												BoolGetDatum(false));
-							vardata->freefunc = ReleaseSysCache;
+							char rel_persistence = get_rel_persistence(index->indexoid);
+
+							if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+							{
+								vardata->statsTuple =
+									get_gtt_att_statistic(index->indexoid,
+														Int16GetDatum(pos + 1),
+														false);
+								vardata->freefunc = release_gtt_statistic_cache;
+							}
+							else
+							{
+								vardata->statsTuple =
+									SearchSysCache3(STATRELATTINH,
+													ObjectIdGetDatum(index->indexoid),
+													Int16GetDatum(pos + 1),
+													BoolGetDatum(false));
+								vardata->freefunc = ReleaseSysCache;
+							}
 
 							if (HeapTupleIsValid(vardata->statsTuple))
 							{
@@ -4708,15 +4722,27 @@ examine_simple_variable(PlannerInfo *root, Var *var,
 	}
 	else if (rte->rtekind == RTE_RELATION)
 	{
-		/*
-		 * Plain table or parent of an inheritance appendrel, so look up the
-		 * column in pg_statistic
-		 */
-		vardata->statsTuple = SearchSysCache3(STATRELATTINH,
-											  ObjectIdGetDatum(rte->relid),
-											  Int16GetDatum(var->varattno),
-											  BoolGetDatum(rte->inh));
-		vardata->freefunc = ReleaseSysCache;
+		char rel_persistence = get_rel_persistence(rte->relid);
+
+		if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata->statsTuple = get_gtt_att_statistic(rte->relid,
+														var->varattno,
+														rte->inh);
+			vardata->freefunc = release_gtt_statistic_cache;
+		}
+		else
+		{
+			/*
+			 * Plain table or parent of an inheritance appendrel, so look up the
+			 * column in pg_statistic
+			 */
+			vardata->statsTuple = SearchSysCache3(STATRELATTINH,
+												  ObjectIdGetDatum(rte->relid),
+												  Int16GetDatum(var->varattno),
+												  BoolGetDatum(rte->inh));
+			vardata->freefunc = ReleaseSysCache;
+		}
 
 		if (HeapTupleIsValid(vardata->statsTuple))
 		{
@@ -6098,6 +6124,7 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	{
 		/* Simple variable --- look to stats for the underlying table */
 		RangeTblEntry *rte = planner_rt_fetch(index->rel->relid, root);
+		char	rel_persistence = get_rel_persistence(rte->relid);
 
 		Assert(rte->rtekind == RTE_RELATION);
 		relid = rte->relid;
@@ -6115,6 +6142,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													rte->inh);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -6126,6 +6160,8 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	}
 	else
 	{
+		char	rel_persistence = get_rel_persistence(index->indexoid);
+
 		/* Expression --- maybe there are stats for the index itself */
 		relid = index->indexoid;
 		colnum = 1;
@@ -6141,6 +6177,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													false);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -7054,6 +7097,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		/* attempt to lookup stats in relation for this index column */
 		if (attnum != 0)
 		{
+			char	rel_persistence = get_rel_persistence(rte->relid);
+
 			/* Simple variable -- look to stats for the underlying table */
 			if (get_relation_stats_hook &&
 				(*get_relation_stats_hook) (root, rte, attnum, &vardata))
@@ -7066,6 +7111,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					elog(ERROR,
 						 "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(rte->relid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple =
@@ -7078,6 +7131,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		}
 		else
 		{
+			char	rel_persistence = get_rel_persistence(index->indexoid);
+
 			/*
 			 * Looks like we've found an expression column in the index. Let's
 			 * see if there's any stats for it.
@@ -7097,6 +7152,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					!vardata.freefunc)
 					elog(ERROR, "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(index->indexoid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple = SearchSysCache3(STATRELATTINH,
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 1e3e6d3..44686ce 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -34,6 +34,7 @@
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_transform.h"
 #include "catalog/pg_type.h"
+#include "catalog/storage_gtt.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "utils/array.h"
@@ -46,6 +47,7 @@
 #include "utils/syscache.h"
 #include "utils/typcache.h"
 
+
 /* Hook for plugins to get control in get_attavgwidth() */
 get_attavgwidth_hook_type get_attavgwidth_hook = NULL;
 
@@ -2878,6 +2880,18 @@ get_attavgwidth(Oid relid, AttrNumber attnum)
 		if (stawidth > 0)
 			return stawidth;
 	}
+	if (get_rel_persistence(relid) == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		tp = get_gtt_att_statistic(relid, attnum, false);
+		if (!HeapTupleIsValid(tp))
+			return 0;
+
+		stawidth = ((Form_pg_statistic) GETSTRUCT(tp))->stawidth;
+		if (stawidth > 0)
+			return stawidth;
+		else
+			return 0;
+	}
 	tp = SearchSysCache3(STATRELATTINH,
 						 ObjectIdGetDatum(relid),
 						 Int16GetDatum(attnum),
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index df025a5..1c30d86 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -1124,6 +1124,16 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
 				relation->rd_islocaltemp = false;
 			}
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			{
+				relation->rd_backend = BackendIdForTempRelations();
+				/*
+				 * For global temp table, all backend can use
+				 * this relation, so rd_islocaltemp always true.
+				 */
+				relation->rd_islocaltemp = true;
+			}
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c",
 				 relation->rd_rel->relpersistence);
@@ -3313,6 +3323,10 @@ RelationBuildLocalRelation(const char *relname,
 			rel->rd_backend = BackendIdForTempRelations();
 			rel->rd_islocaltemp = true;
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			rel->rd_backend = BackendIdForTempRelations();
+			rel->rd_islocaltemp = true;
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relpersistence);
 			break;
@@ -3427,6 +3441,9 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 	TransactionId freezeXid = InvalidTransactionId;
 	RelFileNode newrnode;
 
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+		elog(ERROR, "global temp table does not allow setting new relfilenode");
+
 	/* Allocate a new relfilenode */
 	newrelfilenode = GetNewRelFileNode(relation->rd_rel->reltablespace, NULL,
 									   persistence);
@@ -3467,7 +3484,7 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 				/* handle these directly, at least for now */
 				SMgrRelation srel;
 
-				srel = RelationCreateStorage(newrnode, persistence);
+				srel = RelationCreateStorage(newrnode, persistence, relation);
 				smgrclose(srel);
 			}
 			break;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index e44f71e..44c86c8 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -139,6 +139,18 @@ char	   *GUC_check_errmsg_string;
 char	   *GUC_check_errdetail_string;
 char	   *GUC_check_errhint_string;
 
+/*
+ * num = 0 means disable global temp table feature.
+ * global temp table define can still storage in catalog
+ * just can not use.
+ * num > 0 means database can management num active global temp table.
+ */
+#define	MIN_NUM_ACTIVE_GTT			0
+#define	DEFAULT_NUM_ACTIVE_GTT			1000
+#define	MAX_NUM_ACTIVE_GTT			1000000
+
+int		max_active_gtt = MIN_NUM_ACTIVE_GTT;
+
 static void do_serialize(char **destptr, Size *maxbytes, const char *fmt,...) pg_attribute_printf(3, 4);
 
 static void set_config_sourcefile(const char *name, char *sourcefile,
@@ -1992,6 +2004,15 @@ static struct config_bool ConfigureNamesBool[] =
 static struct config_int ConfigureNamesInt[] =
 {
 	{
+		{"max_active_global_temporary_table", PGC_POSTMASTER, UNGROUPED,
+			gettext_noop("max active global temporary table."),
+			NULL
+		},
+		&max_active_gtt,
+		DEFAULT_NUM_ACTIVE_GTT, MIN_NUM_ACTIVE_GTT, MAX_NUM_ACTIVE_GTT,
+		NULL, NULL, NULL
+	},
+	{
 		{"archive_timeout", PGC_SIGHUP, WAL_ARCHIVING,
 			gettext_noop("Forces a switch to the next WAL file if a "
 						 "new file has not been started within N seconds."),
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 799b698..b98d396 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15583,6 +15583,7 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 	{
 		char	   *ftoptions = NULL;
 		char	   *srvname = NULL;
+		char		*table_type = NULL;
 
 		switch (tbinfo->relkind)
 		{
@@ -15634,9 +15635,15 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 			binary_upgrade_set_pg_class_oids(fout, q,
 											 tbinfo->dobj.catId.oid, false);
 
+		if (tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED)
+			table_type = "UNLOGGED ";
+		else if (tbinfo->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			table_type = "GLOBAL TEMPORARY ";
+		else
+			table_type = "";
+
 		appendPQExpBuffer(q, "CREATE %s%s %s",
-						  tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED ?
-						  "UNLOGGED " : "",
+						  table_type,
 						  reltypename,
 						  qualrelname);
 
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index f3c7eb9..28134e2 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3723,7 +3723,8 @@ listTables(const char *tabtypes, const char *pattern, bool verbose, bool showSys
 		if (pset.sversion >= 90100)
 		{
 			appendPQExpBuffer(&buf,
-							  ",\n  CASE c.relpersistence WHEN 'p' THEN '%s' WHEN 't' THEN '%s' WHEN 'u' THEN '%s' END as \"%s\"",
+							  ",\n  CASE c.relpersistence WHEN 'g' THEN '%s' WHEN 'p' THEN '%s' WHEN 't' THEN '%s' WHEN 'u' THEN '%s' END as \"%s\"",
+							  gettext_noop("session"),
 							  gettext_noop("permanent"),
 							  gettext_noop("temporary"),
 							  gettext_noop("unlogged"),
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index a12fc1f..78958e4 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -165,6 +165,7 @@ typedef FormData_pg_class *Form_pg_class;
 #define		  RELPERSISTENCE_PERMANENT	'p' /* regular table */
 #define		  RELPERSISTENCE_UNLOGGED	'u' /* unlogged permanent table */
 #define		  RELPERSISTENCE_TEMP		't' /* temporary table */
+#define		  RELPERSISTENCE_GLOBAL_TEMP	'g' /* global temporary table */
 
 /* default selection for replica identity (primary key or nothing) */
 #define		  REPLICA_IDENTITY_DEFAULT	'd'
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index fcf2a12..ba0bd5f 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -5484,6 +5484,40 @@
   proparallel => 'r', prorettype => 'float8', proargtypes => 'oid',
   prosrc => 'pg_stat_get_xact_function_self_time' },
 
+# For global temporary table
+{ oid => '4191',
+  descr => 'List local statistics for global temporary table',
+  proname => 'pg_get_gtt_statistics', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid int4 anyelement',
+  proallargtypes => '{oid,int4,anyelement,oid,int2,bool,float4,int4,float4,int2,int2,int2,int2,int2,oid,oid,oid,oid,oid,oid,oid,oid,oid,oid,_float4,_float4,_float4,_float4,_float4,anyarray,anyarray,anyarray,anyarray,anyarray}',
+  proargmodes => '{i,i,i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
+  proargnames => '{relid,att,x,starelid,staattnum,stainherit,stanullfrac,stawidth,stadistinct,stakind1,stakind2,stakind3,stakind4,stakind5,staop1,staop2,staop3,staop4,staop5,stacoll1,stacoll2,stacoll3,stacoll4,stacoll5,stanumbers1,stanumbers2,stanumbers3,stanumbers4,stanumbers5,stavalues1,stavalues2,stavalues3,stavalues4,stavalues5}',
+  prosrc => 'pg_get_gtt_statistics' },
+{ oid => '4192',
+  descr => 'List local relstats for global temporary table',
+  proname => 'pg_get_gtt_relstats', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid',
+  proallargtypes => '{oid,int4,float4,int4,xid,xid}',
+  proargmodes => '{i,o,o,o,o,o}',
+  proargnames => '{relid,relpages,reltuples,relallvisible,relfrozenxid,relminmxid}',
+  prosrc => 'pg_get_gtt_relstats' },
+{ oid => '4193',
+  descr => 'List attached pid for one global temporary table',
+  proname => 'pg_gtt_attached_pid', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid',
+  proallargtypes => '{oid,oid,int4}',
+  proargmodes => '{i,o,o}',
+  proargnames => '{relid,relid,pid}',
+  prosrc => 'pg_gtt_attached_pid' },
+{ oid => '4194',
+  descr => 'List those backends that have used global temporary table',
+  proname => 'pg_list_gtt_relfrozenxids', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => '',
+  proallargtypes => '{int4,xid}',
+  proargmodes => '{o,o}',
+  proargnames => '{pid,relfrozenxid}',
+  prosrc => 'pg_list_gtt_relfrozenxids' },
+
 { oid => '3788',
   descr => 'statistics: timestamp of the current statistics snapshot',
   proname => 'pg_stat_get_snapshot_timestamp', provolatile => 's',
diff --git a/src/include/catalog/storage.h b/src/include/catalog/storage.h
index 048003c..af48cdf 100644
--- a/src/include/catalog/storage.h
+++ b/src/include/catalog/storage.h
@@ -19,7 +19,7 @@
 #include "storage/smgr.h"
 #include "utils/relcache.h"
 
-extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence);
+extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel);
 extern void RelationDropStorage(Relation rel);
 extern void RelationPreserveStorage(RelFileNode rnode, bool atCommit);
 extern void RelationTruncate(Relation rel, BlockNumber nblocks);
diff --git a/src/include/catalog/storage_gtt.h b/src/include/catalog/storage_gtt.h
new file mode 100644
index 0000000..eacc214
--- /dev/null
+++ b/src/include/catalog/storage_gtt.h
@@ -0,0 +1,39 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.h
+ *	  prototypes for functions in backend/catalog/storage_gtt.c
+ *
+ * src/include/catalog/storage_gtt.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef STORAGE_GTT_H
+#define STORAGE_GTT_H
+
+#include "access/htup.h"
+#include "storage/block.h"
+#include "storage/relfilenode.h"
+#include "utils/relcache.h"
+
+extern Size active_gtt_shared_hash_size(void);
+extern void active_gtt_shared_hash_init(void);
+extern void remember_gtt_storage_info(RelFileNode rnode, Relation rel);
+extern void forget_gtt_storage_info(Oid relid);
+extern bool is_other_backend_use_gtt(RelFileNode node);
+extern bool gtt_storage_attached(Oid relid);
+extern Bitmapset *copy_active_gtt_bitmap(RelFileNode node);
+extern void up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+								TupleDesc tupleDescriptor, Datum *values, bool *isnull);
+extern HeapTuple get_gtt_att_statistic(Oid reloid, int attnum, bool inh);
+extern void release_gtt_statistic_cache(HeapTuple tup);
+extern void up_gtt_relstats(Relation relation,
+							BlockNumber num_pages,
+							double num_tuples,
+							BlockNumber num_all_visible_pages,
+							TransactionId relfrozenxid,
+							TransactionId relminmxid);
+extern bool get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+							BlockNumber *relallvisible, TransactionId *relfrozenxid,
+							TransactionId *relminmxid);
+
+#endif							/* STORAGE_H */
diff --git a/src/include/parser/parse_relation.h b/src/include/parser/parse_relation.h
index 93f9446..14cafae 100644
--- a/src/include/parser/parse_relation.h
+++ b/src/include/parser/parse_relation.h
@@ -120,4 +120,7 @@ extern Oid	attnumTypeId(Relation rd, int attid);
 extern Oid	attnumCollationId(Relation rd, int attid);
 extern bool isQueryUsingTempRelation(Query *query);
 
+/* global temp table check */
+extern bool is_query_using_gtt(Query *query);
+
 #endif							/* PARSE_RELATION_H */
diff --git a/src/include/storage/bufpage.h b/src/include/storage/bufpage.h
index 870ecb5..92c590e 100644
--- a/src/include/storage/bufpage.h
+++ b/src/include/storage/bufpage.h
@@ -405,6 +405,8 @@ do { \
 #define PageClearPrunable(page) \
 	(((PageHeader) (page))->pd_prune_xid = InvalidTransactionId)
 
+#define GlobalTempRelationPageIsNotInitialized(rel, page) \
+	((rel)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP && PageIsNew(page))
 
 /* ----------------------------------------------------------------
  *		extern declarations
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 8fda8e4..172eae9 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -220,6 +220,7 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_TBM,
 	LWTRANCHE_PARALLEL_APPEND,
 	LWTRANCHE_SXACT,
+	LWTRANCHE_GTT_CTL,
 	LWTRANCHE_FIRST_USER_DEFINED
 }			BuiltinTrancheIds;
 
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 5b407e6..f13250a 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -117,6 +117,8 @@ struct PGPROC
 	Oid			tempNamespaceId;	/* OID of temp schema this backend is
 									 * using */
 
+	TransactionId session_gtt_frozenxid;	/* session level global temp table relfrozenxid */
+
 	bool		isBackgroundWorker; /* true if background worker. */
 
 	/*
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index a5c7d0c..a86f61f 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -125,4 +125,6 @@ extern void ProcArraySetReplicationSlotXmin(TransactionId xmin,
 extern void ProcArrayGetReplicationSlotXmin(TransactionId *xmin,
 											TransactionId *catalog_xmin);
 
+extern int list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n);
+
 #endif							/* PROCARRAY_H */
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index ce93ace..0f7262e 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -281,6 +281,10 @@ extern int	tcp_user_timeout;
 extern bool trace_sort;
 #endif
 
+/* global temporary table */
+extern int	max_active_gtt;
+/* end */
+
 /*
  * Functions exported by guc.c
  */
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 44ed04d..3f9720d 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -277,6 +277,7 @@ typedef struct StdRdOptions
 	int			parallel_workers;	/* max number of parallel workers */
 	bool		vacuum_index_cleanup;	/* enables index vacuuming and cleanup */
 	bool		vacuum_truncate;	/* enables vacuum to truncate a relation */
+	bool		on_commit_delete_rows;	/* global temp table */
 } StdRdOptions;
 
 #define HEAP_MIN_FILLFACTOR			10
@@ -535,7 +536,8 @@ typedef struct ViewOptions
  *		True if relation's pages are stored in local buffers.
  */
 #define RelationUsesLocalBuffers(relation) \
-	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP || \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 
 /*
  * RELATION_IS_LOCAL
@@ -602,6 +604,17 @@ typedef struct ViewOptions
 	 RelationNeedsWAL(relation) && \
 	 !IsCatalogRelation(relation))
 
+/* global temp table implementations */
+#define RELATION_IS_GLOBAL_TEMP(relation)	((relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+
+#define RELATION_GTT_ON_COMMIT_DELETE(relation)	\
+	((relation)->rd_options && \
+	 ((relation)->rd_rel->relkind == RELKIND_RELATION || (relation)->rd_rel->relkind == RELKIND_PARTITIONED_TABLE) && \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ? \
+	 ((StdRdOptions *) (relation)->rd_options)->on_commit_delete_rows : false)
+
+#define RelationGetRelPersistence(relation) ((relation)->rd_rel->relpersistence)
+
 /* routines in utils/cache/relcache.c */
 extern void RelationIncrementReferenceCount(Relation rel);
 extern void RelationDecrementReferenceCount(Relation rel);
diff --git a/src/test/regress/expected/gtt_clean.out b/src/test/regress/expected/gtt_clean.out
new file mode 100644
index 0000000..50ca9ac
--- /dev/null
+++ b/src/test/regress/expected/gtt_clean.out
@@ -0,0 +1,7 @@
+reset search_path;
+drop schema gtt cascade;
+NOTICE:  drop cascades to 4 other objects
+DETAIL:  drop cascades to table gtt.gtt1
+drop cascades to table gtt.gtt2
+drop cascades to table gtt.gtt3
+drop cascades to table gtt.gtt_t_kenyon
diff --git a/src/test/regress/expected/gtt_function.out b/src/test/regress/expected/gtt_function.out
new file mode 100644
index 0000000..a477917
--- /dev/null
+++ b/src/test/regress/expected/gtt_function.out
@@ -0,0 +1,197 @@
+CREATE SCHEMA IF NOT EXISTS gtt_function;
+set search_path=gtt_function,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt_test_rename(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+)on commit delete rows;
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+ERROR:  cannot create indexes on global temporary tables using concurrent mode
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+ERROR:  not support cluster global temporary tables yet
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+ERROR:  ON COMMIT can only be used on temporary tables
+-- ok
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+ERROR:  regular table cannot specifie on_commit_delete_rows
+-- ok
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+--ok
+CREATE global temp TABLE p_table01 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)on commit delete rows;
+ 
+CREATE global temp TABLE p_table01_2018
+PARTITION OF p_table01
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+ 
+CREATE global temp TABLE p_table01_2017
+PARTITION OF p_table01
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+begin;
+insert into p_table01 values(1,'2018-01-02 00:00:00','test1');
+insert into p_table01 values(1,'2018-01-02 00:00:00','test2');
+select count(*) from p_table01;
+ count 
+-------
+     2
+(1 row)
+
+commit;
+select count(*) from p_table01;
+ count 
+-------
+     0
+(1 row)
+
+--ok
+CREATE global temp TABLE p_table02 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)
+on commit PRESERVE rows;
+CREATE global temp TABLE p_table02_2018
+PARTITION OF p_table02
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+CREATE global temp TABLE p_table02_2017
+PARTITION OF p_table02
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+-- ok
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+ERROR:  The parent table must be global temporary table
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent_global_temp) on commit delete rows;
+select relname ,relkind, relpersistence, reloptions from pg_class where relname like 'p_table0%' or  relname like 'tbl_inherits%' order by relname;
+             relname             | relkind | relpersistence |          reloptions           
+---------------------------------+---------+----------------+-------------------------------
+ p_table01                       | p       | g              | {on_commit_delete_rows=true}
+ p_table01_2017                  | r       | g              | {on_commit_delete_rows=true}
+ p_table01_2018                  | r       | g              | {on_commit_delete_rows=true}
+ p_table01_id_seq                | S       | g              | 
+ p_table02                       | p       | g              | {on_commit_delete_rows=false}
+ p_table02_2017                  | r       | g              | {on_commit_delete_rows=false}
+ p_table02_2018                  | r       | g              | {on_commit_delete_rows=false}
+ p_table02_id_seq                | S       | g              | 
+ tbl_inherits_parent             | r       | p              | 
+ tbl_inherits_parent_global_temp | r       | g              | {on_commit_delete_rows=true}
+ tbl_inherits_partition          | r       | g              | {on_commit_delete_rows=true}
+(11 rows)
+
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+ERROR:  global temp table not support on commit drop clause
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+ERROR:  can not defeine global temp table with on commit and with clause at same time
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+--ok
+alter table gtt_test_rename rename to gtt_test;
+-- ok
+ALTER TABLE gtt_test ADD COLUMN address varchar(30);
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  referenced relation "products" is not a global temp table
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  referenced relation "products" is not a global temp table
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+-- ok
+create global temp table gtt_seq(id int GENERATED ALWAYS AS IDENTITY (START WITH 2) primary key, a int)  on commit PRESERVE rows;
+insert into gtt_seq (a) values(1);
+insert into gtt_seq (a) values(2);
+select * from gtt_seq order by id;
+ id | a 
+----+---
+  2 | 1
+  3 | 2
+(2 rows)
+
+truncate gtt_seq;
+select * from gtt_seq order by id;
+ id | a 
+----+---
+(0 rows)
+
+insert into gtt_seq (a) values(3);
+select * from gtt_seq order by id;
+ id | a 
+----+---
+  4 | 3
+(1 row)
+
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+ERROR:  materialized views must not use global temporary tables or views
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+ERROR:  only support btree index on global temp table
+create index idx_err on gtt1 using gist (a);
+ERROR:  data type integer has no default operator class for access method "gist"
+HINT:  You must specify an operator class for the index or define a default operator class for the data type.
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+ERROR:  only support btree index on global temp table
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+ERROR:  only support btree index on global temp table
+reset search_path;
+drop schema gtt_function cascade;
+NOTICE:  drop cascades to 15 other objects
+DETAIL:  drop cascades to table gtt_function.gtt1
+drop cascades to table gtt_function.gtt_test
+drop cascades to table gtt_function.gtt2
+drop cascades to table gtt_function.gtt3
+drop cascades to table gtt_function.tmp_t0
+drop cascades to table gtt_function.tbl_inherits_parent
+drop cascades to table gtt_function.tbl_inherits_parent_global_temp
+drop cascades to table gtt_function.products
+drop cascades to table gtt_function.measurement
+drop cascades to table gtt_function.p_table01
+drop cascades to table gtt_function.p_table02
+drop cascades to table gtt_function.tbl_inherits_partition
+drop cascades to table gtt_function.gtt5
+drop cascades to table gtt_function.mytable
+drop cascades to table gtt_function.gtt_seq
diff --git a/src/test/regress/expected/gtt_parallel_1.out b/src/test/regress/expected/gtt_parallel_1.out
new file mode 100644
index 0000000..30d8a7b
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_1.out
@@ -0,0 +1,84 @@
+set search_path=gtt,sys;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_parallel_2.out b/src/test/regress/expected/gtt_parallel_2.out
new file mode 100644
index 0000000..850ef3e
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_2.out
@@ -0,0 +1,161 @@
+set search_path=gtt,sys;
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+ 3 | test1
+(3 rows)
+
+rollback;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test2
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 3 | test3
+(1 row)
+
+rollback;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 5 | test5
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 6 | test6
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+ count  
+--------
+ 100000
+(1 row)
+
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+             QUERY PLAN             
+------------------------------------
+ Index Scan using gtt3_pkey on gtt3
+   Index Cond: (a = 300)
+(2 rows)
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid),pg_table_size(oid),pg_indexes_size(oid),pg_total_relation_size(oid) from pg_class where relname = 'gtt_t_kenyon';
+   relname    | pg_relation_size | pg_relation_size | pg_table_size | pg_indexes_size | pg_total_relation_size 
+--------------+------------------+------------------+---------------+-----------------+------------------------
+ gtt_t_kenyon |           450560 |             8192 |        499712 |          475136 |                 974848
+(1 row)
+
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+   relname    
+--------------
+ gtt_t_kenyon
+(1 row)
+
+select
+c.relname, pg_relation_size(c.oid),pg_table_size(c.oid),pg_total_relation_size(c.oid)
+from
+pg_class c
+where
+c.oid in
+(
+select
+i.indexrelid as indexrelid
+from 
+pg_index i ,pg_class cc
+where cc.relname = 'gtt_t_kenyon' and cc.oid = i.indrelid
+)
+order by c.relname;
+      relname       | pg_relation_size | pg_table_size | pg_total_relation_size 
+--------------------+------------------+---------------+------------------------
+ idx_gtt_t_kenyon_1 |            65536 |         65536 |                  65536
+ idx_gtt_t_kenyon_2 |           409600 |        409600 |                 409600
+(2 rows)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_prepare.out b/src/test/regress/expected/gtt_prepare.out
new file mode 100644
index 0000000..9fe5fd4
--- /dev/null
+++ b/src/test/regress/expected/gtt_prepare.out
@@ -0,0 +1,9 @@
+CREATE SCHEMA IF NOT EXISTS gtt;
+set search_path=gtt,sys;
+create global temp table gtt1(a int primary key, b text) on commit delete rows;
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text);
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+create index idx_gtt_t_kenyon_1 on gtt_t_kenyon(id);
+create index idx_gtt_t_kenyon_2 on gtt_t_kenyon(remark);
+reset search_path;
diff --git a/src/test/regress/expected/gtt_stats.out b/src/test/regress/expected/gtt_stats.out
new file mode 100644
index 0000000..b258b7c
--- /dev/null
+++ b/src/test/regress/expected/gtt_stats.out
@@ -0,0 +1,76 @@
+CREATE SCHEMA IF NOT EXISTS gtt_stats;
+set search_path=gtt_stats,sys;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     0
+(1 row)
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     0
+(1 row)
+
+create global temp table gtt(a int primary key, b text) on commit PRESERVE rows;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     0
+(1 row)
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     0
+(1 row)
+
+insert into gtt values(generate_series(1,10000),'test');
+-- expect 1
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     1
+(1 row)
+
+-- expect 2
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     2
+(1 row)
+
+-- expect 0
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+ schemaname | tablename | relpages | reltuples | relallvisible 
+------------+-----------+----------+-----------+---------------
+ gtt_stats  | gtt       |        0 |         0 |             0
+(1 row)
+
+-- expect 0
+select * from pg_gtt_stats order by tablename;
+ schemaname | tablename | attname | inherited | null_frac | avg_width | n_distinct | most_common_vals | most_common_freqs | histogram_bounds | correlation | most_common_elems | most_common_elem_freqs | elem_count_histogram 
+------------+-----------+---------+-----------+-----------+-----------+------------+------------------+-------------------+------------------+-------------+-------------------+------------------------+----------------------
+(0 rows)
+
+analyze gtt;
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+ schemaname | tablename | relpages | reltuples | relallvisible 
+------------+-----------+----------+-----------+---------------
+ gtt_stats  | gtt       |       55 |     10000 |             0
+(1 row)
+
+select * from pg_gtt_stats order by tablename;
+ schemaname | tablename | attname | inherited | null_frac | avg_width | n_distinct | most_common_vals | most_common_freqs |                                                                                                                                                                                                                                                histogram_bounds                                                                                                                                                                                                                                                 | correlation | most_common_elems | most_common_elem_freqs | elem_count_histogram 
+------------+-----------+---------+-----------+-----------+-----------+------------+------------------+-------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+-------------------+------------------------+----------------------
+ gtt_stats  | gtt       | a       | f         |         0 |         4 |         -1 |                  |                   | {1,100,200,300,400,500,600,700,800,900,1000,1100,1200,1300,1400,1500,1600,1700,1800,1900,2000,2100,2200,2300,2400,2500,2600,2700,2800,2900,3000,3100,3200,3300,3400,3500,3600,3700,3800,3900,4000,4100,4200,4300,4400,4500,4600,4700,4800,4900,5000,5100,5200,5300,5400,5500,5600,5700,5800,5900,6000,6100,6200,6300,6400,6500,6600,6700,6800,6900,7000,7100,7200,7300,7400,7500,7600,7700,7800,7900,8000,8100,8200,8300,8400,8500,8600,8700,8800,8900,9000,9100,9200,9300,9400,9500,9600,9700,9800,9900,10000} |           1 |                   |                        | 
+ gtt_stats  | gtt       | b       | f         |         0 |         5 |          1 | {test}           | {1}               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |           1 |                   |                        | 
+(2 rows)
+
+reset search_path;
+drop schema gtt_stats cascade;
+NOTICE:  drop cascades to table gtt_stats.gtt
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index 70e1e2f..30cf4bd 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1348,6 +1348,93 @@ pg_group| SELECT pg_authid.rolname AS groname,
           WHERE (pg_auth_members.roleid = pg_authid.oid)) AS grolist
    FROM pg_authid
   WHERE (NOT pg_authid.rolcanlogin);
+pg_gtt_attached_pids| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.relid,
+    s.pid
+   FROM (pg_class c
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_gtt_attached_pid(c.oid) s(relid, pid)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
+pg_gtt_relstats| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.relpages,
+    s.reltuples,
+    s.relallvisible,
+    s.relfrozenxid,
+    s.relminmxid
+   FROM (pg_class c
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_get_gtt_relstats(c.oid) s(relpages, reltuples, relallvisible, relfrozenxid, relminmxid)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
+pg_gtt_stats| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    a.attname,
+    s.stainherit AS inherited,
+    s.stanullfrac AS null_frac,
+    s.stawidth AS avg_width,
+    s.stadistinct AS n_distinct,
+        CASE
+            WHEN (s.stakind1 = 1) THEN s.stavalues1
+            WHEN (s.stakind2 = 1) THEN s.stavalues2
+            WHEN (s.stakind3 = 1) THEN s.stavalues3
+            WHEN (s.stakind4 = 1) THEN s.stavalues4
+            WHEN (s.stakind5 = 1) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS most_common_vals,
+        CASE
+            WHEN (s.stakind1 = 1) THEN s.stanumbers1
+            WHEN (s.stakind2 = 1) THEN s.stanumbers2
+            WHEN (s.stakind3 = 1) THEN s.stanumbers3
+            WHEN (s.stakind4 = 1) THEN s.stanumbers4
+            WHEN (s.stakind5 = 1) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS most_common_freqs,
+        CASE
+            WHEN (s.stakind1 = 2) THEN s.stavalues1
+            WHEN (s.stakind2 = 2) THEN s.stavalues2
+            WHEN (s.stakind3 = 2) THEN s.stavalues3
+            WHEN (s.stakind4 = 2) THEN s.stavalues4
+            WHEN (s.stakind5 = 2) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS histogram_bounds,
+        CASE
+            WHEN (s.stakind1 = 3) THEN s.stanumbers1[1]
+            WHEN (s.stakind2 = 3) THEN s.stanumbers2[1]
+            WHEN (s.stakind3 = 3) THEN s.stanumbers3[1]
+            WHEN (s.stakind4 = 3) THEN s.stanumbers4[1]
+            WHEN (s.stakind5 = 3) THEN s.stanumbers5[1]
+            ELSE NULL::real
+        END AS correlation,
+        CASE
+            WHEN (s.stakind1 = 4) THEN s.stavalues1
+            WHEN (s.stakind2 = 4) THEN s.stavalues2
+            WHEN (s.stakind3 = 4) THEN s.stavalues3
+            WHEN (s.stakind4 = 4) THEN s.stavalues4
+            WHEN (s.stakind5 = 4) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS most_common_elems,
+        CASE
+            WHEN (s.stakind1 = 4) THEN s.stanumbers1
+            WHEN (s.stakind2 = 4) THEN s.stanumbers2
+            WHEN (s.stakind3 = 4) THEN s.stanumbers3
+            WHEN (s.stakind4 = 4) THEN s.stanumbers4
+            WHEN (s.stakind5 = 4) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS most_common_elem_freqs,
+        CASE
+            WHEN (s.stakind1 = 5) THEN s.stanumbers1
+            WHEN (s.stakind2 = 5) THEN s.stanumbers2
+            WHEN (s.stakind3 = 5) THEN s.stanumbers3
+            WHEN (s.stakind4 = 5) THEN s.stanumbers4
+            WHEN (s.stakind5 = 5) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS elem_count_histogram
+   FROM ((pg_class c
+     JOIN pg_attribute a ON ((c.oid = a.attrelid)))
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_get_gtt_statistics(c.oid, (a.attnum)::integer, ''::text) s(starelid, staattnum, stainherit, stanullfrac, stawidth, stadistinct, stakind1, stakind2, stakind3, stakind4, stakind5, staop1, staop2, staop3, staop4, staop5, stacoll1, stacoll2, stacoll3, stacoll4, stacoll5, stanumbers1, stanumbers2, stanumbers3, stanumbers4, stanumbers5, stavalues1, stavalues2, stavalues3, stavalues4, stavalues5)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND (NOT a.attisdropped) AND has_column_privilege(c.oid, a.attnum, 'select'::text) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
 pg_hba_file_rules| SELECT a.line_number,
     a.type,
     a.database,
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index d33a4e1..643afe4 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -121,3 +121,10 @@ test: fast_default
 
 # run stats by itself because its delay may be insufficient under heavy load
 test: stats
+
+# global temp table test
+test: gtt_stats
+test: gtt_function
+test: gtt_prepare
+test: gtt_parallel_1 gtt_parallel_2
+test: gtt_clean
diff --git a/src/test/regress/sql/gtt_clean.sql b/src/test/regress/sql/gtt_clean.sql
new file mode 100644
index 0000000..f3cf710
--- /dev/null
+++ b/src/test/regress/sql/gtt_clean.sql
@@ -0,0 +1,6 @@
+
+
+reset search_path;
+
+drop schema gtt cascade;
+
diff --git a/src/test/regress/sql/gtt_function.sql b/src/test/regress/sql/gtt_function.sql
new file mode 100644
index 0000000..cfc1879
--- /dev/null
+++ b/src/test/regress/sql/gtt_function.sql
@@ -0,0 +1,163 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt_function;
+
+set search_path=gtt_function,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt_test_rename(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+)on commit delete rows;
+
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+
+-- ok
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+
+-- ok
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+
+--ok
+CREATE global temp TABLE p_table01 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)on commit delete rows;
+ 
+CREATE global temp TABLE p_table01_2018
+PARTITION OF p_table01
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+ 
+CREATE global temp TABLE p_table01_2017
+PARTITION OF p_table01
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+
+begin;
+insert into p_table01 values(1,'2018-01-02 00:00:00','test1');
+insert into p_table01 values(1,'2018-01-02 00:00:00','test2');
+select count(*) from p_table01;
+commit;
+
+select count(*) from p_table01;
+
+--ok
+CREATE global temp TABLE p_table02 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)
+on commit PRESERVE rows;
+
+CREATE global temp TABLE p_table02_2018
+PARTITION OF p_table02
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+
+CREATE global temp TABLE p_table02_2017
+PARTITION OF p_table02
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+
+-- ok
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent_global_temp) on commit delete rows;
+
+select relname ,relkind, relpersistence, reloptions from pg_class where relname like 'p_table0%' or  relname like 'tbl_inherits%' order by relname;
+
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+
+--ok
+alter table gtt_test_rename rename to gtt_test;
+
+-- ok
+ALTER TABLE gtt_test ADD COLUMN address varchar(30);
+
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+
+-- ok
+create global temp table gtt_seq(id int GENERATED ALWAYS AS IDENTITY (START WITH 2) primary key, a int)  on commit PRESERVE rows;
+insert into gtt_seq (a) values(1);
+insert into gtt_seq (a) values(2);
+select * from gtt_seq order by id;
+truncate gtt_seq;
+select * from gtt_seq order by id;
+insert into gtt_seq (a) values(3);
+select * from gtt_seq order by id;
+
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+create index idx_err on gtt1 using gist (a);
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+
+reset search_path;
+
+drop schema gtt_function cascade;
+
diff --git a/src/test/regress/sql/gtt_parallel_1.sql b/src/test/regress/sql/gtt_parallel_1.sql
new file mode 100644
index 0000000..d7d81de
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_1.sql
@@ -0,0 +1,42 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+commit;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+rollback;
+select * from gtt1 order by a;
+
+truncate gtt1;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+select * from gtt1 order by a;
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+
+begin;
+select * from gtt1 order by a;
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_parallel_2.sql b/src/test/regress/sql/gtt_parallel_2.sql
new file mode 100644
index 0000000..5203c2b
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_2.sql
@@ -0,0 +1,76 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+commit;
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+truncate gtt3;
+select * from gtt3 order by a;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+truncate gtt3;
+select * from gtt3 order by a;
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+begin;
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid),pg_table_size(oid),pg_indexes_size(oid),pg_total_relation_size(oid) from pg_class where relname = 'gtt_t_kenyon';
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+
+select
+c.relname, pg_relation_size(c.oid),pg_table_size(c.oid),pg_total_relation_size(c.oid)
+from
+pg_class c
+where
+c.oid in
+(
+select
+i.indexrelid as indexrelid
+from 
+pg_index i ,pg_class cc
+where cc.relname = 'gtt_t_kenyon' and cc.oid = i.indrelid
+)
+order by c.relname;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_prepare.sql b/src/test/regress/sql/gtt_prepare.sql
new file mode 100644
index 0000000..2f4d883
--- /dev/null
+++ b/src/test/regress/sql/gtt_prepare.sql
@@ -0,0 +1,16 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt;
+
+set search_path=gtt,sys;
+
+create global temp table gtt1(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text);
+
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+create index idx_gtt_t_kenyon_1 on gtt_t_kenyon(id);
+create index idx_gtt_t_kenyon_2 on gtt_t_kenyon(remark);
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_stats.sql b/src/test/regress/sql/gtt_stats.sql
new file mode 100644
index 0000000..f041892
--- /dev/null
+++ b/src/test/regress/sql/gtt_stats.sql
@@ -0,0 +1,42 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt_stats;
+
+set search_path=gtt_stats,sys;
+
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+
+create global temp table gtt(a int primary key, b text) on commit PRESERVE rows;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+
+insert into gtt values(generate_series(1,10000),'test');
+
+-- expect 1
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 2
+select count(*) from pg_list_gtt_relfrozenxids();
+
+-- expect 0
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+
+-- expect 0
+select * from pg_gtt_stats order by tablename;
+
+analyze gtt;
+
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+
+select * from pg_gtt_stats order by tablename;
+
+reset search_path;
+
+drop schema gtt_stats cascade;
+

diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c
index 79430d2..b7173c7 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -158,6 +158,19 @@ static relopt_bool boolRelOpts[] =
 		},
 		true
 	},
+	/*
+	 * For global temp table only
+	 * use AccessExclusiveLock for ensure safety
+	 */
+	{
+		{
+			"on_commit_delete_rows",
+			"global temp table on commit options",
+			RELOPT_KIND_HEAP | RELOPT_KIND_PARTITIONED,
+			ShareUpdateExclusiveLock
+		},
+		true
+	},	
 	/* list terminator */
 	{{NULL}}
 };
@@ -1486,6 +1499,8 @@ bytea *
 default_reloptions(Datum reloptions, bool validate, relopt_kind kind)
 {
 	static const relopt_parse_elt tab[] = {
+		{"on_commit_delete_rows", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, on_commit_delete_rows)},
 		{"fillfactor", RELOPT_TYPE_INT, offsetof(StdRdOptions, fillfactor)},
 		{"autovacuum_enabled", RELOPT_TYPE_BOOL,
 		offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, enabled)},
@@ -1586,13 +1601,18 @@ build_reloptions(Datum reloptions, bool validate,
 bytea *
 partitioned_table_reloptions(Datum reloptions, bool validate)
 {
+	static const relopt_parse_elt tab[] = {
+		{"on_commit_delete_rows", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, on_commit_delete_rows)}
+	};
+
 	/*
 	 * There are no options for partitioned tables yet, but this is able to do
 	 * some validation.
 	 */
 	return (bytea *) build_reloptions(reloptions, validate,
 									  RELOPT_KIND_PARTITIONED,
-									  0, NULL, 0);
+									  sizeof(StdRdOptions), tab, lengthof(tab));
 }
 
 /*
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index dd975b1..1610e7d 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -1013,7 +1013,9 @@ gistGetFakeLSN(Relation rel)
 {
 	static XLogRecPtr counter = FirstNormalUnloggedLSN;
 
-	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	/* global temp is same as local temp table */
+	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		rel->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 	{
 		/*
 		 * Temporary relations are only accessible in our session, so a simple
diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index 4871b7f..16b00c9 100644
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -149,7 +149,9 @@ hashbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	 * metapage, nor the first bitmap page.
 	 */
 	sort_threshold = (maintenance_work_mem * 1024L) / BLCKSZ;
-	if (index->rd_rel->relpersistence != RELPERSISTENCE_TEMP)
+	/* global temp table is same as local temp table */
+	if (!(index->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		index->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		sort_threshold = Min(sort_threshold, NBuffers);
 	else
 		sort_threshold = Min(sort_threshold, NLocBuffer);
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 1f6f6d0..5727ccd 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -598,7 +598,7 @@ heapam_relation_set_new_filenode(Relation rel,
 	 */
 	*minmulti = GetOldestMultiXactId();
 
-	srel = RelationCreateStorage(*newrnode, persistence);
+	srel = RelationCreateStorage(*newrnode, persistence, rel);
 
 	/*
 	 * If required, set up an init fork for an unlogged table so that it can
@@ -651,7 +651,7 @@ heapam_relation_copy_data(Relation rel, const RelFileNode *newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index b331f4c..cd02c6b 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -62,6 +62,7 @@
 #include "access/xact.h"
 #include "access/xlog.h"
 #include "catalog/storage.h"
+#include "catalog/storage_gtt.h"
 #include "commands/dbcommands.h"
 #include "commands/progress.h"
 #include "commands/vacuum.h"
@@ -397,8 +398,10 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 	Assert(params->truncate != VACOPT_TERNARY_DEFAULT);
 
 	/* not every AM requires these to be valid, but heap does */
-	Assert(TransactionIdIsNormal(onerel->rd_rel->relfrozenxid));
-	Assert(MultiXactIdIsValid(onerel->rd_rel->relminmxid));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relfrozenxid == InvalidTransactionId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && TransactionIdIsNormal(onerel->rd_rel->relfrozenxid)));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relminmxid == InvalidMultiXactId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && MultiXactIdIsValid(onerel->rd_rel->relminmxid)));
 
 	/* measure elapsed time iff autovacuum logging requires it */
 	if (IsAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index f05cbe7..946c9d2 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -763,7 +763,14 @@ _bt_getbuf(Relation rel, BlockNumber blkno, int access)
 		/* Read an existing block of the relation */
 		buf = ReadBuffer(rel, blkno);
 		LockBuffer(buf, access);
-		_bt_checkpage(rel, buf);
+
+		/* global temp table may be not yet initialized for this backend. */
+		if (RELATION_IS_GLOBAL_TEMP(rel) &&
+			blkno == BTREE_METAPAGE &&
+			PageIsNew(BufferGetPage(buf)))
+			_bt_initmetapage(BufferGetPage(buf), P_NONE, 0);
+		else
+			_bt_checkpage(rel, buf);
 	}
 	else
 	{
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 7f4f784..aba8a9f 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6327,6 +6327,10 @@ StartupXLOG(void)
 	else
 		recoveryTargetTLI = ControlFile->checkPointCopy.ThisTimeLineID;
 
+	/* clean temp relation files */
+	if (max_active_gtt > 0)
+		RemovePgTempFiles();
+
 	/*
 	 * Check for signal files, and if so set up state for offline recovery
 	 */
diff --git a/src/backend/catalog/Makefile b/src/backend/catalog/Makefile
index d5da81c..c753b0e 100644
--- a/src/backend/catalog/Makefile
+++ b/src/backend/catalog/Makefile
@@ -42,6 +42,7 @@ OBJS = \
 	pg_subscription.o \
 	pg_type.o \
 	storage.o \
+	storage_gtt.o \
 	toasting.o
 
 include $(top_srcdir)/src/backend/common.mk
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index 16cb6d8..f28f2c2 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -398,7 +398,9 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class, char relpersistence)
 
 	switch (relpersistence)
 	{
+		/* global temp table is same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			break;
 		case RELPERSISTENCE_UNLOGGED:
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 0fdff29..bd3cd9d 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -61,6 +61,7 @@
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "commands/tablecmds.h"
 #include "commands/typecmds.h"
 #include "executor/executor.h"
@@ -99,6 +100,7 @@ static void AddNewRelationTuple(Relation pg_class_desc,
 								Oid reloftype,
 								Oid relowner,
 								char relkind,
+								char relpersistence,
 								TransactionId relfrozenxid,
 								TransactionId relminmxid,
 								Datum relacl,
@@ -404,6 +406,10 @@ heap_create(const char *relname,
 									 relpersistence,
 									 relkind);
 
+	/* global temp table not create storage file when catalog create */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		create_storage = false;
+
 	/*
 	 * Have the storage manager create the relation's disk file, if needed.
 	 *
@@ -427,7 +433,7 @@ heap_create(const char *relname,
 
 			case RELKIND_INDEX:
 			case RELKIND_SEQUENCE:
-				RelationCreateStorage(rel->rd_node, relpersistence);
+				RelationCreateStorage(rel->rd_node, relpersistence, rel);
 				break;
 
 			case RELKIND_RELATION:
@@ -956,6 +962,7 @@ AddNewRelationTuple(Relation pg_class_desc,
 					Oid reloftype,
 					Oid relowner,
 					char relkind,
+					char relpersistence,
 					TransactionId relfrozenxid,
 					TransactionId relminmxid,
 					Datum relacl,
@@ -994,8 +1001,18 @@ AddNewRelationTuple(Relation pg_class_desc,
 			break;
 	}
 
-	new_rel_reltup->relfrozenxid = relfrozenxid;
-	new_rel_reltup->relminmxid = relminmxid;
+	/* global temp table not remember transaction info in catalog */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		new_rel_reltup->relfrozenxid = InvalidTransactionId;
+		new_rel_reltup->relminmxid = InvalidMultiXactId;
+	}
+	else
+	{
+		new_rel_reltup->relfrozenxid = relfrozenxid;
+		new_rel_reltup->relminmxid = relminmxid;
+	}
+
 	new_rel_reltup->relowner = relowner;
 	new_rel_reltup->reltype = new_type_oid;
 	new_rel_reltup->reloftype = reloftype;
@@ -1357,6 +1374,7 @@ heap_create_with_catalog(const char *relname,
 						reloftypeid,
 						ownerid,
 						relkind,
+						relpersistence,
 						relfrozenxid,
 						relminmxid,
 						PointerGetDatum(relacl),
@@ -1441,11 +1459,15 @@ heap_create_with_catalog(const char *relname,
 	 */
 	StoreConstraints(new_rel_desc, cooked_constraints, is_internal);
 
-	/*
-	 * If there's a special on-commit action, remember it
-	 */
-	if (oncommit != ONCOMMIT_NOOP)
-		register_on_commit_action(relid, oncommit);
+	/* global temp table register action when storage init */
+	if (relpersistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		/*
+		 * If there's a special on-commit action, remember it
+		 */
+		if (oncommit != ONCOMMIT_NOOP)
+			register_on_commit_action(relid, oncommit);
+	}
 
 	/*
 	 * ok, the relation has been cataloged, so close our relations and return
@@ -1937,6 +1959,13 @@ heap_drop_with_catalog(Oid relid)
 	if (relid == defaultPartOid)
 		update_default_partition_oid(parentOid, InvalidOid);
 
+	/* We allow to drop global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (is_other_backend_use_gtt(rel->rd_node))
+			elog(ERROR, "can not drop relation when other backend attached this global temp table");
+	}
+
 	/*
 	 * Schedule unlinking of the relation's physical files at commit.
 	 */
@@ -3165,7 +3194,7 @@ RemoveStatistics(Oid relid, AttrNumber attnum)
  * the specified relation.  Caller must hold exclusive lock on rel.
  */
 static void
-RelationTruncateIndexes(Relation heapRelation)
+RelationTruncateIndexes(Relation heapRelation, LOCKMODE lockmode)
 {
 	ListCell   *indlist;
 
@@ -3177,7 +3206,7 @@ RelationTruncateIndexes(Relation heapRelation)
 		IndexInfo  *indexInfo;
 
 		/* Open the index relation; use exclusive lock, just to be sure */
-		currentIndex = index_open(indexId, AccessExclusiveLock);
+		currentIndex = index_open(indexId, lockmode);
 
 		/*
 		 * Fetch info needed for index_build.  Since we know there are no
@@ -3223,8 +3252,13 @@ heap_truncate(List *relids)
 	{
 		Oid			rid = lfirst_oid(cell);
 		Relation	rel;
+		LOCKMODE	lockmode = AccessExclusiveLock;
+
+		/* truncate global temp table only need RowExclusiveLock */
+		if (get_rel_persistence(rid) == RELPERSISTENCE_GLOBAL_TEMP)
+			lockmode = RowExclusiveLock;
 
-		rel = table_open(rid, AccessExclusiveLock);
+		rel = table_open(rid, lockmode);
 		relations = lappend(relations, rel);
 	}
 
@@ -3257,6 +3291,8 @@ void
 heap_truncate_one_rel(Relation rel)
 {
 	Oid			toastrelid;
+	LOCKMODE	lockmode = AccessExclusiveLock;
+	bool		truncate_toastrel = false;
 
 	/*
 	 * Truncate the relation.  Partitioned tables have no storage, so there is
@@ -3265,23 +3301,40 @@ heap_truncate_one_rel(Relation rel)
 	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 		return;
 
+	toastrelid = rel->rd_rel->reltoastrelid;
+
+	/*
+	 * Truncate global temp table only need RowExclusiveLock
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		lockmode = RowExclusiveLock;
+		if (OidIsValid(toastrelid) &&
+			gtt_storage_attached(toastrelid))
+			truncate_toastrel = true;
+	}
+	else if (OidIsValid(toastrelid))
+		truncate_toastrel = true;
+
 	/* Truncate the underlying relation */
 	table_relation_nontransactional_truncate(rel);
 
 	/* If the relation has indexes, truncate the indexes too */
-	RelationTruncateIndexes(rel);
+	RelationTruncateIndexes(rel, lockmode);
 
 	/* If there is a toast table, truncate that too */
-	toastrelid = rel->rd_rel->reltoastrelid;
-	if (OidIsValid(toastrelid))
+	if (truncate_toastrel)
 	{
-		Relation	toastrel = table_open(toastrelid, AccessExclusiveLock);
+		Relation	toastrel = table_open(toastrelid, lockmode);
 
 		table_relation_nontransactional_truncate(toastrel);
-		RelationTruncateIndexes(toastrel);
+		RelationTruncateIndexes(toastrel, lockmode);
 		/* keep the lock... */
 		table_close(toastrel, NoLock);
 	}
+
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		up_gtt_relstats(rel, 0, 0, 0, RecentXmin, InvalidMultiXactId);
 }
 
 /*
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 3e59e64..9705b1d 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -52,6 +52,7 @@
 #include "catalog/pg_trigger.h"
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
+#include "catalog/storage_gtt.h"
 #include "commands/event_trigger.h"
 #include "commands/progress.h"
 #include "commands/tablecmds.h"
@@ -877,6 +878,26 @@ index_create(Relation heapRelation,
 						indexRelationName, RelationGetRelationName(heapRelation))));
 	}
 
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		if (accessMethodObjectId != BTREE_AM_OID)
+			elog(ERROR, "only support btree index on global temp table");
+
+		/* We allow to create index on global temp table only this session use it */
+		if (is_other_backend_use_gtt(heapRelation->rd_node))
+			elog(ERROR, "can not create index when have other backend attached this global temp table");
+
+		/* No support create index on global temp table use concurrent mode yet */
+		if (concurrent)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("cannot create indexes on global temporary tables using concurrent mode")));
+
+		/* if global temp table not init storage, then skip build index */
+		if (!gtt_storage_attached(heapRelation->rd_node.relNode))
+			flags |= INDEX_CREATE_SKIP_BUILD;
+	}
+
 	/*
 	 * construct tuple descriptor for index tuples
 	 */
@@ -2045,6 +2066,13 @@ index_drop(Oid indexId, bool concurrent, bool concurrent_lock_mode)
 	 */
 	CheckTableNotInUse(userIndexRelation, "DROP INDEX");
 
+	/* We allow to drop index on global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(userHeapRelation))
+	{
+		if (is_other_backend_use_gtt(userHeapRelation->rd_node))
+			elog(ERROR, "can not drop index when other backend attached this global temp table.");
+	}
+
 	/*
 	 * Drop Index Concurrently is more or less the reverse process of Create
 	 * Index Concurrently.
@@ -2651,6 +2679,11 @@ index_update_stats(Relation rel,
 	HeapTuple	tuple;
 	Form_pg_class rd_rel;
 	bool		dirty;
+	bool		is_gtt = false;
+
+	/* update index stats into localhash and rel_rd_rel for global temp table */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		is_gtt = true;
 
 	/*
 	 * We always update the pg_class row using a non-transactional,
@@ -2736,21 +2769,35 @@ index_update_stats(Relation rel,
 		else					/* don't bother for indexes */
 			relallvisible = 0;
 
-		if (rd_rel->relpages != (int32) relpages)
+		if (is_gtt)
+			rel->rd_rel->relpages = (int32) relpages;
+		else if (rd_rel->relpages != (int32) relpages)
 		{
 			rd_rel->relpages = (int32) relpages;
 			dirty = true;
 		}
-		if (rd_rel->reltuples != (float4) reltuples)
+
+		if (is_gtt)
+			rel->rd_rel->reltuples = (float4) reltuples;
+		else if (rd_rel->reltuples != (float4) reltuples)
 		{
 			rd_rel->reltuples = (float4) reltuples;
 			dirty = true;
 		}
-		if (rd_rel->relallvisible != (int32) relallvisible)
+
+		if (is_gtt)
+			rel->rd_rel->relallvisible = (int32) relallvisible;
+		else if (rd_rel->relallvisible != (int32) relallvisible)
 		{
 			rd_rel->relallvisible = (int32) relallvisible;
 			dirty = true;
 		}
+
+		if (is_gtt)
+		{
+			up_gtt_relstats(rel, relpages, reltuples, relallvisible,
+							InvalidTransactionId, InvalidMultiXactId);
+		}
 	}
 
 	/*
@@ -2864,6 +2911,12 @@ index_build(Relation heapRelation,
 		pgstat_progress_update_multi_param(6, index, val);
 	}
 
+	if (RELATION_IS_GLOBAL_TEMP(indexRelation))
+	{
+		if (!gtt_storage_attached(indexRelation->rd_node.relNode))
+			RelationCreateStorage(indexRelation->rd_node, RELPERSISTENCE_GLOBAL_TEMP, indexRelation);
+	}
+
 	/*
 	 * Call the access method's build procedure
 	 */
@@ -3459,6 +3512,15 @@ reindex_index(Oid indexId, bool skip_constraint_checks, char persistence,
 				 errmsg("cannot reindex temporary tables of other sessions")));
 
 	/*
+	 * Because global temp table cannot change relfilenode
+	 * no support reindex on global temp table yet.
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(iRel))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot reindex global temporary tables")));
+
+	/*
 	 * Also check for active uses of the index in the current transaction; we
 	 * don't want to reindex underneath an open indexscan.
 	 */
diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index e70243a..301da79 100644
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -647,6 +647,13 @@ RangeVarAdjustRelationPersistence(RangeVar *newRelation, Oid nspid)
 							 errmsg("cannot create temporary relation in non-temporary schema")));
 			}
 			break;
+		/* global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			if (isAnyTempNamespace(nspid))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+						 errmsg("cannot create global temp relations in temporary schemas")));
+			break;
 		case RELPERSISTENCE_PERMANENT:
 			if (isTempOrTempToastNamespace(nspid))
 				newRelation->relpersistence = RELPERSISTENCE_TEMP;
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index fddfbf1..671c614 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -26,6 +26,7 @@
 #include "access/xlogutils.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "miscadmin.h"
 #include "storage/freespace.h"
 #include "storage/smgr.h"
@@ -75,7 +76,7 @@ static PendingRelDelete *pendingDeletes = NULL; /* head of linked list */
  * transaction aborts later on, the storage will be destroyed.
  */
 SMgrRelation
-RelationCreateStorage(RelFileNode rnode, char relpersistence)
+RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel)
 {
 	PendingRelDelete *pending;
 	SMgrRelation srel;
@@ -85,6 +86,8 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	switch (relpersistence)
 	{
 		case RELPERSISTENCE_TEMP:
+		/* global temp table use same storage strategy as local temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			needs_wal = false;
 			break;
@@ -117,6 +120,10 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	pending->next = pendingDeletes;
 	pendingDeletes = pending;
 
+	/* remember global temp table storage info to localhash */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP && rel)
+		remember_gtt_storage_info(rnode, rel);
+
 	return srel;
 }
 
@@ -486,8 +493,15 @@ smgrDoPendingDeletes(bool isCommit)
 		smgrdounlinkall(srels, nrels, false);
 
 		for (i = 0; i < nrels; i++)
+		{
 			smgrclose(srels[i]);
 
+			/* clean global temp table flags when transaction commit or rollback */
+			if (SmgrIsTemp(srels[i]) && 
+				gtt_storage_attached(srels[i]->smgr_rnode.node.relNode))
+				forget_gtt_storage_info(srels[i]->smgr_rnode.node.relNode);
+		}
+
 		pfree(srels);
 	}
 }
diff --git a/src/backend/catalog/storage_gtt.c b/src/backend/catalog/storage_gtt.c
new file mode 100644
index 0000000..f489cd3
--- /dev/null
+++ b/src/backend/catalog/storage_gtt.c
@@ -0,0 +1,1129 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.c
+ *	  code to create and destroy physical storage for global temparary table
+ *
+ * IDENTIFICATION
+ *	  src/backend/catalog/storage_gtt.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/table.h"
+#include "access/visibilitymap.h"
+#include "access/xact.h"
+#include "access/xlog.h"
+#include "access/xloginsert.h"
+#include "access/xlogutils.h"
+#include "access/htup_details.h"
+#include "access/multixact.h"
+#include "catalog/storage.h"
+#include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/heap.h"
+#include "catalog/namespace.h"
+#include "catalog/pg_type.h"
+#include "catalog/pg_statistic.h"
+#include "commands/tablecmds.h"
+#include "funcapi.h"
+#include "nodes/primnodes.h"
+#include "nodes/pg_list.h"
+#include "nodes/execnodes.h"
+#include "miscadmin.h"
+#include "storage/freespace.h"
+#include "storage/smgr.h"
+#include "storage/ipc.h"
+#include "storage/proc.h"
+#include "storage/procarray.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "storage/sinvaladt.h"
+#include "utils/memutils.h"
+#include "utils/rel.h"
+#include "utils/hsearch.h"
+#include "utils/catcache.h"
+#include "utils/lsyscache.h"
+#include <utils/relcache.h>
+#include "utils/inval.h"
+#include "utils/guc.h"
+
+
+/* Copy from bitmapset.c, because gtt used the function in bitmapset.c */
+#define WORDNUM(x)	((x) / BITS_PER_BITMAPWORD)
+#define BITNUM(x)	((x) % BITS_PER_BITMAPWORD)
+
+#define BITMAPSET_SIZE(nwords)	\
+	(offsetof(Bitmapset, words) + (nwords) * sizeof(bitmapword))
+
+static bool gtt_cleaner_exit_registered = false;
+static HTAB *gtt_storage_local_hash = NULL;
+static HTAB *active_gtt_shared_hash = NULL;
+static MemoryContext gtt_relstats_context = NULL;
+
+/* relfrozenxid of all gtts in the current session */
+static List *gtt_session_relfrozenxid_list = NIL;
+static TransactionId gtt_session_frozenxid = InvalidTransactionId;
+
+typedef struct gtt_ctl_data
+{
+	LWLock			lock;
+	int			max_entry;
+	int			entry_size;
+}gtt_ctl_data;
+
+static gtt_ctl_data *gtt_shared_ctl = NULL;
+
+typedef struct
+{
+	RelFileNode	rnode;
+	Bitmapset	*map;
+	/* bitmap data */
+} gtt_shared_hash_entry;
+
+typedef struct
+{
+	Oid			relid;
+
+	Oid			spcnode;
+	/* pg_class stat */
+	int32		relpages;
+	float4		reltuples;
+	int32		relallvisible;
+	TransactionId relfrozenxid;
+	TransactionId relminmxid;
+	char		relkind;
+	bool		on_commit_delete;
+
+	/* pg_statistic */
+	int			natts;
+	int			*attnum;
+	HeapTuple	*att_stat_tups;
+} gtt_local_hash_entry;
+
+static Size action_gtt_shared_hash_entry_size(void);
+static void gtt_storage_checkin(RelFileNode rnode);
+static void gtt_storage_checkout(RelFileNode rnode, bool skiplock);
+static void gtt_storage_removeall(int code, Datum arg);
+static void insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid);
+static void remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid);
+static void set_gtt_session_relfrozenxid(void);
+
+Datum pg_get_gtt_statistics(PG_FUNCTION_ARGS);
+Datum pg_get_gtt_relstats(PG_FUNCTION_ARGS);
+Datum pg_gtt_attached_pid(PG_FUNCTION_ARGS);
+Datum pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS);
+
+
+static Size
+action_gtt_shared_hash_entry_size(void)
+{
+	int 	wordnum;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	wordnum = WORDNUM(MaxBackends + 1);
+	hash_entry_size += MAXALIGN(sizeof(gtt_shared_hash_entry));
+	hash_entry_size += MAXALIGN(BITMAPSET_SIZE(wordnum + 1));
+
+	return hash_entry_size;
+}
+
+Size
+active_gtt_shared_hash_size(void)
+{
+	Size	size = 0;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	size = MAXALIGN(sizeof(gtt_ctl_data));
+	hash_entry_size = action_gtt_shared_hash_entry_size();
+	size += hash_estimate_size(max_active_gtt, hash_entry_size);
+
+	return size;
+}
+
+void
+active_gtt_shared_hash_init(void)
+{
+	HASHCTL info;
+	bool	found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	gtt_shared_ctl =
+		ShmemInitStruct("gtt_shared_ctl",
+						sizeof(gtt_ctl_data),
+						&found);
+
+	if (!found)
+	{
+		LWLockRegisterTranche(LWTRANCHE_GTT_CTL, "gtt_shared_ctl");
+		LWLockInitialize(&gtt_shared_ctl->lock, LWTRANCHE_GTT_CTL);
+		gtt_shared_ctl->max_entry = max_active_gtt;
+		gtt_shared_ctl->entry_size = action_gtt_shared_hash_entry_size();
+	}
+
+	info.keysize = sizeof(RelFileNode);
+	info.entrysize = gtt_shared_ctl->entry_size;
+	active_gtt_shared_hash =
+		ShmemInitHash("active gtt shared hash",
+						gtt_shared_ctl->max_entry,
+						gtt_shared_ctl->max_entry,
+						&info, HASH_ELEM | HASH_BLOBS | HASH_FIXED_SIZE);
+}
+
+static void
+gtt_storage_checkin(RelFileNode rnode)
+{
+	gtt_shared_hash_entry	*entry;
+	bool			found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+	entry = (gtt_shared_hash_entry *) hash_search(active_gtt_shared_hash,
+												&rnode, HASH_ENTER_NULL, &found);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		ereport(ERROR,
+				(errcode(ERRCODE_OUT_OF_MEMORY),
+				 errmsg("out of shared memory"),
+				 errhint("You might need to increase max_active_gtt.")));
+	}
+
+	if (found == false)
+	{
+		int			wordnum;
+
+		entry->map = (Bitmapset *)((char *)entry + MAXALIGN(sizeof(gtt_shared_hash_entry)));
+		wordnum = WORDNUM(MaxBackends + 1);
+		memset(entry->map, 0, BITMAPSET_SIZE(wordnum + 1));
+		entry->map->nwords = wordnum + 1;
+	}
+
+	bms_add_member(entry->map, MyBackendId);
+	LWLockRelease(&gtt_shared_ctl->lock);
+}
+
+static void
+gtt_storage_checkout(RelFileNode rnode, bool skiplock)
+{
+	gtt_shared_hash_entry	*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (!skiplock)
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(rnode), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		if (!skiplock)
+			LWLockRelease(&gtt_shared_ctl->lock);
+
+		elog(WARNING, "relfilenode %u/%u/%u not exist in gtt shared hash when forget",
+						rnode.dbNode, rnode.spcNode, rnode.relNode);
+		return;
+	}
+
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+	bms_del_member(entry->map, MyBackendId);
+
+	if (bms_is_empty(entry->map))
+	{
+		if (!hash_search(active_gtt_shared_hash, &rnode, HASH_REMOVE, NULL))
+			elog(PANIC, "gtt shared hash table corrupted");
+	}
+
+	if (!skiplock)
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+	return;
+}
+
+Bitmapset *
+copy_active_gtt_bitmap(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	Bitmapset	*map_copy = NULL;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return NULL;
+	}
+
+	Assert(entry->map);
+	if (!bms_is_empty(entry->map))
+		map_copy = bms_copy(entry->map);
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return map_copy;
+}
+
+bool
+is_other_backend_use_gtt(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	bool		in_use = false;
+	int			num_use = 0;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return false;
+	}
+
+	Assert(entry->map);
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+
+	num_use = bms_num_members(entry->map);
+	if (num_use == 0)
+		in_use = false;
+	else if (num_use == 1)
+	{
+		if(bms_is_member(MyBackendId, entry->map))
+			in_use = false;
+		else
+			in_use = true;
+	}
+	else
+		in_use = true;
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return in_use;
+}
+
+void
+remember_gtt_storage_info(RelFileNode rnode, Relation rel)
+{
+	gtt_local_hash_entry	*entry;
+	MemoryContext			oldcontext;
+	Oid			relid = rnode.relNode;
+	bool		found;
+
+	if (max_active_gtt <= 0)
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("Global temporary table feature is disable"),
+			 errhint("You might need to increase max_active_gtt to enable this feature.")));
+
+	if (RecoveryInProgress())
+		elog(ERROR, "readonly mode not support access global temp table yet");
+
+	if (gtt_storage_local_hash == NULL)
+	{
+#define GTT_LOCAL_HASH_SIZE		1024
+		/* First time through: initialize the hash table */
+		HASHCTL		ctl;
+
+		MemSet(&ctl, 0, sizeof(ctl));
+		ctl.keysize = sizeof(Oid);
+		ctl.entrysize = sizeof(gtt_local_hash_entry);
+		gtt_storage_local_hash =
+			hash_create("global temp relation table",
+						GTT_LOCAL_HASH_SIZE,
+						&ctl, HASH_ELEM | HASH_BLOBS);
+
+		if (!CacheMemoryContext)
+			CreateCacheMemoryContext();
+
+		gtt_relstats_context =
+			AllocSetContextCreate(CacheMemoryContext,
+							"gtt relstats context",
+							ALLOCSET_DEFAULT_SIZES);
+	}
+
+	/* Look up or create an entry */
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_ENTER, &found);
+
+	if (found)
+	{
+		elog(ERROR, "backend %d relid %u already exists in global temp table local hash",
+					MyBackendId, relid);
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+
+	entry->spcnode = rnode.spcNode;
+	entry->relpages = 0;
+	entry->reltuples = 0;
+	entry->relallvisible = 0;
+	entry->relkind = rel->rd_rel->relkind;
+	/* only heap contain transaction information */
+	if (entry->relkind == RELKIND_RELATION || entry->relkind == RELKIND_PARTITIONED_TABLE)
+	{
+		int natts = RelationGetNumberOfAttributes(rel);
+		entry->natts = natts;
+		entry->attnum = palloc0(sizeof(int) * natts);
+		entry->att_stat_tups = palloc0(sizeof(HeapTuple) * natts);
+
+		if (RELATION_GTT_ON_COMMIT_DELETE(rel))
+		{
+			entry->on_commit_delete = true;
+			register_on_commit_action(rel->rd_node.relNode, ONCOMMIT_DELETE_ROWS);
+		}
+
+		entry->relfrozenxid = RecentXmin;
+		entry->relminmxid = GetOldestMultiXactId();
+		insert_gtt_relfrozenxid_to_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+		gtt_storage_checkin(rnode);
+	}
+	else
+	{
+		entry->natts = 0;
+		entry->attnum = 0;
+		entry->att_stat_tups = NULL;
+		entry->on_commit_delete = false;
+		entry->relfrozenxid = 0;
+		entry->relminmxid = 0;
+	}
+
+	MemoryContextSwitchTo(oldcontext);
+
+	if (!gtt_cleaner_exit_registered)
+	{
+		before_shmem_exit(gtt_storage_removeall, 0);
+		gtt_cleaner_exit_registered = true;
+	}
+
+	return;
+}
+
+void
+forget_gtt_storage_info(Oid relid)
+{
+	gtt_local_hash_entry		*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+				(void *) &(relid), HASH_FIND, NULL);
+
+	if (entry && entry->relkind == RELKIND_RELATION)
+	{
+		RelFileNode rnode;
+		int			i;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		gtt_storage_checkout(rnode, false);
+
+		Assert(TransactionIdIsNormal(entry->relfrozenxid));
+		remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+
+		for (i = 0; i < entry->natts; i++)
+		{
+			if (entry->att_stat_tups[i])
+			{
+				heap_freetuple(entry->att_stat_tups[i]);
+				entry->att_stat_tups[i] = NULL;
+			}
+		}
+	}
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_REMOVE, NULL);
+
+	return;
+}
+
+/* is the storage file was created in this backend */
+bool
+gtt_storage_attached(Oid relid)
+{
+	bool found;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	if (gtt_storage_local_hash == NULL)
+		return false;
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_FIND, &found);
+
+	return found;
+}
+
+static void
+gtt_storage_removeall(int code, Datum arg)
+{
+	HASH_SEQ_STATUS				status;
+	gtt_local_hash_entry		*entry;
+	int			nrels = 0,
+				maxrels = 0;
+	SMgrRelation	*srels = NULL;
+	RelFileNode		*rnodes = NULL;
+	char			*relkinds = NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	hash_seq_init(&status, gtt_storage_local_hash);
+	while ((entry = (gtt_local_hash_entry *) hash_seq_search(&status)) != NULL)
+	{
+		SMgrRelation srel;
+		RelFileNode rnode;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		srel = smgropen(rnode, MyBackendId);
+
+		/* allocate the initial array, or extend it, if needed */
+		if (maxrels == 0)
+		{
+			maxrels = 32;
+			srels = palloc(sizeof(SMgrRelation) * maxrels);
+			rnodes = palloc(sizeof(RelFileNode) * maxrels);
+			relkinds = palloc(sizeof(char) * maxrels);
+		}
+		else if (maxrels <= nrels)
+		{
+			maxrels *= 2;
+			srels = repalloc(srels, sizeof(SMgrRelation) * maxrels);
+			rnodes = repalloc(rnodes, sizeof(RelFileNode) * maxrels);
+			relkinds = repalloc(relkinds, sizeof(char) * maxrels);
+		}
+
+		srels[nrels] = srel;
+		rnodes[nrels] = rnode;
+		relkinds[nrels] = entry->relkind;
+		nrels++;
+	}
+
+	if (nrels > 0)
+	{
+		int i;
+
+		smgrdounlinkall(srels, nrels, false);
+
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+		for (i = 0; i < nrels; i++)
+		{
+			smgrclose(srels[i]);
+			if (relkinds[i] == RELKIND_RELATION)
+				gtt_storage_checkout(rnodes[i], true);
+		}
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+		pfree(srels);
+		pfree(rnodes);
+		pfree(relkinds);
+	}
+
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;
+
+	return;
+}
+
+/*
+ * Update global temp table relstats(relpage/reltuple/relallvisible) 
+ * to local hashtable
+ */
+void
+up_gtt_relstats(Relation relation,
+					BlockNumber num_pages,
+					double num_tuples,
+					BlockNumber num_all_visible_pages,
+					TransactionId relfrozenxid,
+					TransactionId relminmxid)
+{
+	Oid		relid = RelationGetRelid(relation);
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	Assert(entry->spcnode);
+
+	if (num_pages >= 0 &&
+		entry->relpages != (int32)num_pages)
+		entry->relpages = (int32)num_pages;
+
+	if (num_tuples >= 0 &&
+		num_tuples != (float4)entry->reltuples)
+		entry->reltuples = (float4)num_tuples;
+
+	/* only heap contain transaction information and relallvisible */
+	if (entry->relkind == RELKIND_RELATION)
+	{
+		if (entry->relallvisible >= 0 &&
+			entry->relallvisible != (int32)num_all_visible_pages)
+		{
+			entry->relallvisible = (int32)num_all_visible_pages;
+		}
+
+		if (TransactionIdIsNormal(relfrozenxid) &&
+			entry->relfrozenxid != relfrozenxid &&
+			(TransactionIdPrecedes(entry->relfrozenxid, relfrozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(), entry->relfrozenxid)))
+		{
+			remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+			entry->relfrozenxid = relfrozenxid;
+			insert_gtt_relfrozenxid_to_ordered_list(relfrozenxid);
+			set_gtt_session_relfrozenxid();
+		}
+
+		if (MultiXactIdIsValid(relminmxid) &&
+			entry->relminmxid != relminmxid &&
+			(MultiXactIdPrecedes(entry->relminmxid, relminmxid) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), entry->relminmxid)))
+		{
+			entry->relminmxid = relminmxid;
+		}
+	}
+
+	return;
+}
+
+/*
+ * Search global temp table relstats(relpage/reltuple/relallvisible) 
+ * from local hashtable.
+ */
+bool
+get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+				BlockNumber *relallvisible, TransactionId *relfrozenxid,
+				TransactionId *relminmxid)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	if (gtt_storage_local_hash == NULL)
+		return false;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return false;
+
+	Assert(entry->relid == relid);
+
+	if (relpages)
+		*relpages = entry->relpages;
+
+	if (reltuples)
+		*reltuples = entry->reltuples;
+
+	if (relallvisible)
+		*relallvisible = entry->relallvisible;
+
+	if (relfrozenxid)
+		*relfrozenxid = entry->relfrozenxid;
+
+	if (relminmxid)
+		*relminmxid = entry->relminmxid;
+
+	return true;
+}
+
+/*
+ * Update global temp table statistic info(definition is same as pg_statistic)
+ * to local hashtable where ananyze global temp table
+ */
+void
+up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+					TupleDesc tupleDescriptor, Datum *values, bool *isnull)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	MemoryContext			oldcontext;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	if (entry->relkind != RELKIND_RELATION)
+	{
+		elog(WARNING, "oid %u not a relation", reloid);
+		return;
+	}
+
+	/* todo */
+	if (entry->natts < natts)
+	{
+		elog(WARNING, "reloid %u not support update attstat after add colunm", reloid);
+		return;
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	Assert(entry->relid == reloid);
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == 0)
+		{
+			entry->attnum[i] = attnum;
+			break;
+		}
+		else if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			heap_freetuple(entry->att_stat_tups[i]);
+			entry->att_stat_tups[i] = NULL;
+			break;
+		}
+	}
+
+	Assert(i < entry->natts);
+	Assert(entry->att_stat_tups[i] == NULL);
+	entry->att_stat_tups[i] = heap_form_tuple(tupleDescriptor, values, isnull);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+/*
+ * Search global temp table statistic info(definition is same as pg_statistic)
+ * from local hashtable.
+ */
+HeapTuple
+get_gtt_att_statistic(Oid reloid, int attnum, bool inh)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return NULL;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return NULL;
+
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			return entry->att_stat_tups[i];
+		}
+	}
+
+	return NULL;
+}
+
+void
+release_gtt_statistic_cache(HeapTuple tup)
+{
+	/* do nothing */
+	return;
+}
+
+static void
+insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid)
+{
+	MemoryContext	oldcontext;
+	ListCell	*cell;
+	int			i;
+
+	Assert(TransactionIdIsNormal(relfrozenxid));
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	/* Does the datum belong at the front? */
+	if (gtt_session_relfrozenxid_list == NIL ||
+		TransactionIdFollowsOrEquals(relfrozenxid,
+			linitial_oid(gtt_session_relfrozenxid_list)))
+	{
+		gtt_session_relfrozenxid_list =
+			lcons_oid(relfrozenxid, gtt_session_relfrozenxid_list);
+		MemoryContextSwitchTo(oldcontext);
+
+		return;
+	}
+
+	/* No, so find the entry it belongs after */
+	i = 0;
+	foreach (cell, gtt_session_relfrozenxid_list)
+	{
+		if (TransactionIdFollowsOrEquals(relfrozenxid, lfirst_oid(cell)))
+			break;
+
+		i++;
+	}
+	gtt_session_relfrozenxid_list =
+		list_insert_nth_oid(gtt_session_relfrozenxid_list, i, relfrozenxid);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+static void
+remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid)
+{
+	gtt_session_relfrozenxid_list =
+		list_delete_oid(gtt_session_relfrozenxid_list, relfrozenxid);
+}
+
+static void
+set_gtt_session_relfrozenxid(void)
+{
+	TransactionId gtt_frozenxid = InvalidTransactionId;
+
+	if (gtt_session_relfrozenxid_list)
+		gtt_frozenxid = llast_oid(gtt_session_relfrozenxid_list);
+
+	gtt_session_frozenxid = gtt_frozenxid;
+	if (MyProc->session_gtt_frozenxid != gtt_frozenxid)
+		MyProc->session_gtt_frozenxid = gtt_frozenxid;
+}
+
+Datum
+pg_get_gtt_statistics(PG_FUNCTION_ARGS)
+{
+	HeapTuple	tuple;
+	Relation	rel = NULL;
+	int		attnum = PG_GETARG_INT32(1);
+	Oid		reloid = PG_GETARG_OID(0);
+	char		rel_persistence;
+	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	  tupdesc;
+	MemoryContext oldcontext;
+	Tuplestorestate *tupstore;
+	Relation		pg_tatistic = NULL;
+	TupleDesc		sd;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("set-valued function called in context that cannot accept a set")));
+
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("materialize mode required, but it is not " \
+				"allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+				rsinfo->econtext->ecxt_per_query_memory);
+
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	pg_tatistic = table_open(StatisticRelationId, AccessShareLock);
+	sd = RelationGetDescr(pg_tatistic);
+
+	tuple = get_gtt_att_statistic(reloid, attnum, false);
+	if (tuple)
+	{
+		Datum	values[31];
+		bool	isnull[31];
+		HeapTuple	res = NULL;
+
+		memset(&values, 0, sizeof(values));
+		memset(&isnull, 0, sizeof(isnull));
+		heap_deform_tuple(tuple, sd, values, isnull);
+		res = heap_form_tuple(tupdesc, values, isnull);
+		tuplestore_puttuple(tupstore, res);
+	}
+
+	table_close(rel, NoLock);
+	table_close(pg_tatistic, AccessShareLock);
+	tuplestore_donestoring(tupstore);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_get_gtt_relstats(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc		tupdesc;
+	Tuplestorestate	*tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	Oid		reloid = PG_GETARG_OID(0);
+	char	rel_persistence;
+	BlockNumber	relpages = 0;
+	double		reltuples = 0;
+	BlockNumber	relallvisible = 0;
+	uint32		relfrozenxid = 0;
+	uint32		relminmxid = 0;
+	Relation	rel = NULL;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	if (get_gtt_relstats(reloid,
+						&relpages, &reltuples, &relallvisible,
+						&relfrozenxid, &relminmxid))
+	{
+		Datum	values[5];
+		bool	isnull[5];
+
+		memset(isnull, 0, sizeof(isnull));
+		memset(values, 0, sizeof(values));
+		values[0] = Int32GetDatum(relpages);
+		values[1] = Float4GetDatum((float4)reltuples);
+		values[2] = Int32GetDatum(relallvisible);
+		values[3] = UInt32GetDatum(relfrozenxid);
+		values[4] = UInt32GetDatum(relminmxid);
+		tuple = heap_form_tuple(tupdesc, values, isnull);
+		tuplestore_puttuple(tupstore, tuple);
+	}
+
+	tuplestore_donestoring(tupstore);
+	table_close(rel, NoLock);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_gtt_attached_pid(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	Oid		reloid = PG_GETARG_OID(0);
+	char	rel_persistence;
+	Relation	rel = NULL;
+	PGPROC		*proc = NULL;
+	Bitmapset	*map = NULL;
+	pid_t		pid = 0;
+	int			backendid = 0;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	map = copy_active_gtt_bitmap(rel->rd_node);
+	if (map)
+	{
+		backendid = bms_first_member(map);
+
+		do
+		{
+			proc = BackendIdGetProc(backendid);
+			pid = proc->pid;
+			if (pid > 0)
+			{
+				Datum	values[2];
+				bool	isnull[2];
+
+				memset(isnull, false, sizeof(isnull));
+				memset(values, 0, sizeof(values));
+				values[0] = UInt32GetDatum(reloid);
+				values[1] = Int32GetDatum(pid);
+				tuple = heap_form_tuple(tupdesc, values, isnull);
+				tuplestore_puttuple(tupstore, tuple);
+			}
+			backendid = bms_next_member(map, backendid);
+		} while (backendid > 0);
+
+		pfree(map);
+	}
+
+	tuplestore_donestoring(tupstore);
+	table_close(rel, NoLock);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	int			num_xid = MaxBackends + 1;
+	int			*pids = NULL;
+	uint32		*xids = NULL;
+	int			i = 0;
+	int			j = 0;
+	uint32		oldest = 0;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (max_active_gtt <= 0)
+		return (Datum) 0;
+
+	if (RecoveryInProgress())
+		return (Datum) 0;
+
+	pids = palloc0(sizeof(int) * num_xid);
+	xids = palloc0(sizeof(int) * num_xid);
+	oldest = list_all_session_gtt_frozenxids(num_xid, pids, xids, &i);
+	if (i > 0)
+	{
+		if (i > 0)
+		{
+			pids[i] = 0;
+			xids[i] = oldest;
+			i++;
+		}
+
+		for(j = 0; j < i; j++)
+		{
+			Datum	values[2];
+			bool	isnull[2];
+
+			memset(isnull, false, sizeof(isnull));
+			memset(values, 0, sizeof(values));
+			values[0] = Int32GetDatum(pids[j]);
+			values[1] = UInt32GetDatum(xids[j]);
+			tuple = heap_form_tuple(tupdesc, values, isnull);
+			tuplestore_puttuple(tupstore, tuple);
+		}
+	}
+	tuplestore_donestoring(tupstore);
+	pfree(pids);
+	pfree(xids);
+
+	return (Datum) 0;
+}
+
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index c9e75f4..2adde62 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -186,6 +186,91 @@ CREATE OR REPLACE VIEW pg_sequences AS
     WHERE NOT pg_is_other_temp_schema(N.oid)
           AND relkind = 'S';
 
+-- For global temporary table
+CREATE VIEW pg_gtt_relstats WITH (security_barrier) AS
+ SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.*
+ FROM
+     pg_class c
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_get_gtt_relstats(c.oid) as s
+ WHERE c.relpersistence='g' AND c.relkind in('r','p') AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
+CREATE VIEW pg_gtt_attached_pids WITH (security_barrier) AS
+ SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.*
+ FROM
+     pg_class c
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_gtt_attached_pid(c.oid) as s
+ WHERE c.relpersistence='g' AND c.relkind in('r','p') AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
+CREATE VIEW pg_gtt_stats WITH (security_barrier) AS
+SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    a.attname,
+    s.stainherit AS inherited,
+    s.stanullfrac AS null_frac,
+    s.stawidth AS avg_width,
+    s.stadistinct AS n_distinct,
+        CASE
+            WHEN s.stakind1 = 1 THEN s.stavalues1
+            WHEN s.stakind2 = 1 THEN s.stavalues2
+            WHEN s.stakind3 = 1 THEN s.stavalues3
+            WHEN s.stakind4 = 1 THEN s.stavalues4
+            WHEN s.stakind5 = 1 THEN s.stavalues5
+        END AS most_common_vals,
+        CASE
+            WHEN s.stakind1 = 1 THEN s.stanumbers1
+            WHEN s.stakind2 = 1 THEN s.stanumbers2
+            WHEN s.stakind3 = 1 THEN s.stanumbers3
+            WHEN s.stakind4 = 1 THEN s.stanumbers4
+            WHEN s.stakind5 = 1 THEN s.stanumbers5
+        END AS most_common_freqs,
+        CASE
+            WHEN s.stakind1 = 2 THEN s.stavalues1
+            WHEN s.stakind2 = 2 THEN s.stavalues2
+            WHEN s.stakind3 = 2 THEN s.stavalues3
+            WHEN s.stakind4 = 2 THEN s.stavalues4
+            WHEN s.stakind5 = 2 THEN s.stavalues5
+        END AS histogram_bounds,
+        CASE
+            WHEN s.stakind1 = 3 THEN s.stanumbers1[1]
+            WHEN s.stakind2 = 3 THEN s.stanumbers2[1]
+            WHEN s.stakind3 = 3 THEN s.stanumbers3[1]
+            WHEN s.stakind4 = 3 THEN s.stanumbers4[1]
+            WHEN s.stakind5 = 3 THEN s.stanumbers5[1]
+        END AS correlation,
+        CASE
+            WHEN s.stakind1 = 4 THEN s.stavalues1
+            WHEN s.stakind2 = 4 THEN s.stavalues2
+            WHEN s.stakind3 = 4 THEN s.stavalues3
+            WHEN s.stakind4 = 4 THEN s.stavalues4
+            WHEN s.stakind5 = 4 THEN s.stavalues5
+        END AS most_common_elems,
+        CASE
+            WHEN s.stakind1 = 4 THEN s.stanumbers1
+            WHEN s.stakind2 = 4 THEN s.stanumbers2
+            WHEN s.stakind3 = 4 THEN s.stanumbers3
+            WHEN s.stakind4 = 4 THEN s.stanumbers4
+            WHEN s.stakind5 = 4 THEN s.stanumbers5
+        END AS most_common_elem_freqs,
+        CASE
+            WHEN s.stakind1 = 5 THEN s.stanumbers1
+            WHEN s.stakind2 = 5 THEN s.stanumbers2
+            WHEN s.stakind3 = 5 THEN s.stanumbers3
+            WHEN s.stakind4 = 5 THEN s.stanumbers4
+            WHEN s.stakind5 = 5 THEN s.stanumbers5
+        END AS elem_count_histogram
+   FROM 
+     pg_class c
+     JOIN pg_attribute a ON c.oid = a.attrelid
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_get_gtt_statistics(c.oid, a.attnum, ''::text) as s
+  WHERE c.relpersistence='g' AND c.relkind in('r','p') and NOT a.attisdropped AND has_column_privilege(c.oid, a.attnum, 'select'::text) AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
 CREATE VIEW pg_stats WITH (security_barrier) AS
     SELECT
         nspname AS schemaname,
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index c4420dd..977a984 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -34,6 +34,7 @@
 #include "catalog/pg_inherits.h"
 #include "catalog/pg_namespace.h"
 #include "catalog/pg_statistic_ext.h"
+#include "catalog/storage_gtt.h"
 #include "commands/dbcommands.h"
 #include "commands/progress.h"
 #include "commands/tablecmds.h"
@@ -103,7 +104,7 @@ static int	acquire_inherited_sample_rows(Relation onerel, int elevel,
 										  HeapTuple *rows, int targrows,
 										  double *totalrows, double *totaldeadrows);
 static void update_attstats(Oid relid, bool inh,
-							int natts, VacAttrStats **vacattrstats);
+							int natts, VacAttrStats **vacattrstats, char relpersistence);
 static Datum std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 static Datum ind_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 
@@ -586,14 +587,15 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 		 * pg_statistic for columns we didn't process, we leave them alone.)
 		 */
 		update_attstats(RelationGetRelid(onerel), inh,
-						attr_cnt, vacattrstats);
+						attr_cnt, vacattrstats, RelationGetRelPersistence(onerel));
 
 		for (ind = 0; ind < nindexes; ind++)
 		{
 			AnlIndexData *thisdata = &indexdata[ind];
 
 			update_attstats(RelationGetRelid(Irel[ind]), false,
-							thisdata->attr_cnt, thisdata->vacattrstats);
+							thisdata->attr_cnt, thisdata->vacattrstats,
+							RelationGetRelPersistence(Irel[ind]));
 		}
 
 		/*
@@ -1456,7 +1458,7 @@ acquire_inherited_sample_rows(Relation onerel, int elevel,
  *		by taking a self-exclusive lock on the relation in analyze_rel().
  */
 static void
-update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
+update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats, char relpersistence)
 {
 	Relation	sd;
 	int			attno;
@@ -1558,31 +1560,45 @@ update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
 			}
 		}
 
-		/* Is there already a pg_statistic tuple for this attribute? */
-		oldtup = SearchSysCache3(STATRELATTINH,
-								 ObjectIdGetDatum(relid),
-								 Int16GetDatum(stats->attr->attnum),
-								 BoolGetDatum(inh));
-
-		if (HeapTupleIsValid(oldtup))
+		/* Update column statistic to localhash, not catalog */
+		if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		{
-			/* Yes, replace it */
-			stup = heap_modify_tuple(oldtup,
-									 RelationGetDescr(sd),
-									 values,
-									 nulls,
-									 replaces);
-			ReleaseSysCache(oldtup);
-			CatalogTupleUpdate(sd, &stup->t_self, stup);
+			up_gtt_att_statistic(relid,
+								stats->attr->attnum,
+								inh,
+								natts,
+								RelationGetDescr(sd),
+								values,
+								nulls);
 		}
 		else
 		{
-			/* No, insert new tuple */
-			stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
-			CatalogTupleInsert(sd, stup);
-		}
+			/* Is there already a pg_statistic tuple for this attribute? */
+			oldtup = SearchSysCache3(STATRELATTINH,
+									 ObjectIdGetDatum(relid),
+									 Int16GetDatum(stats->attr->attnum),
+									 BoolGetDatum(inh));
 
-		heap_freetuple(stup);
+			if (HeapTupleIsValid(oldtup))
+			{
+				/* Yes, replace it */
+				stup = heap_modify_tuple(oldtup,
+										 RelationGetDescr(sd),
+										 values,
+										 nulls,
+										 replaces);
+				ReleaseSysCache(oldtup);
+				CatalogTupleUpdate(sd, &stup->t_self, stup);
+			}
+			else
+			{
+				/* No, insert new tuple */
+				stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
+				CatalogTupleInsert(sd, stup);
+			}
+
+			heap_freetuple(stup);
+		}
 	}
 
 	table_close(sd, RowExclusiveLock);
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index e9d7a7f..3088e26 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -391,6 +391,12 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 					 errmsg("cannot vacuum temporary tables of other sessions")));
 	}
 
+	/* not support cluster global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(OldHeap))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support cluster global temporary tables yet")));
+
 	/*
 	 * Also check for active uses of the relation in the current transaction,
 	 * including open scans and pending AFTER trigger events.
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 52ce02f..3d3f7dc 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -2583,6 +2583,16 @@ ReindexMultipleTables(const char *objectName, ReindexObjectType objectKind,
 			!isTempNamespace(classtuple->relnamespace))
 			continue;
 
+		/* not support reindex on global temp table, so skip it */
+		if (classtuple->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			ereport(WARNING,
+				(errmsg("global temp table \"%s.%s\" skip reindexed",
+					get_namespace_name(get_rel_namespace(relid)),
+					get_rel_name(relid))));
+			continue;
+		}
+
 		/* Check user/system classification, and optionally skip */
 		if (objectKind == REINDEX_OBJECT_SYSTEM &&
 			!IsSystemClass(relid, classtuple))
diff --git a/src/backend/commands/lockcmds.c b/src/backend/commands/lockcmds.c
index 329ab84..dfa257c 100644
--- a/src/backend/commands/lockcmds.c
+++ b/src/backend/commands/lockcmds.c
@@ -96,7 +96,8 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
 	 * transaction.
 	 */
 	relpersistence = get_rel_persistence(relid);
-	if (relpersistence == RELPERSISTENCE_TEMP)
+	if (relpersistence == RELPERSISTENCE_TEMP ||
+		relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		MyXactFlags |= XACT_FLAGS_ACCESSEDTEMPNAMESPACE;
 
 	/* Check permissions. */
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index 6aab73b..44f350d 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -94,7 +94,7 @@ static HTAB *seqhashtab = NULL; /* hash table for SeqTable items */
  */
 static SeqTableData *last_used_seq = NULL;
 
-static void fill_seq_with_data(Relation rel, HeapTuple tuple);
+static void fill_seq_with_data(Relation rel, HeapTuple tuple, Buffer buf);
 static Relation lock_and_open_sequence(SeqTable seq);
 static void create_seq_hashtable(void);
 static void init_sequence(Oid relid, SeqTable *p_elm, Relation *p_rel);
@@ -108,6 +108,7 @@ static void init_params(ParseState *pstate, List *options, bool for_identity,
 						List **owned_by);
 static void do_setval(Oid relid, int64 next, bool iscalled);
 static void process_owned_by(Relation seqrel, List *owned_by, bool for_identity);
+int64 get_seqence_start_value(Oid seqid);
 
 
 /*
@@ -222,7 +223,7 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 
 	/* now initialize the sequence's data */
 	tuple = heap_form_tuple(tupDesc, value, null);
-	fill_seq_with_data(rel, tuple);
+	fill_seq_with_data(rel, tuple, InvalidBuffer);
 
 	/* process OWNED BY if given */
 	if (owned_by)
@@ -327,7 +328,7 @@ ResetSequence(Oid seq_relid)
 	/*
 	 * Insert the modified tuple into the new storage file.
 	 */
-	fill_seq_with_data(seq_rel, tuple);
+	fill_seq_with_data(seq_rel, tuple, InvalidBuffer);
 
 	/* Clear local cache so that we don't think we have cached numbers */
 	/* Note that we do not change the currval() state */
@@ -340,17 +341,21 @@ ResetSequence(Oid seq_relid)
  * Initialize a sequence's relation with the specified tuple as content
  */
 static void
-fill_seq_with_data(Relation rel, HeapTuple tuple)
+fill_seq_with_data(Relation rel, HeapTuple tuple, Buffer buf)
 {
-	Buffer		buf;
 	Page		page;
 	sequence_magic *sm;
 	OffsetNumber offnum;
+	bool lockBuffer = false;
 
 	/* Initialize first page of relation with special magic number */
 
-	buf = ReadBuffer(rel, P_NEW);
-	Assert(BufferGetBlockNumber(buf) == 0);
+	if (buf == InvalidBuffer)
+	{
+		buf = ReadBuffer(rel, P_NEW);
+		Assert(BufferGetBlockNumber(buf) == 0);
+		lockBuffer = true;
+	}
 
 	page = BufferGetPage(buf);
 
@@ -360,7 +365,8 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	/* Now insert sequence tuple */
 
-	LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
+	if (lockBuffer)
+		LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 
 	/*
 	 * Since VACUUM does not process sequences, we have to force the tuple to
@@ -410,7 +416,8 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	END_CRIT_SECTION();
 
-	UnlockReleaseBuffer(buf);
+	if (lockBuffer)
+		UnlockReleaseBuffer(buf);
 }
 
 /*
@@ -502,7 +509,7 @@ AlterSequence(ParseState *pstate, AlterSeqStmt *stmt)
 		/*
 		 * Insert the modified tuple into the new storage file.
 		 */
-		fill_seq_with_data(seqrel, newdatatuple);
+		fill_seq_with_data(seqrel, newdatatuple, InvalidBuffer);
 	}
 
 	/* process OWNED BY if given */
@@ -1178,6 +1185,25 @@ read_seq_tuple(Relation rel, Buffer *buf, HeapTuple seqdatatuple)
 	LockBuffer(*buf, BUFFER_LOCK_EXCLUSIVE);
 
 	page = BufferGetPage(*buf);
+	if (GlobalTempRelationPageIsNotInitialized(rel, page))
+	{
+		/* Initialize sequence for global temporary tables */
+		Datum		value[SEQ_COL_LASTCOL] = {0};
+		bool		null[SEQ_COL_LASTCOL] = {false};
+		HeapTuple	tuple;
+		int64		startv = get_seqence_start_value(RelationGetRelid(rel));
+
+		/*
+		 * last_value from pg_sequence.seqstart
+		 * log_cnt = 0
+		 * is_called = false
+		 */
+		value[SEQ_COL_LASTVAL-1] = Int64GetDatumFast(startv); /* start sequence with 1 */
+
+		tuple = heap_form_tuple(RelationGetDescr(rel), value, null);
+		fill_seq_with_data(rel, tuple, *buf);
+		heap_freetuple(tuple);
+	}
 	sm = (sequence_magic *) PageGetSpecialPointer(page);
 
 	if (sm->magic != SEQ_MAGIC)
@@ -1954,3 +1980,23 @@ seq_mask(char *page, BlockNumber blkno)
 
 	mask_unused_space(page);
 }
+
+int64
+get_seqence_start_value(Oid seqid)
+{
+	HeapTuple	seqtuple;
+	Form_pg_sequence	seqform;
+	int64		start;
+
+	seqtuple = SearchSysCache1(SEQRELID, ObjectIdGetDatum(seqid));
+	if (!HeapTupleIsValid(seqtuple))
+		elog(ERROR, "cache lookup failed for sequence %u",
+			 seqid);
+
+	seqform = (Form_pg_sequence) GETSTRUCT(seqtuple);
+	start = seqform->seqstart;
+	ReleaseSysCache(seqtuple);
+
+	return start;
+}
+
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 30b72b6..cc5b991 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -47,6 +47,7 @@
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
 #include "catalog/toasting.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/defrem.h"
@@ -552,6 +553,7 @@ static void refuseDupeIndexAttach(Relation parentIdx, Relation partIdx,
 								  Relation partitionTbl);
 static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
+static bool has_oncommit_option(List *options);
 
 
 /* ----------------------------------------------------------------
@@ -597,6 +599,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	LOCKMODE	parentLockmode;
 	const char *accessMethod = NULL;
 	Oid			accessMethodId = InvalidOid;
+	bool		has_oncommit_clause = false;
 
 	/*
 	 * Truncate relname to appropriate length (probably a waste of time, as
@@ -607,8 +610,10 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Check consistency of arguments
 	 */
+	/* global temp table same as local temp table */
 	if (stmt->oncommit != ONCOMMIT_NOOP
-		&& stmt->relation->relpersistence != RELPERSISTENCE_TEMP)
+		&& !(stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+			 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 				 errmsg("ON COMMIT can only be used on temporary tables")));
@@ -638,7 +643,9 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	 * code.  This is needed because calling code might not expect untrusted
 	 * tables to appear in pg_temp at the front of its search path.
 	 */
-	if (stmt->relation->relpersistence == RELPERSISTENCE_TEMP
+	/* global temp table same as local temp table */
+	if ((stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+		 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		&& InSecurityRestrictedOperation())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -739,6 +746,57 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Parse and validate reloptions, if any.
 	 */
+	/* global temp table */
+	has_oncommit_clause = has_oncommit_option(stmt->options);
+	if (stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP &&
+		(relkind == RELKIND_RELATION || relkind == RELKIND_PARTITIONED_TABLE))
+	{
+		/* inherit table or parition table inherit on commit property from parent table*/
+		if (inheritOids && stmt->oncommit == ONCOMMIT_NOOP && !has_oncommit_clause)
+		{
+			Oid			parent = linitial_oid(inheritOids);
+			Relation	relation = table_open(parent, NoLock);
+
+			if (!RELATION_IS_GLOBAL_TEMP(relation))
+				elog(ERROR, "The parent table must be global temporary table");
+
+			if (RELATION_GTT_ON_COMMIT_DELETE(relation))
+				stmt->oncommit = ONCOMMIT_DELETE_ROWS;
+			else
+				stmt->oncommit = ONCOMMIT_PRESERVE_ROWS;
+			table_close(relation, NoLock);
+		}
+
+		if (has_oncommit_clause)
+		{
+			if (stmt->oncommit != ONCOMMIT_NOOP)
+				elog(ERROR, "can not defeine global temp table with on commit and with clause at same time");
+		}
+		else
+		{
+			DefElem *opt = makeNode(DefElem);
+
+			opt->type = T_DefElem;
+			opt->defnamespace = NULL;
+			opt->defname = "on_commit_delete_rows";
+			opt->defaction = DEFELEM_UNSPEC;
+
+			/* use reloptions to remember on commit clause */
+			if (stmt->oncommit == ONCOMMIT_DELETE_ROWS)
+				opt->arg  = (Node *)makeString("true");
+			else if (stmt->oncommit == ONCOMMIT_PRESERVE_ROWS)
+				opt->arg  = (Node *)makeString("false");
+			else if (stmt->oncommit == ONCOMMIT_NOOP)
+				opt->arg  = (Node *)makeString("false");
+			else
+				elog(ERROR, "global temp table not support on commit drop clause");
+
+			stmt->options = lappend(stmt->options, opt);
+		}
+	}
+	else if (has_oncommit_clause)
+		elog(ERROR, "regular table cannot specifie on_commit_delete_rows");
+
 	reloptions = transformRelOptions((Datum) 0, stmt->options, NULL, validnsps,
 									 true, false);
 
@@ -1800,7 +1858,8 @@ ExecuteTruncateGuts(List *explicit_rels, List *relids, List *relids_logged,
 		 * table or the current physical file to be thrown away anyway.
 		 */
 		if (rel->rd_createSubid == mySubid ||
-			rel->rd_newRelfilenodeSubid == mySubid)
+			rel->rd_newRelfilenodeSubid == mySubid ||
+			RELATION_IS_GLOBAL_TEMP(rel))
 		{
 			/* Immediate, non-rollbackable truncation is OK */
 			heap_truncate_one_rel(rel);
@@ -3359,6 +3418,13 @@ RenameRelationInternal(Oid myrelid, const char *newrelname, bool is_internal, bo
 	 * specially.
 	 */
 	targetrelation = relation_open(myrelid, is_index ? ShareUpdateExclusiveLock : AccessExclusiveLock);
+
+	if (RELATION_IS_GLOBAL_TEMP(targetrelation))
+	{
+		if (is_other_backend_use_gtt(targetrelation->rd_node))
+			elog(ERROR, "can not rename relation when other backend attached this global temp table");
+	}
+
 	namespaceId = RelationGetNamespace(targetrelation);
 
 	/*
@@ -3534,6 +3600,13 @@ AlterTable(AlterTableStmt *stmt, LOCKMODE lockmode,
 	/* Caller is required to provide an adequate lock. */
 	rel = relation_open(context->relid, NoLock);
 
+	/* We allow to alter global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (is_other_backend_use_gtt(rel->rd_node))
+			elog(ERROR, "can not alter relation when other backend attached this global temp table");
+	}
+
 	CheckTableNotInUse(rel, "ALTER TABLE");
 
 	ATController(stmt, rel, stmt->cmds, stmt->relation->inh, lockmode, context);
@@ -8099,6 +8172,13 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 				 errmsg("referenced relation \"%s\" is not a table",
 						RelationGetRelationName(pkrel))));
 
+	/* global temp table not support foreign key constraint yet */
+	if (RELATION_IS_GLOBAL_TEMP(pkrel))
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("referenced relation \"%s\" is not a global temp table",
+						RelationGetRelationName(pkrel))));
+
 	if (!allowSystemTableMods && IsSystemRelation(pkrel))
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -8138,6 +8218,12 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 						 errmsg("constraints on temporary tables must involve temporary tables of this session")));
 			break;
+		/* global temp table not support foreign key constraint yet */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					 errmsg("not support foreign key constraints on global temp table yet")));
+			break;
 	}
 
 	/*
@@ -13174,7 +13260,7 @@ index_copy_data(Relation rel, RelFileNode newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
@@ -14581,7 +14667,9 @@ ATPrepChangePersistence(Relation rel, bool toLogged)
 	 */
 	switch (rel->rd_rel->relpersistence)
 	{
+		/* global temp table same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("cannot change logged status of table \"%s\" because it is temporary",
@@ -17221,3 +17309,20 @@ ATDetachCheckNoForeignKeyRefs(Relation partition)
 		table_close(rel, NoLock);
 	}
 }
+
+static bool
+has_oncommit_option(List *options)
+{
+	ListCell   *listptr;
+
+	foreach(listptr, options)
+	{
+		DefElem    *def = (DefElem *) lfirst(listptr);
+
+		if (pg_strcasecmp(def->defname, "on_commit_delete_rows") == 0)
+			return true;
+	}
+
+	return false;
+}
+
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index d625d17..69ad24f 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -35,6 +35,7 @@
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
 #include "catalog/pg_namespace.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
 #include "commands/vacuum.h"
@@ -1217,6 +1218,17 @@ vac_update_relstats(Relation relation,
 	HeapTuple	ctup;
 	Form_pg_class pgcform;
 	bool		dirty;
+	bool		is_gtt = false;
+
+	 /* global temp table remember relstats to localhash and rel->rd_rel, not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+	{
+		is_gtt = true;
+		up_gtt_relstats(relation,
+						num_pages, num_tuples,
+						num_all_visible_pages,
+						frozenxid, minmulti);
+	}
 
 	rd = table_open(RelationRelationId, RowExclusiveLock);
 
@@ -1230,17 +1242,26 @@ vac_update_relstats(Relation relation,
 	/* Apply statistical updates, if any, to copied tuple */
 
 	dirty = false;
-	if (pgcform->relpages != (int32) num_pages)
+
+	if (is_gtt)
+		relation->rd_rel->relpages = (int32) num_pages;
+	else if (pgcform->relpages != (int32) num_pages)
 	{
 		pgcform->relpages = (int32) num_pages;
 		dirty = true;
 	}
-	if (pgcform->reltuples != (float4) num_tuples)
+
+	if (is_gtt)
+		relation->rd_rel->reltuples = (float4) num_tuples;
+	else if (pgcform->reltuples != (float4) num_tuples)
 	{
 		pgcform->reltuples = (float4) num_tuples;
 		dirty = true;
 	}
-	if (pgcform->relallvisible != (int32) num_all_visible_pages)
+
+	if (is_gtt)
+		relation->rd_rel->relallvisible = (int32) num_all_visible_pages;
+	else if (pgcform->relallvisible != (int32) num_all_visible_pages)
 	{
 		pgcform->relallvisible = (int32) num_all_visible_pages;
 		dirty = true;
@@ -1285,7 +1306,8 @@ vac_update_relstats(Relation relation,
 	 * This should match vac_update_datfrozenxid() concerning what we consider
 	 * to be "in the future".
 	 */
-	if (TransactionIdIsNormal(frozenxid) &&
+	if (!is_gtt &&
+		TransactionIdIsNormal(frozenxid) &&
 		pgcform->relfrozenxid != frozenxid &&
 		(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
 		 TransactionIdPrecedes(ReadNewTransactionId(),
@@ -1296,7 +1318,8 @@ vac_update_relstats(Relation relation,
 	}
 
 	/* Similarly for relminmxid */
-	if (MultiXactIdIsValid(minmulti) &&
+	if (!is_gtt &&
+		MultiXactIdIsValid(minmulti) &&
 		pgcform->relminmxid != minmulti &&
 		(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
 		 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
@@ -1394,6 +1417,10 @@ vac_update_datfrozenxid(void)
 			continue;
 		}
 
+		/* global temp table relstats not in pg_class */
+		if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			continue;
+
 		/*
 		 * Some table AMs might not need per-relation xid / multixid horizons.
 		 * It therefore seems reasonable to allow relfrozenxid and relminmxid
@@ -1451,6 +1478,25 @@ vac_update_datfrozenxid(void)
 	Assert(TransactionIdIsNormal(newFrozenXid));
 	Assert(MultiXactIdIsValid(newMinMulti));
 
+	/*
+	 * Global temp table get frozenxid from MyProc
+	 * to avoid the vacuum truncate clog that gtt need.
+	 */
+	if (max_active_gtt > 0)
+	{
+		TransactionId oldest_gtt_frozenxid =
+			list_all_session_gtt_frozenxids(0, NULL, NULL, NULL);
+
+		if (TransactionIdIsNormal(oldest_gtt_frozenxid) &&
+			TransactionIdPrecedes(oldest_gtt_frozenxid, newFrozenXid))
+		{
+			ereport(WARNING,
+				(errmsg("global temp table oldest FrozenXid is far in the past"),
+				 errhint("please truncate them or kill those sessions that use them.")));
+			newFrozenXid = oldest_gtt_frozenxid;
+		}
+	}
+
 	/* Now fetch the pg_database tuple we need to update. */
 	relation = table_open(DatabaseRelationId, RowExclusiveLock);
 
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 8286d9c..c3992a4 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -591,6 +591,8 @@ static void
 set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 						  RangeTblEntry *rte)
 {
+	char relpersistence;
+
 	/*
 	 * The flag has previously been initialized to false, so we can just
 	 * return if it becomes clear that we can't safely set it.
@@ -618,7 +620,11 @@ set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 			 * the rest of the necessary infrastructure right now anyway.  So
 			 * for now, bail out if we see a temporary table.
 			 */
-			if (get_rel_persistence(rte->relid) == RELPERSISTENCE_TEMP)
+			/* global temp table is same as local temp table */
+			relpersistence = get_rel_persistence(rte->relid);
+
+			if (relpersistence == RELPERSISTENCE_TEMP ||
+				relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 				return;
 
 			/*
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index d6f2153..310a9e2 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -6312,7 +6312,9 @@ plan_create_index_workers(Oid tableOid, Oid indexOid)
 	 * Furthermore, any index predicate or index expressions must be parallel
 	 * safe.
 	 */
+	/* global temp table is same as local temp table */
 	if (heap->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		heap->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexExpressions(index)) ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexPredicate(index)))
 	{
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 748bebf..a5ddbcd 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -2579,6 +2579,11 @@ transformCreateTableAsStmt(ParseState *pstate, CreateTableAsStmt *stmt)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("materialized views must not use temporary tables or views")));
 
+		if (is_query_using_gtt(query))
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("materialized views must not use global temporary tables or views")));
+
 		/*
 		 * A materialized view would either need to save parameters for use in
 		 * maintaining/loading the data or prohibit them entirely.  The latter
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index ba5916b..0ee6931 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3290,17 +3290,11 @@ OptTemp:	TEMPORARY					{ $$ = RELPERSISTENCE_TEMP; }
 			| LOCAL TEMP				{ $$ = RELPERSISTENCE_TEMP; }
 			| GLOBAL TEMPORARY
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED					{ $$ = RELPERSISTENCE_UNLOGGED; }
 			| /*EMPTY*/					{ $$ = RELPERSISTENCE_PERMANENT; }
@@ -11588,19 +11582,13 @@ OptTempTableName:
 				}
 			| GLOBAL TEMPORARY opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED opt_table qualified_name
 				{
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index b875a50..123945b 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -81,6 +81,7 @@ static void expandTupleDesc(TupleDesc tupdesc, Alias *eref,
 							List **colnames, List **colvars);
 static int	specialAttNum(const char *attname);
 static bool isQueryUsingTempRelation_walker(Node *node, void *context);
+static bool is_query_using_gtt_walker(Node *node, void *context);
 
 
 /*
@@ -3579,3 +3580,49 @@ isQueryUsingTempRelation_walker(Node *node, void *context)
 								  isQueryUsingTempRelation_walker,
 								  context);
 }
+
+/* check if the query uses global temp table */
+static bool
+is_query_using_gtt_walker(Node *node, void *context)
+{
+	if (node == NULL)
+		return false;
+
+	if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+		ListCell   *rtable;
+
+		foreach(rtable, query->rtable)
+		{
+			RangeTblEntry *rte = lfirst(rtable);
+
+			if (rte->rtekind == RTE_RELATION)
+			{
+				Relation	rel = relation_open(rte->relid, AccessShareLock);
+				char		relpersistence = rel->rd_rel->relpersistence;
+
+				relation_close(rel, AccessShareLock);
+				if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+					return true;
+			}
+		}
+
+		return query_tree_walker(query,
+								 is_query_using_gtt_walker,
+								 context,
+								 QTW_IGNORE_JOINALIASES);
+	}
+
+	return expression_tree_walker(node,
+								  is_query_using_gtt_walker,
+								  context);
+}
+
+/* check if the query uses global temp table */
+bool
+is_query_using_gtt(Query *query)
+{
+	return is_query_using_gtt_walker((Node *) query, NULL);
+}
+
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index ee2d2b5..9c9abaa 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -437,6 +437,9 @@ generateSerialExtraStmts(CreateStmtContext *cxt, ColumnDef *column,
 	seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
 	seqstmt->options = seqoptions;
 
+	if (cxt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		seqstmt->sequence->relpersistence = cxt->relation->relpersistence;
+
 	/*
 	 * If a sequence data type was specified, add it to the options.  Prepend
 	 * to the list rather than append; in case a user supplied their own AS
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 6d1f28c..ed837d1 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -2086,6 +2086,11 @@ do_autovacuum(void)
 			}
 			continue;
 		}
+		else if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			/* autovacuum skip vacuum global temp table */
+			continue;
+		}
 
 		/* Fetch reloptions and the pgstat entry for this table */
 		relopts = extract_autovac_opts(tuple, pg_class_desc);
@@ -2152,7 +2157,9 @@ do_autovacuum(void)
 		/*
 		 * We cannot safely process other backends' temp tables, so skip 'em.
 		 */
-		if (classForm->relpersistence == RELPERSISTENCE_TEMP)
+		/* autovacuum skip vacuum global temp table */
+		if (classForm->relpersistence == RELPERSISTENCE_TEMP || 
+			classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 			continue;
 
 		relid = classForm->oid;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index aba3960..3c4b96c 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -37,6 +37,7 @@
 #include "access/xlog.h"
 #include "catalog/catalog.h"
 #include "catalog/storage.h"
+#include "catalog/storage_gtt.h"
 #include "executor/instrument.h"
 #include "lib/binaryheap.h"
 #include "miscadmin.h"
@@ -52,6 +53,7 @@
 #include "utils/rel.h"
 #include "utils/resowner_private.h"
 #include "utils/timestamp.h"
+#include "utils/guc.h"
 
 
 /* Note: these two macros only work on shared buffers, not local ones! */
@@ -432,7 +434,7 @@ ForgetPrivateRefCountEntry(PrivateRefCountEntry *ref)
 static Buffer ReadBuffer_common(SMgrRelation reln, char relpersistence,
 								ForkNumber forkNum, BlockNumber blockNum,
 								ReadBufferMode mode, BufferAccessStrategy strategy,
-								bool *hit);
+								bool *hit, Relation rel);
 static bool PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy);
 static void PinBuffer_Locked(BufferDesc *buf);
 static void UnpinBuffer(BufferDesc *buf, bool fixOwner);
@@ -664,7 +666,8 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
 	 */
 	pgstat_count_buffer_read(reln);
 	buf = ReadBuffer_common(reln->rd_smgr, reln->rd_rel->relpersistence,
-							forkNum, blockNum, mode, strategy, &hit);
+							forkNum, blockNum, mode, strategy, &hit,
+							reln);
 	if (hit)
 		pgstat_count_buffer_hit(reln);
 	return buf;
@@ -692,7 +695,7 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 	Assert(InRecovery);
 
 	return ReadBuffer_common(smgr, RELPERSISTENCE_PERMANENT, forkNum, blockNum,
-							 mode, strategy, &hit);
+							 mode, strategy, &hit, NULL);
 }
 
 
@@ -704,7 +707,8 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 static Buffer
 ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 				  BlockNumber blockNum, ReadBufferMode mode,
-				  BufferAccessStrategy strategy, bool *hit)
+				  BufferAccessStrategy strategy, bool *hit,
+				  Relation rel)
 {
 	BufferDesc *bufHdr;
 	Block		bufBlock;
@@ -719,6 +723,15 @@ ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 
 	isExtend = (blockNum == P_NEW);
 
+	/* create storage when first read data page for gtt */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP &&
+		(isExtend || blockNum == 0) &&
+		forkNum == MAIN_FORKNUM &&
+		!gtt_storage_attached(smgr->smgr_rnode.node.relNode))
+	{
+		RelationCreateStorage(smgr->smgr_rnode.node, relpersistence, rel);
+	}
+
 	TRACE_POSTGRESQL_BUFFER_READ_START(forkNum, blockNum,
 									   smgr->smgr_rnode.node.spcNode,
 									   smgr->smgr_rnode.node.dbNode,
@@ -2809,6 +2822,16 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln)
 BlockNumber
 RelationGetNumberOfBlocksInFork(Relation relation, ForkNumber forkNum)
 {
+	/*
+	 * When this backend not init gtt storage
+	 * return 0
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(relation) &&
+		!gtt_storage_attached(relation->rd_node.relNode))
+	{
+		return 0;
+	}
+
 	switch (relation->rd_rel->relkind)
 	{
 		case RELKIND_SEQUENCE:
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 427b0d5..7adb969 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -21,6 +21,7 @@
 #include "access/nbtree.h"
 #include "access/subtrans.h"
 #include "access/twophase.h"
+#include "catalog/storage_gtt.h"
 #include "commands/async.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -147,6 +148,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, BTreeShmemSize());
 		size = add_size(size, SyncScanShmemSize());
 		size = add_size(size, AsyncShmemSize());
+		size = add_size(size, active_gtt_shared_hash_size());
 #ifdef EXEC_BACKEND
 		size = add_size(size, ShmemBackendArraySize());
 #endif
@@ -217,6 +219,8 @@ CreateSharedMemoryAndSemaphores(void)
 	SUBTRANSShmemInit();
 	MultiXactShmemInit();
 	InitBufferPool();
+	/* global temporary table */
+	active_gtt_shared_hash_init();
 
 	/*
 	 * Set up lock manager
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index c3adb2e..eb95e5f 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -62,6 +62,7 @@
 #include "utils/builtins.h"
 #include "utils/rel.h"
 #include "utils/snapmgr.h"
+#include "utils/guc.h"
 
 #define UINT32_ACCESS_ONCE(var)		 ((uint32)(*((volatile uint32 *)&(var))))
 
@@ -4087,3 +4088,77 @@ KnownAssignedXidsReset(void)
 
 	LWLockRelease(ProcArrayLock);
 }
+
+/*
+ * search all active backend to get oldest frozenxid
+ * for global temp table.
+ */
+int
+list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n)
+{
+	ProcArrayStruct *arrayP = procArray;
+	TransactionId result = InvalidTransactionId;
+	int			index;
+	int			flags = 0;
+	int			i = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	if (max_size > 0)
+	{
+		Assert(pids);
+		Assert(xids);
+		Assert(n);
+		*n = 0;
+	}
+
+	if (max_active_gtt <= 0)
+		return InvalidTransactionId;
+
+	if (RecoveryInProgress())
+		return InvalidTransactionId;
+
+	flags |= PROC_IS_AUTOVACUUM;
+	flags |= PROC_IN_LOGICAL_DECODING;
+
+	LWLockAcquire(ProcArrayLock, LW_SHARED);
+	if (max_size > 0 && max_size < arrayP->numProcs)
+	{
+		LWLockRelease(ProcArrayLock);
+		elog(ERROR, "list_all_gtt_frozenxids require more array");
+	}
+
+	for (index = 0; index < arrayP->numProcs; index++)
+	{
+		int			pgprocno = arrayP->pgprocnos[index];
+		volatile PGPROC *proc = &allProcs[pgprocno];
+		volatile PGXACT *pgxact = &allPgXact[pgprocno];
+
+		if (pgxact->vacuumFlags & flags)
+			continue;
+
+		if (proc->databaseId == MyDatabaseId &&
+			TransactionIdIsNormal(proc->session_gtt_frozenxid))
+		{
+			if (result == InvalidTransactionId)
+				result = proc->session_gtt_frozenxid;
+			else if (TransactionIdPrecedes(proc->session_gtt_frozenxid, result))
+				result = proc->session_gtt_frozenxid;
+
+			if (max_size > 0)
+			{
+				pids[i] = proc->pid;
+				xids[i] = proc->session_gtt_frozenxid;
+				i++;
+			}
+		}
+	}
+	LWLockRelease(ProcArrayLock);
+
+	if (max_size > 0)
+		*n = i;
+
+	return result;
+}
+
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 32df8c8..e4e1125 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -395,6 +395,7 @@ InitProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
@@ -577,6 +578,7 @@ InitAuxiliaryProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 85b7115..f5eae8c 100644
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -646,6 +646,12 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 		 */
 		if (zero_damaged_pages || InRecovery)
 			MemSet(buffer, 0, BLCKSZ);
+		else if(SmgrIsTemp(reln) && blocknum == 0 && forknum == MAIN_FORKNUM)
+		{
+			/* global temp table init btree meta page */
+			MemSet(buffer, 0, BLCKSZ);
+			mdwrite(reln, forknum, blocknum, buffer, true);
+		}
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_DATA_CORRUPTED),
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 7c6f057..eb10cf2 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -112,6 +112,7 @@
 #include "catalog/pg_operator.h"
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_statistic_ext.h"
+#include "catalog/storage_gtt.h"
 #include "executor/nodeAgg.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
@@ -4578,12 +4579,25 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
 						}
 						else if (index->indpred == NIL)
 						{
-							vardata->statsTuple =
-								SearchSysCache3(STATRELATTINH,
-												ObjectIdGetDatum(index->indexoid),
-												Int16GetDatum(pos + 1),
-												BoolGetDatum(false));
-							vardata->freefunc = ReleaseSysCache;
+							char rel_persistence = get_rel_persistence(index->indexoid);
+
+							if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+							{
+								vardata->statsTuple =
+									get_gtt_att_statistic(index->indexoid,
+														Int16GetDatum(pos + 1),
+														false);
+								vardata->freefunc = release_gtt_statistic_cache;
+							}
+							else
+							{
+								vardata->statsTuple =
+									SearchSysCache3(STATRELATTINH,
+													ObjectIdGetDatum(index->indexoid),
+													Int16GetDatum(pos + 1),
+													BoolGetDatum(false));
+								vardata->freefunc = ReleaseSysCache;
+							}
 
 							if (HeapTupleIsValid(vardata->statsTuple))
 							{
@@ -4708,15 +4722,27 @@ examine_simple_variable(PlannerInfo *root, Var *var,
 	}
 	else if (rte->rtekind == RTE_RELATION)
 	{
-		/*
-		 * Plain table or parent of an inheritance appendrel, so look up the
-		 * column in pg_statistic
-		 */
-		vardata->statsTuple = SearchSysCache3(STATRELATTINH,
-											  ObjectIdGetDatum(rte->relid),
-											  Int16GetDatum(var->varattno),
-											  BoolGetDatum(rte->inh));
-		vardata->freefunc = ReleaseSysCache;
+		char rel_persistence = get_rel_persistence(rte->relid);
+
+		if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata->statsTuple = get_gtt_att_statistic(rte->relid,
+														var->varattno,
+														rte->inh);
+			vardata->freefunc = release_gtt_statistic_cache;
+		}
+		else
+		{
+			/*
+			 * Plain table or parent of an inheritance appendrel, so look up the
+			 * column in pg_statistic
+			 */
+			vardata->statsTuple = SearchSysCache3(STATRELATTINH,
+												  ObjectIdGetDatum(rte->relid),
+												  Int16GetDatum(var->varattno),
+												  BoolGetDatum(rte->inh));
+			vardata->freefunc = ReleaseSysCache;
+		}
 
 		if (HeapTupleIsValid(vardata->statsTuple))
 		{
@@ -6098,6 +6124,7 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	{
 		/* Simple variable --- look to stats for the underlying table */
 		RangeTblEntry *rte = planner_rt_fetch(index->rel->relid, root);
+		char	rel_persistence = get_rel_persistence(rte->relid);
 
 		Assert(rte->rtekind == RTE_RELATION);
 		relid = rte->relid;
@@ -6115,6 +6142,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													rte->inh);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -6126,6 +6160,8 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	}
 	else
 	{
+		char	rel_persistence = get_rel_persistence(index->indexoid);
+
 		/* Expression --- maybe there are stats for the index itself */
 		relid = index->indexoid;
 		colnum = 1;
@@ -6141,6 +6177,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													false);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -7054,6 +7097,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		/* attempt to lookup stats in relation for this index column */
 		if (attnum != 0)
 		{
+			char	rel_persistence = get_rel_persistence(rte->relid);
+
 			/* Simple variable -- look to stats for the underlying table */
 			if (get_relation_stats_hook &&
 				(*get_relation_stats_hook) (root, rte, attnum, &vardata))
@@ -7066,6 +7111,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					elog(ERROR,
 						 "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(rte->relid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple =
@@ -7078,6 +7131,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		}
 		else
 		{
+			char	rel_persistence = get_rel_persistence(index->indexoid);
+
 			/*
 			 * Looks like we've found an expression column in the index. Let's
 			 * see if there's any stats for it.
@@ -7097,6 +7152,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					!vardata.freefunc)
 					elog(ERROR, "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(index->indexoid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple = SearchSysCache3(STATRELATTINH,
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 1e3e6d3..345e3e9 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -34,6 +34,7 @@
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_transform.h"
 #include "catalog/pg_type.h"
+#include "catalog/storage_gtt.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "utils/array.h"
@@ -2878,6 +2879,18 @@ get_attavgwidth(Oid relid, AttrNumber attnum)
 		if (stawidth > 0)
 			return stawidth;
 	}
+	if (get_rel_persistence(relid) == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		tp = get_gtt_att_statistic(relid, attnum, false);
+		if (!HeapTupleIsValid(tp))
+			return 0;
+
+		stawidth = ((Form_pg_statistic) GETSTRUCT(tp))->stawidth;
+		if (stawidth > 0)
+			return stawidth;
+		else
+			return 0;
+	}
 	tp = SearchSysCache3(STATRELATTINH,
 						 ObjectIdGetDatum(relid),
 						 Int16GetDatum(attnum),
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index df025a5..1f733f4 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -63,6 +63,7 @@
 #include "catalog/pg_type.h"
 #include "catalog/schemapg.h"
 #include "catalog/storage.h"
+#include "catalog/storage_gtt.h"
 #include "commands/policy.h"
 #include "commands/trigger.h"
 #include "miscadmin.h"
@@ -1124,6 +1125,28 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
 				relation->rd_islocaltemp = false;
 			}
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			{
+				BlockNumber     relpages = 0;
+				double          reltuples = 0;
+				BlockNumber     relallvisible = 0;
+
+				relation->rd_backend = BackendIdForTempRelations();
+				/*
+				 * For global temp table, all backend can use
+				 * this relation, so rd_islocaltemp always true.
+				 */
+				relation->rd_islocaltemp = true;
+				get_gtt_relstats(RelationGetRelid(relation),
+								&relpages,
+								&reltuples,
+								&relallvisible,
+								NULL, NULL);
+				relation->rd_rel->relpages = (int32)relpages;
+				relation->rd_rel->reltuples = (float4)reltuples;
+				relation->rd_rel->relallvisible = (int32)relallvisible;
+			}
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c",
 				 relation->rd_rel->relpersistence);
@@ -3313,6 +3336,10 @@ RelationBuildLocalRelation(const char *relname,
 			rel->rd_backend = BackendIdForTempRelations();
 			rel->rd_islocaltemp = true;
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			rel->rd_backend = BackendIdForTempRelations();
+			rel->rd_islocaltemp = true;
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relpersistence);
 			break;
@@ -3427,6 +3454,9 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 	TransactionId freezeXid = InvalidTransactionId;
 	RelFileNode newrnode;
 
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+		elog(ERROR, "global temp table does not allow setting new relfilenode");
+
 	/* Allocate a new relfilenode */
 	newrelfilenode = GetNewRelFileNode(relation->rd_rel->reltablespace, NULL,
 									   persistence);
@@ -3467,7 +3497,7 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 				/* handle these directly, at least for now */
 				SMgrRelation srel;
 
-				srel = RelationCreateStorage(newrnode, persistence);
+				srel = RelationCreateStorage(newrnode, persistence, relation);
 				smgrclose(srel);
 			}
 			break;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index e44f71e..44c86c8 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -139,6 +139,18 @@ char	   *GUC_check_errmsg_string;
 char	   *GUC_check_errdetail_string;
 char	   *GUC_check_errhint_string;
 
+/*
+ * num = 0 means disable global temp table feature.
+ * global temp table define can still storage in catalog
+ * just can not use.
+ * num > 0 means database can management num active global temp table.
+ */
+#define	MIN_NUM_ACTIVE_GTT			0
+#define	DEFAULT_NUM_ACTIVE_GTT			1000
+#define	MAX_NUM_ACTIVE_GTT			1000000
+
+int		max_active_gtt = MIN_NUM_ACTIVE_GTT;
+
 static void do_serialize(char **destptr, Size *maxbytes, const char *fmt,...) pg_attribute_printf(3, 4);
 
 static void set_config_sourcefile(const char *name, char *sourcefile,
@@ -1992,6 +2004,15 @@ static struct config_bool ConfigureNamesBool[] =
 static struct config_int ConfigureNamesInt[] =
 {
 	{
+		{"max_active_global_temporary_table", PGC_POSTMASTER, UNGROUPED,
+			gettext_noop("max active global temporary table."),
+			NULL
+		},
+		&max_active_gtt,
+		DEFAULT_NUM_ACTIVE_GTT, MIN_NUM_ACTIVE_GTT, MAX_NUM_ACTIVE_GTT,
+		NULL, NULL, NULL
+	},
+	{
 		{"archive_timeout", PGC_SIGHUP, WAL_ARCHIVING,
 			gettext_noop("Forces a switch to the next WAL file if a "
 						 "new file has not been started within N seconds."),
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 799b698..b98d396 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15583,6 +15583,7 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 	{
 		char	   *ftoptions = NULL;
 		char	   *srvname = NULL;
+		char		*table_type = NULL;
 
 		switch (tbinfo->relkind)
 		{
@@ -15634,9 +15635,15 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 			binary_upgrade_set_pg_class_oids(fout, q,
 											 tbinfo->dobj.catId.oid, false);
 
+		if (tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED)
+			table_type = "UNLOGGED ";
+		else if (tbinfo->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			table_type = "GLOBAL TEMPORARY ";
+		else
+			table_type = "";
+
 		appendPQExpBuffer(q, "CREATE %s%s %s",
-						  tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED ?
-						  "UNLOGGED " : "",
+						  table_type,
 						  reltypename,
 						  qualrelname);
 
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index f3c7eb9..28134e2 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3723,7 +3723,8 @@ listTables(const char *tabtypes, const char *pattern, bool verbose, bool showSys
 		if (pset.sversion >= 90100)
 		{
 			appendPQExpBuffer(&buf,
-							  ",\n  CASE c.relpersistence WHEN 'p' THEN '%s' WHEN 't' THEN '%s' WHEN 'u' THEN '%s' END as \"%s\"",
+							  ",\n  CASE c.relpersistence WHEN 'g' THEN '%s' WHEN 'p' THEN '%s' WHEN 't' THEN '%s' WHEN 'u' THEN '%s' END as \"%s\"",
+							  gettext_noop("session"),
 							  gettext_noop("permanent"),
 							  gettext_noop("temporary"),
 							  gettext_noop("unlogged"),
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 052d98b..f35d9bf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1003,6 +1003,8 @@ static const pgsql_thing_t words_after_create[] = {
 	{"FOREIGN TABLE", NULL, NULL, NULL},
 	{"FUNCTION", NULL, NULL, Query_for_list_of_functions},
 	{"GROUP", Query_for_list_of_roles},
+	{"GLOBAL", NULL, NULL, NULL, THING_NO_DROP | THING_NO_ALTER}, /* for CREATE GLOBAL TEMP/TEMPORARY TABLE
+																	* ... */
 	{"INDEX", NULL, NULL, &Query_for_list_of_indexes},
 	{"LANGUAGE", Query_for_list_of_languages},
 	{"LARGE OBJECT", NULL, NULL, NULL, THING_NO_CREATE | THING_NO_DROP},
@@ -2326,6 +2328,9 @@ psql_completion(const char *text, int start, int end)
 	/* CREATE FOREIGN DATA WRAPPER */
 	else if (Matches("CREATE", "FOREIGN", "DATA", "WRAPPER", MatchAny))
 		COMPLETE_WITH("HANDLER", "VALIDATOR", "OPTIONS");
+	/* CREATE GLOBAL TEMP/TEMPORARY*/
+	else if (Matches("CREATE", "GLOBAL"))
+		COMPLETE_WITH("TEMP", "TEMPORARY");
 
 	/* CREATE INDEX --- is allowed inside CREATE SCHEMA, so use TailMatches */
 	/* First off we complete CREATE UNIQUE with "INDEX" */
@@ -2534,6 +2539,8 @@ psql_completion(const char *text, int start, int end)
 	/* Complete "CREATE TEMP/TEMPORARY" with the possible temp objects */
 	else if (TailMatches("CREATE", "TEMP|TEMPORARY"))
 		COMPLETE_WITH("SEQUENCE", "TABLE", "VIEW");
+	else if (TailMatches("CREATE", "GLOBAL", "TEMP|TEMPORARY"))
+		COMPLETE_WITH("TABLE");
 	/* Complete "CREATE UNLOGGED" with TABLE or MATVIEW */
 	else if (TailMatches("CREATE", "UNLOGGED"))
 		COMPLETE_WITH("TABLE", "MATERIALIZED VIEW");
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index a12fc1f..78958e4 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -165,6 +165,7 @@ typedef FormData_pg_class *Form_pg_class;
 #define		  RELPERSISTENCE_PERMANENT	'p' /* regular table */
 #define		  RELPERSISTENCE_UNLOGGED	'u' /* unlogged permanent table */
 #define		  RELPERSISTENCE_TEMP		't' /* temporary table */
+#define		  RELPERSISTENCE_GLOBAL_TEMP	'g' /* global temporary table */
 
 /* default selection for replica identity (primary key or nothing) */
 #define		  REPLICA_IDENTITY_DEFAULT	'd'
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index fcf2a12..ba0bd5f 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -5484,6 +5484,40 @@
   proparallel => 'r', prorettype => 'float8', proargtypes => 'oid',
   prosrc => 'pg_stat_get_xact_function_self_time' },
 
+# For global temporary table
+{ oid => '4191',
+  descr => 'List local statistics for global temporary table',
+  proname => 'pg_get_gtt_statistics', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid int4 anyelement',
+  proallargtypes => '{oid,int4,anyelement,oid,int2,bool,float4,int4,float4,int2,int2,int2,int2,int2,oid,oid,oid,oid,oid,oid,oid,oid,oid,oid,_float4,_float4,_float4,_float4,_float4,anyarray,anyarray,anyarray,anyarray,anyarray}',
+  proargmodes => '{i,i,i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
+  proargnames => '{relid,att,x,starelid,staattnum,stainherit,stanullfrac,stawidth,stadistinct,stakind1,stakind2,stakind3,stakind4,stakind5,staop1,staop2,staop3,staop4,staop5,stacoll1,stacoll2,stacoll3,stacoll4,stacoll5,stanumbers1,stanumbers2,stanumbers3,stanumbers4,stanumbers5,stavalues1,stavalues2,stavalues3,stavalues4,stavalues5}',
+  prosrc => 'pg_get_gtt_statistics' },
+{ oid => '4192',
+  descr => 'List local relstats for global temporary table',
+  proname => 'pg_get_gtt_relstats', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid',
+  proallargtypes => '{oid,int4,float4,int4,xid,xid}',
+  proargmodes => '{i,o,o,o,o,o}',
+  proargnames => '{relid,relpages,reltuples,relallvisible,relfrozenxid,relminmxid}',
+  prosrc => 'pg_get_gtt_relstats' },
+{ oid => '4193',
+  descr => 'List attached pid for one global temporary table',
+  proname => 'pg_gtt_attached_pid', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid',
+  proallargtypes => '{oid,oid,int4}',
+  proargmodes => '{i,o,o}',
+  proargnames => '{relid,relid,pid}',
+  prosrc => 'pg_gtt_attached_pid' },
+{ oid => '4194',
+  descr => 'List those backends that have used global temporary table',
+  proname => 'pg_list_gtt_relfrozenxids', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => '',
+  proallargtypes => '{int4,xid}',
+  proargmodes => '{o,o}',
+  proargnames => '{pid,relfrozenxid}',
+  prosrc => 'pg_list_gtt_relfrozenxids' },
+
 { oid => '3788',
   descr => 'statistics: timestamp of the current statistics snapshot',
   proname => 'pg_stat_get_snapshot_timestamp', provolatile => 's',
diff --git a/src/include/catalog/storage.h b/src/include/catalog/storage.h
index 048003c..af48cdf 100644
--- a/src/include/catalog/storage.h
+++ b/src/include/catalog/storage.h
@@ -19,7 +19,7 @@
 #include "storage/smgr.h"
 #include "utils/relcache.h"
 
-extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence);
+extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel);
 extern void RelationDropStorage(Relation rel);
 extern void RelationPreserveStorage(RelFileNode rnode, bool atCommit);
 extern void RelationTruncate(Relation rel, BlockNumber nblocks);
diff --git a/src/include/catalog/storage_gtt.h b/src/include/catalog/storage_gtt.h
new file mode 100644
index 0000000..eacc214
--- /dev/null
+++ b/src/include/catalog/storage_gtt.h
@@ -0,0 +1,39 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.h
+ *	  prototypes for functions in backend/catalog/storage_gtt.c
+ *
+ * src/include/catalog/storage_gtt.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef STORAGE_GTT_H
+#define STORAGE_GTT_H
+
+#include "access/htup.h"
+#include "storage/block.h"
+#include "storage/relfilenode.h"
+#include "utils/relcache.h"
+
+extern Size active_gtt_shared_hash_size(void);
+extern void active_gtt_shared_hash_init(void);
+extern void remember_gtt_storage_info(RelFileNode rnode, Relation rel);
+extern void forget_gtt_storage_info(Oid relid);
+extern bool is_other_backend_use_gtt(RelFileNode node);
+extern bool gtt_storage_attached(Oid relid);
+extern Bitmapset *copy_active_gtt_bitmap(RelFileNode node);
+extern void up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+								TupleDesc tupleDescriptor, Datum *values, bool *isnull);
+extern HeapTuple get_gtt_att_statistic(Oid reloid, int attnum, bool inh);
+extern void release_gtt_statistic_cache(HeapTuple tup);
+extern void up_gtt_relstats(Relation relation,
+							BlockNumber num_pages,
+							double num_tuples,
+							BlockNumber num_all_visible_pages,
+							TransactionId relfrozenxid,
+							TransactionId relminmxid);
+extern bool get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+							BlockNumber *relallvisible, TransactionId *relfrozenxid,
+							TransactionId *relminmxid);
+
+#endif							/* STORAGE_H */
diff --git a/src/include/parser/parse_relation.h b/src/include/parser/parse_relation.h
index 93f9446..14cafae 100644
--- a/src/include/parser/parse_relation.h
+++ b/src/include/parser/parse_relation.h
@@ -120,4 +120,7 @@ extern Oid	attnumTypeId(Relation rd, int attid);
 extern Oid	attnumCollationId(Relation rd, int attid);
 extern bool isQueryUsingTempRelation(Query *query);
 
+/* global temp table check */
+extern bool is_query_using_gtt(Query *query);
+
 #endif							/* PARSE_RELATION_H */
diff --git a/src/include/storage/bufpage.h b/src/include/storage/bufpage.h
index 870ecb5..92c590e 100644
--- a/src/include/storage/bufpage.h
+++ b/src/include/storage/bufpage.h
@@ -405,6 +405,8 @@ do { \
 #define PageClearPrunable(page) \
 	(((PageHeader) (page))->pd_prune_xid = InvalidTransactionId)
 
+#define GlobalTempRelationPageIsNotInitialized(rel, page) \
+	((rel)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP && PageIsNew(page))
 
 /* ----------------------------------------------------------------
  *		extern declarations
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 8fda8e4..172eae9 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -220,6 +220,7 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_TBM,
 	LWTRANCHE_PARALLEL_APPEND,
 	LWTRANCHE_SXACT,
+	LWTRANCHE_GTT_CTL,
 	LWTRANCHE_FIRST_USER_DEFINED
 }			BuiltinTrancheIds;
 
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 5b407e6..f13250a 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -117,6 +117,8 @@ struct PGPROC
 	Oid			tempNamespaceId;	/* OID of temp schema this backend is
 									 * using */
 
+	TransactionId session_gtt_frozenxid;	/* session level global temp table relfrozenxid */
+
 	bool		isBackgroundWorker; /* true if background worker. */
 
 	/*
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index a5c7d0c..a86f61f 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -125,4 +125,6 @@ extern void ProcArraySetReplicationSlotXmin(TransactionId xmin,
 extern void ProcArrayGetReplicationSlotXmin(TransactionId *xmin,
 											TransactionId *catalog_xmin);
 
+extern int list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n);
+
 #endif							/* PROCARRAY_H */
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index ce93ace..0f7262e 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -281,6 +281,10 @@ extern int	tcp_user_timeout;
 extern bool trace_sort;
 #endif
 
+/* global temporary table */
+extern int	max_active_gtt;
+/* end */
+
 /*
  * Functions exported by guc.c
  */
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 44ed04d..3f9720d 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -277,6 +277,7 @@ typedef struct StdRdOptions
 	int			parallel_workers;	/* max number of parallel workers */
 	bool		vacuum_index_cleanup;	/* enables index vacuuming and cleanup */
 	bool		vacuum_truncate;	/* enables vacuum to truncate a relation */
+	bool		on_commit_delete_rows;	/* global temp table */
 } StdRdOptions;
 
 #define HEAP_MIN_FILLFACTOR			10
@@ -535,7 +536,8 @@ typedef struct ViewOptions
  *		True if relation's pages are stored in local buffers.
  */
 #define RelationUsesLocalBuffers(relation) \
-	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP || \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 
 /*
  * RELATION_IS_LOCAL
@@ -602,6 +604,17 @@ typedef struct ViewOptions
 	 RelationNeedsWAL(relation) && \
 	 !IsCatalogRelation(relation))
 
+/* global temp table implementations */
+#define RELATION_IS_GLOBAL_TEMP(relation)	((relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+
+#define RELATION_GTT_ON_COMMIT_DELETE(relation)	\
+	((relation)->rd_options && \
+	 ((relation)->rd_rel->relkind == RELKIND_RELATION || (relation)->rd_rel->relkind == RELKIND_PARTITIONED_TABLE) && \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ? \
+	 ((StdRdOptions *) (relation)->rd_options)->on_commit_delete_rows : false)
+
+#define RelationGetRelPersistence(relation) ((relation)->rd_rel->relpersistence)
+
 /* routines in utils/cache/relcache.c */
 extern void RelationIncrementReferenceCount(Relation rel);
 extern void RelationDecrementReferenceCount(Relation rel);
diff --git a/src/test/regress/expected/gtt_clean.out b/src/test/regress/expected/gtt_clean.out
new file mode 100644
index 0000000..50ca9ac
--- /dev/null
+++ b/src/test/regress/expected/gtt_clean.out
@@ -0,0 +1,7 @@
+reset search_path;
+drop schema gtt cascade;
+NOTICE:  drop cascades to 4 other objects
+DETAIL:  drop cascades to table gtt.gtt1
+drop cascades to table gtt.gtt2
+drop cascades to table gtt.gtt3
+drop cascades to table gtt.gtt_t_kenyon
diff --git a/src/test/regress/expected/gtt_function.out b/src/test/regress/expected/gtt_function.out
new file mode 100644
index 0000000..a477917
--- /dev/null
+++ b/src/test/regress/expected/gtt_function.out
@@ -0,0 +1,197 @@
+CREATE SCHEMA IF NOT EXISTS gtt_function;
+set search_path=gtt_function,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt_test_rename(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+)on commit delete rows;
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+ERROR:  cannot create indexes on global temporary tables using concurrent mode
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+ERROR:  not support cluster global temporary tables yet
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+ERROR:  ON COMMIT can only be used on temporary tables
+-- ok
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+ERROR:  regular table cannot specifie on_commit_delete_rows
+-- ok
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+--ok
+CREATE global temp TABLE p_table01 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)on commit delete rows;
+ 
+CREATE global temp TABLE p_table01_2018
+PARTITION OF p_table01
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+ 
+CREATE global temp TABLE p_table01_2017
+PARTITION OF p_table01
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+begin;
+insert into p_table01 values(1,'2018-01-02 00:00:00','test1');
+insert into p_table01 values(1,'2018-01-02 00:00:00','test2');
+select count(*) from p_table01;
+ count 
+-------
+     2
+(1 row)
+
+commit;
+select count(*) from p_table01;
+ count 
+-------
+     0
+(1 row)
+
+--ok
+CREATE global temp TABLE p_table02 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)
+on commit PRESERVE rows;
+CREATE global temp TABLE p_table02_2018
+PARTITION OF p_table02
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+CREATE global temp TABLE p_table02_2017
+PARTITION OF p_table02
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+-- ok
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+ERROR:  The parent table must be global temporary table
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent_global_temp) on commit delete rows;
+select relname ,relkind, relpersistence, reloptions from pg_class where relname like 'p_table0%' or  relname like 'tbl_inherits%' order by relname;
+             relname             | relkind | relpersistence |          reloptions           
+---------------------------------+---------+----------------+-------------------------------
+ p_table01                       | p       | g              | {on_commit_delete_rows=true}
+ p_table01_2017                  | r       | g              | {on_commit_delete_rows=true}
+ p_table01_2018                  | r       | g              | {on_commit_delete_rows=true}
+ p_table01_id_seq                | S       | g              | 
+ p_table02                       | p       | g              | {on_commit_delete_rows=false}
+ p_table02_2017                  | r       | g              | {on_commit_delete_rows=false}
+ p_table02_2018                  | r       | g              | {on_commit_delete_rows=false}
+ p_table02_id_seq                | S       | g              | 
+ tbl_inherits_parent             | r       | p              | 
+ tbl_inherits_parent_global_temp | r       | g              | {on_commit_delete_rows=true}
+ tbl_inherits_partition          | r       | g              | {on_commit_delete_rows=true}
+(11 rows)
+
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+ERROR:  global temp table not support on commit drop clause
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+ERROR:  can not defeine global temp table with on commit and with clause at same time
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+--ok
+alter table gtt_test_rename rename to gtt_test;
+-- ok
+ALTER TABLE gtt_test ADD COLUMN address varchar(30);
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  referenced relation "products" is not a global temp table
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  referenced relation "products" is not a global temp table
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+-- ok
+create global temp table gtt_seq(id int GENERATED ALWAYS AS IDENTITY (START WITH 2) primary key, a int)  on commit PRESERVE rows;
+insert into gtt_seq (a) values(1);
+insert into gtt_seq (a) values(2);
+select * from gtt_seq order by id;
+ id | a 
+----+---
+  2 | 1
+  3 | 2
+(2 rows)
+
+truncate gtt_seq;
+select * from gtt_seq order by id;
+ id | a 
+----+---
+(0 rows)
+
+insert into gtt_seq (a) values(3);
+select * from gtt_seq order by id;
+ id | a 
+----+---
+  4 | 3
+(1 row)
+
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+ERROR:  materialized views must not use global temporary tables or views
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+ERROR:  only support btree index on global temp table
+create index idx_err on gtt1 using gist (a);
+ERROR:  data type integer has no default operator class for access method "gist"
+HINT:  You must specify an operator class for the index or define a default operator class for the data type.
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+ERROR:  only support btree index on global temp table
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+ERROR:  only support btree index on global temp table
+reset search_path;
+drop schema gtt_function cascade;
+NOTICE:  drop cascades to 15 other objects
+DETAIL:  drop cascades to table gtt_function.gtt1
+drop cascades to table gtt_function.gtt_test
+drop cascades to table gtt_function.gtt2
+drop cascades to table gtt_function.gtt3
+drop cascades to table gtt_function.tmp_t0
+drop cascades to table gtt_function.tbl_inherits_parent
+drop cascades to table gtt_function.tbl_inherits_parent_global_temp
+drop cascades to table gtt_function.products
+drop cascades to table gtt_function.measurement
+drop cascades to table gtt_function.p_table01
+drop cascades to table gtt_function.p_table02
+drop cascades to table gtt_function.tbl_inherits_partition
+drop cascades to table gtt_function.gtt5
+drop cascades to table gtt_function.mytable
+drop cascades to table gtt_function.gtt_seq
diff --git a/src/test/regress/expected/gtt_parallel_1.out b/src/test/regress/expected/gtt_parallel_1.out
new file mode 100644
index 0000000..30d8a7b
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_1.out
@@ -0,0 +1,84 @@
+set search_path=gtt,sys;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_parallel_2.out b/src/test/regress/expected/gtt_parallel_2.out
new file mode 100644
index 0000000..850ef3e
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_2.out
@@ -0,0 +1,161 @@
+set search_path=gtt,sys;
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+ 3 | test1
+(3 rows)
+
+rollback;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test2
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 3 | test3
+(1 row)
+
+rollback;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 5 | test5
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 6 | test6
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+ count  
+--------
+ 100000
+(1 row)
+
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+             QUERY PLAN             
+------------------------------------
+ Index Scan using gtt3_pkey on gtt3
+   Index Cond: (a = 300)
+(2 rows)
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid),pg_table_size(oid),pg_indexes_size(oid),pg_total_relation_size(oid) from pg_class where relname = 'gtt_t_kenyon';
+   relname    | pg_relation_size | pg_relation_size | pg_table_size | pg_indexes_size | pg_total_relation_size 
+--------------+------------------+------------------+---------------+-----------------+------------------------
+ gtt_t_kenyon |           450560 |             8192 |        499712 |          475136 |                 974848
+(1 row)
+
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+   relname    
+--------------
+ gtt_t_kenyon
+(1 row)
+
+select
+c.relname, pg_relation_size(c.oid),pg_table_size(c.oid),pg_total_relation_size(c.oid)
+from
+pg_class c
+where
+c.oid in
+(
+select
+i.indexrelid as indexrelid
+from 
+pg_index i ,pg_class cc
+where cc.relname = 'gtt_t_kenyon' and cc.oid = i.indrelid
+)
+order by c.relname;
+      relname       | pg_relation_size | pg_table_size | pg_total_relation_size 
+--------------------+------------------+---------------+------------------------
+ idx_gtt_t_kenyon_1 |            65536 |         65536 |                  65536
+ idx_gtt_t_kenyon_2 |           409600 |        409600 |                 409600
+(2 rows)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_prepare.out b/src/test/regress/expected/gtt_prepare.out
new file mode 100644
index 0000000..9fe5fd4
--- /dev/null
+++ b/src/test/regress/expected/gtt_prepare.out
@@ -0,0 +1,9 @@
+CREATE SCHEMA IF NOT EXISTS gtt;
+set search_path=gtt,sys;
+create global temp table gtt1(a int primary key, b text) on commit delete rows;
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text);
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+create index idx_gtt_t_kenyon_1 on gtt_t_kenyon(id);
+create index idx_gtt_t_kenyon_2 on gtt_t_kenyon(remark);
+reset search_path;
diff --git a/src/test/regress/expected/gtt_stats.out b/src/test/regress/expected/gtt_stats.out
new file mode 100644
index 0000000..b258b7c
--- /dev/null
+++ b/src/test/regress/expected/gtt_stats.out
@@ -0,0 +1,76 @@
+CREATE SCHEMA IF NOT EXISTS gtt_stats;
+set search_path=gtt_stats,sys;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     0
+(1 row)
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     0
+(1 row)
+
+create global temp table gtt(a int primary key, b text) on commit PRESERVE rows;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     0
+(1 row)
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     0
+(1 row)
+
+insert into gtt values(generate_series(1,10000),'test');
+-- expect 1
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     1
+(1 row)
+
+-- expect 2
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     2
+(1 row)
+
+-- expect 0
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+ schemaname | tablename | relpages | reltuples | relallvisible 
+------------+-----------+----------+-----------+---------------
+ gtt_stats  | gtt       |        0 |         0 |             0
+(1 row)
+
+-- expect 0
+select * from pg_gtt_stats order by tablename;
+ schemaname | tablename | attname | inherited | null_frac | avg_width | n_distinct | most_common_vals | most_common_freqs | histogram_bounds | correlation | most_common_elems | most_common_elem_freqs | elem_count_histogram 
+------------+-----------+---------+-----------+-----------+-----------+------------+------------------+-------------------+------------------+-------------+-------------------+------------------------+----------------------
+(0 rows)
+
+analyze gtt;
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+ schemaname | tablename | relpages | reltuples | relallvisible 
+------------+-----------+----------+-----------+---------------
+ gtt_stats  | gtt       |       55 |     10000 |             0
+(1 row)
+
+select * from pg_gtt_stats order by tablename;
+ schemaname | tablename | attname | inherited | null_frac | avg_width | n_distinct | most_common_vals | most_common_freqs |                                                                                                                                                                                                                                                histogram_bounds                                                                                                                                                                                                                                                 | correlation | most_common_elems | most_common_elem_freqs | elem_count_histogram 
+------------+-----------+---------+-----------+-----------+-----------+------------+------------------+-------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+-------------------+------------------------+----------------------
+ gtt_stats  | gtt       | a       | f         |         0 |         4 |         -1 |                  |                   | {1,100,200,300,400,500,600,700,800,900,1000,1100,1200,1300,1400,1500,1600,1700,1800,1900,2000,2100,2200,2300,2400,2500,2600,2700,2800,2900,3000,3100,3200,3300,3400,3500,3600,3700,3800,3900,4000,4100,4200,4300,4400,4500,4600,4700,4800,4900,5000,5100,5200,5300,5400,5500,5600,5700,5800,5900,6000,6100,6200,6300,6400,6500,6600,6700,6800,6900,7000,7100,7200,7300,7400,7500,7600,7700,7800,7900,8000,8100,8200,8300,8400,8500,8600,8700,8800,8900,9000,9100,9200,9300,9400,9500,9600,9700,9800,9900,10000} |           1 |                   |                        | 
+ gtt_stats  | gtt       | b       | f         |         0 |         5 |          1 | {test}           | {1}               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |           1 |                   |                        | 
+(2 rows)
+
+reset search_path;
+drop schema gtt_stats cascade;
+NOTICE:  drop cascades to table gtt_stats.gtt
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index 70e1e2f..30cf4bd 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1348,6 +1348,93 @@ pg_group| SELECT pg_authid.rolname AS groname,
           WHERE (pg_auth_members.roleid = pg_authid.oid)) AS grolist
    FROM pg_authid
   WHERE (NOT pg_authid.rolcanlogin);
+pg_gtt_attached_pids| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.relid,
+    s.pid
+   FROM (pg_class c
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_gtt_attached_pid(c.oid) s(relid, pid)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
+pg_gtt_relstats| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.relpages,
+    s.reltuples,
+    s.relallvisible,
+    s.relfrozenxid,
+    s.relminmxid
+   FROM (pg_class c
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_get_gtt_relstats(c.oid) s(relpages, reltuples, relallvisible, relfrozenxid, relminmxid)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
+pg_gtt_stats| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    a.attname,
+    s.stainherit AS inherited,
+    s.stanullfrac AS null_frac,
+    s.stawidth AS avg_width,
+    s.stadistinct AS n_distinct,
+        CASE
+            WHEN (s.stakind1 = 1) THEN s.stavalues1
+            WHEN (s.stakind2 = 1) THEN s.stavalues2
+            WHEN (s.stakind3 = 1) THEN s.stavalues3
+            WHEN (s.stakind4 = 1) THEN s.stavalues4
+            WHEN (s.stakind5 = 1) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS most_common_vals,
+        CASE
+            WHEN (s.stakind1 = 1) THEN s.stanumbers1
+            WHEN (s.stakind2 = 1) THEN s.stanumbers2
+            WHEN (s.stakind3 = 1) THEN s.stanumbers3
+            WHEN (s.stakind4 = 1) THEN s.stanumbers4
+            WHEN (s.stakind5 = 1) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS most_common_freqs,
+        CASE
+            WHEN (s.stakind1 = 2) THEN s.stavalues1
+            WHEN (s.stakind2 = 2) THEN s.stavalues2
+            WHEN (s.stakind3 = 2) THEN s.stavalues3
+            WHEN (s.stakind4 = 2) THEN s.stavalues4
+            WHEN (s.stakind5 = 2) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS histogram_bounds,
+        CASE
+            WHEN (s.stakind1 = 3) THEN s.stanumbers1[1]
+            WHEN (s.stakind2 = 3) THEN s.stanumbers2[1]
+            WHEN (s.stakind3 = 3) THEN s.stanumbers3[1]
+            WHEN (s.stakind4 = 3) THEN s.stanumbers4[1]
+            WHEN (s.stakind5 = 3) THEN s.stanumbers5[1]
+            ELSE NULL::real
+        END AS correlation,
+        CASE
+            WHEN (s.stakind1 = 4) THEN s.stavalues1
+            WHEN (s.stakind2 = 4) THEN s.stavalues2
+            WHEN (s.stakind3 = 4) THEN s.stavalues3
+            WHEN (s.stakind4 = 4) THEN s.stavalues4
+            WHEN (s.stakind5 = 4) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS most_common_elems,
+        CASE
+            WHEN (s.stakind1 = 4) THEN s.stanumbers1
+            WHEN (s.stakind2 = 4) THEN s.stanumbers2
+            WHEN (s.stakind3 = 4) THEN s.stanumbers3
+            WHEN (s.stakind4 = 4) THEN s.stanumbers4
+            WHEN (s.stakind5 = 4) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS most_common_elem_freqs,
+        CASE
+            WHEN (s.stakind1 = 5) THEN s.stanumbers1
+            WHEN (s.stakind2 = 5) THEN s.stanumbers2
+            WHEN (s.stakind3 = 5) THEN s.stanumbers3
+            WHEN (s.stakind4 = 5) THEN s.stanumbers4
+            WHEN (s.stakind5 = 5) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS elem_count_histogram
+   FROM ((pg_class c
+     JOIN pg_attribute a ON ((c.oid = a.attrelid)))
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_get_gtt_statistics(c.oid, (a.attnum)::integer, ''::text) s(starelid, staattnum, stainherit, stanullfrac, stawidth, stadistinct, stakind1, stakind2, stakind3, stakind4, stakind5, staop1, staop2, staop3, staop4, staop5, stacoll1, stacoll2, stacoll3, stacoll4, stacoll5, stanumbers1, stanumbers2, stanumbers3, stanumbers4, stanumbers5, stavalues1, stavalues2, stavalues3, stavalues4, stavalues5)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND (NOT a.attisdropped) AND has_column_privilege(c.oid, a.attnum, 'select'::text) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
 pg_hba_file_rules| SELECT a.line_number,
     a.type,
     a.database,
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index d33a4e1..643afe4 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -121,3 +121,10 @@ test: fast_default
 
 # run stats by itself because its delay may be insufficient under heavy load
 test: stats
+
+# global temp table test
+test: gtt_stats
+test: gtt_function
+test: gtt_prepare
+test: gtt_parallel_1 gtt_parallel_2
+test: gtt_clean
diff --git a/src/test/regress/sql/gtt_clean.sql b/src/test/regress/sql/gtt_clean.sql
new file mode 100644
index 0000000..f3cf710
--- /dev/null
+++ b/src/test/regress/sql/gtt_clean.sql
@@ -0,0 +1,6 @@
+
+
+reset search_path;
+
+drop schema gtt cascade;
+
diff --git a/src/test/regress/sql/gtt_function.sql b/src/test/regress/sql/gtt_function.sql
new file mode 100644
index 0000000..cfc1879
--- /dev/null
+++ b/src/test/regress/sql/gtt_function.sql
@@ -0,0 +1,163 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt_function;
+
+set search_path=gtt_function,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt_test_rename(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+)on commit delete rows;
+
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+
+-- ok
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+
+-- ok
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+
+--ok
+CREATE global temp TABLE p_table01 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)on commit delete rows;
+ 
+CREATE global temp TABLE p_table01_2018
+PARTITION OF p_table01
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+ 
+CREATE global temp TABLE p_table01_2017
+PARTITION OF p_table01
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+
+begin;
+insert into p_table01 values(1,'2018-01-02 00:00:00','test1');
+insert into p_table01 values(1,'2018-01-02 00:00:00','test2');
+select count(*) from p_table01;
+commit;
+
+select count(*) from p_table01;
+
+--ok
+CREATE global temp TABLE p_table02 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)
+on commit PRESERVE rows;
+
+CREATE global temp TABLE p_table02_2018
+PARTITION OF p_table02
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+
+CREATE global temp TABLE p_table02_2017
+PARTITION OF p_table02
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+
+-- ok
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent_global_temp) on commit delete rows;
+
+select relname ,relkind, relpersistence, reloptions from pg_class where relname like 'p_table0%' or  relname like 'tbl_inherits%' order by relname;
+
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+
+--ok
+alter table gtt_test_rename rename to gtt_test;
+
+-- ok
+ALTER TABLE gtt_test ADD COLUMN address varchar(30);
+
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+
+-- ok
+create global temp table gtt_seq(id int GENERATED ALWAYS AS IDENTITY (START WITH 2) primary key, a int)  on commit PRESERVE rows;
+insert into gtt_seq (a) values(1);
+insert into gtt_seq (a) values(2);
+select * from gtt_seq order by id;
+truncate gtt_seq;
+select * from gtt_seq order by id;
+insert into gtt_seq (a) values(3);
+select * from gtt_seq order by id;
+
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+create index idx_err on gtt1 using gist (a);
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+
+reset search_path;
+
+drop schema gtt_function cascade;
+
diff --git a/src/test/regress/sql/gtt_parallel_1.sql b/src/test/regress/sql/gtt_parallel_1.sql
new file mode 100644
index 0000000..d7d81de
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_1.sql
@@ -0,0 +1,42 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+commit;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+rollback;
+select * from gtt1 order by a;
+
+truncate gtt1;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+select * from gtt1 order by a;
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+
+begin;
+select * from gtt1 order by a;
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_parallel_2.sql b/src/test/regress/sql/gtt_parallel_2.sql
new file mode 100644
index 0000000..5203c2b
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_2.sql
@@ -0,0 +1,76 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+commit;
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+truncate gtt3;
+select * from gtt3 order by a;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+truncate gtt3;
+select * from gtt3 order by a;
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+begin;
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid),pg_table_size(oid),pg_indexes_size(oid),pg_total_relation_size(oid) from pg_class where relname = 'gtt_t_kenyon';
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+
+select
+c.relname, pg_relation_size(c.oid),pg_table_size(c.oid),pg_total_relation_size(c.oid)
+from
+pg_class c
+where
+c.oid in
+(
+select
+i.indexrelid as indexrelid
+from 
+pg_index i ,pg_class cc
+where cc.relname = 'gtt_t_kenyon' and cc.oid = i.indrelid
+)
+order by c.relname;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_prepare.sql b/src/test/regress/sql/gtt_prepare.sql
new file mode 100644
index 0000000..2f4d883
--- /dev/null
+++ b/src/test/regress/sql/gtt_prepare.sql
@@ -0,0 +1,16 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt;
+
+set search_path=gtt,sys;
+
+create global temp table gtt1(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text);
+
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+create index idx_gtt_t_kenyon_1 on gtt_t_kenyon(id);
+create index idx_gtt_t_kenyon_2 on gtt_t_kenyon(remark);
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_stats.sql b/src/test/regress/sql/gtt_stats.sql
new file mode 100644
index 0000000..f041892
--- /dev/null
+++ b/src/test/regress/sql/gtt_stats.sql
@@ -0,0 +1,42 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt_stats;
+
+set search_path=gtt_stats,sys;
+
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+
+create global temp table gtt(a int primary key, b text) on commit PRESERVE rows;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+
+insert into gtt values(generate_series(1,10000),'test');
+
+-- expect 1
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 2
+select count(*) from pg_list_gtt_relfrozenxids();
+
+-- expect 0
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+
+-- expect 0
+select * from pg_gtt_stats order by tablename;
+
+analyze gtt;
+
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+
+select * from pg_gtt_stats order by tablename;
+
+reset search_path;
+
+drop schema gtt_stats cascade;
+

diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c
index 79430d2..b7173c7 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -158,6 +158,19 @@ static relopt_bool boolRelOpts[] =
 		},
 		true
 	},
+	/*
+	 * For global temp table only
+	 * use AccessExclusiveLock for ensure safety
+	 */
+	{
+		{
+			"on_commit_delete_rows",
+			"global temp table on commit options",
+			RELOPT_KIND_HEAP | RELOPT_KIND_PARTITIONED,
+			ShareUpdateExclusiveLock
+		},
+		true
+	},	
 	/* list terminator */
 	{{NULL}}
 };
@@ -1486,6 +1499,8 @@ bytea *
 default_reloptions(Datum reloptions, bool validate, relopt_kind kind)
 {
 	static const relopt_parse_elt tab[] = {
+		{"on_commit_delete_rows", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, on_commit_delete_rows)},
 		{"fillfactor", RELOPT_TYPE_INT, offsetof(StdRdOptions, fillfactor)},
 		{"autovacuum_enabled", RELOPT_TYPE_BOOL,
 		offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts, enabled)},
@@ -1586,13 +1601,18 @@ build_reloptions(Datum reloptions, bool validate,
 bytea *
 partitioned_table_reloptions(Datum reloptions, bool validate)
 {
+	static const relopt_parse_elt tab[] = {
+		{"on_commit_delete_rows", RELOPT_TYPE_BOOL,
+		offsetof(StdRdOptions, on_commit_delete_rows)}
+	};
+
 	/*
 	 * There are no options for partitioned tables yet, but this is able to do
 	 * some validation.
 	 */
 	return (bytea *) build_reloptions(reloptions, validate,
 									  RELOPT_KIND_PARTITIONED,
-									  0, NULL, 0);
+									  sizeof(StdRdOptions), tab, lengthof(tab));
 }
 
 /*
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index dd975b1..1610e7d 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -1013,7 +1013,9 @@ gistGetFakeLSN(Relation rel)
 {
 	static XLogRecPtr counter = FirstNormalUnloggedLSN;
 
-	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	/* global temp is same as local temp table */
+	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		rel->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 	{
 		/*
 		 * Temporary relations are only accessible in our session, so a simple
diff --git a/src/backend/access/hash/hash.c b/src/backend/access/hash/hash.c
index 4871b7f..16b00c9 100644
--- a/src/backend/access/hash/hash.c
+++ b/src/backend/access/hash/hash.c
@@ -149,7 +149,9 @@ hashbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	 * metapage, nor the first bitmap page.
 	 */
 	sort_threshold = (maintenance_work_mem * 1024L) / BLCKSZ;
-	if (index->rd_rel->relpersistence != RELPERSISTENCE_TEMP)
+	/* global temp table is same as local temp table */
+	if (!(index->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		index->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		sort_threshold = Min(sort_threshold, NBuffers);
 	else
 		sort_threshold = Min(sort_threshold, NLocBuffer);
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 1f6f6d0..5727ccd 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -598,7 +598,7 @@ heapam_relation_set_new_filenode(Relation rel,
 	 */
 	*minmulti = GetOldestMultiXactId();
 
-	srel = RelationCreateStorage(*newrnode, persistence);
+	srel = RelationCreateStorage(*newrnode, persistence, rel);
 
 	/*
 	 * If required, set up an init fork for an unlogged table so that it can
@@ -651,7 +651,7 @@ heapam_relation_copy_data(Relation rel, const RelFileNode *newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(*newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index b331f4c..cd02c6b 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -62,6 +62,7 @@
 #include "access/xact.h"
 #include "access/xlog.h"
 #include "catalog/storage.h"
+#include "catalog/storage_gtt.h"
 #include "commands/dbcommands.h"
 #include "commands/progress.h"
 #include "commands/vacuum.h"
@@ -397,8 +398,10 @@ heap_vacuum_rel(Relation onerel, VacuumParams *params,
 	Assert(params->truncate != VACOPT_TERNARY_DEFAULT);
 
 	/* not every AM requires these to be valid, but heap does */
-	Assert(TransactionIdIsNormal(onerel->rd_rel->relfrozenxid));
-	Assert(MultiXactIdIsValid(onerel->rd_rel->relminmxid));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relfrozenxid == InvalidTransactionId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && TransactionIdIsNormal(onerel->rd_rel->relfrozenxid)));
+	Assert((RELATION_IS_GLOBAL_TEMP(onerel) && onerel->rd_rel->relminmxid == InvalidMultiXactId) ||
+		(!RELATION_IS_GLOBAL_TEMP(onerel) && MultiXactIdIsValid(onerel->rd_rel->relminmxid)));
 
 	/* measure elapsed time iff autovacuum logging requires it */
 	if (IsAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index f05cbe7..946c9d2 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -763,7 +763,14 @@ _bt_getbuf(Relation rel, BlockNumber blkno, int access)
 		/* Read an existing block of the relation */
 		buf = ReadBuffer(rel, blkno);
 		LockBuffer(buf, access);
-		_bt_checkpage(rel, buf);
+
+		/* global temp table may be not yet initialized for this backend. */
+		if (RELATION_IS_GLOBAL_TEMP(rel) &&
+			blkno == BTREE_METAPAGE &&
+			PageIsNew(BufferGetPage(buf)))
+			_bt_initmetapage(BufferGetPage(buf), P_NONE, 0);
+		else
+			_bt_checkpage(rel, buf);
 	}
 	else
 	{
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 7f4f784..aba8a9f 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6327,6 +6327,10 @@ StartupXLOG(void)
 	else
 		recoveryTargetTLI = ControlFile->checkPointCopy.ThisTimeLineID;
 
+	/* clean temp relation files */
+	if (max_active_gtt > 0)
+		RemovePgTempFiles();
+
 	/*
 	 * Check for signal files, and if so set up state for offline recovery
 	 */
diff --git a/src/backend/catalog/Makefile b/src/backend/catalog/Makefile
index d5da81c..c753b0e 100644
--- a/src/backend/catalog/Makefile
+++ b/src/backend/catalog/Makefile
@@ -42,6 +42,7 @@ OBJS = \
 	pg_subscription.o \
 	pg_type.o \
 	storage.o \
+	storage_gtt.o \
 	toasting.o
 
 include $(top_srcdir)/src/backend/common.mk
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index 16cb6d8..f28f2c2 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -398,7 +398,9 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class, char relpersistence)
 
 	switch (relpersistence)
 	{
+		/* global temp table is same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			break;
 		case RELPERSISTENCE_UNLOGGED:
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 0fdff29..bd3cd9d 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -61,6 +61,7 @@
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "commands/tablecmds.h"
 #include "commands/typecmds.h"
 #include "executor/executor.h"
@@ -99,6 +100,7 @@ static void AddNewRelationTuple(Relation pg_class_desc,
 								Oid reloftype,
 								Oid relowner,
 								char relkind,
+								char relpersistence,
 								TransactionId relfrozenxid,
 								TransactionId relminmxid,
 								Datum relacl,
@@ -404,6 +406,10 @@ heap_create(const char *relname,
 									 relpersistence,
 									 relkind);
 
+	/* global temp table not create storage file when catalog create */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		create_storage = false;
+
 	/*
 	 * Have the storage manager create the relation's disk file, if needed.
 	 *
@@ -427,7 +433,7 @@ heap_create(const char *relname,
 
 			case RELKIND_INDEX:
 			case RELKIND_SEQUENCE:
-				RelationCreateStorage(rel->rd_node, relpersistence);
+				RelationCreateStorage(rel->rd_node, relpersistence, rel);
 				break;
 
 			case RELKIND_RELATION:
@@ -956,6 +962,7 @@ AddNewRelationTuple(Relation pg_class_desc,
 					Oid reloftype,
 					Oid relowner,
 					char relkind,
+					char relpersistence,
 					TransactionId relfrozenxid,
 					TransactionId relminmxid,
 					Datum relacl,
@@ -994,8 +1001,18 @@ AddNewRelationTuple(Relation pg_class_desc,
 			break;
 	}
 
-	new_rel_reltup->relfrozenxid = relfrozenxid;
-	new_rel_reltup->relminmxid = relminmxid;
+	/* global temp table not remember transaction info in catalog */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		new_rel_reltup->relfrozenxid = InvalidTransactionId;
+		new_rel_reltup->relminmxid = InvalidMultiXactId;
+	}
+	else
+	{
+		new_rel_reltup->relfrozenxid = relfrozenxid;
+		new_rel_reltup->relminmxid = relminmxid;
+	}
+
 	new_rel_reltup->relowner = relowner;
 	new_rel_reltup->reltype = new_type_oid;
 	new_rel_reltup->reloftype = reloftype;
@@ -1357,6 +1374,7 @@ heap_create_with_catalog(const char *relname,
 						reloftypeid,
 						ownerid,
 						relkind,
+						relpersistence,
 						relfrozenxid,
 						relminmxid,
 						PointerGetDatum(relacl),
@@ -1441,11 +1459,15 @@ heap_create_with_catalog(const char *relname,
 	 */
 	StoreConstraints(new_rel_desc, cooked_constraints, is_internal);
 
-	/*
-	 * If there's a special on-commit action, remember it
-	 */
-	if (oncommit != ONCOMMIT_NOOP)
-		register_on_commit_action(relid, oncommit);
+	/* global temp table register action when storage init */
+	if (relpersistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		/*
+		 * If there's a special on-commit action, remember it
+		 */
+		if (oncommit != ONCOMMIT_NOOP)
+			register_on_commit_action(relid, oncommit);
+	}
 
 	/*
 	 * ok, the relation has been cataloged, so close our relations and return
@@ -1937,6 +1959,13 @@ heap_drop_with_catalog(Oid relid)
 	if (relid == defaultPartOid)
 		update_default_partition_oid(parentOid, InvalidOid);
 
+	/* We allow to drop global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (is_other_backend_use_gtt(rel->rd_node))
+			elog(ERROR, "can not drop relation when other backend attached this global temp table");
+	}
+
 	/*
 	 * Schedule unlinking of the relation's physical files at commit.
 	 */
@@ -3165,7 +3194,7 @@ RemoveStatistics(Oid relid, AttrNumber attnum)
  * the specified relation.  Caller must hold exclusive lock on rel.
  */
 static void
-RelationTruncateIndexes(Relation heapRelation)
+RelationTruncateIndexes(Relation heapRelation, LOCKMODE lockmode)
 {
 	ListCell   *indlist;
 
@@ -3177,7 +3206,7 @@ RelationTruncateIndexes(Relation heapRelation)
 		IndexInfo  *indexInfo;
 
 		/* Open the index relation; use exclusive lock, just to be sure */
-		currentIndex = index_open(indexId, AccessExclusiveLock);
+		currentIndex = index_open(indexId, lockmode);
 
 		/*
 		 * Fetch info needed for index_build.  Since we know there are no
@@ -3223,8 +3252,13 @@ heap_truncate(List *relids)
 	{
 		Oid			rid = lfirst_oid(cell);
 		Relation	rel;
+		LOCKMODE	lockmode = AccessExclusiveLock;
+
+		/* truncate global temp table only need RowExclusiveLock */
+		if (get_rel_persistence(rid) == RELPERSISTENCE_GLOBAL_TEMP)
+			lockmode = RowExclusiveLock;
 
-		rel = table_open(rid, AccessExclusiveLock);
+		rel = table_open(rid, lockmode);
 		relations = lappend(relations, rel);
 	}
 
@@ -3257,6 +3291,8 @@ void
 heap_truncate_one_rel(Relation rel)
 {
 	Oid			toastrelid;
+	LOCKMODE	lockmode = AccessExclusiveLock;
+	bool		truncate_toastrel = false;
 
 	/*
 	 * Truncate the relation.  Partitioned tables have no storage, so there is
@@ -3265,23 +3301,40 @@ heap_truncate_one_rel(Relation rel)
 	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 		return;
 
+	toastrelid = rel->rd_rel->reltoastrelid;
+
+	/*
+	 * Truncate global temp table only need RowExclusiveLock
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		lockmode = RowExclusiveLock;
+		if (OidIsValid(toastrelid) &&
+			gtt_storage_attached(toastrelid))
+			truncate_toastrel = true;
+	}
+	else if (OidIsValid(toastrelid))
+		truncate_toastrel = true;
+
 	/* Truncate the underlying relation */
 	table_relation_nontransactional_truncate(rel);
 
 	/* If the relation has indexes, truncate the indexes too */
-	RelationTruncateIndexes(rel);
+	RelationTruncateIndexes(rel, lockmode);
 
 	/* If there is a toast table, truncate that too */
-	toastrelid = rel->rd_rel->reltoastrelid;
-	if (OidIsValid(toastrelid))
+	if (truncate_toastrel)
 	{
-		Relation	toastrel = table_open(toastrelid, AccessExclusiveLock);
+		Relation	toastrel = table_open(toastrelid, lockmode);
 
 		table_relation_nontransactional_truncate(toastrel);
-		RelationTruncateIndexes(toastrel);
+		RelationTruncateIndexes(toastrel, lockmode);
 		/* keep the lock... */
 		table_close(toastrel, NoLock);
 	}
+
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		up_gtt_relstats(rel, 0, 0, 0, RecentXmin, InvalidMultiXactId);
 }
 
 /*
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 3e59e64..9705b1d 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -52,6 +52,7 @@
 #include "catalog/pg_trigger.h"
 #include "catalog/pg_type.h"
 #include "catalog/storage.h"
+#include "catalog/storage_gtt.h"
 #include "commands/event_trigger.h"
 #include "commands/progress.h"
 #include "commands/tablecmds.h"
@@ -877,6 +878,26 @@ index_create(Relation heapRelation,
 						indexRelationName, RelationGetRelationName(heapRelation))));
 	}
 
+	if (RELATION_IS_GLOBAL_TEMP(heapRelation))
+	{
+		if (accessMethodObjectId != BTREE_AM_OID)
+			elog(ERROR, "only support btree index on global temp table");
+
+		/* We allow to create index on global temp table only this session use it */
+		if (is_other_backend_use_gtt(heapRelation->rd_node))
+			elog(ERROR, "can not create index when have other backend attached this global temp table");
+
+		/* No support create index on global temp table use concurrent mode yet */
+		if (concurrent)
+			ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("cannot create indexes on global temporary tables using concurrent mode")));
+
+		/* if global temp table not init storage, then skip build index */
+		if (!gtt_storage_attached(heapRelation->rd_node.relNode))
+			flags |= INDEX_CREATE_SKIP_BUILD;
+	}
+
 	/*
 	 * construct tuple descriptor for index tuples
 	 */
@@ -2045,6 +2066,13 @@ index_drop(Oid indexId, bool concurrent, bool concurrent_lock_mode)
 	 */
 	CheckTableNotInUse(userIndexRelation, "DROP INDEX");
 
+	/* We allow to drop index on global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(userHeapRelation))
+	{
+		if (is_other_backend_use_gtt(userHeapRelation->rd_node))
+			elog(ERROR, "can not drop index when other backend attached this global temp table.");
+	}
+
 	/*
 	 * Drop Index Concurrently is more or less the reverse process of Create
 	 * Index Concurrently.
@@ -2651,6 +2679,11 @@ index_update_stats(Relation rel,
 	HeapTuple	tuple;
 	Form_pg_class rd_rel;
 	bool		dirty;
+	bool		is_gtt = false;
+
+	/* update index stats into localhash and rel_rd_rel for global temp table */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+		is_gtt = true;
 
 	/*
 	 * We always update the pg_class row using a non-transactional,
@@ -2736,21 +2769,35 @@ index_update_stats(Relation rel,
 		else					/* don't bother for indexes */
 			relallvisible = 0;
 
-		if (rd_rel->relpages != (int32) relpages)
+		if (is_gtt)
+			rel->rd_rel->relpages = (int32) relpages;
+		else if (rd_rel->relpages != (int32) relpages)
 		{
 			rd_rel->relpages = (int32) relpages;
 			dirty = true;
 		}
-		if (rd_rel->reltuples != (float4) reltuples)
+
+		if (is_gtt)
+			rel->rd_rel->reltuples = (float4) reltuples;
+		else if (rd_rel->reltuples != (float4) reltuples)
 		{
 			rd_rel->reltuples = (float4) reltuples;
 			dirty = true;
 		}
-		if (rd_rel->relallvisible != (int32) relallvisible)
+
+		if (is_gtt)
+			rel->rd_rel->relallvisible = (int32) relallvisible;
+		else if (rd_rel->relallvisible != (int32) relallvisible)
 		{
 			rd_rel->relallvisible = (int32) relallvisible;
 			dirty = true;
 		}
+
+		if (is_gtt)
+		{
+			up_gtt_relstats(rel, relpages, reltuples, relallvisible,
+							InvalidTransactionId, InvalidMultiXactId);
+		}
 	}
 
 	/*
@@ -2864,6 +2911,12 @@ index_build(Relation heapRelation,
 		pgstat_progress_update_multi_param(6, index, val);
 	}
 
+	if (RELATION_IS_GLOBAL_TEMP(indexRelation))
+	{
+		if (!gtt_storage_attached(indexRelation->rd_node.relNode))
+			RelationCreateStorage(indexRelation->rd_node, RELPERSISTENCE_GLOBAL_TEMP, indexRelation);
+	}
+
 	/*
 	 * Call the access method's build procedure
 	 */
@@ -3459,6 +3512,15 @@ reindex_index(Oid indexId, bool skip_constraint_checks, char persistence,
 				 errmsg("cannot reindex temporary tables of other sessions")));
 
 	/*
+	 * Because global temp table cannot change relfilenode
+	 * no support reindex on global temp table yet.
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(iRel))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot reindex global temporary tables")));
+
+	/*
 	 * Also check for active uses of the index in the current transaction; we
 	 * don't want to reindex underneath an open indexscan.
 	 */
diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index e70243a..301da79 100644
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -647,6 +647,13 @@ RangeVarAdjustRelationPersistence(RangeVar *newRelation, Oid nspid)
 							 errmsg("cannot create temporary relation in non-temporary schema")));
 			}
 			break;
+		/* global temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			if (isAnyTempNamespace(nspid))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+						 errmsg("cannot create global temp relations in temporary schemas")));
+			break;
 		case RELPERSISTENCE_PERMANENT:
 			if (isTempOrTempToastNamespace(nspid))
 				newRelation->relpersistence = RELPERSISTENCE_TEMP;
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index fddfbf1..671c614 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -26,6 +26,7 @@
 #include "access/xlogutils.h"
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
 #include "miscadmin.h"
 #include "storage/freespace.h"
 #include "storage/smgr.h"
@@ -75,7 +76,7 @@ static PendingRelDelete *pendingDeletes = NULL; /* head of linked list */
  * transaction aborts later on, the storage will be destroyed.
  */
 SMgrRelation
-RelationCreateStorage(RelFileNode rnode, char relpersistence)
+RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel)
 {
 	PendingRelDelete *pending;
 	SMgrRelation srel;
@@ -85,6 +86,8 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	switch (relpersistence)
 	{
 		case RELPERSISTENCE_TEMP:
+		/* global temp table use same storage strategy as local temp table */
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			backend = BackendIdForTempRelations();
 			needs_wal = false;
 			break;
@@ -117,6 +120,10 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 	pending->next = pendingDeletes;
 	pendingDeletes = pending;
 
+	/* remember global temp table storage info to localhash */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP && rel)
+		remember_gtt_storage_info(rnode, rel);
+
 	return srel;
 }
 
@@ -486,8 +493,15 @@ smgrDoPendingDeletes(bool isCommit)
 		smgrdounlinkall(srels, nrels, false);
 
 		for (i = 0; i < nrels; i++)
+		{
 			smgrclose(srels[i]);
 
+			/* clean global temp table flags when transaction commit or rollback */
+			if (SmgrIsTemp(srels[i]) && 
+				gtt_storage_attached(srels[i]->smgr_rnode.node.relNode))
+				forget_gtt_storage_info(srels[i]->smgr_rnode.node.relNode);
+		}
+
 		pfree(srels);
 	}
 }
diff --git a/src/backend/catalog/storage_gtt.c b/src/backend/catalog/storage_gtt.c
new file mode 100644
index 0000000..f489cd3
--- /dev/null
+++ b/src/backend/catalog/storage_gtt.c
@@ -0,0 +1,1129 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.c
+ *	  code to create and destroy physical storage for global temparary table
+ *
+ * IDENTIFICATION
+ *	  src/backend/catalog/storage_gtt.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/table.h"
+#include "access/visibilitymap.h"
+#include "access/xact.h"
+#include "access/xlog.h"
+#include "access/xloginsert.h"
+#include "access/xlogutils.h"
+#include "access/htup_details.h"
+#include "access/multixact.h"
+#include "catalog/storage.h"
+#include "catalog/storage_xlog.h"
+#include "catalog/storage_gtt.h"
+#include "catalog/heap.h"
+#include "catalog/namespace.h"
+#include "catalog/pg_type.h"
+#include "catalog/pg_statistic.h"
+#include "commands/tablecmds.h"
+#include "funcapi.h"
+#include "nodes/primnodes.h"
+#include "nodes/pg_list.h"
+#include "nodes/execnodes.h"
+#include "miscadmin.h"
+#include "storage/freespace.h"
+#include "storage/smgr.h"
+#include "storage/ipc.h"
+#include "storage/proc.h"
+#include "storage/procarray.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "storage/sinvaladt.h"
+#include "utils/memutils.h"
+#include "utils/rel.h"
+#include "utils/hsearch.h"
+#include "utils/catcache.h"
+#include "utils/lsyscache.h"
+#include <utils/relcache.h>
+#include "utils/inval.h"
+#include "utils/guc.h"
+
+
+/* Copy from bitmapset.c, because gtt used the function in bitmapset.c */
+#define WORDNUM(x)	((x) / BITS_PER_BITMAPWORD)
+#define BITNUM(x)	((x) % BITS_PER_BITMAPWORD)
+
+#define BITMAPSET_SIZE(nwords)	\
+	(offsetof(Bitmapset, words) + (nwords) * sizeof(bitmapword))
+
+static bool gtt_cleaner_exit_registered = false;
+static HTAB *gtt_storage_local_hash = NULL;
+static HTAB *active_gtt_shared_hash = NULL;
+static MemoryContext gtt_relstats_context = NULL;
+
+/* relfrozenxid of all gtts in the current session */
+static List *gtt_session_relfrozenxid_list = NIL;
+static TransactionId gtt_session_frozenxid = InvalidTransactionId;
+
+typedef struct gtt_ctl_data
+{
+	LWLock			lock;
+	int			max_entry;
+	int			entry_size;
+}gtt_ctl_data;
+
+static gtt_ctl_data *gtt_shared_ctl = NULL;
+
+typedef struct
+{
+	RelFileNode	rnode;
+	Bitmapset	*map;
+	/* bitmap data */
+} gtt_shared_hash_entry;
+
+typedef struct
+{
+	Oid			relid;
+
+	Oid			spcnode;
+	/* pg_class stat */
+	int32		relpages;
+	float4		reltuples;
+	int32		relallvisible;
+	TransactionId relfrozenxid;
+	TransactionId relminmxid;
+	char		relkind;
+	bool		on_commit_delete;
+
+	/* pg_statistic */
+	int			natts;
+	int			*attnum;
+	HeapTuple	*att_stat_tups;
+} gtt_local_hash_entry;
+
+static Size action_gtt_shared_hash_entry_size(void);
+static void gtt_storage_checkin(RelFileNode rnode);
+static void gtt_storage_checkout(RelFileNode rnode, bool skiplock);
+static void gtt_storage_removeall(int code, Datum arg);
+static void insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid);
+static void remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid);
+static void set_gtt_session_relfrozenxid(void);
+
+Datum pg_get_gtt_statistics(PG_FUNCTION_ARGS);
+Datum pg_get_gtt_relstats(PG_FUNCTION_ARGS);
+Datum pg_gtt_attached_pid(PG_FUNCTION_ARGS);
+Datum pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS);
+
+
+static Size
+action_gtt_shared_hash_entry_size(void)
+{
+	int 	wordnum;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	wordnum = WORDNUM(MaxBackends + 1);
+	hash_entry_size += MAXALIGN(sizeof(gtt_shared_hash_entry));
+	hash_entry_size += MAXALIGN(BITMAPSET_SIZE(wordnum + 1));
+
+	return hash_entry_size;
+}
+
+Size
+active_gtt_shared_hash_size(void)
+{
+	Size	size = 0;
+	Size	hash_entry_size = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	size = MAXALIGN(sizeof(gtt_ctl_data));
+	hash_entry_size = action_gtt_shared_hash_entry_size();
+	size += hash_estimate_size(max_active_gtt, hash_entry_size);
+
+	return size;
+}
+
+void
+active_gtt_shared_hash_init(void)
+{
+	HASHCTL info;
+	bool	found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	gtt_shared_ctl =
+		ShmemInitStruct("gtt_shared_ctl",
+						sizeof(gtt_ctl_data),
+						&found);
+
+	if (!found)
+	{
+		LWLockRegisterTranche(LWTRANCHE_GTT_CTL, "gtt_shared_ctl");
+		LWLockInitialize(&gtt_shared_ctl->lock, LWTRANCHE_GTT_CTL);
+		gtt_shared_ctl->max_entry = max_active_gtt;
+		gtt_shared_ctl->entry_size = action_gtt_shared_hash_entry_size();
+	}
+
+	info.keysize = sizeof(RelFileNode);
+	info.entrysize = gtt_shared_ctl->entry_size;
+	active_gtt_shared_hash =
+		ShmemInitHash("active gtt shared hash",
+						gtt_shared_ctl->max_entry,
+						gtt_shared_ctl->max_entry,
+						&info, HASH_ELEM | HASH_BLOBS | HASH_FIXED_SIZE);
+}
+
+static void
+gtt_storage_checkin(RelFileNode rnode)
+{
+	gtt_shared_hash_entry	*entry;
+	bool			found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+	entry = (gtt_shared_hash_entry *) hash_search(active_gtt_shared_hash,
+												&rnode, HASH_ENTER_NULL, &found);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		ereport(ERROR,
+				(errcode(ERRCODE_OUT_OF_MEMORY),
+				 errmsg("out of shared memory"),
+				 errhint("You might need to increase max_active_gtt.")));
+	}
+
+	if (found == false)
+	{
+		int			wordnum;
+
+		entry->map = (Bitmapset *)((char *)entry + MAXALIGN(sizeof(gtt_shared_hash_entry)));
+		wordnum = WORDNUM(MaxBackends + 1);
+		memset(entry->map, 0, BITMAPSET_SIZE(wordnum + 1));
+		entry->map->nwords = wordnum + 1;
+	}
+
+	bms_add_member(entry->map, MyBackendId);
+	LWLockRelease(&gtt_shared_ctl->lock);
+}
+
+static void
+gtt_storage_checkout(RelFileNode rnode, bool skiplock)
+{
+	gtt_shared_hash_entry	*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (!skiplock)
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(rnode), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		if (!skiplock)
+			LWLockRelease(&gtt_shared_ctl->lock);
+
+		elog(WARNING, "relfilenode %u/%u/%u not exist in gtt shared hash when forget",
+						rnode.dbNode, rnode.spcNode, rnode.relNode);
+		return;
+	}
+
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+	bms_del_member(entry->map, MyBackendId);
+
+	if (bms_is_empty(entry->map))
+	{
+		if (!hash_search(active_gtt_shared_hash, &rnode, HASH_REMOVE, NULL))
+			elog(PANIC, "gtt shared hash table corrupted");
+	}
+
+	if (!skiplock)
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+	return;
+}
+
+Bitmapset *
+copy_active_gtt_bitmap(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	Bitmapset	*map_copy = NULL;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return NULL;
+	}
+
+	Assert(entry->map);
+	if (!bms_is_empty(entry->map))
+		map_copy = bms_copy(entry->map);
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return map_copy;
+}
+
+bool
+is_other_backend_use_gtt(RelFileNode node)
+{
+	gtt_shared_hash_entry	*entry;
+	bool		in_use = false;
+	int			num_use = 0;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	LWLockAcquire(&gtt_shared_ctl->lock, LW_SHARED);
+	entry = hash_search(active_gtt_shared_hash,
+					(void *) &(node), HASH_FIND, NULL);
+
+	if (entry == NULL)
+	{
+		LWLockRelease(&gtt_shared_ctl->lock);
+		return false;
+	}
+
+	Assert(entry->map);
+	Assert(MyBackendId >= 1 && MyBackendId <= MaxBackends);
+
+	num_use = bms_num_members(entry->map);
+	if (num_use == 0)
+		in_use = false;
+	else if (num_use == 1)
+	{
+		if(bms_is_member(MyBackendId, entry->map))
+			in_use = false;
+		else
+			in_use = true;
+	}
+	else
+		in_use = true;
+
+	LWLockRelease(&gtt_shared_ctl->lock);
+
+	return in_use;
+}
+
+void
+remember_gtt_storage_info(RelFileNode rnode, Relation rel)
+{
+	gtt_local_hash_entry	*entry;
+	MemoryContext			oldcontext;
+	Oid			relid = rnode.relNode;
+	bool		found;
+
+	if (max_active_gtt <= 0)
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("Global temporary table feature is disable"),
+			 errhint("You might need to increase max_active_gtt to enable this feature.")));
+
+	if (RecoveryInProgress())
+		elog(ERROR, "readonly mode not support access global temp table yet");
+
+	if (gtt_storage_local_hash == NULL)
+	{
+#define GTT_LOCAL_HASH_SIZE		1024
+		/* First time through: initialize the hash table */
+		HASHCTL		ctl;
+
+		MemSet(&ctl, 0, sizeof(ctl));
+		ctl.keysize = sizeof(Oid);
+		ctl.entrysize = sizeof(gtt_local_hash_entry);
+		gtt_storage_local_hash =
+			hash_create("global temp relation table",
+						GTT_LOCAL_HASH_SIZE,
+						&ctl, HASH_ELEM | HASH_BLOBS);
+
+		if (!CacheMemoryContext)
+			CreateCacheMemoryContext();
+
+		gtt_relstats_context =
+			AllocSetContextCreate(CacheMemoryContext,
+							"gtt relstats context",
+							ALLOCSET_DEFAULT_SIZES);
+	}
+
+	/* Look up or create an entry */
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_ENTER, &found);
+
+	if (found)
+	{
+		elog(ERROR, "backend %d relid %u already exists in global temp table local hash",
+					MyBackendId, relid);
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+
+	entry->spcnode = rnode.spcNode;
+	entry->relpages = 0;
+	entry->reltuples = 0;
+	entry->relallvisible = 0;
+	entry->relkind = rel->rd_rel->relkind;
+	/* only heap contain transaction information */
+	if (entry->relkind == RELKIND_RELATION || entry->relkind == RELKIND_PARTITIONED_TABLE)
+	{
+		int natts = RelationGetNumberOfAttributes(rel);
+		entry->natts = natts;
+		entry->attnum = palloc0(sizeof(int) * natts);
+		entry->att_stat_tups = palloc0(sizeof(HeapTuple) * natts);
+
+		if (RELATION_GTT_ON_COMMIT_DELETE(rel))
+		{
+			entry->on_commit_delete = true;
+			register_on_commit_action(rel->rd_node.relNode, ONCOMMIT_DELETE_ROWS);
+		}
+
+		entry->relfrozenxid = RecentXmin;
+		entry->relminmxid = GetOldestMultiXactId();
+		insert_gtt_relfrozenxid_to_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+		gtt_storage_checkin(rnode);
+	}
+	else
+	{
+		entry->natts = 0;
+		entry->attnum = 0;
+		entry->att_stat_tups = NULL;
+		entry->on_commit_delete = false;
+		entry->relfrozenxid = 0;
+		entry->relminmxid = 0;
+	}
+
+	MemoryContextSwitchTo(oldcontext);
+
+	if (!gtt_cleaner_exit_registered)
+	{
+		before_shmem_exit(gtt_storage_removeall, 0);
+		gtt_cleaner_exit_registered = true;
+	}
+
+	return;
+}
+
+void
+forget_gtt_storage_info(Oid relid)
+{
+	gtt_local_hash_entry		*entry;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+				(void *) &(relid), HASH_FIND, NULL);
+
+	if (entry && entry->relkind == RELKIND_RELATION)
+	{
+		RelFileNode rnode;
+		int			i;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		gtt_storage_checkout(rnode, false);
+
+		Assert(TransactionIdIsNormal(entry->relfrozenxid));
+		remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+		set_gtt_session_relfrozenxid();
+
+		for (i = 0; i < entry->natts; i++)
+		{
+			if (entry->att_stat_tups[i])
+			{
+				heap_freetuple(entry->att_stat_tups[i]);
+				entry->att_stat_tups[i] = NULL;
+			}
+		}
+	}
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_REMOVE, NULL);
+
+	return;
+}
+
+/* is the storage file was created in this backend */
+bool
+gtt_storage_attached(Oid relid)
+{
+	bool found;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	if (gtt_storage_local_hash == NULL)
+		return false;
+
+	hash_search(gtt_storage_local_hash,
+			(void *) &(relid), HASH_FIND, &found);
+
+	return found;
+}
+
+static void
+gtt_storage_removeall(int code, Datum arg)
+{
+	HASH_SEQ_STATUS				status;
+	gtt_local_hash_entry		*entry;
+	int			nrels = 0,
+				maxrels = 0;
+	SMgrRelation	*srels = NULL;
+	RelFileNode		*rnodes = NULL;
+	char			*relkinds = NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	hash_seq_init(&status, gtt_storage_local_hash);
+	while ((entry = (gtt_local_hash_entry *) hash_seq_search(&status)) != NULL)
+	{
+		SMgrRelation srel;
+		RelFileNode rnode;
+
+		rnode.spcNode = entry->spcnode;
+		rnode.dbNode = MyDatabaseId;
+		rnode.relNode = entry->relid;
+
+		srel = smgropen(rnode, MyBackendId);
+
+		/* allocate the initial array, or extend it, if needed */
+		if (maxrels == 0)
+		{
+			maxrels = 32;
+			srels = palloc(sizeof(SMgrRelation) * maxrels);
+			rnodes = palloc(sizeof(RelFileNode) * maxrels);
+			relkinds = palloc(sizeof(char) * maxrels);
+		}
+		else if (maxrels <= nrels)
+		{
+			maxrels *= 2;
+			srels = repalloc(srels, sizeof(SMgrRelation) * maxrels);
+			rnodes = repalloc(rnodes, sizeof(RelFileNode) * maxrels);
+			relkinds = repalloc(relkinds, sizeof(char) * maxrels);
+		}
+
+		srels[nrels] = srel;
+		rnodes[nrels] = rnode;
+		relkinds[nrels] = entry->relkind;
+		nrels++;
+	}
+
+	if (nrels > 0)
+	{
+		int i;
+
+		smgrdounlinkall(srels, nrels, false);
+
+		LWLockAcquire(&gtt_shared_ctl->lock, LW_EXCLUSIVE);
+		for (i = 0; i < nrels; i++)
+		{
+			smgrclose(srels[i]);
+			if (relkinds[i] == RELKIND_RELATION)
+				gtt_storage_checkout(rnodes[i], true);
+		}
+		LWLockRelease(&gtt_shared_ctl->lock);
+
+		pfree(srels);
+		pfree(rnodes);
+		pfree(relkinds);
+	}
+
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;
+
+	return;
+}
+
+/*
+ * Update global temp table relstats(relpage/reltuple/relallvisible) 
+ * to local hashtable
+ */
+void
+up_gtt_relstats(Relation relation,
+					BlockNumber num_pages,
+					double num_tuples,
+					BlockNumber num_all_visible_pages,
+					TransactionId relfrozenxid,
+					TransactionId relminmxid)
+{
+	Oid		relid = RelationGetRelid(relation);
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	Assert(entry->spcnode);
+
+	if (num_pages >= 0 &&
+		entry->relpages != (int32)num_pages)
+		entry->relpages = (int32)num_pages;
+
+	if (num_tuples >= 0 &&
+		num_tuples != (float4)entry->reltuples)
+		entry->reltuples = (float4)num_tuples;
+
+	/* only heap contain transaction information and relallvisible */
+	if (entry->relkind == RELKIND_RELATION)
+	{
+		if (entry->relallvisible >= 0 &&
+			entry->relallvisible != (int32)num_all_visible_pages)
+		{
+			entry->relallvisible = (int32)num_all_visible_pages;
+		}
+
+		if (TransactionIdIsNormal(relfrozenxid) &&
+			entry->relfrozenxid != relfrozenxid &&
+			(TransactionIdPrecedes(entry->relfrozenxid, relfrozenxid) ||
+			 TransactionIdPrecedes(ReadNewTransactionId(), entry->relfrozenxid)))
+		{
+			remove_gtt_relfrozenxid_from_ordered_list(entry->relfrozenxid);
+			entry->relfrozenxid = relfrozenxid;
+			insert_gtt_relfrozenxid_to_ordered_list(relfrozenxid);
+			set_gtt_session_relfrozenxid();
+		}
+
+		if (MultiXactIdIsValid(relminmxid) &&
+			entry->relminmxid != relminmxid &&
+			(MultiXactIdPrecedes(entry->relminmxid, relminmxid) ||
+			 MultiXactIdPrecedes(ReadNextMultiXactId(), entry->relminmxid)))
+		{
+			entry->relminmxid = relminmxid;
+		}
+	}
+
+	return;
+}
+
+/*
+ * Search global temp table relstats(relpage/reltuple/relallvisible) 
+ * from local hashtable.
+ */
+bool
+get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+				BlockNumber *relallvisible, TransactionId *relfrozenxid,
+				TransactionId *relminmxid)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+
+	if (max_active_gtt <= 0)
+		return false;
+
+	if (gtt_storage_local_hash == NULL)
+		return false;
+
+	entry = hash_search(gtt_storage_local_hash,
+					(void *) &relid, HASH_FIND, &found);
+
+	if (!found)
+		return false;
+
+	Assert(entry->relid == relid);
+
+	if (relpages)
+		*relpages = entry->relpages;
+
+	if (reltuples)
+		*reltuples = entry->reltuples;
+
+	if (relallvisible)
+		*relallvisible = entry->relallvisible;
+
+	if (relfrozenxid)
+		*relfrozenxid = entry->relfrozenxid;
+
+	if (relminmxid)
+		*relminmxid = entry->relminmxid;
+
+	return true;
+}
+
+/*
+ * Update global temp table statistic info(definition is same as pg_statistic)
+ * to local hashtable where ananyze global temp table
+ */
+void
+up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+					TupleDesc tupleDescriptor, Datum *values, bool *isnull)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	MemoryContext			oldcontext;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return;
+
+	if (gtt_storage_local_hash == NULL)
+		return;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return;
+
+	if (entry->relkind != RELKIND_RELATION)
+	{
+		elog(WARNING, "oid %u not a relation", reloid);
+		return;
+	}
+
+	/* todo */
+	if (entry->natts < natts)
+	{
+		elog(WARNING, "reloid %u not support update attstat after add colunm", reloid);
+		return;
+	}
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	Assert(entry->relid == reloid);
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == 0)
+		{
+			entry->attnum[i] = attnum;
+			break;
+		}
+		else if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			heap_freetuple(entry->att_stat_tups[i]);
+			entry->att_stat_tups[i] = NULL;
+			break;
+		}
+	}
+
+	Assert(i < entry->natts);
+	Assert(entry->att_stat_tups[i] == NULL);
+	entry->att_stat_tups[i] = heap_form_tuple(tupleDescriptor, values, isnull);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+/*
+ * Search global temp table statistic info(definition is same as pg_statistic)
+ * from local hashtable.
+ */
+HeapTuple
+get_gtt_att_statistic(Oid reloid, int attnum, bool inh)
+{
+	gtt_local_hash_entry	*entry;
+	bool					found;
+	int						i = 0;
+
+	if (max_active_gtt <= 0)
+		return NULL;
+
+	if (gtt_storage_local_hash == NULL)
+		return NULL;
+
+	entry = hash_search(gtt_storage_local_hash,
+						(void *) &reloid, HASH_FIND, &found);
+
+	if (!found)
+		return NULL;
+
+	for (i = 0; i < entry->natts; i++)
+	{
+		if (entry->attnum[i] == attnum)
+		{
+			Assert(entry->att_stat_tups[i]);
+			return entry->att_stat_tups[i];
+		}
+	}
+
+	return NULL;
+}
+
+void
+release_gtt_statistic_cache(HeapTuple tup)
+{
+	/* do nothing */
+	return;
+}
+
+static void
+insert_gtt_relfrozenxid_to_ordered_list(Oid relfrozenxid)
+{
+	MemoryContext	oldcontext;
+	ListCell	*cell;
+	int			i;
+
+	Assert(TransactionIdIsNormal(relfrozenxid));
+
+	oldcontext = MemoryContextSwitchTo(gtt_relstats_context);
+	/* Does the datum belong at the front? */
+	if (gtt_session_relfrozenxid_list == NIL ||
+		TransactionIdFollowsOrEquals(relfrozenxid,
+			linitial_oid(gtt_session_relfrozenxid_list)))
+	{
+		gtt_session_relfrozenxid_list =
+			lcons_oid(relfrozenxid, gtt_session_relfrozenxid_list);
+		MemoryContextSwitchTo(oldcontext);
+
+		return;
+	}
+
+	/* No, so find the entry it belongs after */
+	i = 0;
+	foreach (cell, gtt_session_relfrozenxid_list)
+	{
+		if (TransactionIdFollowsOrEquals(relfrozenxid, lfirst_oid(cell)))
+			break;
+
+		i++;
+	}
+	gtt_session_relfrozenxid_list =
+		list_insert_nth_oid(gtt_session_relfrozenxid_list, i, relfrozenxid);
+	MemoryContextSwitchTo(oldcontext);
+
+	return;
+}
+
+static void
+remove_gtt_relfrozenxid_from_ordered_list(Oid relfrozenxid)
+{
+	gtt_session_relfrozenxid_list =
+		list_delete_oid(gtt_session_relfrozenxid_list, relfrozenxid);
+}
+
+static void
+set_gtt_session_relfrozenxid(void)
+{
+	TransactionId gtt_frozenxid = InvalidTransactionId;
+
+	if (gtt_session_relfrozenxid_list)
+		gtt_frozenxid = llast_oid(gtt_session_relfrozenxid_list);
+
+	gtt_session_frozenxid = gtt_frozenxid;
+	if (MyProc->session_gtt_frozenxid != gtt_frozenxid)
+		MyProc->session_gtt_frozenxid = gtt_frozenxid;
+}
+
+Datum
+pg_get_gtt_statistics(PG_FUNCTION_ARGS)
+{
+	HeapTuple	tuple;
+	Relation	rel = NULL;
+	int		attnum = PG_GETARG_INT32(1);
+	Oid		reloid = PG_GETARG_OID(0);
+	char		rel_persistence;
+	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	  tupdesc;
+	MemoryContext oldcontext;
+	Tuplestorestate *tupstore;
+	Relation		pg_tatistic = NULL;
+	TupleDesc		sd;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("set-valued function called in context that cannot accept a set")));
+
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			errmsg("materialize mode required, but it is not " \
+				"allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+				rsinfo->econtext->ecxt_per_query_memory);
+
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	pg_tatistic = table_open(StatisticRelationId, AccessShareLock);
+	sd = RelationGetDescr(pg_tatistic);
+
+	tuple = get_gtt_att_statistic(reloid, attnum, false);
+	if (tuple)
+	{
+		Datum	values[31];
+		bool	isnull[31];
+		HeapTuple	res = NULL;
+
+		memset(&values, 0, sizeof(values));
+		memset(&isnull, 0, sizeof(isnull));
+		heap_deform_tuple(tuple, sd, values, isnull);
+		res = heap_form_tuple(tupdesc, values, isnull);
+		tuplestore_puttuple(tupstore, res);
+	}
+
+	table_close(rel, NoLock);
+	table_close(pg_tatistic, AccessShareLock);
+	tuplestore_donestoring(tupstore);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_get_gtt_relstats(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc		tupdesc;
+	Tuplestorestate	*tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	Oid		reloid = PG_GETARG_OID(0);
+	char	rel_persistence;
+	BlockNumber	relpages = 0;
+	double		reltuples = 0;
+	BlockNumber	relallvisible = 0;
+	uint32		relfrozenxid = 0;
+	uint32		relminmxid = 0;
+	Relation	rel = NULL;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	if (get_gtt_relstats(reloid,
+						&relpages, &reltuples, &relallvisible,
+						&relfrozenxid, &relminmxid))
+	{
+		Datum	values[5];
+		bool	isnull[5];
+
+		memset(isnull, 0, sizeof(isnull));
+		memset(values, 0, sizeof(values));
+		values[0] = Int32GetDatum(relpages);
+		values[1] = Float4GetDatum((float4)reltuples);
+		values[2] = Int32GetDatum(relallvisible);
+		values[3] = UInt32GetDatum(relfrozenxid);
+		values[4] = UInt32GetDatum(relminmxid);
+		tuple = heap_form_tuple(tupdesc, values, isnull);
+		tuplestore_puttuple(tupstore, tuple);
+	}
+
+	tuplestore_donestoring(tupstore);
+	table_close(rel, NoLock);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_gtt_attached_pid(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	Oid		reloid = PG_GETARG_OID(0);
+	char	rel_persistence;
+	Relation	rel = NULL;
+	PGPROC		*proc = NULL;
+	Bitmapset	*map = NULL;
+	pid_t		pid = 0;
+	int			backendid = 0;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	rel = table_open(reloid, AccessShareLock);
+	rel_persistence = get_rel_persistence(reloid);
+	if (rel_persistence != RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		elog(WARNING, "relation OID %u is not a global temporary table", reloid);
+		table_close(rel, NoLock);
+		return (Datum) 0;
+	}
+
+	map = copy_active_gtt_bitmap(rel->rd_node);
+	if (map)
+	{
+		backendid = bms_first_member(map);
+
+		do
+		{
+			proc = BackendIdGetProc(backendid);
+			pid = proc->pid;
+			if (pid > 0)
+			{
+				Datum	values[2];
+				bool	isnull[2];
+
+				memset(isnull, false, sizeof(isnull));
+				memset(values, 0, sizeof(values));
+				values[0] = UInt32GetDatum(reloid);
+				values[1] = Int32GetDatum(pid);
+				tuple = heap_form_tuple(tupdesc, values, isnull);
+				tuplestore_puttuple(tupstore, tuple);
+			}
+			backendid = bms_next_member(map, backendid);
+		} while (backendid > 0);
+
+		pfree(map);
+	}
+
+	tuplestore_donestoring(tupstore);
+	table_close(rel, NoLock);
+
+	return (Datum) 0;
+}
+
+Datum
+pg_list_gtt_relfrozenxids(PG_FUNCTION_ARGS)
+{
+	ReturnSetInfo	*rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	TupleDesc	tupdesc;
+	Tuplestorestate *tupstore;
+	MemoryContext	oldcontext;
+	HeapTuple	tuple;
+	int			num_xid = MaxBackends + 1;
+	int			*pids = NULL;
+	uint32		*xids = NULL;
+	int			i = 0;
+	int			j = 0;
+	uint32		oldest = 0;
+
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsinfo->allowedModes & SFRM_Materialize))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("materialize mode required, but it is not allowed in this context")));
+
+	oldcontext = MemoryContextSwitchTo(
+			rsinfo->econtext->ecxt_per_query_memory);
+	tupstore = tuplestore_begin_heap(true, false, work_mem);
+	rsinfo->returnMode = SFRM_Materialize;
+	rsinfo->setResult = tupstore;
+	rsinfo->setDesc = tupdesc;
+	MemoryContextSwitchTo(oldcontext);
+
+	if (max_active_gtt <= 0)
+		return (Datum) 0;
+
+	if (RecoveryInProgress())
+		return (Datum) 0;
+
+	pids = palloc0(sizeof(int) * num_xid);
+	xids = palloc0(sizeof(int) * num_xid);
+	oldest = list_all_session_gtt_frozenxids(num_xid, pids, xids, &i);
+	if (i > 0)
+	{
+		if (i > 0)
+		{
+			pids[i] = 0;
+			xids[i] = oldest;
+			i++;
+		}
+
+		for(j = 0; j < i; j++)
+		{
+			Datum	values[2];
+			bool	isnull[2];
+
+			memset(isnull, false, sizeof(isnull));
+			memset(values, 0, sizeof(values));
+			values[0] = Int32GetDatum(pids[j]);
+			values[1] = UInt32GetDatum(xids[j]);
+			tuple = heap_form_tuple(tupdesc, values, isnull);
+			tuplestore_puttuple(tupstore, tuple);
+		}
+	}
+	tuplestore_donestoring(tupstore);
+	pfree(pids);
+	pfree(xids);
+
+	return (Datum) 0;
+}
+
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index c9e75f4..2adde62 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -186,6 +186,91 @@ CREATE OR REPLACE VIEW pg_sequences AS
     WHERE NOT pg_is_other_temp_schema(N.oid)
           AND relkind = 'S';
 
+-- For global temporary table
+CREATE VIEW pg_gtt_relstats WITH (security_barrier) AS
+ SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.*
+ FROM
+     pg_class c
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_get_gtt_relstats(c.oid) as s
+ WHERE c.relpersistence='g' AND c.relkind in('r','p') AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
+CREATE VIEW pg_gtt_attached_pids WITH (security_barrier) AS
+ SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.*
+ FROM
+     pg_class c
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_gtt_attached_pid(c.oid) as s
+ WHERE c.relpersistence='g' AND c.relkind in('r','p') AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
+CREATE VIEW pg_gtt_stats WITH (security_barrier) AS
+SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    a.attname,
+    s.stainherit AS inherited,
+    s.stanullfrac AS null_frac,
+    s.stawidth AS avg_width,
+    s.stadistinct AS n_distinct,
+        CASE
+            WHEN s.stakind1 = 1 THEN s.stavalues1
+            WHEN s.stakind2 = 1 THEN s.stavalues2
+            WHEN s.stakind3 = 1 THEN s.stavalues3
+            WHEN s.stakind4 = 1 THEN s.stavalues4
+            WHEN s.stakind5 = 1 THEN s.stavalues5
+        END AS most_common_vals,
+        CASE
+            WHEN s.stakind1 = 1 THEN s.stanumbers1
+            WHEN s.stakind2 = 1 THEN s.stanumbers2
+            WHEN s.stakind3 = 1 THEN s.stanumbers3
+            WHEN s.stakind4 = 1 THEN s.stanumbers4
+            WHEN s.stakind5 = 1 THEN s.stanumbers5
+        END AS most_common_freqs,
+        CASE
+            WHEN s.stakind1 = 2 THEN s.stavalues1
+            WHEN s.stakind2 = 2 THEN s.stavalues2
+            WHEN s.stakind3 = 2 THEN s.stavalues3
+            WHEN s.stakind4 = 2 THEN s.stavalues4
+            WHEN s.stakind5 = 2 THEN s.stavalues5
+        END AS histogram_bounds,
+        CASE
+            WHEN s.stakind1 = 3 THEN s.stanumbers1[1]
+            WHEN s.stakind2 = 3 THEN s.stanumbers2[1]
+            WHEN s.stakind3 = 3 THEN s.stanumbers3[1]
+            WHEN s.stakind4 = 3 THEN s.stanumbers4[1]
+            WHEN s.stakind5 = 3 THEN s.stanumbers5[1]
+        END AS correlation,
+        CASE
+            WHEN s.stakind1 = 4 THEN s.stavalues1
+            WHEN s.stakind2 = 4 THEN s.stavalues2
+            WHEN s.stakind3 = 4 THEN s.stavalues3
+            WHEN s.stakind4 = 4 THEN s.stavalues4
+            WHEN s.stakind5 = 4 THEN s.stavalues5
+        END AS most_common_elems,
+        CASE
+            WHEN s.stakind1 = 4 THEN s.stanumbers1
+            WHEN s.stakind2 = 4 THEN s.stanumbers2
+            WHEN s.stakind3 = 4 THEN s.stanumbers3
+            WHEN s.stakind4 = 4 THEN s.stanumbers4
+            WHEN s.stakind5 = 4 THEN s.stanumbers5
+        END AS most_common_elem_freqs,
+        CASE
+            WHEN s.stakind1 = 5 THEN s.stanumbers1
+            WHEN s.stakind2 = 5 THEN s.stanumbers2
+            WHEN s.stakind3 = 5 THEN s.stanumbers3
+            WHEN s.stakind4 = 5 THEN s.stanumbers4
+            WHEN s.stakind5 = 5 THEN s.stanumbers5
+        END AS elem_count_histogram
+   FROM 
+     pg_class c
+     JOIN pg_attribute a ON c.oid = a.attrelid
+     LEFT JOIN pg_namespace n ON n.oid = c.relnamespace,
+     pg_get_gtt_statistics(c.oid, a.attnum, ''::text) as s
+  WHERE c.relpersistence='g' AND c.relkind in('r','p') and NOT a.attisdropped AND has_column_privilege(c.oid, a.attnum, 'select'::text) AND (c.relrowsecurity = false OR NOT row_security_active(c.oid));
+
 CREATE VIEW pg_stats WITH (security_barrier) AS
     SELECT
         nspname AS schemaname,
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index c4420dd..977a984 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -34,6 +34,7 @@
 #include "catalog/pg_inherits.h"
 #include "catalog/pg_namespace.h"
 #include "catalog/pg_statistic_ext.h"
+#include "catalog/storage_gtt.h"
 #include "commands/dbcommands.h"
 #include "commands/progress.h"
 #include "commands/tablecmds.h"
@@ -103,7 +104,7 @@ static int	acquire_inherited_sample_rows(Relation onerel, int elevel,
 										  HeapTuple *rows, int targrows,
 										  double *totalrows, double *totaldeadrows);
 static void update_attstats(Oid relid, bool inh,
-							int natts, VacAttrStats **vacattrstats);
+							int natts, VacAttrStats **vacattrstats, char relpersistence);
 static Datum std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 static Datum ind_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
 
@@ -586,14 +587,15 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 		 * pg_statistic for columns we didn't process, we leave them alone.)
 		 */
 		update_attstats(RelationGetRelid(onerel), inh,
-						attr_cnt, vacattrstats);
+						attr_cnt, vacattrstats, RelationGetRelPersistence(onerel));
 
 		for (ind = 0; ind < nindexes; ind++)
 		{
 			AnlIndexData *thisdata = &indexdata[ind];
 
 			update_attstats(RelationGetRelid(Irel[ind]), false,
-							thisdata->attr_cnt, thisdata->vacattrstats);
+							thisdata->attr_cnt, thisdata->vacattrstats,
+							RelationGetRelPersistence(Irel[ind]));
 		}
 
 		/*
@@ -1456,7 +1458,7 @@ acquire_inherited_sample_rows(Relation onerel, int elevel,
  *		by taking a self-exclusive lock on the relation in analyze_rel().
  */
 static void
-update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
+update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats, char relpersistence)
 {
 	Relation	sd;
 	int			attno;
@@ -1558,31 +1560,45 @@ update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
 			}
 		}
 
-		/* Is there already a pg_statistic tuple for this attribute? */
-		oldtup = SearchSysCache3(STATRELATTINH,
-								 ObjectIdGetDatum(relid),
-								 Int16GetDatum(stats->attr->attnum),
-								 BoolGetDatum(inh));
-
-		if (HeapTupleIsValid(oldtup))
+		/* Update column statistic to localhash, not catalog */
+		if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		{
-			/* Yes, replace it */
-			stup = heap_modify_tuple(oldtup,
-									 RelationGetDescr(sd),
-									 values,
-									 nulls,
-									 replaces);
-			ReleaseSysCache(oldtup);
-			CatalogTupleUpdate(sd, &stup->t_self, stup);
+			up_gtt_att_statistic(relid,
+								stats->attr->attnum,
+								inh,
+								natts,
+								RelationGetDescr(sd),
+								values,
+								nulls);
 		}
 		else
 		{
-			/* No, insert new tuple */
-			stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
-			CatalogTupleInsert(sd, stup);
-		}
+			/* Is there already a pg_statistic tuple for this attribute? */
+			oldtup = SearchSysCache3(STATRELATTINH,
+									 ObjectIdGetDatum(relid),
+									 Int16GetDatum(stats->attr->attnum),
+									 BoolGetDatum(inh));
 
-		heap_freetuple(stup);
+			if (HeapTupleIsValid(oldtup))
+			{
+				/* Yes, replace it */
+				stup = heap_modify_tuple(oldtup,
+										 RelationGetDescr(sd),
+										 values,
+										 nulls,
+										 replaces);
+				ReleaseSysCache(oldtup);
+				CatalogTupleUpdate(sd, &stup->t_self, stup);
+			}
+			else
+			{
+				/* No, insert new tuple */
+				stup = heap_form_tuple(RelationGetDescr(sd), values, nulls);
+				CatalogTupleInsert(sd, stup);
+			}
+
+			heap_freetuple(stup);
+		}
 	}
 
 	table_close(sd, RowExclusiveLock);
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index e9d7a7f..3088e26 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -391,6 +391,12 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 					 errmsg("cannot vacuum temporary tables of other sessions")));
 	}
 
+	/* not support cluster global temp table yet */
+	if (RELATION_IS_GLOBAL_TEMP(OldHeap))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not support cluster global temporary tables yet")));
+
 	/*
 	 * Also check for active uses of the relation in the current transaction,
 	 * including open scans and pending AFTER trigger events.
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 52ce02f..3d3f7dc 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -2583,6 +2583,16 @@ ReindexMultipleTables(const char *objectName, ReindexObjectType objectKind,
 			!isTempNamespace(classtuple->relnamespace))
 			continue;
 
+		/* not support reindex on global temp table, so skip it */
+		if (classtuple->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			ereport(WARNING,
+				(errmsg("global temp table \"%s.%s\" skip reindexed",
+					get_namespace_name(get_rel_namespace(relid)),
+					get_rel_name(relid))));
+			continue;
+		}
+
 		/* Check user/system classification, and optionally skip */
 		if (objectKind == REINDEX_OBJECT_SYSTEM &&
 			!IsSystemClass(relid, classtuple))
diff --git a/src/backend/commands/lockcmds.c b/src/backend/commands/lockcmds.c
index 329ab84..dfa257c 100644
--- a/src/backend/commands/lockcmds.c
+++ b/src/backend/commands/lockcmds.c
@@ -96,7 +96,8 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
 	 * transaction.
 	 */
 	relpersistence = get_rel_persistence(relid);
-	if (relpersistence == RELPERSISTENCE_TEMP)
+	if (relpersistence == RELPERSISTENCE_TEMP ||
+		relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		MyXactFlags |= XACT_FLAGS_ACCESSEDTEMPNAMESPACE;
 
 	/* Check permissions. */
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index 6aab73b..44f350d 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -94,7 +94,7 @@ static HTAB *seqhashtab = NULL; /* hash table for SeqTable items */
  */
 static SeqTableData *last_used_seq = NULL;
 
-static void fill_seq_with_data(Relation rel, HeapTuple tuple);
+static void fill_seq_with_data(Relation rel, HeapTuple tuple, Buffer buf);
 static Relation lock_and_open_sequence(SeqTable seq);
 static void create_seq_hashtable(void);
 static void init_sequence(Oid relid, SeqTable *p_elm, Relation *p_rel);
@@ -108,6 +108,7 @@ static void init_params(ParseState *pstate, List *options, bool for_identity,
 						List **owned_by);
 static void do_setval(Oid relid, int64 next, bool iscalled);
 static void process_owned_by(Relation seqrel, List *owned_by, bool for_identity);
+int64 get_seqence_start_value(Oid seqid);
 
 
 /*
@@ -222,7 +223,7 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 
 	/* now initialize the sequence's data */
 	tuple = heap_form_tuple(tupDesc, value, null);
-	fill_seq_with_data(rel, tuple);
+	fill_seq_with_data(rel, tuple, InvalidBuffer);
 
 	/* process OWNED BY if given */
 	if (owned_by)
@@ -327,7 +328,7 @@ ResetSequence(Oid seq_relid)
 	/*
 	 * Insert the modified tuple into the new storage file.
 	 */
-	fill_seq_with_data(seq_rel, tuple);
+	fill_seq_with_data(seq_rel, tuple, InvalidBuffer);
 
 	/* Clear local cache so that we don't think we have cached numbers */
 	/* Note that we do not change the currval() state */
@@ -340,17 +341,21 @@ ResetSequence(Oid seq_relid)
  * Initialize a sequence's relation with the specified tuple as content
  */
 static void
-fill_seq_with_data(Relation rel, HeapTuple tuple)
+fill_seq_with_data(Relation rel, HeapTuple tuple, Buffer buf)
 {
-	Buffer		buf;
 	Page		page;
 	sequence_magic *sm;
 	OffsetNumber offnum;
+	bool lockBuffer = false;
 
 	/* Initialize first page of relation with special magic number */
 
-	buf = ReadBuffer(rel, P_NEW);
-	Assert(BufferGetBlockNumber(buf) == 0);
+	if (buf == InvalidBuffer)
+	{
+		buf = ReadBuffer(rel, P_NEW);
+		Assert(BufferGetBlockNumber(buf) == 0);
+		lockBuffer = true;
+	}
 
 	page = BufferGetPage(buf);
 
@@ -360,7 +365,8 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	/* Now insert sequence tuple */
 
-	LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
+	if (lockBuffer)
+		LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 
 	/*
 	 * Since VACUUM does not process sequences, we have to force the tuple to
@@ -410,7 +416,8 @@ fill_seq_with_data(Relation rel, HeapTuple tuple)
 
 	END_CRIT_SECTION();
 
-	UnlockReleaseBuffer(buf);
+	if (lockBuffer)
+		UnlockReleaseBuffer(buf);
 }
 
 /*
@@ -502,7 +509,7 @@ AlterSequence(ParseState *pstate, AlterSeqStmt *stmt)
 		/*
 		 * Insert the modified tuple into the new storage file.
 		 */
-		fill_seq_with_data(seqrel, newdatatuple);
+		fill_seq_with_data(seqrel, newdatatuple, InvalidBuffer);
 	}
 
 	/* process OWNED BY if given */
@@ -1178,6 +1185,25 @@ read_seq_tuple(Relation rel, Buffer *buf, HeapTuple seqdatatuple)
 	LockBuffer(*buf, BUFFER_LOCK_EXCLUSIVE);
 
 	page = BufferGetPage(*buf);
+	if (GlobalTempRelationPageIsNotInitialized(rel, page))
+	{
+		/* Initialize sequence for global temporary tables */
+		Datum		value[SEQ_COL_LASTCOL] = {0};
+		bool		null[SEQ_COL_LASTCOL] = {false};
+		HeapTuple	tuple;
+		int64		startv = get_seqence_start_value(RelationGetRelid(rel));
+
+		/*
+		 * last_value from pg_sequence.seqstart
+		 * log_cnt = 0
+		 * is_called = false
+		 */
+		value[SEQ_COL_LASTVAL-1] = Int64GetDatumFast(startv); /* start sequence with 1 */
+
+		tuple = heap_form_tuple(RelationGetDescr(rel), value, null);
+		fill_seq_with_data(rel, tuple, *buf);
+		heap_freetuple(tuple);
+	}
 	sm = (sequence_magic *) PageGetSpecialPointer(page);
 
 	if (sm->magic != SEQ_MAGIC)
@@ -1954,3 +1980,23 @@ seq_mask(char *page, BlockNumber blkno)
 
 	mask_unused_space(page);
 }
+
+int64
+get_seqence_start_value(Oid seqid)
+{
+	HeapTuple	seqtuple;
+	Form_pg_sequence	seqform;
+	int64		start;
+
+	seqtuple = SearchSysCache1(SEQRELID, ObjectIdGetDatum(seqid));
+	if (!HeapTupleIsValid(seqtuple))
+		elog(ERROR, "cache lookup failed for sequence %u",
+			 seqid);
+
+	seqform = (Form_pg_sequence) GETSTRUCT(seqtuple);
+	start = seqform->seqstart;
+	ReleaseSysCache(seqtuple);
+
+	return start;
+}
+
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 30b72b6..cc5b991 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -47,6 +47,7 @@
 #include "catalog/storage.h"
 #include "catalog/storage_xlog.h"
 #include "catalog/toasting.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/defrem.h"
@@ -552,6 +553,7 @@ static void refuseDupeIndexAttach(Relation parentIdx, Relation partIdx,
 								  Relation partitionTbl);
 static List *GetParentedForeignKeyRefs(Relation partition);
 static void ATDetachCheckNoForeignKeyRefs(Relation partition);
+static bool has_oncommit_option(List *options);
 
 
 /* ----------------------------------------------------------------
@@ -597,6 +599,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	LOCKMODE	parentLockmode;
 	const char *accessMethod = NULL;
 	Oid			accessMethodId = InvalidOid;
+	bool		has_oncommit_clause = false;
 
 	/*
 	 * Truncate relname to appropriate length (probably a waste of time, as
@@ -607,8 +610,10 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Check consistency of arguments
 	 */
+	/* global temp table same as local temp table */
 	if (stmt->oncommit != ONCOMMIT_NOOP
-		&& stmt->relation->relpersistence != RELPERSISTENCE_TEMP)
+		&& !(stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+			 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP))
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 				 errmsg("ON COMMIT can only be used on temporary tables")));
@@ -638,7 +643,9 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	 * code.  This is needed because calling code might not expect untrusted
 	 * tables to appear in pg_temp at the front of its search path.
 	 */
-	if (stmt->relation->relpersistence == RELPERSISTENCE_TEMP
+	/* global temp table same as local temp table */
+	if ((stmt->relation->relpersistence == RELPERSISTENCE_TEMP ||
+		 stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 		&& InSecurityRestrictedOperation())
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -739,6 +746,57 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	/*
 	 * Parse and validate reloptions, if any.
 	 */
+	/* global temp table */
+	has_oncommit_clause = has_oncommit_option(stmt->options);
+	if (stmt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP &&
+		(relkind == RELKIND_RELATION || relkind == RELKIND_PARTITIONED_TABLE))
+	{
+		/* inherit table or parition table inherit on commit property from parent table*/
+		if (inheritOids && stmt->oncommit == ONCOMMIT_NOOP && !has_oncommit_clause)
+		{
+			Oid			parent = linitial_oid(inheritOids);
+			Relation	relation = table_open(parent, NoLock);
+
+			if (!RELATION_IS_GLOBAL_TEMP(relation))
+				elog(ERROR, "The parent table must be global temporary table");
+
+			if (RELATION_GTT_ON_COMMIT_DELETE(relation))
+				stmt->oncommit = ONCOMMIT_DELETE_ROWS;
+			else
+				stmt->oncommit = ONCOMMIT_PRESERVE_ROWS;
+			table_close(relation, NoLock);
+		}
+
+		if (has_oncommit_clause)
+		{
+			if (stmt->oncommit != ONCOMMIT_NOOP)
+				elog(ERROR, "can not defeine global temp table with on commit and with clause at same time");
+		}
+		else
+		{
+			DefElem *opt = makeNode(DefElem);
+
+			opt->type = T_DefElem;
+			opt->defnamespace = NULL;
+			opt->defname = "on_commit_delete_rows";
+			opt->defaction = DEFELEM_UNSPEC;
+
+			/* use reloptions to remember on commit clause */
+			if (stmt->oncommit == ONCOMMIT_DELETE_ROWS)
+				opt->arg  = (Node *)makeString("true");
+			else if (stmt->oncommit == ONCOMMIT_PRESERVE_ROWS)
+				opt->arg  = (Node *)makeString("false");
+			else if (stmt->oncommit == ONCOMMIT_NOOP)
+				opt->arg  = (Node *)makeString("false");
+			else
+				elog(ERROR, "global temp table not support on commit drop clause");
+
+			stmt->options = lappend(stmt->options, opt);
+		}
+	}
+	else if (has_oncommit_clause)
+		elog(ERROR, "regular table cannot specifie on_commit_delete_rows");
+
 	reloptions = transformRelOptions((Datum) 0, stmt->options, NULL, validnsps,
 									 true, false);
 
@@ -1800,7 +1858,8 @@ ExecuteTruncateGuts(List *explicit_rels, List *relids, List *relids_logged,
 		 * table or the current physical file to be thrown away anyway.
 		 */
 		if (rel->rd_createSubid == mySubid ||
-			rel->rd_newRelfilenodeSubid == mySubid)
+			rel->rd_newRelfilenodeSubid == mySubid ||
+			RELATION_IS_GLOBAL_TEMP(rel))
 		{
 			/* Immediate, non-rollbackable truncation is OK */
 			heap_truncate_one_rel(rel);
@@ -3359,6 +3418,13 @@ RenameRelationInternal(Oid myrelid, const char *newrelname, bool is_internal, bo
 	 * specially.
 	 */
 	targetrelation = relation_open(myrelid, is_index ? ShareUpdateExclusiveLock : AccessExclusiveLock);
+
+	if (RELATION_IS_GLOBAL_TEMP(targetrelation))
+	{
+		if (is_other_backend_use_gtt(targetrelation->rd_node))
+			elog(ERROR, "can not rename relation when other backend attached this global temp table");
+	}
+
 	namespaceId = RelationGetNamespace(targetrelation);
 
 	/*
@@ -3534,6 +3600,13 @@ AlterTable(AlterTableStmt *stmt, LOCKMODE lockmode,
 	/* Caller is required to provide an adequate lock. */
 	rel = relation_open(context->relid, NoLock);
 
+	/* We allow to alter global temp table only this session use it */
+	if (RELATION_IS_GLOBAL_TEMP(rel))
+	{
+		if (is_other_backend_use_gtt(rel->rd_node))
+			elog(ERROR, "can not alter relation when other backend attached this global temp table");
+	}
+
 	CheckTableNotInUse(rel, "ALTER TABLE");
 
 	ATController(stmt, rel, stmt->cmds, stmt->relation->inh, lockmode, context);
@@ -8099,6 +8172,13 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 				 errmsg("referenced relation \"%s\" is not a table",
 						RelationGetRelationName(pkrel))));
 
+	/* global temp table not support foreign key constraint yet */
+	if (RELATION_IS_GLOBAL_TEMP(pkrel))
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("referenced relation \"%s\" is not a global temp table",
+						RelationGetRelationName(pkrel))));
+
 	if (!allowSystemTableMods && IsSystemRelation(pkrel))
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -8138,6 +8218,12 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 						 errmsg("constraints on temporary tables must involve temporary tables of this session")));
 			break;
+		/* global temp table not support foreign key constraint yet */
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+					 errmsg("not support foreign key constraints on global temp table yet")));
+			break;
 	}
 
 	/*
@@ -13174,7 +13260,7 @@ index_copy_data(Relation rel, RelFileNode newrnode)
 	 * NOTE: any conflict in relfilenode value will be caught in
 	 * RelationCreateStorage().
 	 */
-	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence);
+	RelationCreateStorage(newrnode, rel->rd_rel->relpersistence, rel);
 
 	/* copy main fork */
 	RelationCopyStorage(rel->rd_smgr, dstrel, MAIN_FORKNUM,
@@ -14581,7 +14667,9 @@ ATPrepChangePersistence(Relation rel, bool toLogged)
 	 */
 	switch (rel->rd_rel->relpersistence)
 	{
+		/* global temp table same as local temp table */
 		case RELPERSISTENCE_TEMP:
+		case RELPERSISTENCE_GLOBAL_TEMP:
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 					 errmsg("cannot change logged status of table \"%s\" because it is temporary",
@@ -17221,3 +17309,20 @@ ATDetachCheckNoForeignKeyRefs(Relation partition)
 		table_close(rel, NoLock);
 	}
 }
+
+static bool
+has_oncommit_option(List *options)
+{
+	ListCell   *listptr;
+
+	foreach(listptr, options)
+	{
+		DefElem    *def = (DefElem *) lfirst(listptr);
+
+		if (pg_strcasecmp(def->defname, "on_commit_delete_rows") == 0)
+			return true;
+	}
+
+	return false;
+}
+
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index d625d17..69ad24f 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -35,6 +35,7 @@
 #include "catalog/pg_database.h"
 #include "catalog/pg_inherits.h"
 #include "catalog/pg_namespace.h"
+#include "catalog/storage_gtt.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
 #include "commands/vacuum.h"
@@ -1217,6 +1218,17 @@ vac_update_relstats(Relation relation,
 	HeapTuple	ctup;
 	Form_pg_class pgcform;
 	bool		dirty;
+	bool		is_gtt = false;
+
+	 /* global temp table remember relstats to localhash and rel->rd_rel, not catalog */
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+	{
+		is_gtt = true;
+		up_gtt_relstats(relation,
+						num_pages, num_tuples,
+						num_all_visible_pages,
+						frozenxid, minmulti);
+	}
 
 	rd = table_open(RelationRelationId, RowExclusiveLock);
 
@@ -1230,17 +1242,26 @@ vac_update_relstats(Relation relation,
 	/* Apply statistical updates, if any, to copied tuple */
 
 	dirty = false;
-	if (pgcform->relpages != (int32) num_pages)
+
+	if (is_gtt)
+		relation->rd_rel->relpages = (int32) num_pages;
+	else if (pgcform->relpages != (int32) num_pages)
 	{
 		pgcform->relpages = (int32) num_pages;
 		dirty = true;
 	}
-	if (pgcform->reltuples != (float4) num_tuples)
+
+	if (is_gtt)
+		relation->rd_rel->reltuples = (float4) num_tuples;
+	else if (pgcform->reltuples != (float4) num_tuples)
 	{
 		pgcform->reltuples = (float4) num_tuples;
 		dirty = true;
 	}
-	if (pgcform->relallvisible != (int32) num_all_visible_pages)
+
+	if (is_gtt)
+		relation->rd_rel->relallvisible = (int32) num_all_visible_pages;
+	else if (pgcform->relallvisible != (int32) num_all_visible_pages)
 	{
 		pgcform->relallvisible = (int32) num_all_visible_pages;
 		dirty = true;
@@ -1285,7 +1306,8 @@ vac_update_relstats(Relation relation,
 	 * This should match vac_update_datfrozenxid() concerning what we consider
 	 * to be "in the future".
 	 */
-	if (TransactionIdIsNormal(frozenxid) &&
+	if (!is_gtt &&
+		TransactionIdIsNormal(frozenxid) &&
 		pgcform->relfrozenxid != frozenxid &&
 		(TransactionIdPrecedes(pgcform->relfrozenxid, frozenxid) ||
 		 TransactionIdPrecedes(ReadNewTransactionId(),
@@ -1296,7 +1318,8 @@ vac_update_relstats(Relation relation,
 	}
 
 	/* Similarly for relminmxid */
-	if (MultiXactIdIsValid(minmulti) &&
+	if (!is_gtt &&
+		MultiXactIdIsValid(minmulti) &&
 		pgcform->relminmxid != minmulti &&
 		(MultiXactIdPrecedes(pgcform->relminmxid, minmulti) ||
 		 MultiXactIdPrecedes(ReadNextMultiXactId(), pgcform->relminmxid)))
@@ -1394,6 +1417,10 @@ vac_update_datfrozenxid(void)
 			continue;
 		}
 
+		/* global temp table relstats not in pg_class */
+		if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			continue;
+
 		/*
 		 * Some table AMs might not need per-relation xid / multixid horizons.
 		 * It therefore seems reasonable to allow relfrozenxid and relminmxid
@@ -1451,6 +1478,25 @@ vac_update_datfrozenxid(void)
 	Assert(TransactionIdIsNormal(newFrozenXid));
 	Assert(MultiXactIdIsValid(newMinMulti));
 
+	/*
+	 * Global temp table get frozenxid from MyProc
+	 * to avoid the vacuum truncate clog that gtt need.
+	 */
+	if (max_active_gtt > 0)
+	{
+		TransactionId oldest_gtt_frozenxid =
+			list_all_session_gtt_frozenxids(0, NULL, NULL, NULL);
+
+		if (TransactionIdIsNormal(oldest_gtt_frozenxid) &&
+			TransactionIdPrecedes(oldest_gtt_frozenxid, newFrozenXid))
+		{
+			ereport(WARNING,
+				(errmsg("global temp table oldest FrozenXid is far in the past"),
+				 errhint("please truncate them or kill those sessions that use them.")));
+			newFrozenXid = oldest_gtt_frozenxid;
+		}
+	}
+
 	/* Now fetch the pg_database tuple we need to update. */
 	relation = table_open(DatabaseRelationId, RowExclusiveLock);
 
diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 8286d9c..c3992a4 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -591,6 +591,8 @@ static void
 set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 						  RangeTblEntry *rte)
 {
+	char relpersistence;
+
 	/*
 	 * The flag has previously been initialized to false, so we can just
 	 * return if it becomes clear that we can't safely set it.
@@ -618,7 +620,11 @@ set_rel_consider_parallel(PlannerInfo *root, RelOptInfo *rel,
 			 * the rest of the necessary infrastructure right now anyway.  So
 			 * for now, bail out if we see a temporary table.
 			 */
-			if (get_rel_persistence(rte->relid) == RELPERSISTENCE_TEMP)
+			/* global temp table is same as local temp table */
+			relpersistence = get_rel_persistence(rte->relid);
+
+			if (relpersistence == RELPERSISTENCE_TEMP ||
+				relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 				return;
 
 			/*
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index d6f2153..310a9e2 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -6312,7 +6312,9 @@ plan_create_index_workers(Oid tableOid, Oid indexOid)
 	 * Furthermore, any index predicate or index expressions must be parallel
 	 * safe.
 	 */
+	/* global temp table is same as local temp table */
 	if (heap->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
+		heap->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexExpressions(index)) ||
 		!is_parallel_safe(root, (Node *) RelationGetIndexPredicate(index)))
 	{
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 748bebf..a5ddbcd 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -2579,6 +2579,11 @@ transformCreateTableAsStmt(ParseState *pstate, CreateTableAsStmt *stmt)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("materialized views must not use temporary tables or views")));
 
+		if (is_query_using_gtt(query))
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("materialized views must not use global temporary tables or views")));
+
 		/*
 		 * A materialized view would either need to save parameters for use in
 		 * maintaining/loading the data or prohibit them entirely.  The latter
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index ba5916b..0ee6931 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -3290,17 +3290,11 @@ OptTemp:	TEMPORARY					{ $$ = RELPERSISTENCE_TEMP; }
 			| LOCAL TEMP				{ $$ = RELPERSISTENCE_TEMP; }
 			| GLOBAL TEMPORARY
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
-					$$ = RELPERSISTENCE_TEMP;
+					$$ = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED					{ $$ = RELPERSISTENCE_UNLOGGED; }
 			| /*EMPTY*/					{ $$ = RELPERSISTENCE_PERMANENT; }
@@ -11588,19 +11582,13 @@ OptTempTableName:
 				}
 			| GLOBAL TEMPORARY opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| GLOBAL TEMP opt_table qualified_name
 				{
-					ereport(WARNING,
-							(errmsg("GLOBAL is deprecated in temporary table creation"),
-							 parser_errposition(@1)));
 					$$ = $4;
-					$$->relpersistence = RELPERSISTENCE_TEMP;
+					$$->relpersistence = RELPERSISTENCE_GLOBAL_TEMP;
 				}
 			| UNLOGGED opt_table qualified_name
 				{
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index b875a50..123945b 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -81,6 +81,7 @@ static void expandTupleDesc(TupleDesc tupdesc, Alias *eref,
 							List **colnames, List **colvars);
 static int	specialAttNum(const char *attname);
 static bool isQueryUsingTempRelation_walker(Node *node, void *context);
+static bool is_query_using_gtt_walker(Node *node, void *context);
 
 
 /*
@@ -3579,3 +3580,49 @@ isQueryUsingTempRelation_walker(Node *node, void *context)
 								  isQueryUsingTempRelation_walker,
 								  context);
 }
+
+/* check if the query uses global temp table */
+static bool
+is_query_using_gtt_walker(Node *node, void *context)
+{
+	if (node == NULL)
+		return false;
+
+	if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+		ListCell   *rtable;
+
+		foreach(rtable, query->rtable)
+		{
+			RangeTblEntry *rte = lfirst(rtable);
+
+			if (rte->rtekind == RTE_RELATION)
+			{
+				Relation	rel = relation_open(rte->relid, AccessShareLock);
+				char		relpersistence = rel->rd_rel->relpersistence;
+
+				relation_close(rel, AccessShareLock);
+				if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+					return true;
+			}
+		}
+
+		return query_tree_walker(query,
+								 is_query_using_gtt_walker,
+								 context,
+								 QTW_IGNORE_JOINALIASES);
+	}
+
+	return expression_tree_walker(node,
+								  is_query_using_gtt_walker,
+								  context);
+}
+
+/* check if the query uses global temp table */
+bool
+is_query_using_gtt(Query *query)
+{
+	return is_query_using_gtt_walker((Node *) query, NULL);
+}
+
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index ee2d2b5..9c9abaa 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -437,6 +437,9 @@ generateSerialExtraStmts(CreateStmtContext *cxt, ColumnDef *column,
 	seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
 	seqstmt->options = seqoptions;
 
+	if (cxt->relation->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		seqstmt->sequence->relpersistence = cxt->relation->relpersistence;
+
 	/*
 	 * If a sequence data type was specified, add it to the options.  Prepend
 	 * to the list rather than append; in case a user supplied their own AS
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 6d1f28c..ed837d1 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -2086,6 +2086,11 @@ do_autovacuum(void)
 			}
 			continue;
 		}
+		else if (classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			/* autovacuum skip vacuum global temp table */
+			continue;
+		}
 
 		/* Fetch reloptions and the pgstat entry for this table */
 		relopts = extract_autovac_opts(tuple, pg_class_desc);
@@ -2152,7 +2157,9 @@ do_autovacuum(void)
 		/*
 		 * We cannot safely process other backends' temp tables, so skip 'em.
 		 */
-		if (classForm->relpersistence == RELPERSISTENCE_TEMP)
+		/* autovacuum skip vacuum global temp table */
+		if (classForm->relpersistence == RELPERSISTENCE_TEMP || 
+			classForm->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 			continue;
 
 		relid = classForm->oid;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index aba3960..3c4b96c 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -37,6 +37,7 @@
 #include "access/xlog.h"
 #include "catalog/catalog.h"
 #include "catalog/storage.h"
+#include "catalog/storage_gtt.h"
 #include "executor/instrument.h"
 #include "lib/binaryheap.h"
 #include "miscadmin.h"
@@ -52,6 +53,7 @@
 #include "utils/rel.h"
 #include "utils/resowner_private.h"
 #include "utils/timestamp.h"
+#include "utils/guc.h"
 
 
 /* Note: these two macros only work on shared buffers, not local ones! */
@@ -432,7 +434,7 @@ ForgetPrivateRefCountEntry(PrivateRefCountEntry *ref)
 static Buffer ReadBuffer_common(SMgrRelation reln, char relpersistence,
 								ForkNumber forkNum, BlockNumber blockNum,
 								ReadBufferMode mode, BufferAccessStrategy strategy,
-								bool *hit);
+								bool *hit, Relation rel);
 static bool PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy);
 static void PinBuffer_Locked(BufferDesc *buf);
 static void UnpinBuffer(BufferDesc *buf, bool fixOwner);
@@ -664,7 +666,8 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
 	 */
 	pgstat_count_buffer_read(reln);
 	buf = ReadBuffer_common(reln->rd_smgr, reln->rd_rel->relpersistence,
-							forkNum, blockNum, mode, strategy, &hit);
+							forkNum, blockNum, mode, strategy, &hit,
+							reln);
 	if (hit)
 		pgstat_count_buffer_hit(reln);
 	return buf;
@@ -692,7 +695,7 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 	Assert(InRecovery);
 
 	return ReadBuffer_common(smgr, RELPERSISTENCE_PERMANENT, forkNum, blockNum,
-							 mode, strategy, &hit);
+							 mode, strategy, &hit, NULL);
 }
 
 
@@ -704,7 +707,8 @@ ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
 static Buffer
 ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 				  BlockNumber blockNum, ReadBufferMode mode,
-				  BufferAccessStrategy strategy, bool *hit)
+				  BufferAccessStrategy strategy, bool *hit,
+				  Relation rel)
 {
 	BufferDesc *bufHdr;
 	Block		bufBlock;
@@ -719,6 +723,15 @@ ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 
 	isExtend = (blockNum == P_NEW);
 
+	/* create storage when first read data page for gtt */
+	if (relpersistence == RELPERSISTENCE_GLOBAL_TEMP &&
+		(isExtend || blockNum == 0) &&
+		forkNum == MAIN_FORKNUM &&
+		!gtt_storage_attached(smgr->smgr_rnode.node.relNode))
+	{
+		RelationCreateStorage(smgr->smgr_rnode.node, relpersistence, rel);
+	}
+
 	TRACE_POSTGRESQL_BUFFER_READ_START(forkNum, blockNum,
 									   smgr->smgr_rnode.node.spcNode,
 									   smgr->smgr_rnode.node.dbNode,
@@ -2809,6 +2822,16 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln)
 BlockNumber
 RelationGetNumberOfBlocksInFork(Relation relation, ForkNumber forkNum)
 {
+	/*
+	 * When this backend not init gtt storage
+	 * return 0
+	 */
+	if (RELATION_IS_GLOBAL_TEMP(relation) &&
+		!gtt_storage_attached(relation->rd_node.relNode))
+	{
+		return 0;
+	}
+
 	switch (relation->rd_rel->relkind)
 	{
 		case RELKIND_SEQUENCE:
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 427b0d5..7adb969 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -21,6 +21,7 @@
 #include "access/nbtree.h"
 #include "access/subtrans.h"
 #include "access/twophase.h"
+#include "catalog/storage_gtt.h"
 #include "commands/async.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -147,6 +148,7 @@ CreateSharedMemoryAndSemaphores(void)
 		size = add_size(size, BTreeShmemSize());
 		size = add_size(size, SyncScanShmemSize());
 		size = add_size(size, AsyncShmemSize());
+		size = add_size(size, active_gtt_shared_hash_size());
 #ifdef EXEC_BACKEND
 		size = add_size(size, ShmemBackendArraySize());
 #endif
@@ -217,6 +219,8 @@ CreateSharedMemoryAndSemaphores(void)
 	SUBTRANSShmemInit();
 	MultiXactShmemInit();
 	InitBufferPool();
+	/* global temporary table */
+	active_gtt_shared_hash_init();
 
 	/*
 	 * Set up lock manager
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index c3adb2e..eb95e5f 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -62,6 +62,7 @@
 #include "utils/builtins.h"
 #include "utils/rel.h"
 #include "utils/snapmgr.h"
+#include "utils/guc.h"
 
 #define UINT32_ACCESS_ONCE(var)		 ((uint32)(*((volatile uint32 *)&(var))))
 
@@ -4087,3 +4088,77 @@ KnownAssignedXidsReset(void)
 
 	LWLockRelease(ProcArrayLock);
 }
+
+/*
+ * search all active backend to get oldest frozenxid
+ * for global temp table.
+ */
+int
+list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n)
+{
+	ProcArrayStruct *arrayP = procArray;
+	TransactionId result = InvalidTransactionId;
+	int			index;
+	int			flags = 0;
+	int			i = 0;
+
+	if (max_active_gtt <= 0)
+		return 0;
+
+	if (max_size > 0)
+	{
+		Assert(pids);
+		Assert(xids);
+		Assert(n);
+		*n = 0;
+	}
+
+	if (max_active_gtt <= 0)
+		return InvalidTransactionId;
+
+	if (RecoveryInProgress())
+		return InvalidTransactionId;
+
+	flags |= PROC_IS_AUTOVACUUM;
+	flags |= PROC_IN_LOGICAL_DECODING;
+
+	LWLockAcquire(ProcArrayLock, LW_SHARED);
+	if (max_size > 0 && max_size < arrayP->numProcs)
+	{
+		LWLockRelease(ProcArrayLock);
+		elog(ERROR, "list_all_gtt_frozenxids require more array");
+	}
+
+	for (index = 0; index < arrayP->numProcs; index++)
+	{
+		int			pgprocno = arrayP->pgprocnos[index];
+		volatile PGPROC *proc = &allProcs[pgprocno];
+		volatile PGXACT *pgxact = &allPgXact[pgprocno];
+
+		if (pgxact->vacuumFlags & flags)
+			continue;
+
+		if (proc->databaseId == MyDatabaseId &&
+			TransactionIdIsNormal(proc->session_gtt_frozenxid))
+		{
+			if (result == InvalidTransactionId)
+				result = proc->session_gtt_frozenxid;
+			else if (TransactionIdPrecedes(proc->session_gtt_frozenxid, result))
+				result = proc->session_gtt_frozenxid;
+
+			if (max_size > 0)
+			{
+				pids[i] = proc->pid;
+				xids[i] = proc->session_gtt_frozenxid;
+				i++;
+			}
+		}
+	}
+	LWLockRelease(ProcArrayLock);
+
+	if (max_size > 0)
+		*n = i;
+
+	return result;
+}
+
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 32df8c8..e4e1125 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -395,6 +395,7 @@ InitProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
@@ -577,6 +578,7 @@ InitAuxiliaryProcess(void)
 	MyProc->databaseId = InvalidOid;
 	MyProc->roleId = InvalidOid;
 	MyProc->tempNamespaceId = InvalidOid;
+	MyProc->session_gtt_frozenxid = InvalidTransactionId;	/* init session level gtt frozenxid */
 	MyProc->isBackgroundWorker = IsBackgroundWorker;
 	MyPgXact->delayChkpt = false;
 	MyPgXact->vacuumFlags = 0;
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 85b7115..f5eae8c 100644
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -646,6 +646,12 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 		 */
 		if (zero_damaged_pages || InRecovery)
 			MemSet(buffer, 0, BLCKSZ);
+		else if(SmgrIsTemp(reln) && blocknum == 0 && forknum == MAIN_FORKNUM)
+		{
+			/* global temp table init btree meta page */
+			MemSet(buffer, 0, BLCKSZ);
+			mdwrite(reln, forknum, blocknum, buffer, true);
+		}
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_DATA_CORRUPTED),
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 7c6f057..eb10cf2 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -112,6 +112,7 @@
 #include "catalog/pg_operator.h"
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_statistic_ext.h"
+#include "catalog/storage_gtt.h"
 #include "executor/nodeAgg.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
@@ -4578,12 +4579,25 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
 						}
 						else if (index->indpred == NIL)
 						{
-							vardata->statsTuple =
-								SearchSysCache3(STATRELATTINH,
-												ObjectIdGetDatum(index->indexoid),
-												Int16GetDatum(pos + 1),
-												BoolGetDatum(false));
-							vardata->freefunc = ReleaseSysCache;
+							char rel_persistence = get_rel_persistence(index->indexoid);
+
+							if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+							{
+								vardata->statsTuple =
+									get_gtt_att_statistic(index->indexoid,
+														Int16GetDatum(pos + 1),
+														false);
+								vardata->freefunc = release_gtt_statistic_cache;
+							}
+							else
+							{
+								vardata->statsTuple =
+									SearchSysCache3(STATRELATTINH,
+													ObjectIdGetDatum(index->indexoid),
+													Int16GetDatum(pos + 1),
+													BoolGetDatum(false));
+								vardata->freefunc = ReleaseSysCache;
+							}
 
 							if (HeapTupleIsValid(vardata->statsTuple))
 							{
@@ -4708,15 +4722,27 @@ examine_simple_variable(PlannerInfo *root, Var *var,
 	}
 	else if (rte->rtekind == RTE_RELATION)
 	{
-		/*
-		 * Plain table or parent of an inheritance appendrel, so look up the
-		 * column in pg_statistic
-		 */
-		vardata->statsTuple = SearchSysCache3(STATRELATTINH,
-											  ObjectIdGetDatum(rte->relid),
-											  Int16GetDatum(var->varattno),
-											  BoolGetDatum(rte->inh));
-		vardata->freefunc = ReleaseSysCache;
+		char rel_persistence = get_rel_persistence(rte->relid);
+
+		if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata->statsTuple = get_gtt_att_statistic(rte->relid,
+														var->varattno,
+														rte->inh);
+			vardata->freefunc = release_gtt_statistic_cache;
+		}
+		else
+		{
+			/*
+			 * Plain table or parent of an inheritance appendrel, so look up the
+			 * column in pg_statistic
+			 */
+			vardata->statsTuple = SearchSysCache3(STATRELATTINH,
+												  ObjectIdGetDatum(rte->relid),
+												  Int16GetDatum(var->varattno),
+												  BoolGetDatum(rte->inh));
+			vardata->freefunc = ReleaseSysCache;
+		}
 
 		if (HeapTupleIsValid(vardata->statsTuple))
 		{
@@ -6098,6 +6124,7 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	{
 		/* Simple variable --- look to stats for the underlying table */
 		RangeTblEntry *rte = planner_rt_fetch(index->rel->relid, root);
+		char	rel_persistence = get_rel_persistence(rte->relid);
 
 		Assert(rte->rtekind == RTE_RELATION);
 		relid = rte->relid;
@@ -6115,6 +6142,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													rte->inh);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -6126,6 +6160,8 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	}
 	else
 	{
+		char	rel_persistence = get_rel_persistence(index->indexoid);
+
 		/* Expression --- maybe there are stats for the index itself */
 		relid = index->indexoid;
 		colnum = 1;
@@ -6141,6 +6177,13 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 				!vardata.freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
+		else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+		{
+			vardata.statsTuple = get_gtt_att_statistic(relid,
+													colnum,
+													false);
+			vardata.freefunc = release_gtt_statistic_cache;
+		}
 		else
 		{
 			vardata.statsTuple = SearchSysCache3(STATRELATTINH,
@@ -7054,6 +7097,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		/* attempt to lookup stats in relation for this index column */
 		if (attnum != 0)
 		{
+			char	rel_persistence = get_rel_persistence(rte->relid);
+
 			/* Simple variable -- look to stats for the underlying table */
 			if (get_relation_stats_hook &&
 				(*get_relation_stats_hook) (root, rte, attnum, &vardata))
@@ -7066,6 +7111,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					elog(ERROR,
 						 "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(rte->relid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple =
@@ -7078,6 +7131,8 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		}
 		else
 		{
+			char	rel_persistence = get_rel_persistence(index->indexoid);
+
 			/*
 			 * Looks like we've found an expression column in the index. Let's
 			 * see if there's any stats for it.
@@ -7097,6 +7152,14 @@ brincostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 					!vardata.freefunc)
 					elog(ERROR, "no function provided to release variable stats with");
 			}
+			else if (rel_persistence == RELPERSISTENCE_GLOBAL_TEMP)
+			{
+				vardata.statsTuple =
+					get_gtt_att_statistic(index->indexoid,
+										attnum,
+										false);
+				vardata.freefunc = release_gtt_statistic_cache;
+			}
 			else
 			{
 				vardata.statsTuple = SearchSysCache3(STATRELATTINH,
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 1e3e6d3..345e3e9 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -34,6 +34,7 @@
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_transform.h"
 #include "catalog/pg_type.h"
+#include "catalog/storage_gtt.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "utils/array.h"
@@ -2878,6 +2879,18 @@ get_attavgwidth(Oid relid, AttrNumber attnum)
 		if (stawidth > 0)
 			return stawidth;
 	}
+	if (get_rel_persistence(relid) == RELPERSISTENCE_GLOBAL_TEMP)
+	{
+		tp = get_gtt_att_statistic(relid, attnum, false);
+		if (!HeapTupleIsValid(tp))
+			return 0;
+
+		stawidth = ((Form_pg_statistic) GETSTRUCT(tp))->stawidth;
+		if (stawidth > 0)
+			return stawidth;
+		else
+			return 0;
+	}
 	tp = SearchSysCache3(STATRELATTINH,
 						 ObjectIdGetDatum(relid),
 						 Int16GetDatum(attnum),
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index df025a5..1f733f4 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -63,6 +63,7 @@
 #include "catalog/pg_type.h"
 #include "catalog/schemapg.h"
 #include "catalog/storage.h"
+#include "catalog/storage_gtt.h"
 #include "commands/policy.h"
 #include "commands/trigger.h"
 #include "miscadmin.h"
@@ -1124,6 +1125,28 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
 				relation->rd_islocaltemp = false;
 			}
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			{
+				BlockNumber     relpages = 0;
+				double          reltuples = 0;
+				BlockNumber     relallvisible = 0;
+
+				relation->rd_backend = BackendIdForTempRelations();
+				/*
+				 * For global temp table, all backend can use
+				 * this relation, so rd_islocaltemp always true.
+				 */
+				relation->rd_islocaltemp = true;
+				get_gtt_relstats(RelationGetRelid(relation),
+								&relpages,
+								&reltuples,
+								&relallvisible,
+								NULL, NULL);
+				relation->rd_rel->relpages = (int32)relpages;
+				relation->rd_rel->reltuples = (float4)reltuples;
+				relation->rd_rel->relallvisible = (int32)relallvisible;
+			}
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c",
 				 relation->rd_rel->relpersistence);
@@ -3313,6 +3336,10 @@ RelationBuildLocalRelation(const char *relname,
 			rel->rd_backend = BackendIdForTempRelations();
 			rel->rd_islocaltemp = true;
 			break;
+		case RELPERSISTENCE_GLOBAL_TEMP:
+			rel->rd_backend = BackendIdForTempRelations();
+			rel->rd_islocaltemp = true;
+			break;
 		default:
 			elog(ERROR, "invalid relpersistence: %c", relpersistence);
 			break;
@@ -3427,6 +3454,9 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 	TransactionId freezeXid = InvalidTransactionId;
 	RelFileNode newrnode;
 
+	if (RELATION_IS_GLOBAL_TEMP(relation))
+		elog(ERROR, "global temp table does not allow setting new relfilenode");
+
 	/* Allocate a new relfilenode */
 	newrelfilenode = GetNewRelFileNode(relation->rd_rel->reltablespace, NULL,
 									   persistence);
@@ -3467,7 +3497,7 @@ RelationSetNewRelfilenode(Relation relation, char persistence)
 				/* handle these directly, at least for now */
 				SMgrRelation srel;
 
-				srel = RelationCreateStorage(newrnode, persistence);
+				srel = RelationCreateStorage(newrnode, persistence, relation);
 				smgrclose(srel);
 			}
 			break;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index e44f71e..44c86c8 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -139,6 +139,18 @@ char	   *GUC_check_errmsg_string;
 char	   *GUC_check_errdetail_string;
 char	   *GUC_check_errhint_string;
 
+/*
+ * num = 0 means disable global temp table feature.
+ * global temp table define can still storage in catalog
+ * just can not use.
+ * num > 0 means database can management num active global temp table.
+ */
+#define	MIN_NUM_ACTIVE_GTT			0
+#define	DEFAULT_NUM_ACTIVE_GTT			1000
+#define	MAX_NUM_ACTIVE_GTT			1000000
+
+int		max_active_gtt = MIN_NUM_ACTIVE_GTT;
+
 static void do_serialize(char **destptr, Size *maxbytes, const char *fmt,...) pg_attribute_printf(3, 4);
 
 static void set_config_sourcefile(const char *name, char *sourcefile,
@@ -1992,6 +2004,15 @@ static struct config_bool ConfigureNamesBool[] =
 static struct config_int ConfigureNamesInt[] =
 {
 	{
+		{"max_active_global_temporary_table", PGC_POSTMASTER, UNGROUPED,
+			gettext_noop("max active global temporary table."),
+			NULL
+		},
+		&max_active_gtt,
+		DEFAULT_NUM_ACTIVE_GTT, MIN_NUM_ACTIVE_GTT, MAX_NUM_ACTIVE_GTT,
+		NULL, NULL, NULL
+	},
+	{
 		{"archive_timeout", PGC_SIGHUP, WAL_ARCHIVING,
 			gettext_noop("Forces a switch to the next WAL file if a "
 						 "new file has not been started within N seconds."),
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 799b698..b98d396 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15583,6 +15583,7 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 	{
 		char	   *ftoptions = NULL;
 		char	   *srvname = NULL;
+		char		*table_type = NULL;
 
 		switch (tbinfo->relkind)
 		{
@@ -15634,9 +15635,15 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 			binary_upgrade_set_pg_class_oids(fout, q,
 											 tbinfo->dobj.catId.oid, false);
 
+		if (tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED)
+			table_type = "UNLOGGED ";
+		else if (tbinfo->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+			table_type = "GLOBAL TEMPORARY ";
+		else
+			table_type = "";
+
 		appendPQExpBuffer(q, "CREATE %s%s %s",
-						  tbinfo->relpersistence == RELPERSISTENCE_UNLOGGED ?
-						  "UNLOGGED " : "",
+						  table_type,
 						  reltypename,
 						  qualrelname);
 
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index f3c7eb9..28134e2 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -3723,7 +3723,8 @@ listTables(const char *tabtypes, const char *pattern, bool verbose, bool showSys
 		if (pset.sversion >= 90100)
 		{
 			appendPQExpBuffer(&buf,
-							  ",\n  CASE c.relpersistence WHEN 'p' THEN '%s' WHEN 't' THEN '%s' WHEN 'u' THEN '%s' END as \"%s\"",
+							  ",\n  CASE c.relpersistence WHEN 'g' THEN '%s' WHEN 'p' THEN '%s' WHEN 't' THEN '%s' WHEN 'u' THEN '%s' END as \"%s\"",
+							  gettext_noop("session"),
 							  gettext_noop("permanent"),
 							  gettext_noop("temporary"),
 							  gettext_noop("unlogged"),
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 052d98b..f35d9bf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1003,6 +1003,8 @@ static const pgsql_thing_t words_after_create[] = {
 	{"FOREIGN TABLE", NULL, NULL, NULL},
 	{"FUNCTION", NULL, NULL, Query_for_list_of_functions},
 	{"GROUP", Query_for_list_of_roles},
+	{"GLOBAL", NULL, NULL, NULL, THING_NO_DROP | THING_NO_ALTER}, /* for CREATE GLOBAL TEMP/TEMPORARY TABLE
+																	* ... */
 	{"INDEX", NULL, NULL, &Query_for_list_of_indexes},
 	{"LANGUAGE", Query_for_list_of_languages},
 	{"LARGE OBJECT", NULL, NULL, NULL, THING_NO_CREATE | THING_NO_DROP},
@@ -2326,6 +2328,9 @@ psql_completion(const char *text, int start, int end)
 	/* CREATE FOREIGN DATA WRAPPER */
 	else if (Matches("CREATE", "FOREIGN", "DATA", "WRAPPER", MatchAny))
 		COMPLETE_WITH("HANDLER", "VALIDATOR", "OPTIONS");
+	/* CREATE GLOBAL TEMP/TEMPORARY*/
+	else if (Matches("CREATE", "GLOBAL"))
+		COMPLETE_WITH("TEMP", "TEMPORARY");
 
 	/* CREATE INDEX --- is allowed inside CREATE SCHEMA, so use TailMatches */
 	/* First off we complete CREATE UNIQUE with "INDEX" */
@@ -2534,6 +2539,8 @@ psql_completion(const char *text, int start, int end)
 	/* Complete "CREATE TEMP/TEMPORARY" with the possible temp objects */
 	else if (TailMatches("CREATE", "TEMP|TEMPORARY"))
 		COMPLETE_WITH("SEQUENCE", "TABLE", "VIEW");
+	else if (TailMatches("CREATE", "GLOBAL", "TEMP|TEMPORARY"))
+		COMPLETE_WITH("TABLE");
 	/* Complete "CREATE UNLOGGED" with TABLE or MATVIEW */
 	else if (TailMatches("CREATE", "UNLOGGED"))
 		COMPLETE_WITH("TABLE", "MATERIALIZED VIEW");
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index a12fc1f..78958e4 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -165,6 +165,7 @@ typedef FormData_pg_class *Form_pg_class;
 #define		  RELPERSISTENCE_PERMANENT	'p' /* regular table */
 #define		  RELPERSISTENCE_UNLOGGED	'u' /* unlogged permanent table */
 #define		  RELPERSISTENCE_TEMP		't' /* temporary table */
+#define		  RELPERSISTENCE_GLOBAL_TEMP	'g' /* global temporary table */
 
 /* default selection for replica identity (primary key or nothing) */
 #define		  REPLICA_IDENTITY_DEFAULT	'd'
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index fcf2a12..ba0bd5f 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -5484,6 +5484,40 @@
   proparallel => 'r', prorettype => 'float8', proargtypes => 'oid',
   prosrc => 'pg_stat_get_xact_function_self_time' },
 
+# For global temporary table
+{ oid => '4191',
+  descr => 'List local statistics for global temporary table',
+  proname => 'pg_get_gtt_statistics', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid int4 anyelement',
+  proallargtypes => '{oid,int4,anyelement,oid,int2,bool,float4,int4,float4,int2,int2,int2,int2,int2,oid,oid,oid,oid,oid,oid,oid,oid,oid,oid,_float4,_float4,_float4,_float4,_float4,anyarray,anyarray,anyarray,anyarray,anyarray}',
+  proargmodes => '{i,i,i,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}',
+  proargnames => '{relid,att,x,starelid,staattnum,stainherit,stanullfrac,stawidth,stadistinct,stakind1,stakind2,stakind3,stakind4,stakind5,staop1,staop2,staop3,staop4,staop5,stacoll1,stacoll2,stacoll3,stacoll4,stacoll5,stanumbers1,stanumbers2,stanumbers3,stanumbers4,stanumbers5,stavalues1,stavalues2,stavalues3,stavalues4,stavalues5}',
+  prosrc => 'pg_get_gtt_statistics' },
+{ oid => '4192',
+  descr => 'List local relstats for global temporary table',
+  proname => 'pg_get_gtt_relstats', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid',
+  proallargtypes => '{oid,int4,float4,int4,xid,xid}',
+  proargmodes => '{i,o,o,o,o,o}',
+  proargnames => '{relid,relpages,reltuples,relallvisible,relfrozenxid,relminmxid}',
+  prosrc => 'pg_get_gtt_relstats' },
+{ oid => '4193',
+  descr => 'List attached pid for one global temporary table',
+  proname => 'pg_gtt_attached_pid', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => 'oid',
+  proallargtypes => '{oid,oid,int4}',
+  proargmodes => '{i,o,o}',
+  proargnames => '{relid,relid,pid}',
+  prosrc => 'pg_gtt_attached_pid' },
+{ oid => '4194',
+  descr => 'List those backends that have used global temporary table',
+  proname => 'pg_list_gtt_relfrozenxids', provolatile => 'v', proparallel => 'u',
+  prorettype => 'record', proretset => 't', prorows => '10', proargtypes => '',
+  proallargtypes => '{int4,xid}',
+  proargmodes => '{o,o}',
+  proargnames => '{pid,relfrozenxid}',
+  prosrc => 'pg_list_gtt_relfrozenxids' },
+
 { oid => '3788',
   descr => 'statistics: timestamp of the current statistics snapshot',
   proname => 'pg_stat_get_snapshot_timestamp', provolatile => 's',
diff --git a/src/include/catalog/storage.h b/src/include/catalog/storage.h
index 048003c..af48cdf 100644
--- a/src/include/catalog/storage.h
+++ b/src/include/catalog/storage.h
@@ -19,7 +19,7 @@
 #include "storage/smgr.h"
 #include "utils/relcache.h"
 
-extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence);
+extern SMgrRelation RelationCreateStorage(RelFileNode rnode, char relpersistence, Relation rel);
 extern void RelationDropStorage(Relation rel);
 extern void RelationPreserveStorage(RelFileNode rnode, bool atCommit);
 extern void RelationTruncate(Relation rel, BlockNumber nblocks);
diff --git a/src/include/catalog/storage_gtt.h b/src/include/catalog/storage_gtt.h
new file mode 100644
index 0000000..eacc214
--- /dev/null
+++ b/src/include/catalog/storage_gtt.h
@@ -0,0 +1,39 @@
+/*-------------------------------------------------------------------------
+ *
+ * storage_gtt.h
+ *	  prototypes for functions in backend/catalog/storage_gtt.c
+ *
+ * src/include/catalog/storage_gtt.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef STORAGE_GTT_H
+#define STORAGE_GTT_H
+
+#include "access/htup.h"
+#include "storage/block.h"
+#include "storage/relfilenode.h"
+#include "utils/relcache.h"
+
+extern Size active_gtt_shared_hash_size(void);
+extern void active_gtt_shared_hash_init(void);
+extern void remember_gtt_storage_info(RelFileNode rnode, Relation rel);
+extern void forget_gtt_storage_info(Oid relid);
+extern bool is_other_backend_use_gtt(RelFileNode node);
+extern bool gtt_storage_attached(Oid relid);
+extern Bitmapset *copy_active_gtt_bitmap(RelFileNode node);
+extern void up_gtt_att_statistic(Oid reloid, int attnum, bool inh, int natts,
+								TupleDesc tupleDescriptor, Datum *values, bool *isnull);
+extern HeapTuple get_gtt_att_statistic(Oid reloid, int attnum, bool inh);
+extern void release_gtt_statistic_cache(HeapTuple tup);
+extern void up_gtt_relstats(Relation relation,
+							BlockNumber num_pages,
+							double num_tuples,
+							BlockNumber num_all_visible_pages,
+							TransactionId relfrozenxid,
+							TransactionId relminmxid);
+extern bool get_gtt_relstats(Oid relid, BlockNumber *relpages, double *reltuples,
+							BlockNumber *relallvisible, TransactionId *relfrozenxid,
+							TransactionId *relminmxid);
+
+#endif							/* STORAGE_H */
diff --git a/src/include/parser/parse_relation.h b/src/include/parser/parse_relation.h
index 93f9446..14cafae 100644
--- a/src/include/parser/parse_relation.h
+++ b/src/include/parser/parse_relation.h
@@ -120,4 +120,7 @@ extern Oid	attnumTypeId(Relation rd, int attid);
 extern Oid	attnumCollationId(Relation rd, int attid);
 extern bool isQueryUsingTempRelation(Query *query);
 
+/* global temp table check */
+extern bool is_query_using_gtt(Query *query);
+
 #endif							/* PARSE_RELATION_H */
diff --git a/src/include/storage/bufpage.h b/src/include/storage/bufpage.h
index 870ecb5..92c590e 100644
--- a/src/include/storage/bufpage.h
+++ b/src/include/storage/bufpage.h
@@ -405,6 +405,8 @@ do { \
 #define PageClearPrunable(page) \
 	(((PageHeader) (page))->pd_prune_xid = InvalidTransactionId)
 
+#define GlobalTempRelationPageIsNotInitialized(rel, page) \
+	((rel)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP && PageIsNew(page))
 
 /* ----------------------------------------------------------------
  *		extern declarations
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 8fda8e4..172eae9 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -220,6 +220,7 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_TBM,
 	LWTRANCHE_PARALLEL_APPEND,
 	LWTRANCHE_SXACT,
+	LWTRANCHE_GTT_CTL,
 	LWTRANCHE_FIRST_USER_DEFINED
 }			BuiltinTrancheIds;
 
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index 5b407e6..f13250a 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -117,6 +117,8 @@ struct PGPROC
 	Oid			tempNamespaceId;	/* OID of temp schema this backend is
 									 * using */
 
+	TransactionId session_gtt_frozenxid;	/* session level global temp table relfrozenxid */
+
 	bool		isBackgroundWorker; /* true if background worker. */
 
 	/*
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index a5c7d0c..a86f61f 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -125,4 +125,6 @@ extern void ProcArraySetReplicationSlotXmin(TransactionId xmin,
 extern void ProcArrayGetReplicationSlotXmin(TransactionId *xmin,
 											TransactionId *catalog_xmin);
 
+extern int list_all_session_gtt_frozenxids(int max_size, int *pids, uint32 *xids, int *n);
+
 #endif							/* PROCARRAY_H */
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index ce93ace..0f7262e 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -281,6 +281,10 @@ extern int	tcp_user_timeout;
 extern bool trace_sort;
 #endif
 
+/* global temporary table */
+extern int	max_active_gtt;
+/* end */
+
 /*
  * Functions exported by guc.c
  */
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 44ed04d..3f9720d 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -277,6 +277,7 @@ typedef struct StdRdOptions
 	int			parallel_workers;	/* max number of parallel workers */
 	bool		vacuum_index_cleanup;	/* enables index vacuuming and cleanup */
 	bool		vacuum_truncate;	/* enables vacuum to truncate a relation */
+	bool		on_commit_delete_rows;	/* global temp table */
 } StdRdOptions;
 
 #define HEAP_MIN_FILLFACTOR			10
@@ -535,7 +536,8 @@ typedef struct ViewOptions
  *		True if relation's pages are stored in local buffers.
  */
 #define RelationUsesLocalBuffers(relation) \
-	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
+	((relation)->rd_rel->relpersistence == RELPERSISTENCE_TEMP || \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
 
 /*
  * RELATION_IS_LOCAL
@@ -602,6 +604,17 @@ typedef struct ViewOptions
 	 RelationNeedsWAL(relation) && \
 	 !IsCatalogRelation(relation))
 
+/* global temp table implementations */
+#define RELATION_IS_GLOBAL_TEMP(relation)	((relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP)
+
+#define RELATION_GTT_ON_COMMIT_DELETE(relation)	\
+	((relation)->rd_options && \
+	 ((relation)->rd_rel->relkind == RELKIND_RELATION || (relation)->rd_rel->relkind == RELKIND_PARTITIONED_TABLE) && \
+	 (relation)->rd_rel->relpersistence == RELPERSISTENCE_GLOBAL_TEMP ? \
+	 ((StdRdOptions *) (relation)->rd_options)->on_commit_delete_rows : false)
+
+#define RelationGetRelPersistence(relation) ((relation)->rd_rel->relpersistence)
+
 /* routines in utils/cache/relcache.c */
 extern void RelationIncrementReferenceCount(Relation rel);
 extern void RelationDecrementReferenceCount(Relation rel);
diff --git a/src/test/regress/expected/gtt_clean.out b/src/test/regress/expected/gtt_clean.out
new file mode 100644
index 0000000..50ca9ac
--- /dev/null
+++ b/src/test/regress/expected/gtt_clean.out
@@ -0,0 +1,7 @@
+reset search_path;
+drop schema gtt cascade;
+NOTICE:  drop cascades to 4 other objects
+DETAIL:  drop cascades to table gtt.gtt1
+drop cascades to table gtt.gtt2
+drop cascades to table gtt.gtt3
+drop cascades to table gtt.gtt_t_kenyon
diff --git a/src/test/regress/expected/gtt_function.out b/src/test/regress/expected/gtt_function.out
new file mode 100644
index 0000000..a477917
--- /dev/null
+++ b/src/test/regress/expected/gtt_function.out
@@ -0,0 +1,197 @@
+CREATE SCHEMA IF NOT EXISTS gtt_function;
+set search_path=gtt_function,sys;
+create global temp table gtt1(a int primary key, b text);
+create global temp table gtt_test_rename(a int primary key, b text);
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+)on commit delete rows;
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+ERROR:  cannot create indexes on global temporary tables using concurrent mode
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+ERROR:  not support cluster global temporary tables yet
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+ERROR:  ON COMMIT can only be used on temporary tables
+-- ok
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+ERROR:  regular table cannot specifie on_commit_delete_rows
+-- ok
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+--ok
+CREATE global temp TABLE p_table01 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)on commit delete rows;
+ 
+CREATE global temp TABLE p_table01_2018
+PARTITION OF p_table01
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+ 
+CREATE global temp TABLE p_table01_2017
+PARTITION OF p_table01
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+begin;
+insert into p_table01 values(1,'2018-01-02 00:00:00','test1');
+insert into p_table01 values(1,'2018-01-02 00:00:00','test2');
+select count(*) from p_table01;
+ count 
+-------
+     2
+(1 row)
+
+commit;
+select count(*) from p_table01;
+ count 
+-------
+     0
+(1 row)
+
+--ok
+CREATE global temp TABLE p_table02 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)
+on commit PRESERVE rows;
+CREATE global temp TABLE p_table02_2018
+PARTITION OF p_table02
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+CREATE global temp TABLE p_table02_2017
+PARTITION OF p_table02
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+-- ok
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+ERROR:  The parent table must be global temporary table
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent_global_temp) on commit delete rows;
+select relname ,relkind, relpersistence, reloptions from pg_class where relname like 'p_table0%' or  relname like 'tbl_inherits%' order by relname;
+             relname             | relkind | relpersistence |          reloptions           
+---------------------------------+---------+----------------+-------------------------------
+ p_table01                       | p       | g              | {on_commit_delete_rows=true}
+ p_table01_2017                  | r       | g              | {on_commit_delete_rows=true}
+ p_table01_2018                  | r       | g              | {on_commit_delete_rows=true}
+ p_table01_id_seq                | S       | g              | 
+ p_table02                       | p       | g              | {on_commit_delete_rows=false}
+ p_table02_2017                  | r       | g              | {on_commit_delete_rows=false}
+ p_table02_2018                  | r       | g              | {on_commit_delete_rows=false}
+ p_table02_id_seq                | S       | g              | 
+ tbl_inherits_parent             | r       | p              | 
+ tbl_inherits_parent_global_temp | r       | g              | {on_commit_delete_rows=true}
+ tbl_inherits_partition          | r       | g              | {on_commit_delete_rows=true}
+(11 rows)
+
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+ERROR:  global temp table not support on commit drop clause
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+ERROR:  can not defeine global temp table with on commit and with clause at same time
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+--ok
+alter table gtt_test_rename rename to gtt_test;
+-- ok
+ALTER TABLE gtt_test ADD COLUMN address varchar(30);
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  referenced relation "products" is not a global temp table
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+ERROR:  referenced relation "products" is not a global temp table
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+-- ok
+create global temp table gtt_seq(id int GENERATED ALWAYS AS IDENTITY (START WITH 2) primary key, a int)  on commit PRESERVE rows;
+insert into gtt_seq (a) values(1);
+insert into gtt_seq (a) values(2);
+select * from gtt_seq order by id;
+ id | a 
+----+---
+  2 | 1
+  3 | 2
+(2 rows)
+
+truncate gtt_seq;
+select * from gtt_seq order by id;
+ id | a 
+----+---
+(0 rows)
+
+insert into gtt_seq (a) values(3);
+select * from gtt_seq order by id;
+ id | a 
+----+---
+  4 | 3
+(1 row)
+
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+ERROR:  materialized views must not use global temporary tables or views
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+ERROR:  only support btree index on global temp table
+create index idx_err on gtt1 using gist (a);
+ERROR:  data type integer has no default operator class for access method "gist"
+HINT:  You must specify an operator class for the index or define a default operator class for the data type.
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+ERROR:  only support btree index on global temp table
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+ERROR:  only support btree index on global temp table
+reset search_path;
+drop schema gtt_function cascade;
+NOTICE:  drop cascades to 15 other objects
+DETAIL:  drop cascades to table gtt_function.gtt1
+drop cascades to table gtt_function.gtt_test
+drop cascades to table gtt_function.gtt2
+drop cascades to table gtt_function.gtt3
+drop cascades to table gtt_function.tmp_t0
+drop cascades to table gtt_function.tbl_inherits_parent
+drop cascades to table gtt_function.tbl_inherits_parent_global_temp
+drop cascades to table gtt_function.products
+drop cascades to table gtt_function.measurement
+drop cascades to table gtt_function.p_table01
+drop cascades to table gtt_function.p_table02
+drop cascades to table gtt_function.tbl_inherits_partition
+drop cascades to table gtt_function.gtt5
+drop cascades to table gtt_function.mytable
+drop cascades to table gtt_function.gtt_seq
diff --git a/src/test/regress/expected/gtt_parallel_1.out b/src/test/regress/expected/gtt_parallel_1.out
new file mode 100644
index 0000000..30d8a7b
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_1.out
@@ -0,0 +1,84 @@
+set search_path=gtt,sys;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+ a | b 
+---+---
+(0 rows)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_parallel_2.out b/src/test/regress/expected/gtt_parallel_2.out
new file mode 100644
index 0000000..850ef3e
--- /dev/null
+++ b/src/test/regress/expected/gtt_parallel_2.out
@@ -0,0 +1,161 @@
+set search_path=gtt,sys;
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+ 3 | test1
+(3 rows)
+
+rollback;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test1
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+(1 row)
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 1 | test1
+ 2 | test2
+(2 rows)
+
+truncate gtt3;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 3 | test3
+(1 row)
+
+rollback;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+begin;
+select * from gtt3 order by a;
+ a | b 
+---+---
+(0 rows)
+
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 5 | test5
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+ a |   b   
+---+-------
+ 6 | test6
+(1 row)
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+ count  
+--------
+ 100000
+(1 row)
+
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+             QUERY PLAN             
+------------------------------------
+ Index Scan using gtt3_pkey on gtt3
+   Index Cond: (a = 300)
+(2 rows)
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid),pg_table_size(oid),pg_indexes_size(oid),pg_total_relation_size(oid) from pg_class where relname = 'gtt_t_kenyon';
+   relname    | pg_relation_size | pg_relation_size | pg_table_size | pg_indexes_size | pg_total_relation_size 
+--------------+------------------+------------------+---------------+-----------------+------------------------
+ gtt_t_kenyon |           450560 |             8192 |        499712 |          475136 |                 974848
+(1 row)
+
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+   relname    
+--------------
+ gtt_t_kenyon
+(1 row)
+
+select
+c.relname, pg_relation_size(c.oid),pg_table_size(c.oid),pg_total_relation_size(c.oid)
+from
+pg_class c
+where
+c.oid in
+(
+select
+i.indexrelid as indexrelid
+from 
+pg_index i ,pg_class cc
+where cc.relname = 'gtt_t_kenyon' and cc.oid = i.indrelid
+)
+order by c.relname;
+      relname       | pg_relation_size | pg_table_size | pg_total_relation_size 
+--------------------+------------------+---------------+------------------------
+ idx_gtt_t_kenyon_1 |            65536 |         65536 |                  65536
+ idx_gtt_t_kenyon_2 |           409600 |        409600 |                 409600
+(2 rows)
+
+reset search_path;
diff --git a/src/test/regress/expected/gtt_prepare.out b/src/test/regress/expected/gtt_prepare.out
new file mode 100644
index 0000000..9fe5fd4
--- /dev/null
+++ b/src/test/regress/expected/gtt_prepare.out
@@ -0,0 +1,9 @@
+CREATE SCHEMA IF NOT EXISTS gtt;
+set search_path=gtt,sys;
+create global temp table gtt1(a int primary key, b text) on commit delete rows;
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+create global temp table gtt3(a int primary key, b text);
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+create index idx_gtt_t_kenyon_1 on gtt_t_kenyon(id);
+create index idx_gtt_t_kenyon_2 on gtt_t_kenyon(remark);
+reset search_path;
diff --git a/src/test/regress/expected/gtt_stats.out b/src/test/regress/expected/gtt_stats.out
new file mode 100644
index 0000000..b258b7c
--- /dev/null
+++ b/src/test/regress/expected/gtt_stats.out
@@ -0,0 +1,76 @@
+CREATE SCHEMA IF NOT EXISTS gtt_stats;
+set search_path=gtt_stats,sys;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     0
+(1 row)
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     0
+(1 row)
+
+create global temp table gtt(a int primary key, b text) on commit PRESERVE rows;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     0
+(1 row)
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     0
+(1 row)
+
+insert into gtt values(generate_series(1,10000),'test');
+-- expect 1
+select count(*) from pg_gtt_attached_pids;
+ count 
+-------
+     1
+(1 row)
+
+-- expect 2
+select count(*) from pg_list_gtt_relfrozenxids();
+ count 
+-------
+     2
+(1 row)
+
+-- expect 0
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+ schemaname | tablename | relpages | reltuples | relallvisible 
+------------+-----------+----------+-----------+---------------
+ gtt_stats  | gtt       |        0 |         0 |             0
+(1 row)
+
+-- expect 0
+select * from pg_gtt_stats order by tablename;
+ schemaname | tablename | attname | inherited | null_frac | avg_width | n_distinct | most_common_vals | most_common_freqs | histogram_bounds | correlation | most_common_elems | most_common_elem_freqs | elem_count_histogram 
+------------+-----------+---------+-----------+-----------+-----------+------------+------------------+-------------------+------------------+-------------+-------------------+------------------------+----------------------
+(0 rows)
+
+analyze gtt;
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+ schemaname | tablename | relpages | reltuples | relallvisible 
+------------+-----------+----------+-----------+---------------
+ gtt_stats  | gtt       |       55 |     10000 |             0
+(1 row)
+
+select * from pg_gtt_stats order by tablename;
+ schemaname | tablename | attname | inherited | null_frac | avg_width | n_distinct | most_common_vals | most_common_freqs |                                                                                                                                                                                                                                                histogram_bounds                                                                                                                                                                                                                                                 | correlation | most_common_elems | most_common_elem_freqs | elem_count_histogram 
+------------+-----------+---------+-----------+-----------+-----------+------------+------------------+-------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+-------------------+------------------------+----------------------
+ gtt_stats  | gtt       | a       | f         |         0 |         4 |         -1 |                  |                   | {1,100,200,300,400,500,600,700,800,900,1000,1100,1200,1300,1400,1500,1600,1700,1800,1900,2000,2100,2200,2300,2400,2500,2600,2700,2800,2900,3000,3100,3200,3300,3400,3500,3600,3700,3800,3900,4000,4100,4200,4300,4400,4500,4600,4700,4800,4900,5000,5100,5200,5300,5400,5500,5600,5700,5800,5900,6000,6100,6200,6300,6400,6500,6600,6700,6800,6900,7000,7100,7200,7300,7400,7500,7600,7700,7800,7900,8000,8100,8200,8300,8400,8500,8600,8700,8800,8900,9000,9100,9200,9300,9400,9500,9600,9700,9800,9900,10000} |           1 |                   |                        | 
+ gtt_stats  | gtt       | b       | f         |         0 |         5 |          1 | {test}           | {1}               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |           1 |                   |                        | 
+(2 rows)
+
+reset search_path;
+drop schema gtt_stats cascade;
+NOTICE:  drop cascades to table gtt_stats.gtt
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index 70e1e2f..30cf4bd 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1348,6 +1348,93 @@ pg_group| SELECT pg_authid.rolname AS groname,
           WHERE (pg_auth_members.roleid = pg_authid.oid)) AS grolist
    FROM pg_authid
   WHERE (NOT pg_authid.rolcanlogin);
+pg_gtt_attached_pids| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.relid,
+    s.pid
+   FROM (pg_class c
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_gtt_attached_pid(c.oid) s(relid, pid)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
+pg_gtt_relstats| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    s.relpages,
+    s.reltuples,
+    s.relallvisible,
+    s.relfrozenxid,
+    s.relminmxid
+   FROM (pg_class c
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_get_gtt_relstats(c.oid) s(relpages, reltuples, relallvisible, relfrozenxid, relminmxid)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
+pg_gtt_stats| SELECT n.nspname AS schemaname,
+    c.relname AS tablename,
+    a.attname,
+    s.stainherit AS inherited,
+    s.stanullfrac AS null_frac,
+    s.stawidth AS avg_width,
+    s.stadistinct AS n_distinct,
+        CASE
+            WHEN (s.stakind1 = 1) THEN s.stavalues1
+            WHEN (s.stakind2 = 1) THEN s.stavalues2
+            WHEN (s.stakind3 = 1) THEN s.stavalues3
+            WHEN (s.stakind4 = 1) THEN s.stavalues4
+            WHEN (s.stakind5 = 1) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS most_common_vals,
+        CASE
+            WHEN (s.stakind1 = 1) THEN s.stanumbers1
+            WHEN (s.stakind2 = 1) THEN s.stanumbers2
+            WHEN (s.stakind3 = 1) THEN s.stanumbers3
+            WHEN (s.stakind4 = 1) THEN s.stanumbers4
+            WHEN (s.stakind5 = 1) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS most_common_freqs,
+        CASE
+            WHEN (s.stakind1 = 2) THEN s.stavalues1
+            WHEN (s.stakind2 = 2) THEN s.stavalues2
+            WHEN (s.stakind3 = 2) THEN s.stavalues3
+            WHEN (s.stakind4 = 2) THEN s.stavalues4
+            WHEN (s.stakind5 = 2) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS histogram_bounds,
+        CASE
+            WHEN (s.stakind1 = 3) THEN s.stanumbers1[1]
+            WHEN (s.stakind2 = 3) THEN s.stanumbers2[1]
+            WHEN (s.stakind3 = 3) THEN s.stanumbers3[1]
+            WHEN (s.stakind4 = 3) THEN s.stanumbers4[1]
+            WHEN (s.stakind5 = 3) THEN s.stanumbers5[1]
+            ELSE NULL::real
+        END AS correlation,
+        CASE
+            WHEN (s.stakind1 = 4) THEN s.stavalues1
+            WHEN (s.stakind2 = 4) THEN s.stavalues2
+            WHEN (s.stakind3 = 4) THEN s.stavalues3
+            WHEN (s.stakind4 = 4) THEN s.stavalues4
+            WHEN (s.stakind5 = 4) THEN s.stavalues5
+            ELSE NULL::text[]
+        END AS most_common_elems,
+        CASE
+            WHEN (s.stakind1 = 4) THEN s.stanumbers1
+            WHEN (s.stakind2 = 4) THEN s.stanumbers2
+            WHEN (s.stakind3 = 4) THEN s.stanumbers3
+            WHEN (s.stakind4 = 4) THEN s.stanumbers4
+            WHEN (s.stakind5 = 4) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS most_common_elem_freqs,
+        CASE
+            WHEN (s.stakind1 = 5) THEN s.stanumbers1
+            WHEN (s.stakind2 = 5) THEN s.stanumbers2
+            WHEN (s.stakind3 = 5) THEN s.stanumbers3
+            WHEN (s.stakind4 = 5) THEN s.stanumbers4
+            WHEN (s.stakind5 = 5) THEN s.stanumbers5
+            ELSE NULL::real[]
+        END AS elem_count_histogram
+   FROM ((pg_class c
+     JOIN pg_attribute a ON ((c.oid = a.attrelid)))
+     LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))),
+    LATERAL pg_get_gtt_statistics(c.oid, (a.attnum)::integer, ''::text) s(starelid, staattnum, stainherit, stanullfrac, stawidth, stadistinct, stakind1, stakind2, stakind3, stakind4, stakind5, staop1, staop2, staop3, staop4, staop5, stacoll1, stacoll2, stacoll3, stacoll4, stacoll5, stanumbers1, stanumbers2, stanumbers3, stanumbers4, stanumbers5, stavalues1, stavalues2, stavalues3, stavalues4, stavalues5)
+  WHERE ((c.relpersistence = 'g'::"char") AND (c.relkind = ANY (ARRAY['r'::"char", 'p'::"char"])) AND (NOT a.attisdropped) AND has_column_privilege(c.oid, a.attnum, 'select'::text) AND ((c.relrowsecurity = false) OR (NOT row_security_active(c.oid))));
 pg_hba_file_rules| SELECT a.line_number,
     a.type,
     a.database,
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index d33a4e1..643afe4 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -121,3 +121,10 @@ test: fast_default
 
 # run stats by itself because its delay may be insufficient under heavy load
 test: stats
+
+# global temp table test
+test: gtt_stats
+test: gtt_function
+test: gtt_prepare
+test: gtt_parallel_1 gtt_parallel_2
+test: gtt_clean
diff --git a/src/test/regress/sql/gtt_clean.sql b/src/test/regress/sql/gtt_clean.sql
new file mode 100644
index 0000000..f3cf710
--- /dev/null
+++ b/src/test/regress/sql/gtt_clean.sql
@@ -0,0 +1,6 @@
+
+
+reset search_path;
+
+drop schema gtt cascade;
+
diff --git a/src/test/regress/sql/gtt_function.sql b/src/test/regress/sql/gtt_function.sql
new file mode 100644
index 0000000..cfc1879
--- /dev/null
+++ b/src/test/regress/sql/gtt_function.sql
@@ -0,0 +1,163 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt_function;
+
+set search_path=gtt_function,sys;
+
+create global temp table gtt1(a int primary key, b text);
+
+create global temp table gtt_test_rename(a int primary key, b text);
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text) on commit PRESERVE rows;
+
+create global temp table tmp_t0(c0 tsvector,c1 varchar(100));
+
+create table tbl_inherits_parent(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+);
+
+create global temp table tbl_inherits_parent_global_temp(
+a int not null,
+b varchar(32) not null default 'Got u',
+c int check (c > 0),
+d date not null
+)on commit delete rows;
+
+CREATE global temp TABLE products (
+    product_no integer PRIMARY KEY,
+    name text,
+    price numeric
+);
+
+-- ERROR
+create index CONCURRENTLY idx_gtt1 on gtt1 (b);
+
+-- ERROR
+cluster gtt1 using gtt1_pkey;
+
+-- ERROR
+create table gtt1(a int primary key, b text) on commit delete rows;
+
+-- ok
+create table gtt1(a int primary key, b text) with(on_commit_delete_rows=true);
+
+-- ok
+CREATE global temp TABLE measurement (
+    logdate         date not null,
+    peaktemp        int,
+    unitsales       int
+) PARTITION BY RANGE (logdate);
+
+--ok
+CREATE global temp TABLE p_table01 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)on commit delete rows;
+ 
+CREATE global temp TABLE p_table01_2018
+PARTITION OF p_table01
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+ 
+CREATE global temp TABLE p_table01_2017
+PARTITION OF p_table01
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+
+begin;
+insert into p_table01 values(1,'2018-01-02 00:00:00','test1');
+insert into p_table01 values(1,'2018-01-02 00:00:00','test2');
+select count(*) from p_table01;
+commit;
+
+select count(*) from p_table01;
+
+--ok
+CREATE global temp TABLE p_table02 (
+id        bigserial NOT NULL,
+cre_time  timestamp without time zone,
+note      varchar(30)
+) PARTITION BY RANGE (cre_time)
+WITH (
+OIDS = FALSE
+)
+on commit PRESERVE rows;
+
+CREATE global temp TABLE p_table02_2018
+PARTITION OF p_table02
+FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2019-01-01 00:00:00');
+
+CREATE global temp TABLE p_table02_2017
+PARTITION OF p_table02
+FOR VALUES FROM ('2017-01-01 00:00:00') TO ('2018-01-01 00:00:00');
+
+-- ok
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent);
+create global temp table tbl_inherits_partition() inherits (tbl_inherits_parent_global_temp) on commit delete rows;
+
+select relname ,relkind, relpersistence, reloptions from pg_class where relname like 'p_table0%' or  relname like 'tbl_inherits%' order by relname;
+
+-- ERROR
+create global temp table gtt3(a int primary key, b text) on commit drop;
+
+-- ERROR
+create global temp table gtt4(a int primary key, b text) with(on_commit_delete_rows=true) on commit delete rows;
+
+-- ok
+create global temp table gtt5(a int primary key, b text) with(on_commit_delete_rows=true);
+
+--ok
+alter table gtt_test_rename rename to gtt_test;
+
+-- ok
+ALTER TABLE gtt_test ADD COLUMN address varchar(30);
+
+-- ERROR
+CREATE TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE global temp TABLE orders (
+    order_id integer PRIMARY KEY,
+    product_no integer REFERENCES products (product_no),
+    quantity integer
+);
+
+-- ERROR
+CREATE GLOBAL TEMPORARY TABLE mytable (
+  id SERIAL PRIMARY KEY,
+  data text
+) on commit preserve rows;
+
+-- ok
+create global temp table gtt_seq(id int GENERATED ALWAYS AS IDENTITY (START WITH 2) primary key, a int)  on commit PRESERVE rows;
+insert into gtt_seq (a) values(1);
+insert into gtt_seq (a) values(2);
+select * from gtt_seq order by id;
+truncate gtt_seq;
+select * from gtt_seq order by id;
+insert into gtt_seq (a) values(3);
+select * from gtt_seq order by id;
+
+--ERROR
+CREATE MATERIALIZED VIEW mv_gtt1 as select * from gtt1;
+
+-- ALL ERROR
+create index idx_err on gtt1 using hash (a);
+create index idx_err on gtt1 using gist (a);
+create index idx_tmp_t0_1 on tmp_t0 using gin (c0);
+create index idx_tmp_t0_1 on tmp_t0 using gist (c0);
+
+reset search_path;
+
+drop schema gtt_function cascade;
+
diff --git a/src/test/regress/sql/gtt_parallel_1.sql b/src/test/regress/sql/gtt_parallel_1.sql
new file mode 100644
index 0000000..d7d81de
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_1.sql
@@ -0,0 +1,42 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+commit;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+rollback;
+select * from gtt1 order by a;
+
+truncate gtt1;
+select * from gtt1 order by a;
+
+begin;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+select * from gtt1 order by a;
+insert into gtt1 values(1, 'test1');
+rollback;
+select * from gtt1 order by a;
+
+begin;
+select * from gtt1 order by a;
+truncate gtt1;
+insert into gtt1 values(1, 'test1');
+select * from gtt1 order by a;
+truncate gtt1;
+commit;
+select * from gtt1 order by a;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_parallel_2.sql b/src/test/regress/sql/gtt_parallel_2.sql
new file mode 100644
index 0000000..5203c2b
--- /dev/null
+++ b/src/test/regress/sql/gtt_parallel_2.sql
@@ -0,0 +1,76 @@
+
+
+set search_path=gtt,sys;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test1');
+select * from gtt3 order by a;
+commit;
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(3, 'test1');
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+truncate gtt3;
+select * from gtt3 order by a;
+
+insert into gtt3 values(1, 'test1');
+select * from gtt3 order by a;
+
+begin;
+insert into gtt3 values(2, 'test2');
+select * from gtt3 order by a;
+truncate gtt3;
+select * from gtt3 order by a;
+insert into gtt3 values(3, 'test3');
+update gtt3 set a = 3 where b = 'test1';
+select * from gtt3 order by a;
+rollback;
+select * from gtt3 order by a;
+
+begin;
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(5, 'test5');
+select * from gtt3 order by a;
+truncate gtt3;
+insert into gtt3 values(6, 'test6');
+commit;
+select * from gtt3 order by a;
+
+truncate gtt3;
+insert into gtt3 values(generate_series(1,100000), 'testing');
+select count(*) from gtt3;
+analyze gtt3;
+explain (COSTS FALSE) select * from gtt3 where a =300;
+
+insert into gtt_t_kenyon select generate_series(1,2000),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God',500);
+insert into gtt_t_kenyon select generate_series(1,2),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',2000);
+insert into gtt_t_kenyon select generate_series(3,4),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',4000);
+insert into gtt_t_kenyon select generate_series(5,6),repeat('kenyon here'||'^_^',2),repeat('^_^ Kenyon is not God,Remark here!!',5500);
+select relname, pg_relation_size(oid),pg_relation_size(reltoastrelid),pg_table_size(oid),pg_indexes_size(oid),pg_total_relation_size(oid) from pg_class where relname = 'gtt_t_kenyon';
+select relname from pg_class where relname = 'gtt_t_kenyon' and reltoastrelid != 0;
+
+select
+c.relname, pg_relation_size(c.oid),pg_table_size(c.oid),pg_total_relation_size(c.oid)
+from
+pg_class c
+where
+c.oid in
+(
+select
+i.indexrelid as indexrelid
+from 
+pg_index i ,pg_class cc
+where cc.relname = 'gtt_t_kenyon' and cc.oid = i.indrelid
+)
+order by c.relname;
+
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_prepare.sql b/src/test/regress/sql/gtt_prepare.sql
new file mode 100644
index 0000000..2f4d883
--- /dev/null
+++ b/src/test/regress/sql/gtt_prepare.sql
@@ -0,0 +1,16 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt;
+
+set search_path=gtt,sys;
+
+create global temp table gtt1(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt2(a int primary key, b text) on commit delete rows;
+
+create global temp table gtt3(a int primary key, b text);
+
+create global temp table gtt_t_kenyon(id int,vname varchar(48),remark text) on commit PRESERVE rows;
+create index idx_gtt_t_kenyon_1 on gtt_t_kenyon(id);
+create index idx_gtt_t_kenyon_2 on gtt_t_kenyon(remark);
+reset search_path;
+
diff --git a/src/test/regress/sql/gtt_stats.sql b/src/test/regress/sql/gtt_stats.sql
new file mode 100644
index 0000000..f041892
--- /dev/null
+++ b/src/test/regress/sql/gtt_stats.sql
@@ -0,0 +1,42 @@
+
+CREATE SCHEMA IF NOT EXISTS gtt_stats;
+
+set search_path=gtt_stats,sys;
+
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+
+create global temp table gtt(a int primary key, b text) on commit PRESERVE rows;
+-- expect 0
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 0
+select count(*) from pg_list_gtt_relfrozenxids();
+
+insert into gtt values(generate_series(1,10000),'test');
+
+-- expect 1
+select count(*) from pg_gtt_attached_pids;
+
+-- expect 2
+select count(*) from pg_list_gtt_relfrozenxids();
+
+-- expect 0
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+
+-- expect 0
+select * from pg_gtt_stats order by tablename;
+
+analyze gtt;
+
+select schemaname, tablename, relpages, reltuples, relallvisible from pg_gtt_relstats order by tablename;
+
+select * from pg_gtt_stats order by tablename;
+
+reset search_path;
+
+drop schema gtt_stats cascade;
+