Reduce amount of WAL generated by CREATE INDEX for gist, gin and sp-gist

From db400ce9532536da36812dbf0456e756a0ea4724 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Tue, 31 Jul 2018 07:22:17 +0500
Subject: [PATCH 1/4] Relation-into-WAL-function

---
 src/backend/access/transam/generic_xlog.c | 62 +++++++++++++++++++++++
 src/include/access/generic_xlog.h         |  3 ++
 2 files changed, 65 insertions(+)

diff --git a/src/backend/access/transam/generic_xlog.c b/src/backend/access/transam/generic_xlog.c
index ce023548ae..8397b58ee7 100644
--- a/src/backend/access/transam/generic_xlog.c
+++ b/src/backend/access/transam/generic_xlog.c
@@ -80,6 +80,7 @@ static void computeRegionDelta(PageData *pageData,
 static void computeDelta(PageData *pageData, Page curpage, Page targetpage);
 static void applyPageRedo(Page page, const char *delta, Size deltaSize);
 
+static void standard_page_layout_check(Buffer buf);
 
 /*
  * Write next fragment into pageData's delta.
@@ -545,3 +546,64 @@ generic_mask(char *page, BlockNumber blkno)
 
 	mask_unused_space(page);
 }
+
+/*
+ * Check page layout.
+ * Caller must lock the buffer
+ */
+static void
+standard_page_layout_check(Buffer buf)
+{
+	PageHeader ph = (PageHeader) BufferGetPage(buf);
+
+	Assert((ph->pd_lower >= SizeOfPageHeaderData) &&
+		   (ph->pd_lower <= ph->pd_upper) &&
+		   (ph->pd_upper <= ph->pd_special) &&
+		   (ph->pd_special <= BLCKSZ) &&
+		   (ph->pd_special == MAXALIGN(ph->pd_special)));
+}
+
+/*
+ * Function to write generic xlog for every existing block of a relation.
+ * Caller is responsible for locking the relation exclusively.
+ */
+void
+generic_log_relation(Relation rel)
+{
+	BlockNumber blkno;
+	BlockNumber nblocks;
+
+	nblocks = RelationGetNumberOfBlocks(rel);
+
+	elog(DEBUG2, "generic_log_relation '%s', nblocks %u BEGIN.",
+		 RelationGetRelationName(rel), nblocks);
+
+	for (blkno = 0; blkno < nblocks; )
+	{
+		GenericXLogState	*state;
+		Buffer				buffer[MAX_GENERIC_XLOG_PAGES];
+		int					counter,
+							blocks_pack;
+
+		CHECK_FOR_INTERRUPTS();
+
+		blocks_pack = ((nblocks-blkno) < MAX_GENERIC_XLOG_PAGES) ?
+						(nblocks-blkno) : MAX_GENERIC_XLOG_PAGES;
+
+		state = GenericXLogStart(rel);
+
+		for (counter = 0 ; counter < blocks_pack; counter++)
+		{
+			buffer[counter] = ReadBuffer(rel, blkno++);
+			standard_page_layout_check(buffer[counter]);
+			LockBuffer(buffer[counter], BUFFER_LOCK_EXCLUSIVE);
+			GenericXLogRegisterBuffer(state, buffer[counter], GENERIC_XLOG_FULL_IMAGE);
+		}
+
+		GenericXLogFinish(state);
+
+		for (counter = 0 ; counter < blocks_pack; counter++)
+			UnlockReleaseBuffer(buffer[counter]);
+	}
+	elog(DEBUG2, "generic_log_relation '%s' END.", RelationGetRelationName(rel));
+}
diff --git a/src/include/access/generic_xlog.h b/src/include/access/generic_xlog.h
index b23e1f684b..1f4b3b7030 100644
--- a/src/include/access/generic_xlog.h
+++ b/src/include/access/generic_xlog.h
@@ -42,4 +42,7 @@ extern const char *generic_identify(uint8 info);
 extern void generic_desc(StringInfo buf, XLogReaderState *record);
 extern void generic_mask(char *pagedata, BlockNumber blkno);
 
+/* other utils */
+extern void generic_log_relation(Relation rel);
+
 #endif							/* GENERIC_XLOG_H */
-- 
2.17.1

From 8db76f41386e9b205fd16f856a823c9a3fabe6fc Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Tue, 31 Jul 2018 07:22:46 +0500
Subject: [PATCH 2/4] GIN-Optimal-WAL-Usage

---
 src/backend/access/gin/ginbtree.c     |  6 ++---
 src/backend/access/gin/gindatapage.c  | 10 ++++----
 src/backend/access/gin/ginentrypage.c |  2 +-
 src/backend/access/gin/gininsert.c    | 30 ++++++++++--------------
 src/backend/access/gin/ginutil.c      |  4 ++--
 src/backend/access/gin/ginvacuum.c    |  2 +-
 src/backend/access/gin/ginxlog.c      | 33 ---------------------------
 src/backend/access/rmgrdesc/gindesc.c |  6 -----
 src/include/access/gin.h              |  3 ++-
 src/include/access/ginxlog.h          |  2 --
 10 files changed, 27 insertions(+), 71 deletions(-)

diff --git a/src/backend/access/gin/ginbtree.c b/src/backend/access/gin/ginbtree.c
index 030d0f4418..b6d9f1bace 100644
--- a/src/backend/access/gin/ginbtree.c
+++ b/src/backend/access/gin/ginbtree.c
@@ -392,7 +392,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
 		/* It will fit, perform the insertion */
 		START_CRIT_SECTION();
 
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 		{
 			XLogBeginInsert();
 			XLogRegisterBuffer(0, stack->buffer, REGBUF_STANDARD);
@@ -413,7 +413,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
 			MarkBufferDirty(childbuf);
 		}
 
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 		{
 			XLogRecPtr	recptr;
 			ginxlogInsert xlrec;
@@ -591,7 +591,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
 		}
 
 		/* write WAL record */
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 		{
 			XLogRecPtr	recptr;
 
diff --git a/src/backend/access/gin/gindatapage.c b/src/backend/access/gin/gindatapage.c
index 9f20513811..7dd4284e26 100644
--- a/src/backend/access/gin/gindatapage.c
+++ b/src/backend/access/gin/gindatapage.c
@@ -593,7 +593,7 @@ dataBeginPlaceToPageLeaf(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 		 * Great, all the items fit on a single page.  If needed, prepare data
 		 * for a WAL record describing the changes we'll make.
 		 */
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 			computeLeafRecompressWALData(leaf);
 
 		/*
@@ -630,6 +630,7 @@ dataBeginPlaceToPageLeaf(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 		 * subsequent insertions will probably also go to the end. This packs
 		 * the index somewhat tighter when appending to a table, which is very
 		 * common.
+		 *
 		 */
 		if (!btree->isBuild)
 		{
@@ -719,7 +720,7 @@ dataExecPlaceToPageLeaf(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 	dataPlaceToPageLeafRecompress(buf, leaf);
 
 	/* If needed, register WAL data built by computeLeafRecompressWALData */
-	if (RelationNeedsWAL(btree->index))
+	if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 	{
 		XLogRegisterBufData(0, leaf->walinfo, leaf->walinfolen);
 	}
@@ -1152,7 +1153,7 @@ dataExecPlaceToPageInternal(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 	pitem = (PostingItem *) insertdata;
 	GinDataPageAddPostingItem(page, pitem, off);
 
-	if (RelationNeedsWAL(btree->index))
+	if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 	{
 		/*
 		 * This must be static, because it has to survive until XLogInsert,
@@ -1773,6 +1774,7 @@ createPostingTree(Relation index, ItemPointerData *items, uint32 nitems,
 	Pointer		ptr;
 	int			nrootitems;
 	int			rootsize;
+	bool is_build = (buildStats != NULL);
 
 	/* Construct the new root page in memory first. */
 	tmppage = (Page) palloc(BLCKSZ);
@@ -1826,7 +1828,7 @@ createPostingTree(Relation index, ItemPointerData *items, uint32 nitems,
 	PageRestoreTempPage(tmppage, page);
 	MarkBufferDirty(buffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !is_build)
 	{
 		XLogRecPtr	recptr;
 		ginxlogCreatePostingTree data;
diff --git a/src/backend/access/gin/ginentrypage.c b/src/backend/access/gin/ginentrypage.c
index 810769718f..b0fdb23e2b 100644
--- a/src/backend/access/gin/ginentrypage.c
+++ b/src/backend/access/gin/ginentrypage.c
@@ -571,7 +571,7 @@ entryExecPlaceToPage(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 		elog(ERROR, "failed to add item to index page in \"%s\"",
 			 RelationGetRelationName(btree->index));
 
-	if (RelationNeedsWAL(btree->index))
+	if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 	{
 		/*
 		 * This must be static, because it has to survive until XLogInsert,
diff --git a/src/backend/access/gin/gininsert.c b/src/backend/access/gin/gininsert.c
index 5281eb6823..980ab2232c 100644
--- a/src/backend/access/gin/gininsert.c
+++ b/src/backend/access/gin/gininsert.c
@@ -17,6 +17,7 @@
 #include "access/gin_private.h"
 #include "access/ginxlog.h"
 #include "access/xloginsert.h"
+#include "access/generic_xlog.h"
 #include "catalog/index.h"
 #include "miscadmin.h"
 #include "storage/bufmgr.h"
@@ -194,6 +195,7 @@ ginEntryInsert(GinState *ginstate,
 		buildStats->nEntries++;
 
 	ginPrepareEntryScan(&btree, attnum, key, category, ginstate);
+	btree.isBuild = (buildStats != NULL);
 
 	stack = ginFindLeafPage(&btree, false, NULL);
 	page = BufferGetPage(stack->buffer);
@@ -346,23 +348,6 @@ ginbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	GinInitBuffer(RootBuffer, GIN_LEAF);
 	MarkBufferDirty(RootBuffer);
 
-	if (RelationNeedsWAL(index))
-	{
-		XLogRecPtr	recptr;
-		Page		page;
-
-		XLogBeginInsert();
-		XLogRegisterBuffer(0, MetaBuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-		XLogRegisterBuffer(1, RootBuffer, REGBUF_WILL_INIT);
-
-		recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_CREATE_INDEX);
-
-		page = BufferGetPage(RootBuffer);
-		PageSetLSN(page, recptr);
-
-		page = BufferGetPage(MetaBuffer);
-		PageSetLSN(page, recptr);
-	}
 
 	UnlockReleaseBuffer(MetaBuffer);
 	UnlockReleaseBuffer(RootBuffer);
@@ -417,7 +402,16 @@ ginbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	 * Update metapage stats
 	 */
 	buildstate.buildStats.nTotalPages = RelationGetNumberOfBlocks(index);
-	ginUpdateStats(index, &buildstate.buildStats);
+	ginUpdateStats(index, &buildstate.buildStats, true);
+
+	/*
+	 * Create generic wal records for all pages of relation, if necessary.
+	 * It seems reasonable not to generate WAL, if we recieved interrupt
+	 * signal.
+	 */
+	CHECK_FOR_INTERRUPTS();
+	if (RelationNeedsWAL(index))
+		generic_log_relation(index);
 
 	/*
 	 * Return statistics
diff --git a/src/backend/access/gin/ginutil.c b/src/backend/access/gin/ginutil.c
index 0a32182dd7..37d3e89acb 100644
--- a/src/backend/access/gin/ginutil.c
+++ b/src/backend/access/gin/ginutil.c
@@ -666,7 +666,7 @@ ginGetStats(Relation index, GinStatsData *stats)
  * Note: nPendingPages and ginVersion are *not* copied over
  */
 void
-ginUpdateStats(Relation index, const GinStatsData *stats)
+ginUpdateStats(Relation index, const GinStatsData *stats, bool is_build)
 {
 	Buffer		metabuffer;
 	Page		metapage;
@@ -696,7 +696,7 @@ ginUpdateStats(Relation index, const GinStatsData *stats)
 
 	MarkBufferDirty(metabuffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !is_build)
 	{
 		XLogRecPtr	recptr;
 		ginxlogUpdateMeta data;
diff --git a/src/backend/access/gin/ginvacuum.c b/src/backend/access/gin/ginvacuum.c
index 3104bc12b6..1d8626fd5e 100644
--- a/src/backend/access/gin/ginvacuum.c
+++ b/src/backend/access/gin/ginvacuum.c
@@ -765,7 +765,7 @@ ginvacuumcleanup(IndexVacuumInfo *info, IndexBulkDeleteResult *stats)
 
 	/* Update the metapage with accurate page and entry counts */
 	idxStat.nTotalPages = npages;
-	ginUpdateStats(info->index, &idxStat);
+	ginUpdateStats(info->index, &idxStat, false);
 
 	/* Finally, vacuum the FSM */
 	IndexFreeSpaceMapVacuum(info->index);
diff --git a/src/backend/access/gin/ginxlog.c b/src/backend/access/gin/ginxlog.c
index 7a1e94a1d5..13a78a2a3b 100644
--- a/src/backend/access/gin/ginxlog.c
+++ b/src/backend/access/gin/ginxlog.c
@@ -40,36 +40,6 @@ ginRedoClearIncompleteSplit(XLogReaderState *record, uint8 block_id)
 		UnlockReleaseBuffer(buffer);
 }
 
-static void
-ginRedoCreateIndex(XLogReaderState *record)
-{
-	XLogRecPtr	lsn = record->EndRecPtr;
-	Buffer		RootBuffer,
-				MetaBuffer;
-	Page		page;
-
-	MetaBuffer = XLogInitBufferForRedo(record, 0);
-	Assert(BufferGetBlockNumber(MetaBuffer) == GIN_METAPAGE_BLKNO);
-	page = (Page) BufferGetPage(MetaBuffer);
-
-	GinInitMetabuffer(MetaBuffer);
-
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(MetaBuffer);
-
-	RootBuffer = XLogInitBufferForRedo(record, 1);
-	Assert(BufferGetBlockNumber(RootBuffer) == GIN_ROOT_BLKNO);
-	page = (Page) BufferGetPage(RootBuffer);
-
-	GinInitBuffer(RootBuffer, GIN_LEAF);
-
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(RootBuffer);
-
-	UnlockReleaseBuffer(RootBuffer);
-	UnlockReleaseBuffer(MetaBuffer);
-}
-
 static void
 ginRedoCreatePTree(XLogReaderState *record)
 {
@@ -724,9 +694,6 @@ gin_redo(XLogReaderState *record)
 	oldCtx = MemoryContextSwitchTo(opCtx);
 	switch (info)
 	{
-		case XLOG_GIN_CREATE_INDEX:
-			ginRedoCreateIndex(record);
-			break;
 		case XLOG_GIN_CREATE_PTREE:
 			ginRedoCreatePTree(record);
 			break;
diff --git a/src/backend/access/rmgrdesc/gindesc.c b/src/backend/access/rmgrdesc/gindesc.c
index 3456187e3d..1bb1733666 100644
--- a/src/backend/access/rmgrdesc/gindesc.c
+++ b/src/backend/access/rmgrdesc/gindesc.c
@@ -78,9 +78,6 @@ gin_desc(StringInfo buf, XLogReaderState *record)
 
 	switch (info)
 	{
-		case XLOG_GIN_CREATE_INDEX:
-			/* no further information */
-			break;
 		case XLOG_GIN_CREATE_PTREE:
 			/* no further information */
 			break;
@@ -188,9 +185,6 @@ gin_identify(uint8 info)
 
 	switch (info & ~XLR_INFO_MASK)
 	{
-		case XLOG_GIN_CREATE_INDEX:
-			id = "CREATE_INDEX";
-			break;
 		case XLOG_GIN_CREATE_PTREE:
 			id = "CREATE_PTREE";
 			break;
diff --git a/src/include/access/gin.h b/src/include/access/gin.h
index 3d8a130b69..0fa33f5a19 100644
--- a/src/include/access/gin.h
+++ b/src/include/access/gin.h
@@ -71,6 +71,7 @@ extern int	gin_pending_list_limit;
 
 /* ginutil.c */
 extern void ginGetStats(Relation index, GinStatsData *stats);
-extern void ginUpdateStats(Relation index, const GinStatsData *stats);
+extern void ginUpdateStats(Relation index,
+						   const GinStatsData *stats, bool is_build);
 
 #endif							/* GIN_H */
diff --git a/src/include/access/ginxlog.h b/src/include/access/ginxlog.h
index 64a3c9e18b..5c74973444 100644
--- a/src/include/access/ginxlog.h
+++ b/src/include/access/ginxlog.h
@@ -16,8 +16,6 @@
 #include "lib/stringinfo.h"
 #include "storage/off.h"
 
-#define XLOG_GIN_CREATE_INDEX  0x00
-
 #define XLOG_GIN_CREATE_PTREE  0x10
 
 typedef struct ginxlogCreatePostingTree
-- 
2.17.1

From 49a5fc72492f4917990bfeb7bd6c4fd06e52a7d5 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Tue, 31 Jul 2018 07:23:11 +0500
Subject: [PATCH 3/4] GIST-Optimal-WAL-Usage

---
 src/backend/access/gist/gist.c         | 46 ++++++++++++++++++--------
 src/backend/access/gist/gistbuild.c    | 32 ++++++++++--------
 src/backend/access/gist/gistutil.c     |  2 +-
 src/backend/access/gist/gistxlog.c     | 22 ------------
 src/backend/access/rmgrdesc/gistdesc.c |  5 ---
 src/include/access/gist_private.h      | 10 +++---
 src/include/access/gistxlog.h          |  1 -
 7 files changed, 57 insertions(+), 61 deletions(-)

diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index 8a42effdf7..227998b1f8 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -172,7 +172,7 @@ gistinsert(Relation r, Datum *values, bool *isnull,
 						 values, isnull, true /* size is currently bogus */ );
 	itup->t_tid = *ht_ctid;
 
-	gistdoinsert(r, itup, 0, giststate);
+	gistdoinsert(r, itup, 0, giststate, false);
 
 	/* cleanup */
 	MemoryContextSwitchTo(oldCxt);
@@ -218,7 +218,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 				BlockNumber *newblkno,
 				Buffer leftchildbuf,
 				List **splitinfo,
-				bool markfollowright)
+				bool markfollowright,
+				bool is_build)
 {
 	BlockNumber blkno = BufferGetBlockNumber(buffer);
 	Page		page = BufferGetPage(buffer);
@@ -457,7 +458,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		 * insertion for that. NB: The number of pages and data segments
 		 * specified here must match the calculations in gistXLogSplit()!
 		 */
-		if (RelationNeedsWAL(rel))
+		if (RelationNeedsWAL(rel) && !is_build)
 			XLogEnsureRecordSpace(npage, 1 + npage * 2);
 
 		START_CRIT_SECTION();
@@ -478,18 +479,20 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		PageRestoreTempPage(dist->page, BufferGetPage(dist->buffer));
 		dist->page = BufferGetPage(dist->buffer);
 
-		/* Write the WAL record */
-		if (RelationNeedsWAL(rel))
+		/*
+		 * Write the WAL record.
+		 * Do not write XLog entry if the insertion is caused by
+		 * index build process.
+		 */
+		if (RelationNeedsWAL(rel) && !is_build)
 			recptr = gistXLogSplit(is_leaf,
-								   dist, oldrlink, oldnsn, leftchildbuf,
-								   markfollowright);
+								dist, oldrlink, oldnsn, leftchildbuf,
+								markfollowright);
 		else
 			recptr = gistGetFakeLSN(rel);
 
 		for (ptr = dist; ptr; ptr = ptr->next)
-		{
 			PageSetLSN(ptr->page, recptr);
-		}
 
 		/*
 		 * Return the new child buffers to the caller.
@@ -543,7 +546,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		if (BufferIsValid(leftchildbuf))
 			MarkBufferDirty(leftchildbuf);
 
-		if (RelationNeedsWAL(rel))
+
+		if (RelationNeedsWAL(rel) && !is_build)
 		{
 			OffsetNumber ndeloffs = 0,
 						deloffs[1];
@@ -566,6 +570,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 			PageSetLSN(page, recptr);
 		}
 
+
 		if (newblkno)
 			*newblkno = blkno;
 	}
@@ -582,17 +587,28 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 	 * the full page image. There's a chicken-and-egg problem: if we updated
 	 * the child pages first, we wouldn't know the recptr of the WAL record
 	 * we're about to write.
+	 *
+	 * We use fakeLSNs for inserions caused by index build. And when it is
+	 * finished, we write generic_xlog entry for each index page and update
+	 * all LSNs. In order to keep NSNs less then LSNs after this update, we
+	 * set NSN to InvalidXLogRecPtr, which is the smallest possible NSN.
 	 */
+
 	if (BufferIsValid(leftchildbuf))
 	{
 		Page		leftpg = BufferGetPage(leftchildbuf);
+		XLogRecPtr	fakerecptr = InvalidXLogRecPtr;
 
-		GistPageSetNSN(leftpg, recptr);
-		GistClearFollowRight(leftpg);
+		if (!is_build)
+			GistPageSetNSN(leftpg, recptr);
+		else
+			GistPageSetNSN(leftpg, fakerecptr);
 
+		GistClearFollowRight(leftpg);
 		PageSetLSN(leftpg, recptr);
 	}
 
+
 	END_CRIT_SECTION();
 
 	return is_split;
@@ -604,7 +620,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
  * so it does not bother releasing palloc'd allocations.
  */
 void
-gistdoinsert(Relation r, IndexTuple itup, Size freespace, GISTSTATE *giststate)
+gistdoinsert(Relation r, IndexTuple itup, Size freespace,
+			 GISTSTATE *giststate, bool is_build)
 {
 	ItemId		iid;
 	IndexTuple	idxtuple;
@@ -616,6 +633,7 @@ gistdoinsert(Relation r, IndexTuple itup, Size freespace, GISTSTATE *giststate)
 	memset(&state, 0, sizeof(GISTInsertState));
 	state.freespace = freespace;
 	state.r = r;
+	state.is_build = is_build;
 
 	/* Start from the root */
 	firststack.blkno = GIST_ROOT_BLKNO;
@@ -1232,7 +1250,7 @@ gistinserttuples(GISTInsertState *state, GISTInsertStack *stack,
 							   oldoffnum, NULL,
 							   leftchild,
 							   &splitinfo,
-							   true);
+							   true, state->is_build);
 
 	/*
 	 * Before recursing up in case the page was split, release locks on the
diff --git a/src/backend/access/gist/gistbuild.c b/src/backend/access/gist/gistbuild.c
index 434f15f014..b61dbf8ac3 100644
--- a/src/backend/access/gist/gistbuild.c
+++ b/src/backend/access/gist/gistbuild.c
@@ -20,6 +20,7 @@
 #include "access/gist_private.h"
 #include "access/gistxlog.h"
 #include "access/xloginsert.h"
+#include "access/generic_xlog.h"
 #include "catalog/index.h"
 #include "miscadmin.h"
 #include "optimizer/cost.h"
@@ -178,18 +179,12 @@ gistbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 
 	MarkBufferDirty(buffer);
 
-	if (RelationNeedsWAL(index))
-	{
-		XLogRecPtr	recptr;
-
-		XLogBeginInsert();
-		XLogRegisterBuffer(0, buffer, REGBUF_WILL_INIT);
-
-		recptr = XLogInsert(RM_GIST_ID, XLOG_GIST_CREATE_INDEX);
-		PageSetLSN(page, recptr);
-	}
-	else
-		PageSetLSN(page, gistGetFakeLSN(heap));
+	/*
+	 * Do not write index pages to WAL unitl index build is finished.
+	 * But we still need increasing LSNs on each page, so use FakeLSN,
+	 * even for relations which eventually need WAL.
+	 */
+	PageSetLSN(page, gistGetFakeLSN(heap));
 
 	UnlockReleaseBuffer(buffer);
 
@@ -222,6 +217,15 @@ gistbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 
 	freeGISTstate(buildstate.giststate);
 
+	/*
+	 * Create generic wal records for all pages of relation, if necessary.
+	 * It seems reasonable not to generate WAL, if we recieved interrupt
+	 * signal.
+	 */
+	CHECK_FOR_INTERRUPTS();
+	if (RelationNeedsWAL(index))
+		generic_log_relation(index);
+
 	/*
 	 * Return statistics
 	 */
@@ -484,7 +488,7 @@ gistBuildCallback(Relation index,
 		 * locked, we call gistdoinsert directly.
 		 */
 		gistdoinsert(index, itup, buildstate->freespace,
-					 buildstate->giststate);
+					 buildstate->giststate, true);
 	}
 
 	/* Update tuple count and total size. */
@@ -690,7 +694,7 @@ gistbufferinginserttuples(GISTBuildState *buildstate, Buffer buffer, int level,
 							   itup, ntup, oldoffnum, &placed_to_blk,
 							   InvalidBuffer,
 							   &splitinfo,
-							   false);
+							   false, true);
 
 	/*
 	 * If this is a root split, update the root path item kept in memory. This
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index 12804c321c..0b3f8db679 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -974,6 +974,7 @@ gistproperty(Oid index_oid, int attno,
  * Temporary and unlogged GiST indexes are not WAL-logged, but we need LSNs
  * to detect concurrent page splits anyway. This function provides a fake
  * sequence of LSNs for that purpose.
+ * Persistent relations are also not WAL-logged while we build index.
  */
 XLogRecPtr
 gistGetFakeLSN(Relation rel)
@@ -994,7 +995,6 @@ gistGetFakeLSN(Relation rel)
 		 * Unlogged relations are accessible from other backends, and survive
 		 * (clean) restarts. GetFakeLSNForUnloggedRel() handles that for us.
 		 */
-		Assert(rel->rd_rel->relpersistence == RELPERSISTENCE_UNLOGGED);
 		return GetFakeLSNForUnloggedRel();
 	}
 }
diff --git a/src/backend/access/gist/gistxlog.c b/src/backend/access/gist/gistxlog.c
index 1e09126978..9b0abccdaf 100644
--- a/src/backend/access/gist/gistxlog.c
+++ b/src/backend/access/gist/gistxlog.c
@@ -281,25 +281,6 @@ gistRedoPageSplitRecord(XLogReaderState *record)
 	UnlockReleaseBuffer(firstbuffer);
 }
 
-static void
-gistRedoCreateIndex(XLogReaderState *record)
-{
-	XLogRecPtr	lsn = record->EndRecPtr;
-	Buffer		buffer;
-	Page		page;
-
-	buffer = XLogInitBufferForRedo(record, 0);
-	Assert(BufferGetBlockNumber(buffer) == GIST_ROOT_BLKNO);
-	page = (Page) BufferGetPage(buffer);
-
-	GISTInitBuffer(buffer, F_LEAF);
-
-	PageSetLSN(page, lsn);
-
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-}
-
 void
 gist_redo(XLogReaderState *record)
 {
@@ -321,9 +302,6 @@ gist_redo(XLogReaderState *record)
 		case XLOG_GIST_PAGE_SPLIT:
 			gistRedoPageSplitRecord(record);
 			break;
-		case XLOG_GIST_CREATE_INDEX:
-			gistRedoCreateIndex(record);
-			break;
 		default:
 			elog(PANIC, "gist_redo: unknown op code %u", info);
 	}
diff --git a/src/backend/access/rmgrdesc/gistdesc.c b/src/backend/access/rmgrdesc/gistdesc.c
index e5e925e0c5..1685a2fb8a 100644
--- a/src/backend/access/rmgrdesc/gistdesc.c
+++ b/src/backend/access/rmgrdesc/gistdesc.c
@@ -44,8 +44,6 @@ gist_desc(StringInfo buf, XLogReaderState *record)
 		case XLOG_GIST_PAGE_SPLIT:
 			out_gistxlogPageSplit(buf, (gistxlogPageSplit *) rec);
 			break;
-		case XLOG_GIST_CREATE_INDEX:
-			break;
 	}
 }
 
@@ -62,9 +60,6 @@ gist_identify(uint8 info)
 		case XLOG_GIST_PAGE_SPLIT:
 			id = "PAGE_SPLIT";
 			break;
-		case XLOG_GIST_CREATE_INDEX:
-			id = "CREATE_INDEX";
-			break;
 	}
 
 	return id;
diff --git a/src/include/access/gist_private.h b/src/include/access/gist_private.h
index 36ed7244ba..0588fc716a 100644
--- a/src/include/access/gist_private.h
+++ b/src/include/access/gist_private.h
@@ -241,6 +241,7 @@ typedef struct
 {
 	Relation	r;
 	Size		freespace;		/* free space to be left */
+	bool		is_build;
 
 	GISTInsertStack *stack;
 } GISTInsertState;
@@ -387,9 +388,9 @@ extern MemoryContext createTempGistContext(void);
 extern GISTSTATE *initGISTstate(Relation index);
 extern void freeGISTstate(GISTSTATE *giststate);
 extern void gistdoinsert(Relation r,
-			 IndexTuple itup,
-			 Size freespace,
-			 GISTSTATE *GISTstate);
+						 IndexTuple itup,
+						 Size freespace,
+						 GISTSTATE* giststate, bool is_build);
 
 /* A List of these is returned from gistplacetopage() in *splitinfo */
 typedef struct
@@ -404,7 +405,8 @@ extern bool gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 				OffsetNumber oldoffnum, BlockNumber *newblkno,
 				Buffer leftchildbuf,
 				List **splitinfo,
-				bool markleftchild);
+				bool markleftchild,
+				bool is_build);
 
 extern SplitedPageLayout *gistSplit(Relation r, Page page, IndexTuple *itup,
 		  int len, GISTSTATE *giststate);
diff --git a/src/include/access/gistxlog.h b/src/include/access/gistxlog.h
index 1a2b9496d0..5932fc395b 100644
--- a/src/include/access/gistxlog.h
+++ b/src/include/access/gistxlog.h
@@ -21,7 +21,6 @@
  /* #define XLOG_GIST_NEW_ROOT			 0x20 */	/* not used anymore */
 #define XLOG_GIST_PAGE_SPLIT		0x30
  /* #define XLOG_GIST_INSERT_COMPLETE	 0x40 */	/* not used anymore */
-#define XLOG_GIST_CREATE_INDEX		0x50
  /* #define XLOG_GIST_PAGE_DELETE		 0x60 */	/* not used anymore */
 
 /*
-- 
2.17.1

From 41ec17abe5a60b5dedee28aa940c8556bc0e402f Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Tue, 31 Jul 2018 07:23:36 +0500
Subject: [PATCH 4/4]  SPGIST-Optimal-WAL-Usage

---
 src/backend/access/rmgrdesc/spgdesc.c   |  5 ----
 src/backend/access/spgist/spgdoinsert.c | 12 ++++-----
 src/backend/access/spgist/spginsert.c   | 24 +++--------------
 src/backend/access/spgist/spgxlog.c     | 35 -------------------------
 src/include/access/spgxlog.h            |  1 -
 5 files changed, 10 insertions(+), 67 deletions(-)

diff --git a/src/backend/access/rmgrdesc/spgdesc.c b/src/backend/access/rmgrdesc/spgdesc.c
index 92b1392974..14beb5702f 100644
--- a/src/backend/access/rmgrdesc/spgdesc.c
+++ b/src/backend/access/rmgrdesc/spgdesc.c
@@ -24,8 +24,6 @@ spg_desc(StringInfo buf, XLogReaderState *record)
 
 	switch (info)
 	{
-		case XLOG_SPGIST_CREATE_INDEX:
-			break;
 		case XLOG_SPGIST_ADD_LEAF:
 			{
 				spgxlogAddLeaf *xlrec = (spgxlogAddLeaf *) rec;
@@ -88,9 +86,6 @@ spg_identify(uint8 info)
 
 	switch (info & ~XLR_INFO_MASK)
 	{
-		case XLOG_SPGIST_CREATE_INDEX:
-			id = "CREATE_INDEX";
-			break;
 		case XLOG_SPGIST_ADD_LEAF:
 			id = "ADD_LEAF";
 			break;
diff --git a/src/backend/access/spgist/spgdoinsert.c b/src/backend/access/spgist/spgdoinsert.c
index 098e09c574..e84ffdfb16 100644
--- a/src/backend/access/spgist/spgdoinsert.c
+++ b/src/backend/access/spgist/spgdoinsert.c
@@ -289,7 +289,7 @@ addLeafTuple(Relation index, SpGistState *state, SpGistLeafTuple leafTuple,
 
 	MarkBufferDirty(current->buffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 		int			flags;
@@ -516,7 +516,7 @@ moveLeafs(Relation index, SpGistState *state,
 	MarkBufferDirty(current->buffer);
 	MarkBufferDirty(nbuf);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 
@@ -1334,7 +1334,7 @@ doPickSplit(Relation index, SpGistState *state,
 		saveCurrent.buffer = InvalidBuffer;
 	}
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 		int			flags;
@@ -1531,7 +1531,7 @@ spgAddNodeAction(Relation index, SpGistState *state,
 
 		MarkBufferDirty(current->buffer);
 
-		if (RelationNeedsWAL(index))
+		if (RelationNeedsWAL(index) && !state->isBuild)
 		{
 			XLogRecPtr	recptr;
 
@@ -1644,7 +1644,7 @@ spgAddNodeAction(Relation index, SpGistState *state,
 
 		MarkBufferDirty(saveCurrent.buffer);
 
-		if (RelationNeedsWAL(index))
+		if (RelationNeedsWAL(index) && !state->isBuild)
 		{
 			XLogRecPtr	recptr;
 			int			flags;
@@ -1840,7 +1840,7 @@ spgSplitNodeAction(Relation index, SpGistState *state,
 
 	MarkBufferDirty(current->buffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 
diff --git a/src/backend/access/spgist/spginsert.c b/src/backend/access/spgist/spginsert.c
index 7dd0d61fbb..18ee9f8cbe 100644
--- a/src/backend/access/spgist/spginsert.c
+++ b/src/backend/access/spgist/spginsert.c
@@ -21,6 +21,7 @@
 #include "access/spgxlog.h"
 #include "access/xlog.h"
 #include "access/xloginsert.h"
+#include "access/generic_xlog.h"
 #include "catalog/index.h"
 #include "miscadmin.h"
 #include "storage/bufmgr.h"
@@ -104,26 +105,6 @@ spgbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	SpGistInitBuffer(nullbuffer, SPGIST_LEAF | SPGIST_NULLS);
 	MarkBufferDirty(nullbuffer);
 
-	if (RelationNeedsWAL(index))
-	{
-		XLogRecPtr	recptr;
-
-		XLogBeginInsert();
-
-		/*
-		 * Replay will re-initialize the pages, so don't take full pages
-		 * images.  No other data to log.
-		 */
-		XLogRegisterBuffer(0, metabuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-		XLogRegisterBuffer(1, rootbuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-		XLogRegisterBuffer(2, nullbuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-
-		recptr = XLogInsert(RM_SPGIST_ID, XLOG_SPGIST_CREATE_INDEX);
-
-		PageSetLSN(BufferGetPage(metabuffer), recptr);
-		PageSetLSN(BufferGetPage(rootbuffer), recptr);
-		PageSetLSN(BufferGetPage(nullbuffer), recptr);
-	}
 
 	END_CRIT_SECTION();
 
@@ -150,6 +131,9 @@ spgbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 
 	SpGistUpdateMetaPage(index);
 
+	if (RelationNeedsWAL(index))
+		generic_log_relation(index);
+
 	result = (IndexBuildResult *) palloc0(sizeof(IndexBuildResult));
 	result->heap_tuples = reltuples;
 	result->index_tuples = buildstate.indtuples;
diff --git a/src/backend/access/spgist/spgxlog.c b/src/backend/access/spgist/spgxlog.c
index 9e2bd3f811..2c42f1be42 100644
--- a/src/backend/access/spgist/spgxlog.c
+++ b/src/backend/access/spgist/spgxlog.c
@@ -72,38 +72,6 @@ addOrReplaceTuple(Page page, Item tuple, int size, OffsetNumber offset)
 			 size);
 }
 
-static void
-spgRedoCreateIndex(XLogReaderState *record)
-{
-	XLogRecPtr	lsn = record->EndRecPtr;
-	Buffer		buffer;
-	Page		page;
-
-	buffer = XLogInitBufferForRedo(record, 0);
-	Assert(BufferGetBlockNumber(buffer) == SPGIST_METAPAGE_BLKNO);
-	page = (Page) BufferGetPage(buffer);
-	SpGistInitMetapage(page);
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-
-	buffer = XLogInitBufferForRedo(record, 1);
-	Assert(BufferGetBlockNumber(buffer) == SPGIST_ROOT_BLKNO);
-	SpGistInitBuffer(buffer, SPGIST_LEAF);
-	page = (Page) BufferGetPage(buffer);
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-
-	buffer = XLogInitBufferForRedo(record, 2);
-	Assert(BufferGetBlockNumber(buffer) == SPGIST_NULL_BLKNO);
-	SpGistInitBuffer(buffer, SPGIST_LEAF | SPGIST_NULLS);
-	page = (Page) BufferGetPage(buffer);
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-}
-
 static void
 spgRedoAddLeaf(XLogReaderState *record)
 {
@@ -976,9 +944,6 @@ spg_redo(XLogReaderState *record)
 	oldCxt = MemoryContextSwitchTo(opCtx);
 	switch (info)
 	{
-		case XLOG_SPGIST_CREATE_INDEX:
-			spgRedoCreateIndex(record);
-			break;
 		case XLOG_SPGIST_ADD_LEAF:
 			spgRedoAddLeaf(record);
 			break;
diff --git a/src/include/access/spgxlog.h b/src/include/access/spgxlog.h
index b72ccb5cc4..44ad891de3 100644
--- a/src/include/access/spgxlog.h
+++ b/src/include/access/spgxlog.h
@@ -18,7 +18,6 @@
 #include "storage/off.h"
 
 /* XLOG record types for SPGiST */
-#define XLOG_SPGIST_CREATE_INDEX	0x00
 #define XLOG_SPGIST_ADD_LEAF		0x10
 #define XLOG_SPGIST_MOVE_LEAFS		0x20
 #define XLOG_SPGIST_ADD_NODE		0x30
-- 
2.17.1

From afc270f37cd082fb6e9f4ad694ea4cb123d98062 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Tue, 5 Feb 2019 08:11:47 +0500
Subject: [PATCH 1/4] Relation-into-WAL-function

---
 src/backend/access/spgist/spgutils.c      |  1 +
 src/backend/access/transam/generic_xlog.c | 39 +++++++++++++++++++++++
 src/include/access/generic_xlog.h         |  3 ++
 3 files changed, 43 insertions(+)

diff --git a/src/backend/access/spgist/spgutils.c b/src/backend/access/spgist/spgutils.c
index 8e63c1fad2..b782bc2338 100644
--- a/src/backend/access/spgist/spgutils.c
+++ b/src/backend/access/spgist/spgutils.c
@@ -550,6 +550,7 @@ SpGistInitBuffer(Buffer b, uint16 f)
 {
 	Assert(BufferGetPageSize(b) == BLCKSZ);
 	SpGistInitPage(BufferGetPage(b), f);
+	MarkBufferDirty(b);
 }
 
 /*
diff --git a/src/backend/access/transam/generic_xlog.c b/src/backend/access/transam/generic_xlog.c
index 5b00b7275b..643da48345 100644
--- a/src/backend/access/transam/generic_xlog.c
+++ b/src/backend/access/transam/generic_xlog.c
@@ -542,3 +542,42 @@ generic_mask(char *page, BlockNumber blkno)
 
 	mask_unused_space(page);
 }
+
+/*
+ * Function to write generic xlog for every existing block of a relation.
+ * Caller is responsible for locking the relation exclusively.
+ */
+void
+generic_log_relation(Relation rel)
+{
+	BlockNumber blkno;
+	BlockNumber nblocks = RelationGetNumberOfBlocks(rel);
+
+	for (blkno = 0; blkno < nblocks; )
+	{
+		GenericXLogState	*state;
+		Buffer				buffer[MAX_GENERIC_XLOG_PAGES];
+		int					i,
+							blocks_pack;
+
+		CHECK_FOR_INTERRUPTS();
+
+		blocks_pack = ((nblocks-blkno) < MAX_GENERIC_XLOG_PAGES) ?
+						(nblocks-blkno) : MAX_GENERIC_XLOG_PAGES;
+
+		state = GenericXLogStart(rel);
+
+		for (i = 0 ; i < blocks_pack; i++)
+		{
+			buffer[i] = ReadBuffer(rel, blkno);
+			LockBuffer(buffer[i], BUFFER_LOCK_EXCLUSIVE);
+			GenericXLogRegisterBuffer(state, buffer[i], GENERIC_XLOG_FULL_IMAGE);
+			blkno++;
+		}
+
+		GenericXLogFinish(state);
+
+		for (i = 0 ; i < blocks_pack; i++)
+			UnlockReleaseBuffer(buffer[i]);
+	}
+}
diff --git a/src/include/access/generic_xlog.h b/src/include/access/generic_xlog.h
index cb5b5b713a..e3bbf014cc 100644
--- a/src/include/access/generic_xlog.h
+++ b/src/include/access/generic_xlog.h
@@ -42,4 +42,7 @@ extern const char *generic_identify(uint8 info);
 extern void generic_desc(StringInfo buf, XLogReaderState *record);
 extern void generic_mask(char *pagedata, BlockNumber blkno);
 
+/* other utils */
+extern void generic_log_relation(Relation rel);
+
 #endif							/* GENERIC_XLOG_H */
-- 
2.17.1

From 25dc935da9d5502a06fb9dc1eea4912fa0f48be1 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Tue, 5 Feb 2019 08:13:29 +0500
Subject: [PATCH 2/4] GIN-Optimal-WAL-Usage

---
 src/backend/access/gin/ginbtree.c     |  6 ++---
 src/backend/access/gin/gindatapage.c  | 10 ++++----
 src/backend/access/gin/ginentrypage.c |  2 +-
 src/backend/access/gin/gininsert.c    | 30 ++++++++++--------------
 src/backend/access/gin/ginutil.c      |  4 ++--
 src/backend/access/gin/ginvacuum.c    |  2 +-
 src/backend/access/gin/ginxlog.c      | 33 ---------------------------
 src/backend/access/rmgrdesc/gindesc.c |  6 -----
 src/include/access/gin.h              |  3 ++-
 src/include/access/ginxlog.h          |  2 --
 10 files changed, 27 insertions(+), 71 deletions(-)

diff --git a/src/backend/access/gin/ginbtree.c b/src/backend/access/gin/ginbtree.c
index 533949e46a..9f82eef8c3 100644
--- a/src/backend/access/gin/ginbtree.c
+++ b/src/backend/access/gin/ginbtree.c
@@ -396,7 +396,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
 		/* It will fit, perform the insertion */
 		START_CRIT_SECTION();
 
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 		{
 			XLogBeginInsert();
 			XLogRegisterBuffer(0, stack->buffer, REGBUF_STANDARD);
@@ -417,7 +417,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
 			MarkBufferDirty(childbuf);
 		}
 
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 		{
 			XLogRecPtr	recptr;
 			ginxlogInsert xlrec;
@@ -595,7 +595,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
 		}
 
 		/* write WAL record */
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 		{
 			XLogRecPtr	recptr;
 
diff --git a/src/backend/access/gin/gindatapage.c b/src/backend/access/gin/gindatapage.c
index 3ad8b76710..a73cf944b3 100644
--- a/src/backend/access/gin/gindatapage.c
+++ b/src/backend/access/gin/gindatapage.c
@@ -593,7 +593,7 @@ dataBeginPlaceToPageLeaf(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 		 * Great, all the items fit on a single page.  If needed, prepare data
 		 * for a WAL record describing the changes we'll make.
 		 */
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 			computeLeafRecompressWALData(leaf);
 
 		/*
@@ -630,6 +630,7 @@ dataBeginPlaceToPageLeaf(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 		 * subsequent insertions will probably also go to the end. This packs
 		 * the index somewhat tighter when appending to a table, which is very
 		 * common.
+		 *
 		 */
 		if (!btree->isBuild)
 		{
@@ -719,7 +720,7 @@ dataExecPlaceToPageLeaf(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 	dataPlaceToPageLeafRecompress(buf, leaf);
 
 	/* If needed, register WAL data built by computeLeafRecompressWALData */
-	if (RelationNeedsWAL(btree->index))
+	if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 	{
 		XLogRegisterBufData(0, leaf->walinfo, leaf->walinfolen);
 	}
@@ -1152,7 +1153,7 @@ dataExecPlaceToPageInternal(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 	pitem = (PostingItem *) insertdata;
 	GinDataPageAddPostingItem(page, pitem, off);
 
-	if (RelationNeedsWAL(btree->index))
+	if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 	{
 		/*
 		 * This must be static, because it has to survive until XLogInsert,
@@ -1773,6 +1774,7 @@ createPostingTree(Relation index, ItemPointerData *items, uint32 nitems,
 	Pointer		ptr;
 	int			nrootitems;
 	int			rootsize;
+	bool is_build = (buildStats != NULL);
 
 	/* Construct the new root page in memory first. */
 	tmppage = (Page) palloc(BLCKSZ);
@@ -1826,7 +1828,7 @@ createPostingTree(Relation index, ItemPointerData *items, uint32 nitems,
 	PageRestoreTempPage(tmppage, page);
 	MarkBufferDirty(buffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !is_build)
 	{
 		XLogRecPtr	recptr;
 		ginxlogCreatePostingTree data;
diff --git a/src/backend/access/gin/ginentrypage.c b/src/backend/access/gin/ginentrypage.c
index 4889de2a4f..1f5ba33d51 100644
--- a/src/backend/access/gin/ginentrypage.c
+++ b/src/backend/access/gin/ginentrypage.c
@@ -571,7 +571,7 @@ entryExecPlaceToPage(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 		elog(ERROR, "failed to add item to index page in \"%s\"",
 			 RelationGetRelationName(btree->index));
 
-	if (RelationNeedsWAL(btree->index))
+	if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 	{
 		/*
 		 * This must be static, because it has to survive until XLogInsert,
diff --git a/src/backend/access/gin/gininsert.c b/src/backend/access/gin/gininsert.c
index 524ac5be8b..6307743afd 100644
--- a/src/backend/access/gin/gininsert.c
+++ b/src/backend/access/gin/gininsert.c
@@ -17,6 +17,7 @@
 #include "access/gin_private.h"
 #include "access/ginxlog.h"
 #include "access/xloginsert.h"
+#include "access/generic_xlog.h"
 #include "catalog/index.h"
 #include "miscadmin.h"
 #include "storage/bufmgr.h"
@@ -194,6 +195,7 @@ ginEntryInsert(GinState *ginstate,
 		buildStats->nEntries++;
 
 	ginPrepareEntryScan(&btree, attnum, key, category, ginstate);
+	btree.isBuild = (buildStats != NULL);
 
 	stack = ginFindLeafPage(&btree, false, false, NULL);
 	page = BufferGetPage(stack->buffer);
@@ -346,23 +348,6 @@ ginbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	GinInitBuffer(RootBuffer, GIN_LEAF);
 	MarkBufferDirty(RootBuffer);
 
-	if (RelationNeedsWAL(index))
-	{
-		XLogRecPtr	recptr;
-		Page		page;
-
-		XLogBeginInsert();
-		XLogRegisterBuffer(0, MetaBuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-		XLogRegisterBuffer(1, RootBuffer, REGBUF_WILL_INIT);
-
-		recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_CREATE_INDEX);
-
-		page = BufferGetPage(RootBuffer);
-		PageSetLSN(page, recptr);
-
-		page = BufferGetPage(MetaBuffer);
-		PageSetLSN(page, recptr);
-	}
 
 	UnlockReleaseBuffer(MetaBuffer);
 	UnlockReleaseBuffer(RootBuffer);
@@ -417,7 +402,16 @@ ginbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	 * Update metapage stats
 	 */
 	buildstate.buildStats.nTotalPages = RelationGetNumberOfBlocks(index);
-	ginUpdateStats(index, &buildstate.buildStats);
+	ginUpdateStats(index, &buildstate.buildStats, true);
+
+	/*
+	 * Create generic wal records for all pages of relation, if necessary.
+	 * It seems reasonable not to generate WAL, if we recieved interrupt
+	 * signal.
+	 */
+	CHECK_FOR_INTERRUPTS();
+	if (RelationNeedsWAL(index))
+		generic_log_relation(index);
 
 	/*
 	 * Return statistics
diff --git a/src/backend/access/gin/ginutil.c b/src/backend/access/gin/ginutil.c
index afc20232ac..51b20bca6e 100644
--- a/src/backend/access/gin/ginutil.c
+++ b/src/backend/access/gin/ginutil.c
@@ -661,7 +661,7 @@ ginGetStats(Relation index, GinStatsData *stats)
  * Note: nPendingPages and ginVersion are *not* copied over
  */
 void
-ginUpdateStats(Relation index, const GinStatsData *stats)
+ginUpdateStats(Relation index, const GinStatsData *stats, bool is_build)
 {
 	Buffer		metabuffer;
 	Page		metapage;
@@ -691,7 +691,7 @@ ginUpdateStats(Relation index, const GinStatsData *stats)
 
 	MarkBufferDirty(metabuffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !is_build)
 	{
 		XLogRecPtr	recptr;
 		ginxlogUpdateMeta data;
diff --git a/src/backend/access/gin/ginvacuum.c b/src/backend/access/gin/ginvacuum.c
index dfe885b101..b9a28d1863 100644
--- a/src/backend/access/gin/ginvacuum.c
+++ b/src/backend/access/gin/ginvacuum.c
@@ -759,7 +759,7 @@ ginvacuumcleanup(IndexVacuumInfo *info, IndexBulkDeleteResult *stats)
 
 	/* Update the metapage with accurate page and entry counts */
 	idxStat.nTotalPages = npages;
-	ginUpdateStats(info->index, &idxStat);
+	ginUpdateStats(info->index, &idxStat, false);
 
 	/* Finally, vacuum the FSM */
 	IndexFreeSpaceMapVacuum(info->index);
diff --git a/src/backend/access/gin/ginxlog.c b/src/backend/access/gin/ginxlog.c
index c467ffa346..b648af1ff6 100644
--- a/src/backend/access/gin/ginxlog.c
+++ b/src/backend/access/gin/ginxlog.c
@@ -40,36 +40,6 @@ ginRedoClearIncompleteSplit(XLogReaderState *record, uint8 block_id)
 		UnlockReleaseBuffer(buffer);
 }
 
-static void
-ginRedoCreateIndex(XLogReaderState *record)
-{
-	XLogRecPtr	lsn = record->EndRecPtr;
-	Buffer		RootBuffer,
-				MetaBuffer;
-	Page		page;
-
-	MetaBuffer = XLogInitBufferForRedo(record, 0);
-	Assert(BufferGetBlockNumber(MetaBuffer) == GIN_METAPAGE_BLKNO);
-	page = (Page) BufferGetPage(MetaBuffer);
-
-	GinInitMetabuffer(MetaBuffer);
-
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(MetaBuffer);
-
-	RootBuffer = XLogInitBufferForRedo(record, 1);
-	Assert(BufferGetBlockNumber(RootBuffer) == GIN_ROOT_BLKNO);
-	page = (Page) BufferGetPage(RootBuffer);
-
-	GinInitBuffer(RootBuffer, GIN_LEAF);
-
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(RootBuffer);
-
-	UnlockReleaseBuffer(RootBuffer);
-	UnlockReleaseBuffer(MetaBuffer);
-}
-
 static void
 ginRedoCreatePTree(XLogReaderState *record)
 {
@@ -767,9 +737,6 @@ gin_redo(XLogReaderState *record)
 	oldCtx = MemoryContextSwitchTo(opCtx);
 	switch (info)
 	{
-		case XLOG_GIN_CREATE_INDEX:
-			ginRedoCreateIndex(record);
-			break;
 		case XLOG_GIN_CREATE_PTREE:
 			ginRedoCreatePTree(record);
 			break;
diff --git a/src/backend/access/rmgrdesc/gindesc.c b/src/backend/access/rmgrdesc/gindesc.c
index ef30ce16b0..f3f4e1b214 100644
--- a/src/backend/access/rmgrdesc/gindesc.c
+++ b/src/backend/access/rmgrdesc/gindesc.c
@@ -78,9 +78,6 @@ gin_desc(StringInfo buf, XLogReaderState *record)
 
 	switch (info)
 	{
-		case XLOG_GIN_CREATE_INDEX:
-			/* no further information */
-			break;
 		case XLOG_GIN_CREATE_PTREE:
 			/* no further information */
 			break;
@@ -188,9 +185,6 @@ gin_identify(uint8 info)
 
 	switch (info & ~XLR_INFO_MASK)
 	{
-		case XLOG_GIN_CREATE_INDEX:
-			id = "CREATE_INDEX";
-			break;
 		case XLOG_GIN_CREATE_PTREE:
 			id = "CREATE_PTREE";
 			break;
diff --git a/src/include/access/gin.h b/src/include/access/gin.h
index 61fa697039..d559ffc703 100644
--- a/src/include/access/gin.h
+++ b/src/include/access/gin.h
@@ -71,6 +71,7 @@ extern int	gin_pending_list_limit;
 
 /* ginutil.c */
 extern void ginGetStats(Relation index, GinStatsData *stats);
-extern void ginUpdateStats(Relation index, const GinStatsData *stats);
+extern void ginUpdateStats(Relation index,
+						   const GinStatsData *stats, bool is_build);
 
 #endif							/* GIN_H */
diff --git a/src/include/access/ginxlog.h b/src/include/access/ginxlog.h
index 9bd4e0b9ba..2c5d743cac 100644
--- a/src/include/access/ginxlog.h
+++ b/src/include/access/ginxlog.h
@@ -16,8 +16,6 @@
 #include "lib/stringinfo.h"
 #include "storage/off.h"
 
-#define XLOG_GIN_CREATE_INDEX  0x00
-
 #define XLOG_GIN_CREATE_PTREE  0x10
 
 typedef struct ginxlogCreatePostingTree
-- 
2.17.1

From f032a0645d86c57e3b89a294dfb46cfad1119825 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Tue, 5 Feb 2019 08:14:41 +0500
Subject: [PATCH 3/4] GIST-Optimal-WAL-Usage

---
 src/backend/access/gist/gist.c         | 47 ++++++++++++++++++--------
 src/backend/access/gist/gistbuild.c    | 32 ++++++++++--------
 src/backend/access/gist/gistutil.c     |  2 +-
 src/backend/access/gist/gistxlog.c     | 22 ------------
 src/backend/access/rmgrdesc/gistdesc.c |  5 ---
 src/include/access/gist_private.h      |  7 ++--
 src/include/access/gistxlog.h          |  1 -
 7 files changed, 56 insertions(+), 60 deletions(-)

diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index b75b3a8dac..710c1bfd3a 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -173,7 +173,7 @@ gistinsert(Relation r, Datum *values, bool *isnull,
 						 values, isnull, true /* size is currently bogus */ );
 	itup->t_tid = *ht_ctid;
 
-	gistdoinsert(r, itup, 0, giststate, heapRel);
+	gistdoinsert(r, itup, 0, giststate, heapRel, false);
 
 	/* cleanup */
 	MemoryContextSwitchTo(oldCxt);
@@ -220,7 +220,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 				Buffer leftchildbuf,
 				List **splitinfo,
 				bool markfollowright,
-				Relation heapRel)
+				Relation heapRel,
+				bool is_build)
 {
 	BlockNumber blkno = BufferGetBlockNumber(buffer);
 	Page		page = BufferGetPage(buffer);
@@ -459,7 +460,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		 * insertion for that. NB: The number of pages and data segments
 		 * specified here must match the calculations in gistXLogSplit()!
 		 */
-		if (RelationNeedsWAL(rel))
+		if (RelationNeedsWAL(rel) && !is_build)
 			XLogEnsureRecordSpace(npage, 1 + npage * 2);
 
 		START_CRIT_SECTION();
@@ -480,18 +481,20 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		PageRestoreTempPage(dist->page, BufferGetPage(dist->buffer));
 		dist->page = BufferGetPage(dist->buffer);
 
-		/* Write the WAL record */
-		if (RelationNeedsWAL(rel))
+		/*
+		 * Write the WAL record.
+		 * Do not write XLog entry if the insertion is caused by
+		 * index build process.
+		 */
+		if (RelationNeedsWAL(rel) && !is_build)
 			recptr = gistXLogSplit(is_leaf,
-								   dist, oldrlink, oldnsn, leftchildbuf,
-								   markfollowright);
+								dist, oldrlink, oldnsn, leftchildbuf,
+								markfollowright);
 		else
 			recptr = gistGetFakeLSN(rel);
 
 		for (ptr = dist; ptr; ptr = ptr->next)
-		{
 			PageSetLSN(ptr->page, recptr);
-		}
 
 		/*
 		 * Return the new child buffers to the caller.
@@ -545,7 +548,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		if (BufferIsValid(leftchildbuf))
 			MarkBufferDirty(leftchildbuf);
 
-		if (RelationNeedsWAL(rel))
+
+		if (RelationNeedsWAL(rel) && !is_build)
 		{
 			OffsetNumber ndeloffs = 0,
 						deloffs[1];
@@ -568,6 +572,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 			PageSetLSN(page, recptr);
 		}
 
+
 		if (newblkno)
 			*newblkno = blkno;
 	}
@@ -584,17 +589,28 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 	 * the full page image. There's a chicken-and-egg problem: if we updated
 	 * the child pages first, we wouldn't know the recptr of the WAL record
 	 * we're about to write.
+	 *
+	 * We use fakeLSNs for inserions caused by index build. And when it is
+	 * finished, we write generic_xlog entry for each index page and update
+	 * all LSNs. In order to keep NSNs less then LSNs after this update, we
+	 * set NSN to InvalidXLogRecPtr, which is the smallest possible NSN.
 	 */
+
 	if (BufferIsValid(leftchildbuf))
 	{
 		Page		leftpg = BufferGetPage(leftchildbuf);
+		XLogRecPtr	fakerecptr = InvalidXLogRecPtr;
 
-		GistPageSetNSN(leftpg, recptr);
-		GistClearFollowRight(leftpg);
+		if (!is_build)
+			GistPageSetNSN(leftpg, recptr);
+		else
+			GistPageSetNSN(leftpg, fakerecptr);
 
+		GistClearFollowRight(leftpg);
 		PageSetLSN(leftpg, recptr);
 	}
 
+
 	END_CRIT_SECTION();
 
 	return is_split;
@@ -605,9 +621,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
  * this routine assumes it is invoked in a short-lived memory context,
  * so it does not bother releasing palloc'd allocations.
  */
-void
 gistdoinsert(Relation r, IndexTuple itup, Size freespace,
-			 GISTSTATE *giststate, Relation heapRel)
+			 GISTSTATE *giststate, Relation heapRel, bool is_build)
 {
 	ItemId		iid;
 	IndexTuple	idxtuple;
@@ -620,6 +635,7 @@ gistdoinsert(Relation r, IndexTuple itup, Size freespace,
 	state.freespace = freespace;
 	state.r = r;
 	state.heapRel = heapRel;
+	state.is_build = is_build;
 
 	/* Start from the root */
 	firststack.blkno = GIST_ROOT_BLKNO;
@@ -1237,7 +1253,8 @@ gistinserttuples(GISTInsertState *state, GISTInsertStack *stack,
 							   leftchild,
 							   &splitinfo,
 							   true,
-							   state->heapRel);
+							   state->heapRel,
+							   state->is_build);
 
 	/*
 	 * Before recursing up in case the page was split, release locks on the
diff --git a/src/backend/access/gist/gistbuild.c b/src/backend/access/gist/gistbuild.c
index bd142a3560..2e98e55187 100644
--- a/src/backend/access/gist/gistbuild.c
+++ b/src/backend/access/gist/gistbuild.c
@@ -17,6 +17,7 @@
 #include <math.h>
 
 #include "access/genam.h"
+#include "access/generic_xlog.h"
 #include "access/gist_private.h"
 #include "access/gistxlog.h"
 #include "access/xloginsert.h"
@@ -180,18 +181,12 @@ gistbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 
 	MarkBufferDirty(buffer);
 
-	if (RelationNeedsWAL(index))
-	{
-		XLogRecPtr	recptr;
-
-		XLogBeginInsert();
-		XLogRegisterBuffer(0, buffer, REGBUF_WILL_INIT);
-
-		recptr = XLogInsert(RM_GIST_ID, XLOG_GIST_CREATE_INDEX);
-		PageSetLSN(page, recptr);
-	}
-	else
-		PageSetLSN(page, gistGetFakeLSN(heap));
+	/*
+	 * Do not write index pages to WAL unitl index build is finished.
+	 * But we still need increasing LSNs on each page, so use FakeLSN,
+	 * even for relations which eventually need WAL.
+	 */
+	PageSetLSN(page, gistGetFakeLSN(heap));
 
 	UnlockReleaseBuffer(buffer);
 
@@ -224,6 +219,15 @@ gistbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 
 	freeGISTstate(buildstate.giststate);
 
+	/*
+	 * Create generic wal records for all pages of relation, if necessary.
+	 * It seems reasonable not to generate WAL, if we recieved interrupt
+	 * signal.
+	 */
+	CHECK_FOR_INTERRUPTS();
+	if (RelationNeedsWAL(index))
+		generic_log_relation(index);
+
 	/*
 	 * Return statistics
 	 */
@@ -486,7 +490,7 @@ gistBuildCallback(Relation index,
 		 * locked, we call gistdoinsert directly.
 		 */
 		gistdoinsert(index, itup, buildstate->freespace,
-					 buildstate->giststate, buildstate->heaprel);
+					 buildstate->giststate, buildstate->heaprel, true);
 	}
 
 	/* Update tuple count and total size. */
@@ -693,7 +697,7 @@ gistbufferinginserttuples(GISTBuildState *buildstate, Buffer buffer, int level,
 							   InvalidBuffer,
 							   &splitinfo,
 							   false,
-							   buildstate->heaprel);
+							   buildstate->heaprel, true);
 
 	/*
 	 * If this is a root split, update the root path item kept in memory. This
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index 8d3dfad27b..f7088e2d94 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -949,6 +949,7 @@ gistproperty(Oid index_oid, int attno,
  * Temporary and unlogged GiST indexes are not WAL-logged, but we need LSNs
  * to detect concurrent page splits anyway. This function provides a fake
  * sequence of LSNs for that purpose.
+ * Persistent relations are also not WAL-logged while we build index.
  */
 XLogRecPtr
 gistGetFakeLSN(Relation rel)
@@ -969,7 +970,6 @@ gistGetFakeLSN(Relation rel)
 		 * Unlogged relations are accessible from other backends, and survive
 		 * (clean) restarts. GetFakeLSNForUnloggedRel() handles that for us.
 		 */
-		Assert(rel->rd_rel->relpersistence == RELPERSISTENCE_UNLOGGED);
 		return GetFakeLSNForUnloggedRel();
 	}
 }
diff --git a/src/backend/access/gist/gistxlog.c b/src/backend/access/gist/gistxlog.c
index 408bd5390a..66d5bb831f 100644
--- a/src/backend/access/gist/gistxlog.c
+++ b/src/backend/access/gist/gistxlog.c
@@ -489,25 +489,6 @@ gistRedoPageSplitRecord(XLogReaderState *record)
 	UnlockReleaseBuffer(firstbuffer);
 }
 
-static void
-gistRedoCreateIndex(XLogReaderState *record)
-{
-	XLogRecPtr	lsn = record->EndRecPtr;
-	Buffer		buffer;
-	Page		page;
-
-	buffer = XLogInitBufferForRedo(record, 0);
-	Assert(BufferGetBlockNumber(buffer) == GIST_ROOT_BLKNO);
-	page = (Page) BufferGetPage(buffer);
-
-	GISTInitBuffer(buffer, F_LEAF);
-
-	PageSetLSN(page, lsn);
-
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-}
-
 void
 gist_redo(XLogReaderState *record)
 {
@@ -532,9 +513,6 @@ gist_redo(XLogReaderState *record)
 		case XLOG_GIST_PAGE_SPLIT:
 			gistRedoPageSplitRecord(record);
 			break;
-		case XLOG_GIST_CREATE_INDEX:
-			gistRedoCreateIndex(record);
-			break;
 		default:
 			elog(PANIC, "gist_redo: unknown op code %u", info);
 	}
diff --git a/src/backend/access/rmgrdesc/gistdesc.c b/src/backend/access/rmgrdesc/gistdesc.c
index e468c9e15a..75f1ed747e 100644
--- a/src/backend/access/rmgrdesc/gistdesc.c
+++ b/src/backend/access/rmgrdesc/gistdesc.c
@@ -52,8 +52,6 @@ gist_desc(StringInfo buf, XLogReaderState *record)
 		case XLOG_GIST_PAGE_SPLIT:
 			out_gistxlogPageSplit(buf, (gistxlogPageSplit *) rec);
 			break;
-		case XLOG_GIST_CREATE_INDEX:
-			break;
 	}
 }
 
@@ -73,9 +71,6 @@ gist_identify(uint8 info)
 		case XLOG_GIST_PAGE_SPLIT:
 			id = "PAGE_SPLIT";
 			break;
-		case XLOG_GIST_CREATE_INDEX:
-			id = "CREATE_INDEX";
-			break;
 	}
 
 	return id;
diff --git a/src/include/access/gist_private.h b/src/include/access/gist_private.h
index 3698942f9d..b1680bfd6d 100644
--- a/src/include/access/gist_private.h
+++ b/src/include/access/gist_private.h
@@ -242,6 +242,7 @@ typedef struct
 	Relation	r;
 	Relation	heapRel;
 	Size		freespace;		/* free space to be left */
+	bool		is_build;
 
 	GISTInsertStack *stack;
 } GISTInsertState;
@@ -391,7 +392,8 @@ extern void gistdoinsert(Relation r,
 			 IndexTuple itup,
 			 Size freespace,
 			 GISTSTATE *GISTstate,
-			 Relation heapRel);
+			 Relation heapRel,
+			 bool is_build);
 
 /* A List of these is returned from gistplacetopage() in *splitinfo */
 typedef struct
@@ -407,7 +409,8 @@ extern bool gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 				Buffer leftchildbuf,
 				List **splitinfo,
 				bool markleftchild,
-				Relation heapRel);
+				Relation heapRel,
+				bool is_build);
 
 extern SplitedPageLayout *gistSplit(Relation r, Page page, IndexTuple *itup,
 		  int len, GISTSTATE *giststate);
diff --git a/src/include/access/gistxlog.h b/src/include/access/gistxlog.h
index 5117aabf1a..2ee80e244e 100644
--- a/src/include/access/gistxlog.h
+++ b/src/include/access/gistxlog.h
@@ -22,7 +22,6 @@
  /* #define XLOG_GIST_NEW_ROOT			 0x20 */	/* not used anymore */
 #define XLOG_GIST_PAGE_SPLIT		0x30
  /* #define XLOG_GIST_INSERT_COMPLETE	 0x40 */	/* not used anymore */
-#define XLOG_GIST_CREATE_INDEX		0x50
  /* #define XLOG_GIST_PAGE_DELETE		 0x60 */	/* not used anymore */
 
 /*
-- 
2.17.1

From 3dbe3d827173244e9bda928147f35e0929266215 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Tue, 5 Feb 2019 08:15:06 +0500
Subject: [PATCH 4/4] SPGIST-Optimal-WAL-Usage

---
 src/backend/access/rmgrdesc/spgdesc.c   |  5 ----
 src/backend/access/spgist/spgdoinsert.c | 12 ++++-----
 src/backend/access/spgist/spginsert.c   | 24 +++--------------
 src/backend/access/spgist/spgxlog.c     | 35 -------------------------
 src/include/access/spgxlog.h            |  1 -
 5 files changed, 10 insertions(+), 67 deletions(-)

diff --git a/src/backend/access/rmgrdesc/spgdesc.c b/src/backend/access/rmgrdesc/spgdesc.c
index 37af31a764..40c1c8b3f9 100644
--- a/src/backend/access/rmgrdesc/spgdesc.c
+++ b/src/backend/access/rmgrdesc/spgdesc.c
@@ -24,8 +24,6 @@ spg_desc(StringInfo buf, XLogReaderState *record)
 
 	switch (info)
 	{
-		case XLOG_SPGIST_CREATE_INDEX:
-			break;
 		case XLOG_SPGIST_ADD_LEAF:
 			{
 				spgxlogAddLeaf *xlrec = (spgxlogAddLeaf *) rec;
@@ -88,9 +86,6 @@ spg_identify(uint8 info)
 
 	switch (info & ~XLR_INFO_MASK)
 	{
-		case XLOG_SPGIST_CREATE_INDEX:
-			id = "CREATE_INDEX";
-			break;
 		case XLOG_SPGIST_ADD_LEAF:
 			id = "ADD_LEAF";
 			break;
diff --git a/src/backend/access/spgist/spgdoinsert.c b/src/backend/access/spgist/spgdoinsert.c
index 0d07b8b291..c34c44cd8b 100644
--- a/src/backend/access/spgist/spgdoinsert.c
+++ b/src/backend/access/spgist/spgdoinsert.c
@@ -289,7 +289,7 @@ addLeafTuple(Relation index, SpGistState *state, SpGistLeafTuple leafTuple,
 
 	MarkBufferDirty(current->buffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 		int			flags;
@@ -516,7 +516,7 @@ moveLeafs(Relation index, SpGistState *state,
 	MarkBufferDirty(current->buffer);
 	MarkBufferDirty(nbuf);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 
@@ -1334,7 +1334,7 @@ doPickSplit(Relation index, SpGistState *state,
 		saveCurrent.buffer = InvalidBuffer;
 	}
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 		int			flags;
@@ -1531,7 +1531,7 @@ spgAddNodeAction(Relation index, SpGistState *state,
 
 		MarkBufferDirty(current->buffer);
 
-		if (RelationNeedsWAL(index))
+		if (RelationNeedsWAL(index) && !state->isBuild)
 		{
 			XLogRecPtr	recptr;
 
@@ -1644,7 +1644,7 @@ spgAddNodeAction(Relation index, SpGistState *state,
 
 		MarkBufferDirty(saveCurrent.buffer);
 
-		if (RelationNeedsWAL(index))
+		if (RelationNeedsWAL(index) && !state->isBuild)
 		{
 			XLogRecPtr	recptr;
 			int			flags;
@@ -1840,7 +1840,7 @@ spgSplitNodeAction(Relation index, SpGistState *state,
 
 	MarkBufferDirty(current->buffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 
diff --git a/src/backend/access/spgist/spginsert.c b/src/backend/access/spgist/spginsert.c
index f428a15138..5da0183a9b 100644
--- a/src/backend/access/spgist/spginsert.c
+++ b/src/backend/access/spgist/spginsert.c
@@ -21,6 +21,7 @@
 #include "access/spgxlog.h"
 #include "access/xlog.h"
 #include "access/xloginsert.h"
+#include "access/generic_xlog.h"
 #include "catalog/index.h"
 #include "miscadmin.h"
 #include "storage/bufmgr.h"
@@ -104,26 +105,6 @@ spgbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	SpGistInitBuffer(nullbuffer, SPGIST_LEAF | SPGIST_NULLS);
 	MarkBufferDirty(nullbuffer);
 
-	if (RelationNeedsWAL(index))
-	{
-		XLogRecPtr	recptr;
-
-		XLogBeginInsert();
-
-		/*
-		 * Replay will re-initialize the pages, so don't take full pages
-		 * images.  No other data to log.
-		 */
-		XLogRegisterBuffer(0, metabuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-		XLogRegisterBuffer(1, rootbuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-		XLogRegisterBuffer(2, nullbuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-
-		recptr = XLogInsert(RM_SPGIST_ID, XLOG_SPGIST_CREATE_INDEX);
-
-		PageSetLSN(BufferGetPage(metabuffer), recptr);
-		PageSetLSN(BufferGetPage(rootbuffer), recptr);
-		PageSetLSN(BufferGetPage(nullbuffer), recptr);
-	}
 
 	END_CRIT_SECTION();
 
@@ -150,6 +131,9 @@ spgbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 
 	SpGistUpdateMetaPage(index);
 
+	if (RelationNeedsWAL(index))
+		generic_log_relation(index);
+
 	result = (IndexBuildResult *) palloc0(sizeof(IndexBuildResult));
 	result->heap_tuples = reltuples;
 	result->index_tuples = buildstate.indtuples;
diff --git a/src/backend/access/spgist/spgxlog.c b/src/backend/access/spgist/spgxlog.c
index 71836ee8a5..ebe6ae8715 100644
--- a/src/backend/access/spgist/spgxlog.c
+++ b/src/backend/access/spgist/spgxlog.c
@@ -72,38 +72,6 @@ addOrReplaceTuple(Page page, Item tuple, int size, OffsetNumber offset)
 			 size);
 }
 
-static void
-spgRedoCreateIndex(XLogReaderState *record)
-{
-	XLogRecPtr	lsn = record->EndRecPtr;
-	Buffer		buffer;
-	Page		page;
-
-	buffer = XLogInitBufferForRedo(record, 0);
-	Assert(BufferGetBlockNumber(buffer) == SPGIST_METAPAGE_BLKNO);
-	page = (Page) BufferGetPage(buffer);
-	SpGistInitMetapage(page);
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-
-	buffer = XLogInitBufferForRedo(record, 1);
-	Assert(BufferGetBlockNumber(buffer) == SPGIST_ROOT_BLKNO);
-	SpGistInitBuffer(buffer, SPGIST_LEAF);
-	page = (Page) BufferGetPage(buffer);
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-
-	buffer = XLogInitBufferForRedo(record, 2);
-	Assert(BufferGetBlockNumber(buffer) == SPGIST_NULL_BLKNO);
-	SpGistInitBuffer(buffer, SPGIST_LEAF | SPGIST_NULLS);
-	page = (Page) BufferGetPage(buffer);
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-}
-
 static void
 spgRedoAddLeaf(XLogReaderState *record)
 {
@@ -976,9 +944,6 @@ spg_redo(XLogReaderState *record)
 	oldCxt = MemoryContextSwitchTo(opCtx);
 	switch (info)
 	{
-		case XLOG_SPGIST_CREATE_INDEX:
-			spgRedoCreateIndex(record);
-			break;
 		case XLOG_SPGIST_ADD_LEAF:
 			spgRedoAddLeaf(record);
 			break;
diff --git a/src/include/access/spgxlog.h b/src/include/access/spgxlog.h
index 6527fc9eb1..8199b3f250 100644
--- a/src/include/access/spgxlog.h
+++ b/src/include/access/spgxlog.h
@@ -18,7 +18,6 @@
 #include "storage/off.h"
 
 /* XLOG record types for SPGiST */
-#define XLOG_SPGIST_CREATE_INDEX	0x00
 #define XLOG_SPGIST_ADD_LEAF		0x10
 #define XLOG_SPGIST_MOVE_LEAFS		0x20
 #define XLOG_SPGIST_ADD_NODE		0x30
-- 
2.17.1

From ec20e8896181cf8b26755acaa6028a62a0c709e7 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Wed, 6 Feb 2019 14:39:59 +0500
Subject: [PATCH 1/4] Relation-into-WAL-function

---
 src/backend/access/transam/generic_xlog.c | 48 +++++++++++++++++++++++
 src/include/access/generic_xlog.h         |  3 ++
 2 files changed, 51 insertions(+)

diff --git a/src/backend/access/transam/generic_xlog.c b/src/backend/access/transam/generic_xlog.c
index 5b00b7275b..c22e361747 100644
--- a/src/backend/access/transam/generic_xlog.c
+++ b/src/backend/access/transam/generic_xlog.c
@@ -542,3 +542,51 @@ generic_mask(char *page, BlockNumber blkno)
 
 	mask_unused_space(page);
 }
+
+/*
+ * Function to write generic xlog for every existing block of a relation.
+ * Caller is responsible for locking the relation exclusively.
+ */
+void
+generic_log_relation(Relation rel)
+{
+	BlockNumber 		blkno;
+	BlockNumber 		nblocks;
+	int					npbuf = 0;
+	GenericXLogState	*state = NULL;
+	Buffer				bufpack[MAX_GENERIC_XLOG_PAGES];
+
+	CHECK_FOR_INTERRUPTS();
+	nblocks = RelationGetNumberOfBlocks(rel);
+
+	/*
+	 * Iterate over all index pages and WAL-logging it. Pages are grouping into
+	 * the packages before adding to a WAL-record. Zero-pages are
+	 * not logged.
+	 */
+	for (blkno = 0; blkno < nblocks; blkno++)
+	{
+		Buffer	buf;
+
+		buf = ReadBuffer(rel, blkno);
+		if (!PageIsNew(BufferGetPage(buf)))
+		{
+			if (npbuf == 0)
+				state = GenericXLogStart(rel);
+
+			LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
+			GenericXLogRegisterBuffer(state, buf, GENERIC_XLOG_FULL_IMAGE);
+			bufpack[npbuf++] = buf;
+		}
+		else
+			ReleaseBuffer(buf);
+
+		if ((npbuf == MAX_GENERIC_XLOG_PAGES) || (blkno == nblocks-1))
+		{
+			GenericXLogFinish(state);
+
+			for (; npbuf > 0; npbuf--)
+				UnlockReleaseBuffer(bufpack[npbuf-1]);
+		}
+	}
+}
diff --git a/src/include/access/generic_xlog.h b/src/include/access/generic_xlog.h
index cb5b5b713a..e3bbf014cc 100644
--- a/src/include/access/generic_xlog.h
+++ b/src/include/access/generic_xlog.h
@@ -42,4 +42,7 @@ extern const char *generic_identify(uint8 info);
 extern void generic_desc(StringInfo buf, XLogReaderState *record);
 extern void generic_mask(char *pagedata, BlockNumber blkno);
 
+/* other utils */
+extern void generic_log_relation(Relation rel);
+
 #endif							/* GENERIC_XLOG_H */
-- 
2.17.1

From 6fa828f6737d9c2dbcd2c2ce61a150e79e2bc1d2 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Wed, 6 Feb 2019 14:40:29 +0500
Subject: [PATCH 2/4] GIN-Optimal-WAL-Usage

---
 src/backend/access/gin/ginbtree.c     |  6 ++---
 src/backend/access/gin/gindatapage.c  |  9 ++++----
 src/backend/access/gin/ginentrypage.c |  2 +-
 src/backend/access/gin/gininsert.c    | 30 ++++++++++--------------
 src/backend/access/gin/ginutil.c      |  4 ++--
 src/backend/access/gin/ginvacuum.c    |  2 +-
 src/backend/access/gin/ginxlog.c      | 33 ---------------------------
 src/backend/access/rmgrdesc/gindesc.c |  6 -----
 src/include/access/gin.h              |  3 ++-
 src/include/access/ginxlog.h          |  2 --
 10 files changed, 26 insertions(+), 71 deletions(-)

diff --git a/src/backend/access/gin/ginbtree.c b/src/backend/access/gin/ginbtree.c
index 533949e46a..9f82eef8c3 100644
--- a/src/backend/access/gin/ginbtree.c
+++ b/src/backend/access/gin/ginbtree.c
@@ -396,7 +396,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
 		/* It will fit, perform the insertion */
 		START_CRIT_SECTION();
 
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 		{
 			XLogBeginInsert();
 			XLogRegisterBuffer(0, stack->buffer, REGBUF_STANDARD);
@@ -417,7 +417,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
 			MarkBufferDirty(childbuf);
 		}
 
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 		{
 			XLogRecPtr	recptr;
 			ginxlogInsert xlrec;
@@ -595,7 +595,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
 		}
 
 		/* write WAL record */
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 		{
 			XLogRecPtr	recptr;
 
diff --git a/src/backend/access/gin/gindatapage.c b/src/backend/access/gin/gindatapage.c
index 3ad8b76710..f3aff62c8e 100644
--- a/src/backend/access/gin/gindatapage.c
+++ b/src/backend/access/gin/gindatapage.c
@@ -593,7 +593,7 @@ dataBeginPlaceToPageLeaf(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 		 * Great, all the items fit on a single page.  If needed, prepare data
 		 * for a WAL record describing the changes we'll make.
 		 */
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 			computeLeafRecompressWALData(leaf);
 
 		/*
@@ -719,7 +719,7 @@ dataExecPlaceToPageLeaf(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 	dataPlaceToPageLeafRecompress(buf, leaf);
 
 	/* If needed, register WAL data built by computeLeafRecompressWALData */
-	if (RelationNeedsWAL(btree->index))
+	if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 	{
 		XLogRegisterBufData(0, leaf->walinfo, leaf->walinfolen);
 	}
@@ -1152,7 +1152,7 @@ dataExecPlaceToPageInternal(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 	pitem = (PostingItem *) insertdata;
 	GinDataPageAddPostingItem(page, pitem, off);
 
-	if (RelationNeedsWAL(btree->index))
+	if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 	{
 		/*
 		 * This must be static, because it has to survive until XLogInsert,
@@ -1773,6 +1773,7 @@ createPostingTree(Relation index, ItemPointerData *items, uint32 nitems,
 	Pointer		ptr;
 	int			nrootitems;
 	int			rootsize;
+	bool is_build = (buildStats != NULL);
 
 	/* Construct the new root page in memory first. */
 	tmppage = (Page) palloc(BLCKSZ);
@@ -1826,7 +1827,7 @@ createPostingTree(Relation index, ItemPointerData *items, uint32 nitems,
 	PageRestoreTempPage(tmppage, page);
 	MarkBufferDirty(buffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !is_build)
 	{
 		XLogRecPtr	recptr;
 		ginxlogCreatePostingTree data;
diff --git a/src/backend/access/gin/ginentrypage.c b/src/backend/access/gin/ginentrypage.c
index 4889de2a4f..1f5ba33d51 100644
--- a/src/backend/access/gin/ginentrypage.c
+++ b/src/backend/access/gin/ginentrypage.c
@@ -571,7 +571,7 @@ entryExecPlaceToPage(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 		elog(ERROR, "failed to add item to index page in \"%s\"",
 			 RelationGetRelationName(btree->index));
 
-	if (RelationNeedsWAL(btree->index))
+	if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 	{
 		/*
 		 * This must be static, because it has to survive until XLogInsert,
diff --git a/src/backend/access/gin/gininsert.c b/src/backend/access/gin/gininsert.c
index 524ac5be8b..6307743afd 100644
--- a/src/backend/access/gin/gininsert.c
+++ b/src/backend/access/gin/gininsert.c
@@ -17,6 +17,7 @@
 #include "access/gin_private.h"
 #include "access/ginxlog.h"
 #include "access/xloginsert.h"
+#include "access/generic_xlog.h"
 #include "catalog/index.h"
 #include "miscadmin.h"
 #include "storage/bufmgr.h"
@@ -194,6 +195,7 @@ ginEntryInsert(GinState *ginstate,
 		buildStats->nEntries++;
 
 	ginPrepareEntryScan(&btree, attnum, key, category, ginstate);
+	btree.isBuild = (buildStats != NULL);
 
 	stack = ginFindLeafPage(&btree, false, false, NULL);
 	page = BufferGetPage(stack->buffer);
@@ -346,23 +348,6 @@ ginbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	GinInitBuffer(RootBuffer, GIN_LEAF);
 	MarkBufferDirty(RootBuffer);
 
-	if (RelationNeedsWAL(index))
-	{
-		XLogRecPtr	recptr;
-		Page		page;
-
-		XLogBeginInsert();
-		XLogRegisterBuffer(0, MetaBuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-		XLogRegisterBuffer(1, RootBuffer, REGBUF_WILL_INIT);
-
-		recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_CREATE_INDEX);
-
-		page = BufferGetPage(RootBuffer);
-		PageSetLSN(page, recptr);
-
-		page = BufferGetPage(MetaBuffer);
-		PageSetLSN(page, recptr);
-	}
 
 	UnlockReleaseBuffer(MetaBuffer);
 	UnlockReleaseBuffer(RootBuffer);
@@ -417,7 +402,16 @@ ginbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	 * Update metapage stats
 	 */
 	buildstate.buildStats.nTotalPages = RelationGetNumberOfBlocks(index);
-	ginUpdateStats(index, &buildstate.buildStats);
+	ginUpdateStats(index, &buildstate.buildStats, true);
+
+	/*
+	 * Create generic wal records for all pages of relation, if necessary.
+	 * It seems reasonable not to generate WAL, if we recieved interrupt
+	 * signal.
+	 */
+	CHECK_FOR_INTERRUPTS();
+	if (RelationNeedsWAL(index))
+		generic_log_relation(index);
 
 	/*
 	 * Return statistics
diff --git a/src/backend/access/gin/ginutil.c b/src/backend/access/gin/ginutil.c
index afc20232ac..51b20bca6e 100644
--- a/src/backend/access/gin/ginutil.c
+++ b/src/backend/access/gin/ginutil.c
@@ -661,7 +661,7 @@ ginGetStats(Relation index, GinStatsData *stats)
  * Note: nPendingPages and ginVersion are *not* copied over
  */
 void
-ginUpdateStats(Relation index, const GinStatsData *stats)
+ginUpdateStats(Relation index, const GinStatsData *stats, bool is_build)
 {
 	Buffer		metabuffer;
 	Page		metapage;
@@ -691,7 +691,7 @@ ginUpdateStats(Relation index, const GinStatsData *stats)
 
 	MarkBufferDirty(metabuffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !is_build)
 	{
 		XLogRecPtr	recptr;
 		ginxlogUpdateMeta data;
diff --git a/src/backend/access/gin/ginvacuum.c b/src/backend/access/gin/ginvacuum.c
index dfe885b101..b9a28d1863 100644
--- a/src/backend/access/gin/ginvacuum.c
+++ b/src/backend/access/gin/ginvacuum.c
@@ -759,7 +759,7 @@ ginvacuumcleanup(IndexVacuumInfo *info, IndexBulkDeleteResult *stats)
 
 	/* Update the metapage with accurate page and entry counts */
 	idxStat.nTotalPages = npages;
-	ginUpdateStats(info->index, &idxStat);
+	ginUpdateStats(info->index, &idxStat, false);
 
 	/* Finally, vacuum the FSM */
 	IndexFreeSpaceMapVacuum(info->index);
diff --git a/src/backend/access/gin/ginxlog.c b/src/backend/access/gin/ginxlog.c
index c467ffa346..b648af1ff6 100644
--- a/src/backend/access/gin/ginxlog.c
+++ b/src/backend/access/gin/ginxlog.c
@@ -40,36 +40,6 @@ ginRedoClearIncompleteSplit(XLogReaderState *record, uint8 block_id)
 		UnlockReleaseBuffer(buffer);
 }
 
-static void
-ginRedoCreateIndex(XLogReaderState *record)
-{
-	XLogRecPtr	lsn = record->EndRecPtr;
-	Buffer		RootBuffer,
-				MetaBuffer;
-	Page		page;
-
-	MetaBuffer = XLogInitBufferForRedo(record, 0);
-	Assert(BufferGetBlockNumber(MetaBuffer) == GIN_METAPAGE_BLKNO);
-	page = (Page) BufferGetPage(MetaBuffer);
-
-	GinInitMetabuffer(MetaBuffer);
-
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(MetaBuffer);
-
-	RootBuffer = XLogInitBufferForRedo(record, 1);
-	Assert(BufferGetBlockNumber(RootBuffer) == GIN_ROOT_BLKNO);
-	page = (Page) BufferGetPage(RootBuffer);
-
-	GinInitBuffer(RootBuffer, GIN_LEAF);
-
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(RootBuffer);
-
-	UnlockReleaseBuffer(RootBuffer);
-	UnlockReleaseBuffer(MetaBuffer);
-}
-
 static void
 ginRedoCreatePTree(XLogReaderState *record)
 {
@@ -767,9 +737,6 @@ gin_redo(XLogReaderState *record)
 	oldCtx = MemoryContextSwitchTo(opCtx);
 	switch (info)
 	{
-		case XLOG_GIN_CREATE_INDEX:
-			ginRedoCreateIndex(record);
-			break;
 		case XLOG_GIN_CREATE_PTREE:
 			ginRedoCreatePTree(record);
 			break;
diff --git a/src/backend/access/rmgrdesc/gindesc.c b/src/backend/access/rmgrdesc/gindesc.c
index ef30ce16b0..f3f4e1b214 100644
--- a/src/backend/access/rmgrdesc/gindesc.c
+++ b/src/backend/access/rmgrdesc/gindesc.c
@@ -78,9 +78,6 @@ gin_desc(StringInfo buf, XLogReaderState *record)
 
 	switch (info)
 	{
-		case XLOG_GIN_CREATE_INDEX:
-			/* no further information */
-			break;
 		case XLOG_GIN_CREATE_PTREE:
 			/* no further information */
 			break;
@@ -188,9 +185,6 @@ gin_identify(uint8 info)
 
 	switch (info & ~XLR_INFO_MASK)
 	{
-		case XLOG_GIN_CREATE_INDEX:
-			id = "CREATE_INDEX";
-			break;
 		case XLOG_GIN_CREATE_PTREE:
 			id = "CREATE_PTREE";
 			break;
diff --git a/src/include/access/gin.h b/src/include/access/gin.h
index 61fa697039..d559ffc703 100644
--- a/src/include/access/gin.h
+++ b/src/include/access/gin.h
@@ -71,6 +71,7 @@ extern int	gin_pending_list_limit;
 
 /* ginutil.c */
 extern void ginGetStats(Relation index, GinStatsData *stats);
-extern void ginUpdateStats(Relation index, const GinStatsData *stats);
+extern void ginUpdateStats(Relation index,
+						   const GinStatsData *stats, bool is_build);
 
 #endif							/* GIN_H */
diff --git a/src/include/access/ginxlog.h b/src/include/access/ginxlog.h
index 9bd4e0b9ba..2c5d743cac 100644
--- a/src/include/access/ginxlog.h
+++ b/src/include/access/ginxlog.h
@@ -16,8 +16,6 @@
 #include "lib/stringinfo.h"
 #include "storage/off.h"
 
-#define XLOG_GIN_CREATE_INDEX  0x00
-
 #define XLOG_GIN_CREATE_PTREE  0x10
 
 typedef struct ginxlogCreatePostingTree
-- 
2.17.1

From 679aa38c664eecba4a0d049feffe2537be3ebe21 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Wed, 6 Feb 2019 14:41:08 +0500
Subject: [PATCH 3/4] GiST-Optimal-WAL-Usage

---
 src/backend/access/gist/gist.c         | 46 ++++++++++++++++++--------
 src/backend/access/gist/gistbuild.c    | 32 ++++++++++--------
 src/backend/access/gist/gistutil.c     |  2 +-
 src/backend/access/gist/gistxlog.c     | 22 ------------
 src/backend/access/rmgrdesc/gistdesc.c |  5 ---
 src/include/access/gist_private.h      |  7 ++--
 src/include/access/gistxlog.h          |  1 -
 7 files changed, 56 insertions(+), 59 deletions(-)

diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index b75b3a8dac..c8f4e41db9 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -173,7 +173,7 @@ gistinsert(Relation r, Datum *values, bool *isnull,
 						 values, isnull, true /* size is currently bogus */ );
 	itup->t_tid = *ht_ctid;
 
-	gistdoinsert(r, itup, 0, giststate, heapRel);
+	gistdoinsert(r, itup, 0, giststate, heapRel, false);
 
 	/* cleanup */
 	MemoryContextSwitchTo(oldCxt);
@@ -220,7 +220,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 				Buffer leftchildbuf,
 				List **splitinfo,
 				bool markfollowright,
-				Relation heapRel)
+				Relation heapRel,
+				bool is_build)
 {
 	BlockNumber blkno = BufferGetBlockNumber(buffer);
 	Page		page = BufferGetPage(buffer);
@@ -459,7 +460,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		 * insertion for that. NB: The number of pages and data segments
 		 * specified here must match the calculations in gistXLogSplit()!
 		 */
-		if (RelationNeedsWAL(rel))
+		if (RelationNeedsWAL(rel) && !is_build)
 			XLogEnsureRecordSpace(npage, 1 + npage * 2);
 
 		START_CRIT_SECTION();
@@ -480,18 +481,20 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		PageRestoreTempPage(dist->page, BufferGetPage(dist->buffer));
 		dist->page = BufferGetPage(dist->buffer);
 
-		/* Write the WAL record */
-		if (RelationNeedsWAL(rel))
+		/*
+		 * Write the WAL record.
+		 * Do not write XLog entry if the insertion is caused by
+		 * index build process.
+		 */
+		if (RelationNeedsWAL(rel) && !is_build)
 			recptr = gistXLogSplit(is_leaf,
-								   dist, oldrlink, oldnsn, leftchildbuf,
-								   markfollowright);
+								dist, oldrlink, oldnsn, leftchildbuf,
+								markfollowright);
 		else
 			recptr = gistGetFakeLSN(rel);
 
 		for (ptr = dist; ptr; ptr = ptr->next)
-		{
 			PageSetLSN(ptr->page, recptr);
-		}
 
 		/*
 		 * Return the new child buffers to the caller.
@@ -545,7 +548,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		if (BufferIsValid(leftchildbuf))
 			MarkBufferDirty(leftchildbuf);
 
-		if (RelationNeedsWAL(rel))
+
+		if (RelationNeedsWAL(rel) && !is_build)
 		{
 			OffsetNumber ndeloffs = 0,
 						deloffs[1];
@@ -568,6 +572,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 			PageSetLSN(page, recptr);
 		}
 
+
 		if (newblkno)
 			*newblkno = blkno;
 	}
@@ -584,17 +589,28 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 	 * the full page image. There's a chicken-and-egg problem: if we updated
 	 * the child pages first, we wouldn't know the recptr of the WAL record
 	 * we're about to write.
+	 *
+	 * We use fakeLSNs for inserions caused by index build. And when it is
+	 * finished, we write generic_xlog entry for each index page and update
+	 * all LSNs. In order to keep NSNs less then LSNs after this update, we
+	 * set NSN to InvalidXLogRecPtr, which is the smallest possible NSN.
 	 */
+
 	if (BufferIsValid(leftchildbuf))
 	{
 		Page		leftpg = BufferGetPage(leftchildbuf);
+		XLogRecPtr	fakerecptr = InvalidXLogRecPtr;
 
-		GistPageSetNSN(leftpg, recptr);
-		GistClearFollowRight(leftpg);
+		if (!is_build)
+			GistPageSetNSN(leftpg, recptr);
+		else
+			GistPageSetNSN(leftpg, fakerecptr);
 
+		GistClearFollowRight(leftpg);
 		PageSetLSN(leftpg, recptr);
 	}
 
+
 	END_CRIT_SECTION();
 
 	return is_split;
@@ -607,7 +623,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
  */
 void
 gistdoinsert(Relation r, IndexTuple itup, Size freespace,
-			 GISTSTATE *giststate, Relation heapRel)
+			 GISTSTATE *giststate, Relation heapRel, bool is_build)
 {
 	ItemId		iid;
 	IndexTuple	idxtuple;
@@ -620,6 +636,7 @@ gistdoinsert(Relation r, IndexTuple itup, Size freespace,
 	state.freespace = freespace;
 	state.r = r;
 	state.heapRel = heapRel;
+	state.is_build = is_build;
 
 	/* Start from the root */
 	firststack.blkno = GIST_ROOT_BLKNO;
@@ -1237,7 +1254,8 @@ gistinserttuples(GISTInsertState *state, GISTInsertStack *stack,
 							   leftchild,
 							   &splitinfo,
 							   true,
-							   state->heapRel);
+							   state->heapRel,
+							   state->is_build);
 
 	/*
 	 * Before recursing up in case the page was split, release locks on the
diff --git a/src/backend/access/gist/gistbuild.c b/src/backend/access/gist/gistbuild.c
index bd142a3560..2e98e55187 100644
--- a/src/backend/access/gist/gistbuild.c
+++ b/src/backend/access/gist/gistbuild.c
@@ -17,6 +17,7 @@
 #include <math.h>
 
 #include "access/genam.h"
+#include "access/generic_xlog.h"
 #include "access/gist_private.h"
 #include "access/gistxlog.h"
 #include "access/xloginsert.h"
@@ -180,18 +181,12 @@ gistbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 
 	MarkBufferDirty(buffer);
 
-	if (RelationNeedsWAL(index))
-	{
-		XLogRecPtr	recptr;
-
-		XLogBeginInsert();
-		XLogRegisterBuffer(0, buffer, REGBUF_WILL_INIT);
-
-		recptr = XLogInsert(RM_GIST_ID, XLOG_GIST_CREATE_INDEX);
-		PageSetLSN(page, recptr);
-	}
-	else
-		PageSetLSN(page, gistGetFakeLSN(heap));
+	/*
+	 * Do not write index pages to WAL unitl index build is finished.
+	 * But we still need increasing LSNs on each page, so use FakeLSN,
+	 * even for relations which eventually need WAL.
+	 */
+	PageSetLSN(page, gistGetFakeLSN(heap));
 
 	UnlockReleaseBuffer(buffer);
 
@@ -224,6 +219,15 @@ gistbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 
 	freeGISTstate(buildstate.giststate);
 
+	/*
+	 * Create generic wal records for all pages of relation, if necessary.
+	 * It seems reasonable not to generate WAL, if we recieved interrupt
+	 * signal.
+	 */
+	CHECK_FOR_INTERRUPTS();
+	if (RelationNeedsWAL(index))
+		generic_log_relation(index);
+
 	/*
 	 * Return statistics
 	 */
@@ -486,7 +490,7 @@ gistBuildCallback(Relation index,
 		 * locked, we call gistdoinsert directly.
 		 */
 		gistdoinsert(index, itup, buildstate->freespace,
-					 buildstate->giststate, buildstate->heaprel);
+					 buildstate->giststate, buildstate->heaprel, true);
 	}
 
 	/* Update tuple count and total size. */
@@ -693,7 +697,7 @@ gistbufferinginserttuples(GISTBuildState *buildstate, Buffer buffer, int level,
 							   InvalidBuffer,
 							   &splitinfo,
 							   false,
-							   buildstate->heaprel);
+							   buildstate->heaprel, true);
 
 	/*
 	 * If this is a root split, update the root path item kept in memory. This
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index 8d3dfad27b..f7088e2d94 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -949,6 +949,7 @@ gistproperty(Oid index_oid, int attno,
  * Temporary and unlogged GiST indexes are not WAL-logged, but we need LSNs
  * to detect concurrent page splits anyway. This function provides a fake
  * sequence of LSNs for that purpose.
+ * Persistent relations are also not WAL-logged while we build index.
  */
 XLogRecPtr
 gistGetFakeLSN(Relation rel)
@@ -969,7 +970,6 @@ gistGetFakeLSN(Relation rel)
 		 * Unlogged relations are accessible from other backends, and survive
 		 * (clean) restarts. GetFakeLSNForUnloggedRel() handles that for us.
 		 */
-		Assert(rel->rd_rel->relpersistence == RELPERSISTENCE_UNLOGGED);
 		return GetFakeLSNForUnloggedRel();
 	}
 }
diff --git a/src/backend/access/gist/gistxlog.c b/src/backend/access/gist/gistxlog.c
index 408bd5390a..66d5bb831f 100644
--- a/src/backend/access/gist/gistxlog.c
+++ b/src/backend/access/gist/gistxlog.c
@@ -489,25 +489,6 @@ gistRedoPageSplitRecord(XLogReaderState *record)
 	UnlockReleaseBuffer(firstbuffer);
 }
 
-static void
-gistRedoCreateIndex(XLogReaderState *record)
-{
-	XLogRecPtr	lsn = record->EndRecPtr;
-	Buffer		buffer;
-	Page		page;
-
-	buffer = XLogInitBufferForRedo(record, 0);
-	Assert(BufferGetBlockNumber(buffer) == GIST_ROOT_BLKNO);
-	page = (Page) BufferGetPage(buffer);
-
-	GISTInitBuffer(buffer, F_LEAF);
-
-	PageSetLSN(page, lsn);
-
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-}
-
 void
 gist_redo(XLogReaderState *record)
 {
@@ -532,9 +513,6 @@ gist_redo(XLogReaderState *record)
 		case XLOG_GIST_PAGE_SPLIT:
 			gistRedoPageSplitRecord(record);
 			break;
-		case XLOG_GIST_CREATE_INDEX:
-			gistRedoCreateIndex(record);
-			break;
 		default:
 			elog(PANIC, "gist_redo: unknown op code %u", info);
 	}
diff --git a/src/backend/access/rmgrdesc/gistdesc.c b/src/backend/access/rmgrdesc/gistdesc.c
index e468c9e15a..75f1ed747e 100644
--- a/src/backend/access/rmgrdesc/gistdesc.c
+++ b/src/backend/access/rmgrdesc/gistdesc.c
@@ -52,8 +52,6 @@ gist_desc(StringInfo buf, XLogReaderState *record)
 		case XLOG_GIST_PAGE_SPLIT:
 			out_gistxlogPageSplit(buf, (gistxlogPageSplit *) rec);
 			break;
-		case XLOG_GIST_CREATE_INDEX:
-			break;
 	}
 }
 
@@ -73,9 +71,6 @@ gist_identify(uint8 info)
 		case XLOG_GIST_PAGE_SPLIT:
 			id = "PAGE_SPLIT";
 			break;
-		case XLOG_GIST_CREATE_INDEX:
-			id = "CREATE_INDEX";
-			break;
 	}
 
 	return id;
diff --git a/src/include/access/gist_private.h b/src/include/access/gist_private.h
index 3698942f9d..b1680bfd6d 100644
--- a/src/include/access/gist_private.h
+++ b/src/include/access/gist_private.h
@@ -242,6 +242,7 @@ typedef struct
 	Relation	r;
 	Relation	heapRel;
 	Size		freespace;		/* free space to be left */
+	bool		is_build;
 
 	GISTInsertStack *stack;
 } GISTInsertState;
@@ -391,7 +392,8 @@ extern void gistdoinsert(Relation r,
 			 IndexTuple itup,
 			 Size freespace,
 			 GISTSTATE *GISTstate,
-			 Relation heapRel);
+			 Relation heapRel,
+			 bool is_build);
 
 /* A List of these is returned from gistplacetopage() in *splitinfo */
 typedef struct
@@ -407,7 +409,8 @@ extern bool gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 				Buffer leftchildbuf,
 				List **splitinfo,
 				bool markleftchild,
-				Relation heapRel);
+				Relation heapRel,
+				bool is_build);
 
 extern SplitedPageLayout *gistSplit(Relation r, Page page, IndexTuple *itup,
 		  int len, GISTSTATE *giststate);
diff --git a/src/include/access/gistxlog.h b/src/include/access/gistxlog.h
index 5117aabf1a..2ee80e244e 100644
--- a/src/include/access/gistxlog.h
+++ b/src/include/access/gistxlog.h
@@ -22,7 +22,6 @@
  /* #define XLOG_GIST_NEW_ROOT			 0x20 */	/* not used anymore */
 #define XLOG_GIST_PAGE_SPLIT		0x30
  /* #define XLOG_GIST_INSERT_COMPLETE	 0x40 */	/* not used anymore */
-#define XLOG_GIST_CREATE_INDEX		0x50
  /* #define XLOG_GIST_PAGE_DELETE		 0x60 */	/* not used anymore */
 
 /*
-- 
2.17.1

From c89f89c963078dda856394cb1189d9d0580018f6 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Wed, 6 Feb 2019 14:41:25 +0500
Subject: [PATCH 4/4] SP-GiST-Optimal-WAL-Usage

---
 src/backend/access/rmgrdesc/spgdesc.c   |  5 ----
 src/backend/access/spgist/spgdoinsert.c | 12 ++++-----
 src/backend/access/spgist/spginsert.c   | 24 +++--------------
 src/backend/access/spgist/spgxlog.c     | 35 -------------------------
 src/include/access/spgxlog.h            |  1 -
 5 files changed, 10 insertions(+), 67 deletions(-)

diff --git a/src/backend/access/rmgrdesc/spgdesc.c b/src/backend/access/rmgrdesc/spgdesc.c
index 37af31a764..40c1c8b3f9 100644
--- a/src/backend/access/rmgrdesc/spgdesc.c
+++ b/src/backend/access/rmgrdesc/spgdesc.c
@@ -24,8 +24,6 @@ spg_desc(StringInfo buf, XLogReaderState *record)
 
 	switch (info)
 	{
-		case XLOG_SPGIST_CREATE_INDEX:
-			break;
 		case XLOG_SPGIST_ADD_LEAF:
 			{
 				spgxlogAddLeaf *xlrec = (spgxlogAddLeaf *) rec;
@@ -88,9 +86,6 @@ spg_identify(uint8 info)
 
 	switch (info & ~XLR_INFO_MASK)
 	{
-		case XLOG_SPGIST_CREATE_INDEX:
-			id = "CREATE_INDEX";
-			break;
 		case XLOG_SPGIST_ADD_LEAF:
 			id = "ADD_LEAF";
 			break;
diff --git a/src/backend/access/spgist/spgdoinsert.c b/src/backend/access/spgist/spgdoinsert.c
index 0d07b8b291..c34c44cd8b 100644
--- a/src/backend/access/spgist/spgdoinsert.c
+++ b/src/backend/access/spgist/spgdoinsert.c
@@ -289,7 +289,7 @@ addLeafTuple(Relation index, SpGistState *state, SpGistLeafTuple leafTuple,
 
 	MarkBufferDirty(current->buffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 		int			flags;
@@ -516,7 +516,7 @@ moveLeafs(Relation index, SpGistState *state,
 	MarkBufferDirty(current->buffer);
 	MarkBufferDirty(nbuf);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 
@@ -1334,7 +1334,7 @@ doPickSplit(Relation index, SpGistState *state,
 		saveCurrent.buffer = InvalidBuffer;
 	}
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 		int			flags;
@@ -1531,7 +1531,7 @@ spgAddNodeAction(Relation index, SpGistState *state,
 
 		MarkBufferDirty(current->buffer);
 
-		if (RelationNeedsWAL(index))
+		if (RelationNeedsWAL(index) && !state->isBuild)
 		{
 			XLogRecPtr	recptr;
 
@@ -1644,7 +1644,7 @@ spgAddNodeAction(Relation index, SpGistState *state,
 
 		MarkBufferDirty(saveCurrent.buffer);
 
-		if (RelationNeedsWAL(index))
+		if (RelationNeedsWAL(index) && !state->isBuild)
 		{
 			XLogRecPtr	recptr;
 			int			flags;
@@ -1840,7 +1840,7 @@ spgSplitNodeAction(Relation index, SpGistState *state,
 
 	MarkBufferDirty(current->buffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 
diff --git a/src/backend/access/spgist/spginsert.c b/src/backend/access/spgist/spginsert.c
index f428a15138..5da0183a9b 100644
--- a/src/backend/access/spgist/spginsert.c
+++ b/src/backend/access/spgist/spginsert.c
@@ -21,6 +21,7 @@
 #include "access/spgxlog.h"
 #include "access/xlog.h"
 #include "access/xloginsert.h"
+#include "access/generic_xlog.h"
 #include "catalog/index.h"
 #include "miscadmin.h"
 #include "storage/bufmgr.h"
@@ -104,26 +105,6 @@ spgbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	SpGistInitBuffer(nullbuffer, SPGIST_LEAF | SPGIST_NULLS);
 	MarkBufferDirty(nullbuffer);
 
-	if (RelationNeedsWAL(index))
-	{
-		XLogRecPtr	recptr;
-
-		XLogBeginInsert();
-
-		/*
-		 * Replay will re-initialize the pages, so don't take full pages
-		 * images.  No other data to log.
-		 */
-		XLogRegisterBuffer(0, metabuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-		XLogRegisterBuffer(1, rootbuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-		XLogRegisterBuffer(2, nullbuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-
-		recptr = XLogInsert(RM_SPGIST_ID, XLOG_SPGIST_CREATE_INDEX);
-
-		PageSetLSN(BufferGetPage(metabuffer), recptr);
-		PageSetLSN(BufferGetPage(rootbuffer), recptr);
-		PageSetLSN(BufferGetPage(nullbuffer), recptr);
-	}
 
 	END_CRIT_SECTION();
 
@@ -150,6 +131,9 @@ spgbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 
 	SpGistUpdateMetaPage(index);
 
+	if (RelationNeedsWAL(index))
+		generic_log_relation(index);
+
 	result = (IndexBuildResult *) palloc0(sizeof(IndexBuildResult));
 	result->heap_tuples = reltuples;
 	result->index_tuples = buildstate.indtuples;
diff --git a/src/backend/access/spgist/spgxlog.c b/src/backend/access/spgist/spgxlog.c
index 71836ee8a5..ebe6ae8715 100644
--- a/src/backend/access/spgist/spgxlog.c
+++ b/src/backend/access/spgist/spgxlog.c
@@ -72,38 +72,6 @@ addOrReplaceTuple(Page page, Item tuple, int size, OffsetNumber offset)
 			 size);
 }
 
-static void
-spgRedoCreateIndex(XLogReaderState *record)
-{
-	XLogRecPtr	lsn = record->EndRecPtr;
-	Buffer		buffer;
-	Page		page;
-
-	buffer = XLogInitBufferForRedo(record, 0);
-	Assert(BufferGetBlockNumber(buffer) == SPGIST_METAPAGE_BLKNO);
-	page = (Page) BufferGetPage(buffer);
-	SpGistInitMetapage(page);
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-
-	buffer = XLogInitBufferForRedo(record, 1);
-	Assert(BufferGetBlockNumber(buffer) == SPGIST_ROOT_BLKNO);
-	SpGistInitBuffer(buffer, SPGIST_LEAF);
-	page = (Page) BufferGetPage(buffer);
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-
-	buffer = XLogInitBufferForRedo(record, 2);
-	Assert(BufferGetBlockNumber(buffer) == SPGIST_NULL_BLKNO);
-	SpGistInitBuffer(buffer, SPGIST_LEAF | SPGIST_NULLS);
-	page = (Page) BufferGetPage(buffer);
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-}
-
 static void
 spgRedoAddLeaf(XLogReaderState *record)
 {
@@ -976,9 +944,6 @@ spg_redo(XLogReaderState *record)
 	oldCxt = MemoryContextSwitchTo(opCtx);
 	switch (info)
 	{
-		case XLOG_SPGIST_CREATE_INDEX:
-			spgRedoCreateIndex(record);
-			break;
 		case XLOG_SPGIST_ADD_LEAF:
 			spgRedoAddLeaf(record);
 			break;
diff --git a/src/include/access/spgxlog.h b/src/include/access/spgxlog.h
index 6527fc9eb1..8199b3f250 100644
--- a/src/include/access/spgxlog.h
+++ b/src/include/access/spgxlog.h
@@ -18,7 +18,6 @@
 #include "storage/off.h"
 
 /* XLOG record types for SPGiST */
-#define XLOG_SPGIST_CREATE_INDEX	0x00
 #define XLOG_SPGIST_ADD_LEAF		0x10
 #define XLOG_SPGIST_MOVE_LEAFS		0x20
 #define XLOG_SPGIST_ADD_NODE		0x30
-- 
2.17.1

From d3093aa9a7628979b892d31449eda6228ef169ce Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Mon, 1 Apr 2019 08:33:46 +0500
Subject: [PATCH 1/4] Relation-into-WAL-function

---
 src/backend/access/transam/generic_xlog.c | 48 +++++++++++++++++++++++
 src/include/access/generic_xlog.h         |  3 ++
 2 files changed, 51 insertions(+)

diff --git a/src/backend/access/transam/generic_xlog.c b/src/backend/access/transam/generic_xlog.c
index 5b00b7275b..c22e361747 100644
--- a/src/backend/access/transam/generic_xlog.c
+++ b/src/backend/access/transam/generic_xlog.c
@@ -542,3 +542,51 @@ generic_mask(char *page, BlockNumber blkno)
 
 	mask_unused_space(page);
 }
+
+/*
+ * Function to write generic xlog for every existing block of a relation.
+ * Caller is responsible for locking the relation exclusively.
+ */
+void
+generic_log_relation(Relation rel)
+{
+	BlockNumber 		blkno;
+	BlockNumber 		nblocks;
+	int					npbuf = 0;
+	GenericXLogState	*state = NULL;
+	Buffer				bufpack[MAX_GENERIC_XLOG_PAGES];
+
+	CHECK_FOR_INTERRUPTS();
+	nblocks = RelationGetNumberOfBlocks(rel);
+
+	/*
+	 * Iterate over all index pages and WAL-logging it. Pages are grouping into
+	 * the packages before adding to a WAL-record. Zero-pages are
+	 * not logged.
+	 */
+	for (blkno = 0; blkno < nblocks; blkno++)
+	{
+		Buffer	buf;
+
+		buf = ReadBuffer(rel, blkno);
+		if (!PageIsNew(BufferGetPage(buf)))
+		{
+			if (npbuf == 0)
+				state = GenericXLogStart(rel);
+
+			LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
+			GenericXLogRegisterBuffer(state, buf, GENERIC_XLOG_FULL_IMAGE);
+			bufpack[npbuf++] = buf;
+		}
+		else
+			ReleaseBuffer(buf);
+
+		if ((npbuf == MAX_GENERIC_XLOG_PAGES) || (blkno == nblocks-1))
+		{
+			GenericXLogFinish(state);
+
+			for (; npbuf > 0; npbuf--)
+				UnlockReleaseBuffer(bufpack[npbuf-1]);
+		}
+	}
+}
diff --git a/src/include/access/generic_xlog.h b/src/include/access/generic_xlog.h
index cb5b5b713a..e3bbf014cc 100644
--- a/src/include/access/generic_xlog.h
+++ b/src/include/access/generic_xlog.h
@@ -42,4 +42,7 @@ extern const char *generic_identify(uint8 info);
 extern void generic_desc(StringInfo buf, XLogReaderState *record);
 extern void generic_mask(char *pagedata, BlockNumber blkno);
 
+/* other utils */
+extern void generic_log_relation(Relation rel);
+
 #endif							/* GENERIC_XLOG_H */
-- 
2.17.1

From 9a0172346c8a942b6a493aca8c47452256a2932f Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Mon, 1 Apr 2019 08:37:32 +0500
Subject: [PATCH 2/4] GIN-Optimal-WAL-Usage

---
 src/backend/access/gin/ginbtree.c     |  6 ++---
 src/backend/access/gin/gindatapage.c  |  9 ++++----
 src/backend/access/gin/ginentrypage.c |  2 +-
 src/backend/access/gin/gininsert.c    | 30 ++++++++++--------------
 src/backend/access/gin/ginutil.c      |  4 ++--
 src/backend/access/gin/ginvacuum.c    |  2 +-
 src/backend/access/gin/ginxlog.c      | 33 ---------------------------
 src/backend/access/rmgrdesc/gindesc.c |  6 -----
 src/include/access/gin.h              |  3 ++-
 src/include/access/ginxlog.h          |  2 --
 10 files changed, 26 insertions(+), 71 deletions(-)

diff --git a/src/backend/access/gin/ginbtree.c b/src/backend/access/gin/ginbtree.c
index 533949e46a..9f82eef8c3 100644
--- a/src/backend/access/gin/ginbtree.c
+++ b/src/backend/access/gin/ginbtree.c
@@ -396,7 +396,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
 		/* It will fit, perform the insertion */
 		START_CRIT_SECTION();
 
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 		{
 			XLogBeginInsert();
 			XLogRegisterBuffer(0, stack->buffer, REGBUF_STANDARD);
@@ -417,7 +417,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
 			MarkBufferDirty(childbuf);
 		}
 
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 		{
 			XLogRecPtr	recptr;
 			ginxlogInsert xlrec;
@@ -595,7 +595,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
 		}
 
 		/* write WAL record */
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 		{
 			XLogRecPtr	recptr;
 
diff --git a/src/backend/access/gin/gindatapage.c b/src/backend/access/gin/gindatapage.c
index 3ad8b76710..f3aff62c8e 100644
--- a/src/backend/access/gin/gindatapage.c
+++ b/src/backend/access/gin/gindatapage.c
@@ -593,7 +593,7 @@ dataBeginPlaceToPageLeaf(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 		 * Great, all the items fit on a single page.  If needed, prepare data
 		 * for a WAL record describing the changes we'll make.
 		 */
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 			computeLeafRecompressWALData(leaf);
 
 		/*
@@ -719,7 +719,7 @@ dataExecPlaceToPageLeaf(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 	dataPlaceToPageLeafRecompress(buf, leaf);
 
 	/* If needed, register WAL data built by computeLeafRecompressWALData */
-	if (RelationNeedsWAL(btree->index))
+	if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 	{
 		XLogRegisterBufData(0, leaf->walinfo, leaf->walinfolen);
 	}
@@ -1152,7 +1152,7 @@ dataExecPlaceToPageInternal(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 	pitem = (PostingItem *) insertdata;
 	GinDataPageAddPostingItem(page, pitem, off);
 
-	if (RelationNeedsWAL(btree->index))
+	if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 	{
 		/*
 		 * This must be static, because it has to survive until XLogInsert,
@@ -1773,6 +1773,7 @@ createPostingTree(Relation index, ItemPointerData *items, uint32 nitems,
 	Pointer		ptr;
 	int			nrootitems;
 	int			rootsize;
+	bool is_build = (buildStats != NULL);
 
 	/* Construct the new root page in memory first. */
 	tmppage = (Page) palloc(BLCKSZ);
@@ -1826,7 +1827,7 @@ createPostingTree(Relation index, ItemPointerData *items, uint32 nitems,
 	PageRestoreTempPage(tmppage, page);
 	MarkBufferDirty(buffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !is_build)
 	{
 		XLogRecPtr	recptr;
 		ginxlogCreatePostingTree data;
diff --git a/src/backend/access/gin/ginentrypage.c b/src/backend/access/gin/ginentrypage.c
index 4889de2a4f..1f5ba33d51 100644
--- a/src/backend/access/gin/ginentrypage.c
+++ b/src/backend/access/gin/ginentrypage.c
@@ -571,7 +571,7 @@ entryExecPlaceToPage(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 		elog(ERROR, "failed to add item to index page in \"%s\"",
 			 RelationGetRelationName(btree->index));
 
-	if (RelationNeedsWAL(btree->index))
+	if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 	{
 		/*
 		 * This must be static, because it has to survive until XLogInsert,
diff --git a/src/backend/access/gin/gininsert.c b/src/backend/access/gin/gininsert.c
index b02f69b0dc..a15ca7f942 100644
--- a/src/backend/access/gin/gininsert.c
+++ b/src/backend/access/gin/gininsert.c
@@ -17,6 +17,7 @@
 #include "access/gin_private.h"
 #include "access/ginxlog.h"
 #include "access/xloginsert.h"
+#include "access/generic_xlog.h"
 #include "access/tableam.h"
 #include "catalog/index.h"
 #include "miscadmin.h"
@@ -195,6 +196,7 @@ ginEntryInsert(GinState *ginstate,
 		buildStats->nEntries++;
 
 	ginPrepareEntryScan(&btree, attnum, key, category, ginstate);
+	btree.isBuild = (buildStats != NULL);
 
 	stack = ginFindLeafPage(&btree, false, false, NULL);
 	page = BufferGetPage(stack->buffer);
@@ -347,23 +349,6 @@ ginbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	GinInitBuffer(RootBuffer, GIN_LEAF);
 	MarkBufferDirty(RootBuffer);
 
-	if (RelationNeedsWAL(index))
-	{
-		XLogRecPtr	recptr;
-		Page		page;
-
-		XLogBeginInsert();
-		XLogRegisterBuffer(0, MetaBuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-		XLogRegisterBuffer(1, RootBuffer, REGBUF_WILL_INIT);
-
-		recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_CREATE_INDEX);
-
-		page = BufferGetPage(RootBuffer);
-		PageSetLSN(page, recptr);
-
-		page = BufferGetPage(MetaBuffer);
-		PageSetLSN(page, recptr);
-	}
 
 	UnlockReleaseBuffer(MetaBuffer);
 	UnlockReleaseBuffer(RootBuffer);
@@ -419,7 +404,16 @@ ginbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	 * Update metapage stats
 	 */
 	buildstate.buildStats.nTotalPages = RelationGetNumberOfBlocks(index);
-	ginUpdateStats(index, &buildstate.buildStats);
+	ginUpdateStats(index, &buildstate.buildStats, true);
+
+	/*
+	 * Create generic wal records for all pages of relation, if necessary.
+	 * It seems reasonable not to generate WAL, if we recieved interrupt
+	 * signal.
+	 */
+	CHECK_FOR_INTERRUPTS();
+	if (RelationNeedsWAL(index))
+		generic_log_relation(index);
 
 	/*
 	 * Return statistics
diff --git a/src/backend/access/gin/ginutil.c b/src/backend/access/gin/ginutil.c
index afc20232ac..51b20bca6e 100644
--- a/src/backend/access/gin/ginutil.c
+++ b/src/backend/access/gin/ginutil.c
@@ -661,7 +661,7 @@ ginGetStats(Relation index, GinStatsData *stats)
  * Note: nPendingPages and ginVersion are *not* copied over
  */
 void
-ginUpdateStats(Relation index, const GinStatsData *stats)
+ginUpdateStats(Relation index, const GinStatsData *stats, bool is_build)
 {
 	Buffer		metabuffer;
 	Page		metapage;
@@ -691,7 +691,7 @@ ginUpdateStats(Relation index, const GinStatsData *stats)
 
 	MarkBufferDirty(metabuffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !is_build)
 	{
 		XLogRecPtr	recptr;
 		ginxlogUpdateMeta data;
diff --git a/src/backend/access/gin/ginvacuum.c b/src/backend/access/gin/ginvacuum.c
index dfe885b101..b9a28d1863 100644
--- a/src/backend/access/gin/ginvacuum.c
+++ b/src/backend/access/gin/ginvacuum.c
@@ -759,7 +759,7 @@ ginvacuumcleanup(IndexVacuumInfo *info, IndexBulkDeleteResult *stats)
 
 	/* Update the metapage with accurate page and entry counts */
 	idxStat.nTotalPages = npages;
-	ginUpdateStats(info->index, &idxStat);
+	ginUpdateStats(info->index, &idxStat, false);
 
 	/* Finally, vacuum the FSM */
 	IndexFreeSpaceMapVacuum(info->index);
diff --git a/src/backend/access/gin/ginxlog.c b/src/backend/access/gin/ginxlog.c
index c467ffa346..b648af1ff6 100644
--- a/src/backend/access/gin/ginxlog.c
+++ b/src/backend/access/gin/ginxlog.c
@@ -40,36 +40,6 @@ ginRedoClearIncompleteSplit(XLogReaderState *record, uint8 block_id)
 		UnlockReleaseBuffer(buffer);
 }
 
-static void
-ginRedoCreateIndex(XLogReaderState *record)
-{
-	XLogRecPtr	lsn = record->EndRecPtr;
-	Buffer		RootBuffer,
-				MetaBuffer;
-	Page		page;
-
-	MetaBuffer = XLogInitBufferForRedo(record, 0);
-	Assert(BufferGetBlockNumber(MetaBuffer) == GIN_METAPAGE_BLKNO);
-	page = (Page) BufferGetPage(MetaBuffer);
-
-	GinInitMetabuffer(MetaBuffer);
-
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(MetaBuffer);
-
-	RootBuffer = XLogInitBufferForRedo(record, 1);
-	Assert(BufferGetBlockNumber(RootBuffer) == GIN_ROOT_BLKNO);
-	page = (Page) BufferGetPage(RootBuffer);
-
-	GinInitBuffer(RootBuffer, GIN_LEAF);
-
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(RootBuffer);
-
-	UnlockReleaseBuffer(RootBuffer);
-	UnlockReleaseBuffer(MetaBuffer);
-}
-
 static void
 ginRedoCreatePTree(XLogReaderState *record)
 {
@@ -767,9 +737,6 @@ gin_redo(XLogReaderState *record)
 	oldCtx = MemoryContextSwitchTo(opCtx);
 	switch (info)
 	{
-		case XLOG_GIN_CREATE_INDEX:
-			ginRedoCreateIndex(record);
-			break;
 		case XLOG_GIN_CREATE_PTREE:
 			ginRedoCreatePTree(record);
 			break;
diff --git a/src/backend/access/rmgrdesc/gindesc.c b/src/backend/access/rmgrdesc/gindesc.c
index ef30ce16b0..f3f4e1b214 100644
--- a/src/backend/access/rmgrdesc/gindesc.c
+++ b/src/backend/access/rmgrdesc/gindesc.c
@@ -78,9 +78,6 @@ gin_desc(StringInfo buf, XLogReaderState *record)
 
 	switch (info)
 	{
-		case XLOG_GIN_CREATE_INDEX:
-			/* no further information */
-			break;
 		case XLOG_GIN_CREATE_PTREE:
 			/* no further information */
 			break;
@@ -188,9 +185,6 @@ gin_identify(uint8 info)
 
 	switch (info & ~XLR_INFO_MASK)
 	{
-		case XLOG_GIN_CREATE_INDEX:
-			id = "CREATE_INDEX";
-			break;
 		case XLOG_GIN_CREATE_PTREE:
 			id = "CREATE_PTREE";
 			break;
diff --git a/src/include/access/gin.h b/src/include/access/gin.h
index 61fa697039..d559ffc703 100644
--- a/src/include/access/gin.h
+++ b/src/include/access/gin.h
@@ -71,6 +71,7 @@ extern int	gin_pending_list_limit;
 
 /* ginutil.c */
 extern void ginGetStats(Relation index, GinStatsData *stats);
-extern void ginUpdateStats(Relation index, const GinStatsData *stats);
+extern void ginUpdateStats(Relation index,
+						   const GinStatsData *stats, bool is_build);
 
 #endif							/* GIN_H */
diff --git a/src/include/access/ginxlog.h b/src/include/access/ginxlog.h
index 9bd4e0b9ba..2c5d743cac 100644
--- a/src/include/access/ginxlog.h
+++ b/src/include/access/ginxlog.h
@@ -16,8 +16,6 @@
 #include "lib/stringinfo.h"
 #include "storage/off.h"
 
-#define XLOG_GIN_CREATE_INDEX  0x00
-
 #define XLOG_GIN_CREATE_PTREE  0x10
 
 typedef struct ginxlogCreatePostingTree
-- 
2.17.1

From 3e73e862c1aa20bf4eeca20ba4381a1d3c6f19d9 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Mon, 1 Apr 2019 09:07:32 +0500
Subject: [PATCH 3/4] GiST-Optimal-WAL-Usage

---
 src/backend/access/gist/gist.c         | 46 ++++++++++++++++++--------
 src/backend/access/gist/gistbuild.c    | 32 ++++++++++--------
 src/backend/access/gist/gistutil.c     |  2 +-
 src/backend/access/gist/gistxlog.c     | 22 ------------
 src/backend/access/rmgrdesc/gistdesc.c |  5 ---
 src/include/access/gist_private.h      |  7 ++--
 src/include/access/gistxlog.h          |  1 -
 7 files changed, 56 insertions(+), 59 deletions(-)

diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index 2fddb23496..0e2b6c3014 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -172,7 +172,7 @@ gistinsert(Relation r, Datum *values, bool *isnull,
 						 values, isnull, true /* size is currently bogus */ );
 	itup->t_tid = *ht_ctid;
 
-	gistdoinsert(r, itup, 0, giststate, heapRel);
+	gistdoinsert(r, itup, 0, giststate, heapRel, false);
 
 	/* cleanup */
 	MemoryContextSwitchTo(oldCxt);
@@ -219,7 +219,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 				Buffer leftchildbuf,
 				List **splitinfo,
 				bool markfollowright,
-				Relation heapRel)
+				Relation heapRel,
+				bool is_build)
 {
 	BlockNumber blkno = BufferGetBlockNumber(buffer);
 	Page		page = BufferGetPage(buffer);
@@ -458,7 +459,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		 * insertion for that. NB: The number of pages and data segments
 		 * specified here must match the calculations in gistXLogSplit()!
 		 */
-		if (RelationNeedsWAL(rel))
+		if (RelationNeedsWAL(rel) && !is_build)
 			XLogEnsureRecordSpace(npage, 1 + npage * 2);
 
 		START_CRIT_SECTION();
@@ -479,18 +480,20 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		PageRestoreTempPage(dist->page, BufferGetPage(dist->buffer));
 		dist->page = BufferGetPage(dist->buffer);
 
-		/* Write the WAL record */
-		if (RelationNeedsWAL(rel))
+		/*
+		 * Write the WAL record.
+		 * Do not write XLog entry if the insertion is caused by
+		 * index build process.
+		 */
+		if (RelationNeedsWAL(rel) && !is_build)
 			recptr = gistXLogSplit(is_leaf,
-								   dist, oldrlink, oldnsn, leftchildbuf,
-								   markfollowright);
+								dist, oldrlink, oldnsn, leftchildbuf,
+								markfollowright);
 		else
 			recptr = gistGetFakeLSN(rel);
 
 		for (ptr = dist; ptr; ptr = ptr->next)
-		{
 			PageSetLSN(ptr->page, recptr);
-		}
 
 		/*
 		 * Return the new child buffers to the caller.
@@ -544,7 +547,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		if (BufferIsValid(leftchildbuf))
 			MarkBufferDirty(leftchildbuf);
 
-		if (RelationNeedsWAL(rel))
+
+		if (RelationNeedsWAL(rel) && !is_build)
 		{
 			OffsetNumber ndeloffs = 0,
 						deloffs[1];
@@ -567,6 +571,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 			PageSetLSN(page, recptr);
 		}
 
+
 		if (newblkno)
 			*newblkno = blkno;
 	}
@@ -583,17 +588,28 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 	 * the full page image. There's a chicken-and-egg problem: if we updated
 	 * the child pages first, we wouldn't know the recptr of the WAL record
 	 * we're about to write.
+	 *
+	 * We use fakeLSNs for inserions caused by index build. And when it is
+	 * finished, we write generic_xlog entry for each index page and update
+	 * all LSNs. In order to keep NSNs less then LSNs after this update, we
+	 * set NSN to InvalidXLogRecPtr, which is the smallest possible NSN.
 	 */
+
 	if (BufferIsValid(leftchildbuf))
 	{
 		Page		leftpg = BufferGetPage(leftchildbuf);
+		XLogRecPtr	fakerecptr = InvalidXLogRecPtr;
 
-		GistPageSetNSN(leftpg, recptr);
-		GistClearFollowRight(leftpg);
+		if (!is_build)
+			GistPageSetNSN(leftpg, recptr);
+		else
+			GistPageSetNSN(leftpg, fakerecptr);
 
+		GistClearFollowRight(leftpg);
 		PageSetLSN(leftpg, recptr);
 	}
 
+
 	END_CRIT_SECTION();
 
 	return is_split;
@@ -606,7 +622,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
  */
 void
 gistdoinsert(Relation r, IndexTuple itup, Size freespace,
-			 GISTSTATE *giststate, Relation heapRel)
+			 GISTSTATE *giststate, Relation heapRel, bool is_build)
 {
 	ItemId		iid;
 	IndexTuple	idxtuple;
@@ -619,6 +635,7 @@ gistdoinsert(Relation r, IndexTuple itup, Size freespace,
 	state.freespace = freespace;
 	state.r = r;
 	state.heapRel = heapRel;
+	state.is_build = is_build;
 
 	/* Start from the root */
 	firststack.blkno = GIST_ROOT_BLKNO;
@@ -1251,7 +1268,8 @@ gistinserttuples(GISTInsertState *state, GISTInsertStack *stack,
 							   leftchild,
 							   &splitinfo,
 							   true,
-							   state->heapRel);
+							   state->heapRel,
+							   state->is_build);
 
 	/*
 	 * Before recursing up in case the page was split, release locks on the
diff --git a/src/backend/access/gist/gistbuild.c b/src/backend/access/gist/gistbuild.c
index 3652fde5bb..8d0d285cab 100644
--- a/src/backend/access/gist/gistbuild.c
+++ b/src/backend/access/gist/gistbuild.c
@@ -17,6 +17,7 @@
 #include <math.h>
 
 #include "access/genam.h"
+#include "access/generic_xlog.h"
 #include "access/gist_private.h"
 #include "access/gistxlog.h"
 #include "access/tableam.h"
@@ -181,18 +182,12 @@ gistbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 
 	MarkBufferDirty(buffer);
 
-	if (RelationNeedsWAL(index))
-	{
-		XLogRecPtr	recptr;
-
-		XLogBeginInsert();
-		XLogRegisterBuffer(0, buffer, REGBUF_WILL_INIT);
-
-		recptr = XLogInsert(RM_GIST_ID, XLOG_GIST_CREATE_INDEX);
-		PageSetLSN(page, recptr);
-	}
-	else
-		PageSetLSN(page, gistGetFakeLSN(heap));
+	/*
+	 * Do not write index pages to WAL unitl index build is finished.
+	 * But we still need increasing LSNs on each page, so use FakeLSN,
+	 * even for relations which eventually need WAL.
+	 */
+	PageSetLSN(page, gistGetFakeLSN(heap));
 
 	UnlockReleaseBuffer(buffer);
 
@@ -226,6 +221,15 @@ gistbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 
 	freeGISTstate(buildstate.giststate);
 
+	/*
+	 * Create generic wal records for all pages of relation, if necessary.
+	 * It seems reasonable not to generate WAL, if we recieved interrupt
+	 * signal.
+	 */
+	CHECK_FOR_INTERRUPTS();
+	if (RelationNeedsWAL(index))
+		generic_log_relation(index);
+
 	/*
 	 * Return statistics
 	 */
@@ -488,7 +492,7 @@ gistBuildCallback(Relation index,
 		 * locked, we call gistdoinsert directly.
 		 */
 		gistdoinsert(index, itup, buildstate->freespace,
-					 buildstate->giststate, buildstate->heaprel);
+					 buildstate->giststate, buildstate->heaprel, true);
 	}
 
 	/* Update tuple count and total size. */
@@ -695,7 +699,7 @@ gistbufferinginserttuples(GISTBuildState *buildstate, Buffer buffer, int level,
 							   InvalidBuffer,
 							   &splitinfo,
 							   false,
-							   buildstate->heaprel);
+							   buildstate->heaprel, true);
 
 	/*
 	 * If this is a root split, update the root path item kept in memory. This
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index 2163cc482d..af278e5ded 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -1004,6 +1004,7 @@ gistproperty(Oid index_oid, int attno,
  * Temporary and unlogged GiST indexes are not WAL-logged, but we need LSNs
  * to detect concurrent page splits anyway. This function provides a fake
  * sequence of LSNs for that purpose.
+ * Persistent relations are also not WAL-logged while we build index.
  */
 XLogRecPtr
 gistGetFakeLSN(Relation rel)
@@ -1024,7 +1025,6 @@ gistGetFakeLSN(Relation rel)
 		 * Unlogged relations are accessible from other backends, and survive
 		 * (clean) restarts. GetFakeLSNForUnloggedRel() handles that for us.
 		 */
-		Assert(rel->rd_rel->relpersistence == RELPERSISTENCE_UNLOGGED);
 		return GetFakeLSNForUnloggedRel();
 	}
 }
diff --git a/src/backend/access/gist/gistxlog.c b/src/backend/access/gist/gistxlog.c
index cb80ab00cd..4fb1855e89 100644
--- a/src/backend/access/gist/gistxlog.c
+++ b/src/backend/access/gist/gistxlog.c
@@ -490,25 +490,6 @@ gistRedoPageSplitRecord(XLogReaderState *record)
 	UnlockReleaseBuffer(firstbuffer);
 }
 
-static void
-gistRedoCreateIndex(XLogReaderState *record)
-{
-	XLogRecPtr	lsn = record->EndRecPtr;
-	Buffer		buffer;
-	Page		page;
-
-	buffer = XLogInitBufferForRedo(record, 0);
-	Assert(BufferGetBlockNumber(buffer) == GIST_ROOT_BLKNO);
-	page = (Page) BufferGetPage(buffer);
-
-	GISTInitBuffer(buffer, F_LEAF);
-
-	PageSetLSN(page, lsn);
-
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-}
-
 /* redo page deletion */
 static void
 gistRedoPageDelete(XLogReaderState *record)
@@ -594,9 +575,6 @@ gist_redo(XLogReaderState *record)
 		case XLOG_GIST_PAGE_SPLIT:
 			gistRedoPageSplitRecord(record);
 			break;
-		case XLOG_GIST_CREATE_INDEX:
-			gistRedoCreateIndex(record);
-			break;
 		case XLOG_GIST_PAGE_DELETE:
 			gistRedoPageDelete(record);
 			break;
diff --git a/src/backend/access/rmgrdesc/gistdesc.c b/src/backend/access/rmgrdesc/gistdesc.c
index 3ff4f83d38..eb308c72d6 100644
--- a/src/backend/access/rmgrdesc/gistdesc.c
+++ b/src/backend/access/rmgrdesc/gistdesc.c
@@ -71,8 +71,6 @@ gist_desc(StringInfo buf, XLogReaderState *record)
 		case XLOG_GIST_PAGE_SPLIT:
 			out_gistxlogPageSplit(buf, (gistxlogPageSplit *) rec);
 			break;
-		case XLOG_GIST_CREATE_INDEX:
-			break;
 		case XLOG_GIST_PAGE_DELETE:
 			out_gistxlogPageDelete(buf, (gistxlogPageDelete *) rec);
 			break;
@@ -98,9 +96,6 @@ gist_identify(uint8 info)
 		case XLOG_GIST_PAGE_SPLIT:
 			id = "PAGE_SPLIT";
 			break;
-		case XLOG_GIST_CREATE_INDEX:
-			id = "CREATE_INDEX";
-			break;
 		case XLOG_GIST_PAGE_DELETE:
 			id = "PAGE_DELETE";
 			break;
diff --git a/src/include/access/gist_private.h b/src/include/access/gist_private.h
index 02dc285a78..78e2e3fb31 100644
--- a/src/include/access/gist_private.h
+++ b/src/include/access/gist_private.h
@@ -244,6 +244,7 @@ typedef struct
 	Relation	r;
 	Relation	heapRel;
 	Size		freespace;		/* free space to be left */
+	bool		is_build;
 
 	GISTInsertStack *stack;
 } GISTInsertState;
@@ -393,7 +394,8 @@ extern void gistdoinsert(Relation r,
 			 IndexTuple itup,
 			 Size freespace,
 			 GISTSTATE *GISTstate,
-			 Relation heapRel);
+			 Relation heapRel,
+			 bool is_build);
 
 /* A List of these is returned from gistplacetopage() in *splitinfo */
 typedef struct
@@ -409,7 +411,8 @@ extern bool gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 				Buffer leftchildbuf,
 				List **splitinfo,
 				bool markleftchild,
-				Relation heapRel);
+				Relation heapRel,
+				bool is_build);
 
 extern SplitedPageLayout *gistSplit(Relation r, Page page, IndexTuple *itup,
 		  int len, GISTSTATE *giststate);
diff --git a/src/include/access/gistxlog.h b/src/include/access/gistxlog.h
index 2f87b67a53..80931497ca 100644
--- a/src/include/access/gistxlog.h
+++ b/src/include/access/gistxlog.h
@@ -23,7 +23,6 @@
 										  * FSM */
 #define XLOG_GIST_PAGE_SPLIT		0x30
  /* #define XLOG_GIST_INSERT_COMPLETE	 0x40 */	/* not used anymore */
-#define XLOG_GIST_CREATE_INDEX		0x50
 #define XLOG_GIST_PAGE_DELETE		0x60
 
 /*
-- 
2.17.1

From 19968269bc08f71ed1eaf4f33d1e06da6fda9708 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Mon, 1 Apr 2019 09:07:51 +0500
Subject: [PATCH 4/4] SP-GiST-Optimal-WAL-Usage

---
 src/backend/access/rmgrdesc/spgdesc.c   |  5 ----
 src/backend/access/spgist/spgdoinsert.c | 12 ++++-----
 src/backend/access/spgist/spginsert.c   | 24 +++--------------
 src/backend/access/spgist/spgxlog.c     | 35 -------------------------
 src/include/access/spgxlog.h            |  1 -
 5 files changed, 10 insertions(+), 67 deletions(-)

diff --git a/src/backend/access/rmgrdesc/spgdesc.c b/src/backend/access/rmgrdesc/spgdesc.c
index 37af31a764..40c1c8b3f9 100644
--- a/src/backend/access/rmgrdesc/spgdesc.c
+++ b/src/backend/access/rmgrdesc/spgdesc.c
@@ -24,8 +24,6 @@ spg_desc(StringInfo buf, XLogReaderState *record)
 
 	switch (info)
 	{
-		case XLOG_SPGIST_CREATE_INDEX:
-			break;
 		case XLOG_SPGIST_ADD_LEAF:
 			{
 				spgxlogAddLeaf *xlrec = (spgxlogAddLeaf *) rec;
@@ -88,9 +86,6 @@ spg_identify(uint8 info)
 
 	switch (info & ~XLR_INFO_MASK)
 	{
-		case XLOG_SPGIST_CREATE_INDEX:
-			id = "CREATE_INDEX";
-			break;
 		case XLOG_SPGIST_ADD_LEAF:
 			id = "ADD_LEAF";
 			break;
diff --git a/src/backend/access/spgist/spgdoinsert.c b/src/backend/access/spgist/spgdoinsert.c
index 0d07b8b291..c34c44cd8b 100644
--- a/src/backend/access/spgist/spgdoinsert.c
+++ b/src/backend/access/spgist/spgdoinsert.c
@@ -289,7 +289,7 @@ addLeafTuple(Relation index, SpGistState *state, SpGistLeafTuple leafTuple,
 
 	MarkBufferDirty(current->buffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 		int			flags;
@@ -516,7 +516,7 @@ moveLeafs(Relation index, SpGistState *state,
 	MarkBufferDirty(current->buffer);
 	MarkBufferDirty(nbuf);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 
@@ -1334,7 +1334,7 @@ doPickSplit(Relation index, SpGistState *state,
 		saveCurrent.buffer = InvalidBuffer;
 	}
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 		int			flags;
@@ -1531,7 +1531,7 @@ spgAddNodeAction(Relation index, SpGistState *state,
 
 		MarkBufferDirty(current->buffer);
 
-		if (RelationNeedsWAL(index))
+		if (RelationNeedsWAL(index) && !state->isBuild)
 		{
 			XLogRecPtr	recptr;
 
@@ -1644,7 +1644,7 @@ spgAddNodeAction(Relation index, SpGistState *state,
 
 		MarkBufferDirty(saveCurrent.buffer);
 
-		if (RelationNeedsWAL(index))
+		if (RelationNeedsWAL(index) && !state->isBuild)
 		{
 			XLogRecPtr	recptr;
 			int			flags;
@@ -1840,7 +1840,7 @@ spgSplitNodeAction(Relation index, SpGistState *state,
 
 	MarkBufferDirty(current->buffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 
diff --git a/src/backend/access/spgist/spginsert.c b/src/backend/access/spgist/spginsert.c
index 390ad9ac51..6ec48b9f93 100644
--- a/src/backend/access/spgist/spginsert.c
+++ b/src/backend/access/spgist/spginsert.c
@@ -22,6 +22,7 @@
 #include "access/tableam.h"
 #include "access/xlog.h"
 #include "access/xloginsert.h"
+#include "access/generic_xlog.h"
 #include "catalog/index.h"
 #include "miscadmin.h"
 #include "storage/bufmgr.h"
@@ -105,26 +106,6 @@ spgbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	SpGistInitBuffer(nullbuffer, SPGIST_LEAF | SPGIST_NULLS);
 	MarkBufferDirty(nullbuffer);
 
-	if (RelationNeedsWAL(index))
-	{
-		XLogRecPtr	recptr;
-
-		XLogBeginInsert();
-
-		/*
-		 * Replay will re-initialize the pages, so don't take full pages
-		 * images.  No other data to log.
-		 */
-		XLogRegisterBuffer(0, metabuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-		XLogRegisterBuffer(1, rootbuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-		XLogRegisterBuffer(2, nullbuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-
-		recptr = XLogInsert(RM_SPGIST_ID, XLOG_SPGIST_CREATE_INDEX);
-
-		PageSetLSN(BufferGetPage(metabuffer), recptr);
-		PageSetLSN(BufferGetPage(rootbuffer), recptr);
-		PageSetLSN(BufferGetPage(nullbuffer), recptr);
-	}
 
 	END_CRIT_SECTION();
 
@@ -151,6 +132,9 @@ spgbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 
 	SpGistUpdateMetaPage(index);
 
+	if (RelationNeedsWAL(index))
+		generic_log_relation(index);
+
 	result = (IndexBuildResult *) palloc0(sizeof(IndexBuildResult));
 	result->heap_tuples = reltuples;
 	result->index_tuples = buildstate.indtuples;
diff --git a/src/backend/access/spgist/spgxlog.c b/src/backend/access/spgist/spgxlog.c
index 71836ee8a5..ebe6ae8715 100644
--- a/src/backend/access/spgist/spgxlog.c
+++ b/src/backend/access/spgist/spgxlog.c
@@ -72,38 +72,6 @@ addOrReplaceTuple(Page page, Item tuple, int size, OffsetNumber offset)
 			 size);
 }
 
-static void
-spgRedoCreateIndex(XLogReaderState *record)
-{
-	XLogRecPtr	lsn = record->EndRecPtr;
-	Buffer		buffer;
-	Page		page;
-
-	buffer = XLogInitBufferForRedo(record, 0);
-	Assert(BufferGetBlockNumber(buffer) == SPGIST_METAPAGE_BLKNO);
-	page = (Page) BufferGetPage(buffer);
-	SpGistInitMetapage(page);
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-
-	buffer = XLogInitBufferForRedo(record, 1);
-	Assert(BufferGetBlockNumber(buffer) == SPGIST_ROOT_BLKNO);
-	SpGistInitBuffer(buffer, SPGIST_LEAF);
-	page = (Page) BufferGetPage(buffer);
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-
-	buffer = XLogInitBufferForRedo(record, 2);
-	Assert(BufferGetBlockNumber(buffer) == SPGIST_NULL_BLKNO);
-	SpGistInitBuffer(buffer, SPGIST_LEAF | SPGIST_NULLS);
-	page = (Page) BufferGetPage(buffer);
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-}
-
 static void
 spgRedoAddLeaf(XLogReaderState *record)
 {
@@ -976,9 +944,6 @@ spg_redo(XLogReaderState *record)
 	oldCxt = MemoryContextSwitchTo(opCtx);
 	switch (info)
 	{
-		case XLOG_SPGIST_CREATE_INDEX:
-			spgRedoCreateIndex(record);
-			break;
 		case XLOG_SPGIST_ADD_LEAF:
 			spgRedoAddLeaf(record);
 			break;
diff --git a/src/include/access/spgxlog.h b/src/include/access/spgxlog.h
index 6527fc9eb1..8199b3f250 100644
--- a/src/include/access/spgxlog.h
+++ b/src/include/access/spgxlog.h
@@ -18,7 +18,6 @@
 #include "storage/off.h"
 
 /* XLOG record types for SPGiST */
-#define XLOG_SPGIST_CREATE_INDEX	0x00
 #define XLOG_SPGIST_ADD_LEAF		0x10
 #define XLOG_SPGIST_MOVE_LEAFS		0x20
 #define XLOG_SPGIST_ADD_NODE		0x30
-- 
2.17.1

From 2edd0ada13b4749487d0f046191ef2bcf8b11ca3 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Tue, 2 Apr 2019 09:42:59 +0500
Subject: [PATCH 1/4] Relation-into-WAL-function

---
 src/backend/access/transam/generic_xlog.c | 63 +++++++++++++++++++++++
 src/include/access/generic_xlog.h         |  3 ++
 2 files changed, 66 insertions(+)

diff --git a/src/backend/access/transam/generic_xlog.c b/src/backend/access/transam/generic_xlog.c
index 5b00b7275b..0d5025f78a 100644
--- a/src/backend/access/transam/generic_xlog.c
+++ b/src/backend/access/transam/generic_xlog.c
@@ -16,6 +16,7 @@
 #include "access/bufmask.h"
 #include "access/generic_xlog.h"
 #include "access/xlogutils.h"
+#include "catalog/pg_control.h"
 #include "miscadmin.h"
 #include "utils/memutils.h"
 
@@ -542,3 +543,65 @@ generic_mask(char *page, BlockNumber blkno)
 
 	mask_unused_space(page);
 }
+
+/*
+ * Function for WAL-logging all pages of a relation.
+ * Caller is responsible for locking the relation exclusively.
+ */
+void
+log_relation(Relation rel)
+{
+	BlockNumber 		blkno = 0;
+	BlockNumber 		nblocks;
+	Buffer				bufpack[XLR_MAX_BLOCK_ID];
+
+	CHECK_FOR_INTERRUPTS();
+
+	/*
+	 * Iterate over all index pages and WAL-logging it. Pages are grouping into
+	 * the packages before adding to a WAL-record. Zero pages are not logged.
+	 */
+	nblocks = RelationGetNumberOfBlocks(rel);
+	while (blkno < nblocks)
+	{
+		XLogRecPtr recptr;
+		int8 nbufs = 0;
+		int8 i;
+
+		/*
+		 * Assemble package of relation blocks. Try to combine the maximum
+		 * possible number of blocks in one record.
+		 */
+		while (nbufs < XLR_MAX_BLOCK_ID && blkno < nblocks)
+		{
+			Buffer buf = ReadBuffer(rel, blkno);
+
+			if (!PageIsNew(BufferGetPage(buf)))
+				bufpack[nbufs++] = buf;
+			else
+				ReleaseBuffer(buf);
+			blkno++;
+		}
+
+		XLogBeginInsert();
+		XLogEnsureRecordSpace(nbufs, 0);
+
+		START_CRIT_SECTION();
+		for (i = 0; i < nbufs; i++)
+		{
+			LockBuffer(bufpack[i], BUFFER_LOCK_EXCLUSIVE);
+			XLogRegisterBuffer(i, bufpack[i], REGBUF_FORCE_IMAGE | REGBUF_STANDARD);
+		}
+
+		recptr = XLogInsert(RM_XLOG_ID, XLOG_FPI);
+
+		for (i = 0; i < nbufs; i++)
+		{
+			Page page = BufferGetPage(bufpack[i]);
+			PageSetLSN(page, recptr);
+			MarkBufferDirty(bufpack[i]);
+			UnlockReleaseBuffer(bufpack[i]);
+		}
+		END_CRIT_SECTION();
+	}
+}
diff --git a/src/include/access/generic_xlog.h b/src/include/access/generic_xlog.h
index cb5b5b713a..8abfa486c7 100644
--- a/src/include/access/generic_xlog.h
+++ b/src/include/access/generic_xlog.h
@@ -42,4 +42,7 @@ extern const char *generic_identify(uint8 info);
 extern void generic_desc(StringInfo buf, XLogReaderState *record);
 extern void generic_mask(char *pagedata, BlockNumber blkno);
 
+/* other utils */
+extern void log_relation(Relation rel);
+
 #endif							/* GENERIC_XLOG_H */
-- 
2.17.1

From 8857657efa8f3347010d3b251315f800dd03bf8d Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Tue, 2 Apr 2019 09:43:20 +0500
Subject: [PATCH 2/4] GIN-Optimal-WAL-Usage

---
 src/backend/access/gin/ginbtree.c     |  6 ++---
 src/backend/access/gin/gindatapage.c  |  9 ++++----
 src/backend/access/gin/ginentrypage.c |  2 +-
 src/backend/access/gin/gininsert.c    | 30 ++++++++++--------------
 src/backend/access/gin/ginutil.c      |  4 ++--
 src/backend/access/gin/ginvacuum.c    |  2 +-
 src/backend/access/gin/ginxlog.c      | 33 ---------------------------
 src/backend/access/rmgrdesc/gindesc.c |  6 -----
 src/include/access/gin.h              |  3 ++-
 src/include/access/ginxlog.h          |  2 --
 10 files changed, 26 insertions(+), 71 deletions(-)

diff --git a/src/backend/access/gin/ginbtree.c b/src/backend/access/gin/ginbtree.c
index 533949e46a..9f82eef8c3 100644
--- a/src/backend/access/gin/ginbtree.c
+++ b/src/backend/access/gin/ginbtree.c
@@ -396,7 +396,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
 		/* It will fit, perform the insertion */
 		START_CRIT_SECTION();
 
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 		{
 			XLogBeginInsert();
 			XLogRegisterBuffer(0, stack->buffer, REGBUF_STANDARD);
@@ -417,7 +417,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
 			MarkBufferDirty(childbuf);
 		}
 
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 		{
 			XLogRecPtr	recptr;
 			ginxlogInsert xlrec;
@@ -595,7 +595,7 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
 		}
 
 		/* write WAL record */
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 		{
 			XLogRecPtr	recptr;
 
diff --git a/src/backend/access/gin/gindatapage.c b/src/backend/access/gin/gindatapage.c
index 3ad8b76710..f3aff62c8e 100644
--- a/src/backend/access/gin/gindatapage.c
+++ b/src/backend/access/gin/gindatapage.c
@@ -593,7 +593,7 @@ dataBeginPlaceToPageLeaf(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 		 * Great, all the items fit on a single page.  If needed, prepare data
 		 * for a WAL record describing the changes we'll make.
 		 */
-		if (RelationNeedsWAL(btree->index))
+		if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 			computeLeafRecompressWALData(leaf);
 
 		/*
@@ -719,7 +719,7 @@ dataExecPlaceToPageLeaf(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 	dataPlaceToPageLeafRecompress(buf, leaf);
 
 	/* If needed, register WAL data built by computeLeafRecompressWALData */
-	if (RelationNeedsWAL(btree->index))
+	if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 	{
 		XLogRegisterBufData(0, leaf->walinfo, leaf->walinfolen);
 	}
@@ -1152,7 +1152,7 @@ dataExecPlaceToPageInternal(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 	pitem = (PostingItem *) insertdata;
 	GinDataPageAddPostingItem(page, pitem, off);
 
-	if (RelationNeedsWAL(btree->index))
+	if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 	{
 		/*
 		 * This must be static, because it has to survive until XLogInsert,
@@ -1773,6 +1773,7 @@ createPostingTree(Relation index, ItemPointerData *items, uint32 nitems,
 	Pointer		ptr;
 	int			nrootitems;
 	int			rootsize;
+	bool is_build = (buildStats != NULL);
 
 	/* Construct the new root page in memory first. */
 	tmppage = (Page) palloc(BLCKSZ);
@@ -1826,7 +1827,7 @@ createPostingTree(Relation index, ItemPointerData *items, uint32 nitems,
 	PageRestoreTempPage(tmppage, page);
 	MarkBufferDirty(buffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !is_build)
 	{
 		XLogRecPtr	recptr;
 		ginxlogCreatePostingTree data;
diff --git a/src/backend/access/gin/ginentrypage.c b/src/backend/access/gin/ginentrypage.c
index 4889de2a4f..1f5ba33d51 100644
--- a/src/backend/access/gin/ginentrypage.c
+++ b/src/backend/access/gin/ginentrypage.c
@@ -571,7 +571,7 @@ entryExecPlaceToPage(GinBtree btree, Buffer buf, GinBtreeStack *stack,
 		elog(ERROR, "failed to add item to index page in \"%s\"",
 			 RelationGetRelationName(btree->index));
 
-	if (RelationNeedsWAL(btree->index))
+	if (RelationNeedsWAL(btree->index) && !btree->isBuild)
 	{
 		/*
 		 * This must be static, because it has to survive until XLogInsert,
diff --git a/src/backend/access/gin/gininsert.c b/src/backend/access/gin/gininsert.c
index b02f69b0dc..44f2bdce9c 100644
--- a/src/backend/access/gin/gininsert.c
+++ b/src/backend/access/gin/gininsert.c
@@ -17,6 +17,7 @@
 #include "access/gin_private.h"
 #include "access/ginxlog.h"
 #include "access/xloginsert.h"
+#include "access/generic_xlog.h"
 #include "access/tableam.h"
 #include "catalog/index.h"
 #include "miscadmin.h"
@@ -195,6 +196,7 @@ ginEntryInsert(GinState *ginstate,
 		buildStats->nEntries++;
 
 	ginPrepareEntryScan(&btree, attnum, key, category, ginstate);
+	btree.isBuild = (buildStats != NULL);
 
 	stack = ginFindLeafPage(&btree, false, false, NULL);
 	page = BufferGetPage(stack->buffer);
@@ -347,23 +349,6 @@ ginbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	GinInitBuffer(RootBuffer, GIN_LEAF);
 	MarkBufferDirty(RootBuffer);
 
-	if (RelationNeedsWAL(index))
-	{
-		XLogRecPtr	recptr;
-		Page		page;
-
-		XLogBeginInsert();
-		XLogRegisterBuffer(0, MetaBuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-		XLogRegisterBuffer(1, RootBuffer, REGBUF_WILL_INIT);
-
-		recptr = XLogInsert(RM_GIN_ID, XLOG_GIN_CREATE_INDEX);
-
-		page = BufferGetPage(RootBuffer);
-		PageSetLSN(page, recptr);
-
-		page = BufferGetPage(MetaBuffer);
-		PageSetLSN(page, recptr);
-	}
 
 	UnlockReleaseBuffer(MetaBuffer);
 	UnlockReleaseBuffer(RootBuffer);
@@ -419,7 +404,16 @@ ginbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	 * Update metapage stats
 	 */
 	buildstate.buildStats.nTotalPages = RelationGetNumberOfBlocks(index);
-	ginUpdateStats(index, &buildstate.buildStats);
+	ginUpdateStats(index, &buildstate.buildStats, true);
+
+	/*
+	 * Create generic wal records for all pages of relation, if necessary.
+	 * It seems reasonable not to generate WAL, if we recieved interrupt
+	 * signal.
+	 */
+	CHECK_FOR_INTERRUPTS();
+	if (RelationNeedsWAL(index))
+		log_relation(index);
 
 	/*
 	 * Return statistics
diff --git a/src/backend/access/gin/ginutil.c b/src/backend/access/gin/ginutil.c
index afc20232ac..51b20bca6e 100644
--- a/src/backend/access/gin/ginutil.c
+++ b/src/backend/access/gin/ginutil.c
@@ -661,7 +661,7 @@ ginGetStats(Relation index, GinStatsData *stats)
  * Note: nPendingPages and ginVersion are *not* copied over
  */
 void
-ginUpdateStats(Relation index, const GinStatsData *stats)
+ginUpdateStats(Relation index, const GinStatsData *stats, bool is_build)
 {
 	Buffer		metabuffer;
 	Page		metapage;
@@ -691,7 +691,7 @@ ginUpdateStats(Relation index, const GinStatsData *stats)
 
 	MarkBufferDirty(metabuffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !is_build)
 	{
 		XLogRecPtr	recptr;
 		ginxlogUpdateMeta data;
diff --git a/src/backend/access/gin/ginvacuum.c b/src/backend/access/gin/ginvacuum.c
index dfe885b101..b9a28d1863 100644
--- a/src/backend/access/gin/ginvacuum.c
+++ b/src/backend/access/gin/ginvacuum.c
@@ -759,7 +759,7 @@ ginvacuumcleanup(IndexVacuumInfo *info, IndexBulkDeleteResult *stats)
 
 	/* Update the metapage with accurate page and entry counts */
 	idxStat.nTotalPages = npages;
-	ginUpdateStats(info->index, &idxStat);
+	ginUpdateStats(info->index, &idxStat, false);
 
 	/* Finally, vacuum the FSM */
 	IndexFreeSpaceMapVacuum(info->index);
diff --git a/src/backend/access/gin/ginxlog.c b/src/backend/access/gin/ginxlog.c
index c467ffa346..b648af1ff6 100644
--- a/src/backend/access/gin/ginxlog.c
+++ b/src/backend/access/gin/ginxlog.c
@@ -40,36 +40,6 @@ ginRedoClearIncompleteSplit(XLogReaderState *record, uint8 block_id)
 		UnlockReleaseBuffer(buffer);
 }
 
-static void
-ginRedoCreateIndex(XLogReaderState *record)
-{
-	XLogRecPtr	lsn = record->EndRecPtr;
-	Buffer		RootBuffer,
-				MetaBuffer;
-	Page		page;
-
-	MetaBuffer = XLogInitBufferForRedo(record, 0);
-	Assert(BufferGetBlockNumber(MetaBuffer) == GIN_METAPAGE_BLKNO);
-	page = (Page) BufferGetPage(MetaBuffer);
-
-	GinInitMetabuffer(MetaBuffer);
-
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(MetaBuffer);
-
-	RootBuffer = XLogInitBufferForRedo(record, 1);
-	Assert(BufferGetBlockNumber(RootBuffer) == GIN_ROOT_BLKNO);
-	page = (Page) BufferGetPage(RootBuffer);
-
-	GinInitBuffer(RootBuffer, GIN_LEAF);
-
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(RootBuffer);
-
-	UnlockReleaseBuffer(RootBuffer);
-	UnlockReleaseBuffer(MetaBuffer);
-}
-
 static void
 ginRedoCreatePTree(XLogReaderState *record)
 {
@@ -767,9 +737,6 @@ gin_redo(XLogReaderState *record)
 	oldCtx = MemoryContextSwitchTo(opCtx);
 	switch (info)
 	{
-		case XLOG_GIN_CREATE_INDEX:
-			ginRedoCreateIndex(record);
-			break;
 		case XLOG_GIN_CREATE_PTREE:
 			ginRedoCreatePTree(record);
 			break;
diff --git a/src/backend/access/rmgrdesc/gindesc.c b/src/backend/access/rmgrdesc/gindesc.c
index ef30ce16b0..f3f4e1b214 100644
--- a/src/backend/access/rmgrdesc/gindesc.c
+++ b/src/backend/access/rmgrdesc/gindesc.c
@@ -78,9 +78,6 @@ gin_desc(StringInfo buf, XLogReaderState *record)
 
 	switch (info)
 	{
-		case XLOG_GIN_CREATE_INDEX:
-			/* no further information */
-			break;
 		case XLOG_GIN_CREATE_PTREE:
 			/* no further information */
 			break;
@@ -188,9 +185,6 @@ gin_identify(uint8 info)
 
 	switch (info & ~XLR_INFO_MASK)
 	{
-		case XLOG_GIN_CREATE_INDEX:
-			id = "CREATE_INDEX";
-			break;
 		case XLOG_GIN_CREATE_PTREE:
 			id = "CREATE_PTREE";
 			break;
diff --git a/src/include/access/gin.h b/src/include/access/gin.h
index 61fa697039..d559ffc703 100644
--- a/src/include/access/gin.h
+++ b/src/include/access/gin.h
@@ -71,6 +71,7 @@ extern int	gin_pending_list_limit;
 
 /* ginutil.c */
 extern void ginGetStats(Relation index, GinStatsData *stats);
-extern void ginUpdateStats(Relation index, const GinStatsData *stats);
+extern void ginUpdateStats(Relation index,
+						   const GinStatsData *stats, bool is_build);
 
 #endif							/* GIN_H */
diff --git a/src/include/access/ginxlog.h b/src/include/access/ginxlog.h
index 9bd4e0b9ba..2c5d743cac 100644
--- a/src/include/access/ginxlog.h
+++ b/src/include/access/ginxlog.h
@@ -16,8 +16,6 @@
 #include "lib/stringinfo.h"
 #include "storage/off.h"
 
-#define XLOG_GIN_CREATE_INDEX  0x00
-
 #define XLOG_GIN_CREATE_PTREE  0x10
 
 typedef struct ginxlogCreatePostingTree
-- 
2.17.1

From 4d1b410dd2817a735e51ccb179ac6df6847eda41 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Tue, 2 Apr 2019 09:43:42 +0500
Subject: [PATCH 3/4] GiST-Optimal-WAL-Usage

---
 src/backend/access/gist/gist.c         | 46 ++++++++++++++++++--------
 src/backend/access/gist/gistbuild.c    | 32 ++++++++++--------
 src/backend/access/gist/gistutil.c     |  2 +-
 src/backend/access/gist/gistxlog.c     | 22 ------------
 src/backend/access/rmgrdesc/gistdesc.c |  5 ---
 src/include/access/gist_private.h      |  7 ++--
 src/include/access/gistxlog.h          |  1 -
 7 files changed, 56 insertions(+), 59 deletions(-)

diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index 2fddb23496..0e2b6c3014 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -172,7 +172,7 @@ gistinsert(Relation r, Datum *values, bool *isnull,
 						 values, isnull, true /* size is currently bogus */ );
 	itup->t_tid = *ht_ctid;
 
-	gistdoinsert(r, itup, 0, giststate, heapRel);
+	gistdoinsert(r, itup, 0, giststate, heapRel, false);
 
 	/* cleanup */
 	MemoryContextSwitchTo(oldCxt);
@@ -219,7 +219,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 				Buffer leftchildbuf,
 				List **splitinfo,
 				bool markfollowright,
-				Relation heapRel)
+				Relation heapRel,
+				bool is_build)
 {
 	BlockNumber blkno = BufferGetBlockNumber(buffer);
 	Page		page = BufferGetPage(buffer);
@@ -458,7 +459,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		 * insertion for that. NB: The number of pages and data segments
 		 * specified here must match the calculations in gistXLogSplit()!
 		 */
-		if (RelationNeedsWAL(rel))
+		if (RelationNeedsWAL(rel) && !is_build)
 			XLogEnsureRecordSpace(npage, 1 + npage * 2);
 
 		START_CRIT_SECTION();
@@ -479,18 +480,20 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		PageRestoreTempPage(dist->page, BufferGetPage(dist->buffer));
 		dist->page = BufferGetPage(dist->buffer);
 
-		/* Write the WAL record */
-		if (RelationNeedsWAL(rel))
+		/*
+		 * Write the WAL record.
+		 * Do not write XLog entry if the insertion is caused by
+		 * index build process.
+		 */
+		if (RelationNeedsWAL(rel) && !is_build)
 			recptr = gistXLogSplit(is_leaf,
-								   dist, oldrlink, oldnsn, leftchildbuf,
-								   markfollowright);
+								dist, oldrlink, oldnsn, leftchildbuf,
+								markfollowright);
 		else
 			recptr = gistGetFakeLSN(rel);
 
 		for (ptr = dist; ptr; ptr = ptr->next)
-		{
 			PageSetLSN(ptr->page, recptr);
-		}
 
 		/*
 		 * Return the new child buffers to the caller.
@@ -544,7 +547,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		if (BufferIsValid(leftchildbuf))
 			MarkBufferDirty(leftchildbuf);
 
-		if (RelationNeedsWAL(rel))
+
+		if (RelationNeedsWAL(rel) && !is_build)
 		{
 			OffsetNumber ndeloffs = 0,
 						deloffs[1];
@@ -567,6 +571,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 			PageSetLSN(page, recptr);
 		}
 
+
 		if (newblkno)
 			*newblkno = blkno;
 	}
@@ -583,17 +588,28 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 	 * the full page image. There's a chicken-and-egg problem: if we updated
 	 * the child pages first, we wouldn't know the recptr of the WAL record
 	 * we're about to write.
+	 *
+	 * We use fakeLSNs for inserions caused by index build. And when it is
+	 * finished, we write generic_xlog entry for each index page and update
+	 * all LSNs. In order to keep NSNs less then LSNs after this update, we
+	 * set NSN to InvalidXLogRecPtr, which is the smallest possible NSN.
 	 */
+
 	if (BufferIsValid(leftchildbuf))
 	{
 		Page		leftpg = BufferGetPage(leftchildbuf);
+		XLogRecPtr	fakerecptr = InvalidXLogRecPtr;
 
-		GistPageSetNSN(leftpg, recptr);
-		GistClearFollowRight(leftpg);
+		if (!is_build)
+			GistPageSetNSN(leftpg, recptr);
+		else
+			GistPageSetNSN(leftpg, fakerecptr);
 
+		GistClearFollowRight(leftpg);
 		PageSetLSN(leftpg, recptr);
 	}
 
+
 	END_CRIT_SECTION();
 
 	return is_split;
@@ -606,7 +622,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
  */
 void
 gistdoinsert(Relation r, IndexTuple itup, Size freespace,
-			 GISTSTATE *giststate, Relation heapRel)
+			 GISTSTATE *giststate, Relation heapRel, bool is_build)
 {
 	ItemId		iid;
 	IndexTuple	idxtuple;
@@ -619,6 +635,7 @@ gistdoinsert(Relation r, IndexTuple itup, Size freespace,
 	state.freespace = freespace;
 	state.r = r;
 	state.heapRel = heapRel;
+	state.is_build = is_build;
 
 	/* Start from the root */
 	firststack.blkno = GIST_ROOT_BLKNO;
@@ -1251,7 +1268,8 @@ gistinserttuples(GISTInsertState *state, GISTInsertStack *stack,
 							   leftchild,
 							   &splitinfo,
 							   true,
-							   state->heapRel);
+							   state->heapRel,
+							   state->is_build);
 
 	/*
 	 * Before recursing up in case the page was split, release locks on the
diff --git a/src/backend/access/gist/gistbuild.c b/src/backend/access/gist/gistbuild.c
index 3652fde5bb..aa05c0a8ee 100644
--- a/src/backend/access/gist/gistbuild.c
+++ b/src/backend/access/gist/gistbuild.c
@@ -17,6 +17,7 @@
 #include <math.h>
 
 #include "access/genam.h"
+#include "access/generic_xlog.h"
 #include "access/gist_private.h"
 #include "access/gistxlog.h"
 #include "access/tableam.h"
@@ -181,18 +182,12 @@ gistbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 
 	MarkBufferDirty(buffer);
 
-	if (RelationNeedsWAL(index))
-	{
-		XLogRecPtr	recptr;
-
-		XLogBeginInsert();
-		XLogRegisterBuffer(0, buffer, REGBUF_WILL_INIT);
-
-		recptr = XLogInsert(RM_GIST_ID, XLOG_GIST_CREATE_INDEX);
-		PageSetLSN(page, recptr);
-	}
-	else
-		PageSetLSN(page, gistGetFakeLSN(heap));
+	/*
+	 * Do not write index pages to WAL unitl index build is finished.
+	 * But we still need increasing LSNs on each page, so use FakeLSN,
+	 * even for relations which eventually need WAL.
+	 */
+	PageSetLSN(page, gistGetFakeLSN(heap));
 
 	UnlockReleaseBuffer(buffer);
 
@@ -226,6 +221,15 @@ gistbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 
 	freeGISTstate(buildstate.giststate);
 
+	/*
+	 * Create generic wal records for all pages of relation, if necessary.
+	 * It seems reasonable not to generate WAL, if we recieved interrupt
+	 * signal.
+	 */
+	CHECK_FOR_INTERRUPTS();
+	if (RelationNeedsWAL(index))
+		log_relation(index);
+
 	/*
 	 * Return statistics
 	 */
@@ -488,7 +492,7 @@ gistBuildCallback(Relation index,
 		 * locked, we call gistdoinsert directly.
 		 */
 		gistdoinsert(index, itup, buildstate->freespace,
-					 buildstate->giststate, buildstate->heaprel);
+					 buildstate->giststate, buildstate->heaprel, true);
 	}
 
 	/* Update tuple count and total size. */
@@ -695,7 +699,7 @@ gistbufferinginserttuples(GISTBuildState *buildstate, Buffer buffer, int level,
 							   InvalidBuffer,
 							   &splitinfo,
 							   false,
-							   buildstate->heaprel);
+							   buildstate->heaprel, true);
 
 	/*
 	 * If this is a root split, update the root path item kept in memory. This
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index 2163cc482d..af278e5ded 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -1004,6 +1004,7 @@ gistproperty(Oid index_oid, int attno,
  * Temporary and unlogged GiST indexes are not WAL-logged, but we need LSNs
  * to detect concurrent page splits anyway. This function provides a fake
  * sequence of LSNs for that purpose.
+ * Persistent relations are also not WAL-logged while we build index.
  */
 XLogRecPtr
 gistGetFakeLSN(Relation rel)
@@ -1024,7 +1025,6 @@ gistGetFakeLSN(Relation rel)
 		 * Unlogged relations are accessible from other backends, and survive
 		 * (clean) restarts. GetFakeLSNForUnloggedRel() handles that for us.
 		 */
-		Assert(rel->rd_rel->relpersistence == RELPERSISTENCE_UNLOGGED);
 		return GetFakeLSNForUnloggedRel();
 	}
 }
diff --git a/src/backend/access/gist/gistxlog.c b/src/backend/access/gist/gistxlog.c
index cb80ab00cd..4fb1855e89 100644
--- a/src/backend/access/gist/gistxlog.c
+++ b/src/backend/access/gist/gistxlog.c
@@ -490,25 +490,6 @@ gistRedoPageSplitRecord(XLogReaderState *record)
 	UnlockReleaseBuffer(firstbuffer);
 }
 
-static void
-gistRedoCreateIndex(XLogReaderState *record)
-{
-	XLogRecPtr	lsn = record->EndRecPtr;
-	Buffer		buffer;
-	Page		page;
-
-	buffer = XLogInitBufferForRedo(record, 0);
-	Assert(BufferGetBlockNumber(buffer) == GIST_ROOT_BLKNO);
-	page = (Page) BufferGetPage(buffer);
-
-	GISTInitBuffer(buffer, F_LEAF);
-
-	PageSetLSN(page, lsn);
-
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-}
-
 /* redo page deletion */
 static void
 gistRedoPageDelete(XLogReaderState *record)
@@ -594,9 +575,6 @@ gist_redo(XLogReaderState *record)
 		case XLOG_GIST_PAGE_SPLIT:
 			gistRedoPageSplitRecord(record);
 			break;
-		case XLOG_GIST_CREATE_INDEX:
-			gistRedoCreateIndex(record);
-			break;
 		case XLOG_GIST_PAGE_DELETE:
 			gistRedoPageDelete(record);
 			break;
diff --git a/src/backend/access/rmgrdesc/gistdesc.c b/src/backend/access/rmgrdesc/gistdesc.c
index 3ff4f83d38..eb308c72d6 100644
--- a/src/backend/access/rmgrdesc/gistdesc.c
+++ b/src/backend/access/rmgrdesc/gistdesc.c
@@ -71,8 +71,6 @@ gist_desc(StringInfo buf, XLogReaderState *record)
 		case XLOG_GIST_PAGE_SPLIT:
 			out_gistxlogPageSplit(buf, (gistxlogPageSplit *) rec);
 			break;
-		case XLOG_GIST_CREATE_INDEX:
-			break;
 		case XLOG_GIST_PAGE_DELETE:
 			out_gistxlogPageDelete(buf, (gistxlogPageDelete *) rec);
 			break;
@@ -98,9 +96,6 @@ gist_identify(uint8 info)
 		case XLOG_GIST_PAGE_SPLIT:
 			id = "PAGE_SPLIT";
 			break;
-		case XLOG_GIST_CREATE_INDEX:
-			id = "CREATE_INDEX";
-			break;
 		case XLOG_GIST_PAGE_DELETE:
 			id = "PAGE_DELETE";
 			break;
diff --git a/src/include/access/gist_private.h b/src/include/access/gist_private.h
index 02dc285a78..78e2e3fb31 100644
--- a/src/include/access/gist_private.h
+++ b/src/include/access/gist_private.h
@@ -244,6 +244,7 @@ typedef struct
 	Relation	r;
 	Relation	heapRel;
 	Size		freespace;		/* free space to be left */
+	bool		is_build;
 
 	GISTInsertStack *stack;
 } GISTInsertState;
@@ -393,7 +394,8 @@ extern void gistdoinsert(Relation r,
 			 IndexTuple itup,
 			 Size freespace,
 			 GISTSTATE *GISTstate,
-			 Relation heapRel);
+			 Relation heapRel,
+			 bool is_build);
 
 /* A List of these is returned from gistplacetopage() in *splitinfo */
 typedef struct
@@ -409,7 +411,8 @@ extern bool gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 				Buffer leftchildbuf,
 				List **splitinfo,
 				bool markleftchild,
-				Relation heapRel);
+				Relation heapRel,
+				bool is_build);
 
 extern SplitedPageLayout *gistSplit(Relation r, Page page, IndexTuple *itup,
 		  int len, GISTSTATE *giststate);
diff --git a/src/include/access/gistxlog.h b/src/include/access/gistxlog.h
index 2f87b67a53..80931497ca 100644
--- a/src/include/access/gistxlog.h
+++ b/src/include/access/gistxlog.h
@@ -23,7 +23,6 @@
 										  * FSM */
 #define XLOG_GIST_PAGE_SPLIT		0x30
  /* #define XLOG_GIST_INSERT_COMPLETE	 0x40 */	/* not used anymore */
-#define XLOG_GIST_CREATE_INDEX		0x50
 #define XLOG_GIST_PAGE_DELETE		0x60
 
 /*
-- 
2.17.1

From 98b3de012d116e1056ae3de9e17d14b59b646808 Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Tue, 2 Apr 2019 09:43:54 +0500
Subject: [PATCH 4/4] SP-GiST-Optimal-WAL-Usage

---
 src/backend/access/rmgrdesc/spgdesc.c   |  5 ----
 src/backend/access/spgist/spgdoinsert.c | 12 ++++-----
 src/backend/access/spgist/spginsert.c   | 24 +++--------------
 src/backend/access/spgist/spgxlog.c     | 35 -------------------------
 src/include/access/spgxlog.h            |  1 -
 5 files changed, 10 insertions(+), 67 deletions(-)

diff --git a/src/backend/access/rmgrdesc/spgdesc.c b/src/backend/access/rmgrdesc/spgdesc.c
index 37af31a764..40c1c8b3f9 100644
--- a/src/backend/access/rmgrdesc/spgdesc.c
+++ b/src/backend/access/rmgrdesc/spgdesc.c
@@ -24,8 +24,6 @@ spg_desc(StringInfo buf, XLogReaderState *record)
 
 	switch (info)
 	{
-		case XLOG_SPGIST_CREATE_INDEX:
-			break;
 		case XLOG_SPGIST_ADD_LEAF:
 			{
 				spgxlogAddLeaf *xlrec = (spgxlogAddLeaf *) rec;
@@ -88,9 +86,6 @@ spg_identify(uint8 info)
 
 	switch (info & ~XLR_INFO_MASK)
 	{
-		case XLOG_SPGIST_CREATE_INDEX:
-			id = "CREATE_INDEX";
-			break;
 		case XLOG_SPGIST_ADD_LEAF:
 			id = "ADD_LEAF";
 			break;
diff --git a/src/backend/access/spgist/spgdoinsert.c b/src/backend/access/spgist/spgdoinsert.c
index 0d07b8b291..c34c44cd8b 100644
--- a/src/backend/access/spgist/spgdoinsert.c
+++ b/src/backend/access/spgist/spgdoinsert.c
@@ -289,7 +289,7 @@ addLeafTuple(Relation index, SpGistState *state, SpGistLeafTuple leafTuple,
 
 	MarkBufferDirty(current->buffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 		int			flags;
@@ -516,7 +516,7 @@ moveLeafs(Relation index, SpGistState *state,
 	MarkBufferDirty(current->buffer);
 	MarkBufferDirty(nbuf);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 
@@ -1334,7 +1334,7 @@ doPickSplit(Relation index, SpGistState *state,
 		saveCurrent.buffer = InvalidBuffer;
 	}
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 		int			flags;
@@ -1531,7 +1531,7 @@ spgAddNodeAction(Relation index, SpGistState *state,
 
 		MarkBufferDirty(current->buffer);
 
-		if (RelationNeedsWAL(index))
+		if (RelationNeedsWAL(index) && !state->isBuild)
 		{
 			XLogRecPtr	recptr;
 
@@ -1644,7 +1644,7 @@ spgAddNodeAction(Relation index, SpGistState *state,
 
 		MarkBufferDirty(saveCurrent.buffer);
 
-		if (RelationNeedsWAL(index))
+		if (RelationNeedsWAL(index) && !state->isBuild)
 		{
 			XLogRecPtr	recptr;
 			int			flags;
@@ -1840,7 +1840,7 @@ spgSplitNodeAction(Relation index, SpGistState *state,
 
 	MarkBufferDirty(current->buffer);
 
-	if (RelationNeedsWAL(index))
+	if (RelationNeedsWAL(index) && !state->isBuild)
 	{
 		XLogRecPtr	recptr;
 
diff --git a/src/backend/access/spgist/spginsert.c b/src/backend/access/spgist/spginsert.c
index 390ad9ac51..0c3608ad8a 100644
--- a/src/backend/access/spgist/spginsert.c
+++ b/src/backend/access/spgist/spginsert.c
@@ -22,6 +22,7 @@
 #include "access/tableam.h"
 #include "access/xlog.h"
 #include "access/xloginsert.h"
+#include "access/generic_xlog.h"
 #include "catalog/index.h"
 #include "miscadmin.h"
 #include "storage/bufmgr.h"
@@ -105,26 +106,6 @@ spgbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	SpGistInitBuffer(nullbuffer, SPGIST_LEAF | SPGIST_NULLS);
 	MarkBufferDirty(nullbuffer);
 
-	if (RelationNeedsWAL(index))
-	{
-		XLogRecPtr	recptr;
-
-		XLogBeginInsert();
-
-		/*
-		 * Replay will re-initialize the pages, so don't take full pages
-		 * images.  No other data to log.
-		 */
-		XLogRegisterBuffer(0, metabuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-		XLogRegisterBuffer(1, rootbuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-		XLogRegisterBuffer(2, nullbuffer, REGBUF_WILL_INIT | REGBUF_STANDARD);
-
-		recptr = XLogInsert(RM_SPGIST_ID, XLOG_SPGIST_CREATE_INDEX);
-
-		PageSetLSN(BufferGetPage(metabuffer), recptr);
-		PageSetLSN(BufferGetPage(rootbuffer), recptr);
-		PageSetLSN(BufferGetPage(nullbuffer), recptr);
-	}
 
 	END_CRIT_SECTION();
 
@@ -151,6 +132,9 @@ spgbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 
 	SpGistUpdateMetaPage(index);
 
+	if (RelationNeedsWAL(index))
+		log_relation(index);
+
 	result = (IndexBuildResult *) palloc0(sizeof(IndexBuildResult));
 	result->heap_tuples = reltuples;
 	result->index_tuples = buildstate.indtuples;
diff --git a/src/backend/access/spgist/spgxlog.c b/src/backend/access/spgist/spgxlog.c
index 71836ee8a5..ebe6ae8715 100644
--- a/src/backend/access/spgist/spgxlog.c
+++ b/src/backend/access/spgist/spgxlog.c
@@ -72,38 +72,6 @@ addOrReplaceTuple(Page page, Item tuple, int size, OffsetNumber offset)
 			 size);
 }
 
-static void
-spgRedoCreateIndex(XLogReaderState *record)
-{
-	XLogRecPtr	lsn = record->EndRecPtr;
-	Buffer		buffer;
-	Page		page;
-
-	buffer = XLogInitBufferForRedo(record, 0);
-	Assert(BufferGetBlockNumber(buffer) == SPGIST_METAPAGE_BLKNO);
-	page = (Page) BufferGetPage(buffer);
-	SpGistInitMetapage(page);
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-
-	buffer = XLogInitBufferForRedo(record, 1);
-	Assert(BufferGetBlockNumber(buffer) == SPGIST_ROOT_BLKNO);
-	SpGistInitBuffer(buffer, SPGIST_LEAF);
-	page = (Page) BufferGetPage(buffer);
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-
-	buffer = XLogInitBufferForRedo(record, 2);
-	Assert(BufferGetBlockNumber(buffer) == SPGIST_NULL_BLKNO);
-	SpGistInitBuffer(buffer, SPGIST_LEAF | SPGIST_NULLS);
-	page = (Page) BufferGetPage(buffer);
-	PageSetLSN(page, lsn);
-	MarkBufferDirty(buffer);
-	UnlockReleaseBuffer(buffer);
-}
-
 static void
 spgRedoAddLeaf(XLogReaderState *record)
 {
@@ -976,9 +944,6 @@ spg_redo(XLogReaderState *record)
 	oldCxt = MemoryContextSwitchTo(opCtx);
 	switch (info)
 	{
-		case XLOG_SPGIST_CREATE_INDEX:
-			spgRedoCreateIndex(record);
-			break;
 		case XLOG_SPGIST_ADD_LEAF:
 			spgRedoAddLeaf(record);
 			break;
diff --git a/src/include/access/spgxlog.h b/src/include/access/spgxlog.h
index 6527fc9eb1..8199b3f250 100644
--- a/src/include/access/spgxlog.h
+++ b/src/include/access/spgxlog.h
@@ -18,7 +18,6 @@
 #include "storage/off.h"
 
 /* XLOG record types for SPGiST */
-#define XLOG_SPGIST_CREATE_INDEX	0x00
 #define XLOG_SPGIST_ADD_LEAF		0x10
 #define XLOG_SPGIST_MOVE_LEAFS		0x20
 #define XLOG_SPGIST_ADD_NODE		0x30
-- 
2.17.1