From 42475042baa09b3fd3ddb8f39f7a6304c49449de Mon Sep 17 00:00:00 2001 From: Melanie Plageman Date: Thu, 15 Feb 2024 21:04:18 -0500 Subject: [PATCH v6 14/14] BitmapHeapScan uses streaming read API Remove all of the code to do prefetching from BitmapHeapScan code and rely on the streaming read API prefetching. Heap table AM implements a streaming read callback which uses the iterator to get the next valid block that needs to be fetched for the streaming read API. --- src/backend/access/heap/heapam.c | 68 +++++ src/backend/access/heap/heapam_handler.c | 88 +++--- src/backend/executor/nodeBitmapHeapscan.c | 352 +--------------------- src/include/access/heapam.h | 4 + src/include/access/tableam.h | 22 +- src/include/nodes/execnodes.h | 22 -- 6 files changed, 116 insertions(+), 440 deletions(-) diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index e7bed84f75b..0f370bfec3e 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -111,6 +111,8 @@ static XLogRecPtr log_heap_new_cid(Relation relation, HeapTuple tup); static HeapTuple ExtractReplicaIdentity(Relation relation, HeapTuple tp, bool key_required, bool *copy); +static BlockNumber bitmapheap_pgsr_next(PgStreamingRead *pgsr, void *pgsr_private, + void *per_buffer_data); /* * Each tuple lock mode has a corresponding heavyweight lock, and one or two @@ -331,6 +333,22 @@ initscan(HeapScanDesc scan, ScanKey key, bool keep_startblock) if (key != NULL && scan->rs_base.rs_nkeys > 0) memcpy(scan->rs_base.rs_key, key, scan->rs_base.rs_nkeys * sizeof(ScanKeyData)); + if (scan->rs_base.rs_flags & SO_TYPE_BITMAPSCAN) + { + if (scan->rs_pgsr) + pg_streaming_read_free(scan->rs_pgsr); + + scan->rs_pgsr = pg_streaming_read_buffer_alloc(PGSR_FLAG_DEFAULT, + scan, + sizeof(TBMIterateResult), + scan->rs_strategy, + BMR_REL(scan->rs_base.rs_rd), + MAIN_FORKNUM, + bitmapheap_pgsr_next); + + + } + /* * Currently, we only have a stats counter for sequential heap scans (but * e.g for bitmap scans the underlying bitmap index scans will be counted, @@ -951,6 +969,7 @@ heap_beginscan(Relation relation, Snapshot snapshot, scan->rs_base.rs_flags = flags; scan->rs_base.rs_parallel = parallel_scan; scan->rs_strategy = NULL; /* set in initscan */ + scan->rs_pgsr = NULL; scan->rs_vmbuffer = InvalidBuffer; scan->rs_empty_tuples_pending = 0; @@ -1089,6 +1108,9 @@ heap_endscan(TableScanDesc sscan) if (scan->rs_base.rs_flags & SO_TEMP_SNAPSHOT) UnregisterSnapshot(scan->rs_base.rs_snapshot); + if (scan->rs_base.rs_flags & SO_TYPE_BITMAPSCAN && scan->rs_pgsr) + pg_streaming_read_free(scan->rs_pgsr); + pfree(scan); } @@ -10246,3 +10268,49 @@ HeapCheckForSerializableConflictOut(bool visible, Relation relation, CheckForSerializableConflictOut(relation, xid, snapshot); } + +static BlockNumber +bitmapheap_pgsr_next(PgStreamingRead *pgsr, void *pgsr_private, + void *per_buffer_data) +{ + TBMIterateResult *tbmres = per_buffer_data; + HeapScanDesc hdesc = (HeapScanDesc) pgsr_private; + + for (;;) + { + CHECK_FOR_INTERRUPTS(); + + if (hdesc->rs_base.shared_tbmiterator) + tbm_shared_iterate(hdesc->rs_base.shared_tbmiterator, tbmres); + else + tbm_iterate(hdesc->rs_base.tbmiterator, tbmres); + + /* no more entries in the bitmap */ + if (!BlockNumberIsValid(tbmres->blockno)) + return InvalidBlockNumber; + + /* + * Ignore any claimed entries past what we think is the end of the + * relation. It may have been extended after the start of our scan (we + * only hold an AccessShareLock, and it could be inserts from this + * backend). We don't take this optimization in SERIALIZABLE + * isolation though, as we need to examine all invisible tuples + * reachable by the index. + */ + if (!IsolationIsSerializable() && tbmres->blockno >= hdesc->rs_nblocks) + continue; + + if (hdesc->rs_base.rs_flags & SO_CAN_SKIP_FETCH && + !tbmres->recheck && + VM_ALL_VISIBLE(hdesc->rs_base.rs_rd, tbmres->blockno, &hdesc->rs_vmbuffer)) + { + hdesc->rs_empty_tuples_pending += tbmres->ntuples; + continue; + } + + return tbmres->blockno; + } + + /* not reachable */ + Assert(false); +} diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c index 022753e203a..9727613e87f 100644 --- a/src/backend/access/heap/heapam_handler.c +++ b/src/backend/access/heap/heapam_handler.c @@ -2111,79 +2111,65 @@ heapam_estimate_rel_size(Relation rel, int32 *attr_widths, */ static bool -heapam_scan_bitmap_next_block(TableScanDesc scan, - bool *recheck, bool *lossy, BlockNumber *blockno) +heapam_scan_bitmap_next_block(TableScanDesc scan, bool *recheck, bool *lossy) { HeapScanDesc hscan = (HeapScanDesc) scan; + void *io_private; BlockNumber block; Buffer buffer; Snapshot snapshot; int ntup; - TBMIterateResult tbmres; + TBMIterateResult *tbmres; + + Assert(hscan->rs_pgsr); hscan->rs_cindex = 0; hscan->rs_ntuples = 0; - *blockno = InvalidBlockNumber; *recheck = true; - do + /* Release buffer containing previous block. */ + if (BufferIsValid(hscan->rs_cbuf)) { - CHECK_FOR_INTERRUPTS(); + ReleaseBuffer(hscan->rs_cbuf); + hscan->rs_cbuf = InvalidBuffer; + } - if (scan->shared_tbmiterator) - tbm_shared_iterate(scan->shared_tbmiterator, &tbmres); - else - tbm_iterate(scan->tbmiterator, &tbmres); + hscan->rs_cbuf = pg_streaming_read_buffer_get_next(hscan->rs_pgsr, &io_private); - if (!BlockNumberIsValid(tbmres.blockno)) + if (BufferIsInvalid(hscan->rs_cbuf)) + { + if (BufferIsValid(hscan->rs_vmbuffer)) { - /* no more entries in the bitmap */ - Assert(hscan->rs_empty_tuples_pending == 0); - return false; + ReleaseBuffer(hscan->rs_vmbuffer); + hscan->rs_vmbuffer = InvalidBuffer; } /* - * Ignore any claimed entries past what we think is the end of the - * relation. It may have been extended after the start of our scan (we - * only hold an AccessShareLock, and it could be inserts from this - * backend). We don't take this optimization in SERIALIZABLE - * isolation though, as we need to examine all invisible tuples - * reachable by the index. + * Bitmap is exhausted. Time to emit empty tuples if relevant. We emit + * all empty tuples at the end instead of emitting them per block we + * skip fetching. This is necessary because the streaming read API + * will only return TBMIterateResults for blocks actually fetched. + * When we skip fetching a block, we keep track of how many empty + * tuples to emit at the end of the BitmapHeapScan. We do not recheck + * all NULL tuples. */ - } while (!IsolationIsSerializable() && tbmres.blockno >= hscan->rs_nblocks); + *recheck = false; + return hscan->rs_empty_tuples_pending > 0; + } - /* Got a valid block */ - *blockno = tbmres.blockno; - *recheck = tbmres.recheck; + Assert(io_private); - /* - * We can skip fetching the heap page if we don't need any fields from the - * heap, and the bitmap entries don't need rechecking, and all tuples on - * the page are visible to our transaction. - */ - if (scan->rs_flags & SO_CAN_SKIP_FETCH && - !tbmres.recheck && - VM_ALL_VISIBLE(scan->rs_rd, tbmres.blockno, &hscan->rs_vmbuffer)) - { - /* can't be lossy in the skip_fetch case */ - Assert(tbmres.ntuples >= 0); - Assert(hscan->rs_empty_tuples_pending >= 0); + tbmres = io_private; - hscan->rs_empty_tuples_pending += tbmres.ntuples; + Assert(BufferGetBlockNumber(hscan->rs_cbuf) == tbmres->blockno); - return true; - } + *recheck = tbmres->recheck; - block = tbmres.blockno; + hscan->rs_cblock = tbmres->blockno; + hscan->rs_ntuples = tbmres->ntuples; - /* - * Acquire pin on the target heap page, trading in any pin we held before. - */ - hscan->rs_cbuf = ReleaseAndReadBuffer(hscan->rs_cbuf, - scan->rs_rd, - block); - hscan->rs_cblock = block; + block = tbmres->blockno; buffer = hscan->rs_cbuf; snapshot = scan->rs_snapshot; @@ -2204,7 +2190,7 @@ heapam_scan_bitmap_next_block(TableScanDesc scan, /* * We need two separate strategies for lossy and non-lossy cases. */ - if (tbmres.ntuples >= 0) + if (tbmres->ntuples >= 0) { /* * Bitmap is non-lossy, so we just look through the offsets listed in @@ -2213,9 +2199,9 @@ heapam_scan_bitmap_next_block(TableScanDesc scan, */ int curslot; - for (curslot = 0; curslot < tbmres.ntuples; curslot++) + for (curslot = 0; curslot < tbmres->ntuples; curslot++) { - OffsetNumber offnum = tbmres.offsets[curslot]; + OffsetNumber offnum = tbmres->offsets[curslot]; ItemPointerData tid; HeapTupleData heapTuple; @@ -2265,7 +2251,7 @@ heapam_scan_bitmap_next_block(TableScanDesc scan, Assert(ntup <= MaxHeapTuplesPerPage); hscan->rs_ntuples = ntup; - *lossy = tbmres.ntuples < 0; + *lossy = tbmres->ntuples < 0; /* * Return true to indicate that a valid block was found and the bitmap is diff --git a/src/backend/executor/nodeBitmapHeapscan.c b/src/backend/executor/nodeBitmapHeapscan.c index b3b9448627b..c437718f980 100644 --- a/src/backend/executor/nodeBitmapHeapscan.c +++ b/src/backend/executor/nodeBitmapHeapscan.c @@ -51,10 +51,6 @@ static TupleTableSlot *BitmapHeapNext(BitmapHeapScanState *node); static inline void BitmapDoneInitializingSharedState(ParallelBitmapHeapState *pstate); -static inline void BitmapAdjustPrefetchIterator(BitmapHeapScanState *node); -static inline void BitmapAdjustPrefetchTarget(BitmapHeapScanState *node); -static inline void BitmapPrefetch(BitmapHeapScanState *node, - TableScanDesc scan); static bool BitmapShouldInitializeSharedState(ParallelBitmapHeapState *pstate); @@ -86,14 +82,6 @@ BitmapHeapNext(BitmapHeapScanState *node) /* * If we haven't yet performed the underlying index scan, do it, and begin * the iteration over the bitmap. - * - * For prefetching, we use *two* iterators, one for the pages we are - * actually scanning and another that runs ahead of the first for - * prefetching. node->prefetch_pages tracks exactly how many pages ahead - * the prefetch iterator is. Also, node->prefetch_target tracks the - * desired prefetch distance, which starts small and increases up to the - * node->prefetch_maximum. This is to avoid doing a lot of prefetching in - * a scan that stops after a few tuples because of a LIMIT. */ if (!node->initialized) { @@ -109,15 +97,6 @@ BitmapHeapNext(BitmapHeapScanState *node) node->tbm = tbm; tbmiterator = tbm_begin_iterate(tbm); - -#ifdef USE_PREFETCH - if (node->prefetch_maximum > 0) - { - node->prefetch_iterator = tbm_begin_iterate(tbm); - node->prefetch_pages = 0; - node->prefetch_target = -1; - } -#endif /* USE_PREFETCH */ } else { @@ -140,20 +119,6 @@ BitmapHeapNext(BitmapHeapScanState *node) * multiple processes to iterate jointly. */ pstate->tbmiterator = tbm_prepare_shared_iterate(tbm); -#ifdef USE_PREFETCH - if (node->prefetch_maximum > 0) - { - pstate->prefetch_iterator = - tbm_prepare_shared_iterate(tbm); - - /* - * We don't need the mutex here as we haven't yet woke up - * others. - */ - pstate->prefetch_pages = 0; - pstate->prefetch_target = -1; - } -#endif /* We have initialized the shared state so wake up others. */ BitmapDoneInitializingSharedState(pstate); @@ -161,14 +126,6 @@ BitmapHeapNext(BitmapHeapScanState *node) /* Allocate a private iterator and attach the shared state to it */ shared_tbmiterator = tbm_attach_shared_iterate(dsa, pstate->tbmiterator); - -#ifdef USE_PREFETCH - if (node->prefetch_maximum > 0) - { - node->shared_prefetch_iterator = - tbm_attach_shared_iterate(dsa, pstate->prefetch_iterator); - } -#endif /* USE_PREFETCH */ } /* @@ -212,37 +169,6 @@ BitmapHeapNext(BitmapHeapScanState *node) { CHECK_FOR_INTERRUPTS(); -#ifdef USE_PREFETCH - - /* - * Try to prefetch at least a few pages even before we get to the - * second page if we don't stop reading after the first tuple. - */ - if (!pstate) - { - if (node->prefetch_target < node->prefetch_maximum) - node->prefetch_target++; - } - else if (pstate->prefetch_target < node->prefetch_maximum) - { - /* take spinlock while updating shared state */ - SpinLockAcquire(&pstate->mutex); - if (pstate->prefetch_target < node->prefetch_maximum) - pstate->prefetch_target++; - SpinLockRelease(&pstate->mutex); - } -#endif /* USE_PREFETCH */ - - /* - * We issue prefetch requests *after* fetching the current page to - * try to avoid having prefetching interfere with the main I/O. - * Also, this should happen only when we have determined there is - * still something to do on the current page, else we may - * uselessly prefetch the same page we are just about to request - * for real. - */ - BitmapPrefetch(node, scan); - /* * If we are using lossy info, we have to recheck the qual * conditions at every tuple. @@ -264,27 +190,13 @@ BitmapHeapNext(BitmapHeapScanState *node) } new_page: - - BitmapAdjustPrefetchIterator(node); - - if (!table_scan_bitmap_next_block(scan, &node->recheck, &lossy, &node->blockno)) + if (!table_scan_bitmap_next_block(scan, &node->recheck, &lossy)) break; if (lossy) node->lossy_pages++; else node->exact_pages++; - - /* - * If serial, we can validate that the prefetch block stays ahead of - * the current block. - */ - Assert(node->pstate == NULL || - node->prefetch_iterator == NULL || - node->pfblockno > node->blockno); - - /* Adjust the prefetch target */ - BitmapAdjustPrefetchTarget(node); } /* @@ -308,225 +220,6 @@ BitmapDoneInitializingSharedState(ParallelBitmapHeapState *pstate) ConditionVariableBroadcast(&pstate->cv); } -/* - * BitmapAdjustPrefetchIterator - Adjust the prefetch iterator - * - * We keep track of how far the prefetch iterator is ahead of the main - * iterator in prefetch_pages. For each block the main iterator returns, we - * decrement prefetch_pages. - */ -static inline void -BitmapAdjustPrefetchIterator(BitmapHeapScanState *node) -{ -#ifdef USE_PREFETCH - ParallelBitmapHeapState *pstate = node->pstate; - TBMIterateResult tbmpre; - - if (pstate == NULL) - { - TBMIterator *prefetch_iterator = node->prefetch_iterator; - - if (node->prefetch_pages > 0) - { - /* The main iterator has closed the distance by one page */ - node->prefetch_pages--; - } - else if (prefetch_iterator) - { - /* Do not let the prefetch iterator get behind the main one */ - tbm_iterate(prefetch_iterator, &tbmpre); - node->pfblockno = tbmpre.blockno; - } - return; - } - - /* - * Adjusting the prefetch iterator before invoking - * table_scan_bitmap_next_block() keeps prefetch distance higher across - * the parallel workers. - */ - if (node->prefetch_maximum > 0) - { - TBMSharedIterator *prefetch_iterator = node->shared_prefetch_iterator; - - SpinLockAcquire(&pstate->mutex); - if (pstate->prefetch_pages > 0) - { - pstate->prefetch_pages--; - SpinLockRelease(&pstate->mutex); - } - else - { - /* Release the mutex before iterating */ - SpinLockRelease(&pstate->mutex); - - /* - * In case of shared mode, we can not ensure that the current - * blockno of the main iterator and that of the prefetch iterator - * are same. It's possible that whatever blockno we are - * prefetching will be processed by another process. Therefore, - * we don't validate the blockno here as we do in non-parallel - * case. - */ - if (prefetch_iterator) - { - tbm_shared_iterate(prefetch_iterator, &tbmpre); - node->pfblockno = tbmpre.blockno; - } - } - } -#endif /* USE_PREFETCH */ -} - -/* - * BitmapAdjustPrefetchTarget - Adjust the prefetch target - * - * Increase prefetch target if it's not yet at the max. Note that - * we will increase it to zero after fetching the very first - * page/tuple, then to one after the second tuple is fetched, then - * it doubles as later pages are fetched. - */ -static inline void -BitmapAdjustPrefetchTarget(BitmapHeapScanState *node) -{ -#ifdef USE_PREFETCH - ParallelBitmapHeapState *pstate = node->pstate; - - if (pstate == NULL) - { - if (node->prefetch_target >= node->prefetch_maximum) - /* don't increase any further */ ; - else if (node->prefetch_target >= node->prefetch_maximum / 2) - node->prefetch_target = node->prefetch_maximum; - else if (node->prefetch_target > 0) - node->prefetch_target *= 2; - else - node->prefetch_target++; - return; - } - - /* Do an unlocked check first to save spinlock acquisitions. */ - if (pstate->prefetch_target < node->prefetch_maximum) - { - SpinLockAcquire(&pstate->mutex); - if (pstate->prefetch_target >= node->prefetch_maximum) - /* don't increase any further */ ; - else if (pstate->prefetch_target >= node->prefetch_maximum / 2) - pstate->prefetch_target = node->prefetch_maximum; - else if (pstate->prefetch_target > 0) - pstate->prefetch_target *= 2; - else - pstate->prefetch_target++; - SpinLockRelease(&pstate->mutex); - } -#endif /* USE_PREFETCH */ -} - -/* - * BitmapPrefetch - Prefetch, if prefetch_pages are behind prefetch_target - */ -static inline void -BitmapPrefetch(BitmapHeapScanState *node, TableScanDesc scan) -{ -#ifdef USE_PREFETCH - ParallelBitmapHeapState *pstate = node->pstate; - - if (pstate == NULL) - { - TBMIterator *prefetch_iterator = node->prefetch_iterator; - - if (prefetch_iterator) - { - while (node->prefetch_pages < node->prefetch_target) - { - TBMIterateResult tbmpre; - bool skip_fetch; - - tbm_iterate(prefetch_iterator, &tbmpre); - - if (!BlockNumberIsValid(tbmpre.blockno)) - { - /* No more pages to prefetch */ - tbm_end_iterate(prefetch_iterator); - node->prefetch_iterator = NULL; - break; - } - node->prefetch_pages++; - node->pfblockno = tbmpre.blockno; - - /* - * If we expect not to have to actually read this heap page, - * skip this prefetch call, but continue to run the prefetch - * logic normally. (Would it be better not to increment - * prefetch_pages?) - */ - skip_fetch = (scan->rs_flags & SO_CAN_SKIP_FETCH && - !tbmpre.recheck && - VM_ALL_VISIBLE(node->ss.ss_currentRelation, - tbmpre.blockno, - &node->pvmbuffer)); - - if (!skip_fetch) - PrefetchBuffer(scan->rs_rd, MAIN_FORKNUM, tbmpre.blockno); - } - } - - return; - } - - if (pstate->prefetch_pages < pstate->prefetch_target) - { - TBMSharedIterator *prefetch_iterator = node->shared_prefetch_iterator; - - if (prefetch_iterator) - { - while (1) - { - TBMIterateResult tbmpre; - bool do_prefetch = false; - bool skip_fetch; - - /* - * Recheck under the mutex. If some other process has already - * done enough prefetching then we need not to do anything. - */ - SpinLockAcquire(&pstate->mutex); - if (pstate->prefetch_pages < pstate->prefetch_target) - { - pstate->prefetch_pages++; - do_prefetch = true; - } - SpinLockRelease(&pstate->mutex); - - if (!do_prefetch) - return; - - tbm_shared_iterate(prefetch_iterator, &tbmpre); - if (!BlockNumberIsValid(tbmpre.blockno)) - { - /* No more pages to prefetch */ - tbm_end_shared_iterate(prefetch_iterator); - node->shared_prefetch_iterator = NULL; - break; - } - - node->pfblockno = tbmpre.blockno; - - /* As above, skip prefetch if we expect not to need page */ - skip_fetch = (scan->rs_flags & SO_CAN_SKIP_FETCH && - !tbmpre.recheck && - VM_ALL_VISIBLE(node->ss.ss_currentRelation, - tbmpre.blockno, - &node->pvmbuffer)); - - if (!skip_fetch) - PrefetchBuffer(scan->rs_rd, MAIN_FORKNUM, tbmpre.blockno); - } - } - } -#endif /* USE_PREFETCH */ -} - /* * BitmapHeapRecheck -- access method routine to recheck a tuple in EvalPlanQual */ @@ -572,23 +265,12 @@ ExecReScanBitmapHeapScan(BitmapHeapScanState *node) if (node->ss.ss_currentScanDesc) table_rescan(node->ss.ss_currentScanDesc, NULL); - /* release bitmaps and buffers if any */ - if (node->prefetch_iterator) - tbm_end_iterate(node->prefetch_iterator); - if (node->shared_prefetch_iterator) - tbm_end_shared_iterate(node->shared_prefetch_iterator); + /* release bitmaps if any */ if (node->tbm) tbm_free(node->tbm); - if (node->pvmbuffer != InvalidBuffer) - ReleaseBuffer(node->pvmbuffer); node->tbm = NULL; - node->prefetch_iterator = NULL; node->initialized = false; - node->shared_prefetch_iterator = NULL; - node->pvmbuffer = InvalidBuffer; node->recheck = true; - node->blockno = InvalidBlockNumber; - node->pfblockno = InvalidBlockNumber; ExecScanReScan(&node->ss); @@ -627,16 +309,10 @@ ExecEndBitmapHeapScan(BitmapHeapScanState *node) table_endscan(scanDesc); /* - * release bitmaps and buffers if any + * release bitmaps if any */ - if (node->prefetch_iterator) - tbm_end_iterate(node->prefetch_iterator); if (node->tbm) tbm_free(node->tbm); - if (node->shared_prefetch_iterator) - tbm_end_shared_iterate(node->shared_prefetch_iterator); - if (node->pvmbuffer != InvalidBuffer) - ReleaseBuffer(node->pvmbuffer); } /* ---------------------------------------------------------------- @@ -669,18 +345,11 @@ ExecInitBitmapHeapScan(BitmapHeapScan *node, EState *estate, int eflags) scanstate->ss.ps.ExecProcNode = ExecBitmapHeapScan; scanstate->tbm = NULL; - scanstate->pvmbuffer = InvalidBuffer; scanstate->exact_pages = 0; scanstate->lossy_pages = 0; - scanstate->prefetch_iterator = NULL; - scanstate->prefetch_pages = 0; - scanstate->prefetch_target = 0; scanstate->initialized = false; - scanstate->shared_prefetch_iterator = NULL; scanstate->pstate = NULL; scanstate->recheck = true; - scanstate->blockno = InvalidBlockNumber; - scanstate->pfblockno = InvalidBlockNumber; /* * Miscellaneous initialization @@ -720,13 +389,6 @@ ExecInitBitmapHeapScan(BitmapHeapScan *node, EState *estate, int eflags) scanstate->bitmapqualorig = ExecInitQual(node->bitmapqualorig, (PlanState *) scanstate); - /* - * Maximum number of prefetches for the tablespace if configured, - * otherwise the current value of the effective_io_concurrency GUC. - */ - scanstate->prefetch_maximum = - get_tablespace_io_concurrency(currentRelation->rd_rel->reltablespace); - scanstate->ss.ss_currentRelation = currentRelation; /* @@ -803,14 +465,10 @@ ExecBitmapHeapInitializeDSM(BitmapHeapScanState *node, return; pstate = shm_toc_allocate(pcxt->toc, sizeof(ParallelBitmapHeapState)); - pstate->tbmiterator = 0; - pstate->prefetch_iterator = 0; /* Initialize the mutex */ SpinLockInit(&pstate->mutex); - pstate->prefetch_pages = 0; - pstate->prefetch_target = 0; pstate->state = BM_INITIAL; ConditionVariableInit(&pstate->cv); @@ -841,11 +499,7 @@ ExecBitmapHeapReInitializeDSM(BitmapHeapScanState *node, if (DsaPointerIsValid(pstate->tbmiterator)) tbm_free_shared_area(dsa, pstate->tbmiterator); - if (DsaPointerIsValid(pstate->prefetch_iterator)) - tbm_free_shared_area(dsa, pstate->prefetch_iterator); - pstate->tbmiterator = InvalidDsaPointer; - pstate->prefetch_iterator = InvalidDsaPointer; } /* ---------------------------------------------------------------- diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h index 3dfb19ec7d5..1cad9c04f01 100644 --- a/src/include/access/heapam.h +++ b/src/include/access/heapam.h @@ -26,6 +26,7 @@ #include "storage/dsm.h" #include "storage/lockdefs.h" #include "storage/shm_toc.h" +#include "storage/streaming_read.h" #include "utils/relcache.h" #include "utils/snapshot.h" @@ -72,6 +73,9 @@ typedef struct HeapScanDescData */ ParallelBlockTableScanWorkerData *rs_parallelworkerdata; + /* Streaming read control object for scans supporting it */ + PgStreamingRead *rs_pgsr; + /* * These fields are only used for bitmap scans for the "skip fetch" * optimization. Bitmap scans needing no fields from the heap may skip diff --git a/src/include/access/tableam.h b/src/include/access/tableam.h index d214abeb201..5a963f9293f 100644 --- a/src/include/access/tableam.h +++ b/src/include/access/tableam.h @@ -792,23 +792,11 @@ typedef struct TableAmRoutine * lossy indicates whether or not the block's representation in the bitmap * is lossy or exact. * - * XXX: Currently this may only be implemented if the AM uses md.c as its - * storage manager, and uses ItemPointer->ip_blkid in a manner that maps - * blockids directly to the underlying storage. nodeBitmapHeapscan.c - * performs prefetching directly using that interface. This probably - * needs to be rectified at a later point. - * - * XXX: Currently this may only be implemented if the AM uses the - * visibilitymap, as nodeBitmapHeapscan.c unconditionally accesses it to - * perform prefetching. This probably needs to be rectified at a later - * point. - * * Optional callback, but either both scan_bitmap_next_block and * scan_bitmap_next_tuple need to exist, or neither. */ - bool (*scan_bitmap_next_block) (TableScanDesc scan, - bool *recheck, bool *lossy, - BlockNumber *blockno); + bool (*scan_bitmap_next_block) (TableScanDesc scan, bool *recheck, + bool *lossy); /* * Fetch the next tuple of a bitmap table scan into `slot` and return true @@ -1983,8 +1971,7 @@ table_relation_estimate_size(Relation rel, int32 *attr_widths, * used after verifying the presence (at plan time or such). */ static inline bool -table_scan_bitmap_next_block(TableScanDesc scan, - bool *recheck, bool *lossy, BlockNumber *blockno) +table_scan_bitmap_next_block(TableScanDesc scan, bool *recheck, bool *lossy) { /* * We don't expect direct calls to table_scan_bitmap_next_block with valid @@ -1994,8 +1981,7 @@ table_scan_bitmap_next_block(TableScanDesc scan, if (unlikely(TransactionIdIsValid(CheckXidAlive) && !bsysscan)) elog(ERROR, "unexpected table_scan_bitmap_next_block call during logical decoding"); - return scan->rs_rd->rd_tableam->scan_bitmap_next_block(scan, recheck, - lossy, blockno); + return scan->rs_rd->rd_tableam->scan_bitmap_next_block(scan, recheck, lossy); } /* diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h index 9ec7eaceeb7..6a48f583d7c 100644 --- a/src/include/nodes/execnodes.h +++ b/src/include/nodes/execnodes.h @@ -1682,11 +1682,8 @@ typedef enum /* ---------------- * ParallelBitmapHeapState information * tbmiterator iterator for scanning current pages - * prefetch_iterator iterator for prefetching ahead of current page * mutex mutual exclusion for the prefetching variable * and state - * prefetch_pages # pages prefetch iterator is ahead of current - * prefetch_target current target prefetch distance * state current state of the TIDBitmap * cv conditional wait variable * ---------------- @@ -1694,10 +1691,7 @@ typedef enum typedef struct ParallelBitmapHeapState { dsa_pointer tbmiterator; - dsa_pointer prefetch_iterator; slock_t mutex; - int prefetch_pages; - int prefetch_target; SharedBitmapState state; ConditionVariable cv; } ParallelBitmapHeapState; @@ -1707,19 +1701,11 @@ typedef struct ParallelBitmapHeapState * * bitmapqualorig execution state for bitmapqualorig expressions * tbm bitmap obtained from child index scan(s) - * pvmbuffer buffer for visibility-map lookups of prefetched pages * exact_pages total number of exact pages retrieved * lossy_pages total number of lossy pages retrieved - * prefetch_iterator iterator for prefetching ahead of current page - * prefetch_pages # pages prefetch iterator is ahead of current - * prefetch_target current target prefetch distance - * prefetch_maximum maximum value for prefetch_target * initialized is node is ready to iterate - * shared_prefetch_iterator shared iterator for prefetching * pstate shared state for parallel bitmap scan * recheck do current page's tuples need recheck - * blockno used to validate pf and current block in sync - * pfblockno used to validate pf stays ahead of current block * ---------------- */ typedef struct BitmapHeapScanState @@ -1727,19 +1713,11 @@ typedef struct BitmapHeapScanState ScanState ss; /* its first field is NodeTag */ ExprState *bitmapqualorig; TIDBitmap *tbm; - Buffer pvmbuffer; long exact_pages; long lossy_pages; - TBMIterator *prefetch_iterator; - int prefetch_pages; - int prefetch_target; - int prefetch_maximum; bool initialized; - TBMSharedIterator *shared_prefetch_iterator; ParallelBitmapHeapState *pstate; bool recheck; - BlockNumber blockno; - BlockNumber pfblockno; } BitmapHeapScanState; /* ---------------- -- 2.40.1