Fixed crash with debugging disabled [skip ci]

.github/workflows/build.yml

@@ -97,7 +97,7 @@ jobs:
         with:
           postgres-version: ${{ matrix.postgres }}
       - run: |
-          call "C:\Program Files\Microsoft Visual Studio\${{ matrix.os == 'windows-2025' && 18 || 2022 }}\Enterprise\VC\Auxiliary\Build\vcvars64.bat" && ^
+          call "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Auxiliary\Build\vcvars64.bat" && ^
           nmake /NOLOGO /F Makefile.win && ^
           nmake /NOLOGO /F Makefile.win install && ^
           nmake /NOLOGO /F Makefile.win installcheck ${{ matrix.postgres != 17 && 'PG_REGRESS=$(PGROOT)\bin\pg_regress' || '' }} && ^

CHANGELOG.md

@@ -1,8 +1,3 @@
-## 0.8.3 (unreleased)
-
-- Fixed possible index corruption with HNSW vacuuming
-- Fixed performance regression with Hamming distance and Jaccard distance with Postgres 18
-
 ## 0.8.2 (2026-02-25)
 
 - Fixed buffer overflow with parallel HNSW index build - [more info](https://github.com/pgvector/pgvector/issues/959)

README.md

@@ -1329,7 +1329,7 @@ make clean && PG_CFLAGS="-DUSE_ASSERT_CHECKING" make && make install
 To enable benchmarking:
 
 ```sh
-make clean && PG_CFLAGS="-DHNSW_BENCH -DIVFFLAT_BENCH" make && make install
+make clean && PG_CFLAGS="-DIVFFLAT_BENCH" make && make install
 ```
 
 To show memory usage:

src/bitutils.c

@@ -31,12 +31,10 @@
 #define BIT_TARGET_CLONES
 #endif
 
-/* Use built-ins when possible for Postgres < 19 for inlining */
+/* Use built-ins when possible for inlining */
-#if PG_VERSION_NUM >= 190000
+#if defined(HAVE__BUILTIN_POPCOUNT) && defined(HAVE_LONG_INT_64)
-#define popcount64(x) pg_popcount64(x)
-#elif defined(HAVE__BUILTIN_POPCOUNT) && (defined(HAVE_LONG_INT_64) || SIZEOF_LONG == 8)
 #define popcount64(x) __builtin_popcountl(x)
-#elif defined(HAVE__BUILTIN_POPCOUNT) && (defined(HAVE_LONG_LONG_INT_64) || SIZEOF_LONG_LONG == 8)
+#elif defined(HAVE__BUILTIN_POPCOUNT) && defined(HAVE_LONG_LONG_INT_64)
 #define popcount64(x) __builtin_popcountll(x)
 #elif !defined(_MSC_VER)
 /* Fails to resolve with MSVC */

src/hnsw.c

@@ -258,6 +258,11 @@ hnswvalidate(Oid opclassoid)
 	return true;
 }
 
+static void
+hnswunguardbatch(IndexScanDesc scan, IndexScanBatch batch)
+{
+}
+
 /*
  * Define index handler
  *
@@ -279,6 +284,7 @@ hnswhandler(PG_FUNCTION_ARGS)
 		.amconsistentequality = false,
 		.amconsistentordering = false,
 		.amcanbackward = false,
+		.amcanmarkpos = false,
 		.amcanunique = false,
 		.amcanmulticol = false,
 		.amoptionalkey = true,
@@ -290,11 +296,7 @@ hnswhandler(PG_FUNCTION_ARGS)
 		.amcanparallel = false,
 		.amcanbuildparallel = true,
 		.amcaninclude = false,
-#if PG_VERSION_NUM >= 170000
-		.amusemaintenanceworkmem = true,
-#else
 		.amusemaintenanceworkmem = false,
-#endif
 		.amsummarizing = false,
 		.amparallelvacuumoptions = VACUUM_OPTION_PARALLEL_BULKDEL,
 		.amkeytype = InvalidOid,
@@ -315,11 +317,14 @@ hnswhandler(PG_FUNCTION_ARGS)
 		.amadjustmembers = NULL,
 		.ambeginscan = hnswbeginscan,
 		.amrescan = hnswrescan,
-		.amgettuple = hnswgettuple,
+		.amgettuple = NULL,
+		.amgetbatch = hnswgetbatch,
+		.amunguardbatch = hnswunguardbatch,
+		.amkillitemsbatch = NULL,
+		.amgettransform = NULL,
 		.amgetbitmap = NULL,
 		.amendscan = hnswendscan,
-		.ammarkpos = NULL,
+		.amposreset = NULL,
-		.amrestrpos = NULL,
 		.amestimateparallelscan = NULL,
 		.aminitparallelscan = NULL,
 		.amparallelrescan = NULL,
@@ -355,11 +360,7 @@ hnswhandler(PG_FUNCTION_ARGS)
 	amroutine->amcanbuildparallel = true;
 #endif
 	amroutine->amcaninclude = false;
-#if PG_VERSION_NUM >= 170000
+	amroutine->amusemaintenanceworkmem = false; /* not used during VACUUM */
-	amroutine->amusemaintenanceworkmem = true;
-#else
-	amroutine->amusemaintenanceworkmem = false;
-#endif
 #if PG_VERSION_NUM >= 160000
 	amroutine->amsummarizing = false;
 #endif

src/hnsw.h

@@ -18,20 +18,10 @@
 #include "utils/sampling.h"
 #include "vector.h"
 
-#ifdef HNSW_BENCH
-#include "portability/instr_time.h"
-#endif
-
 #if PG_VERSION_NUM >= 190000
 typedef Pointer Item;
 #endif
 
-#if PG_VERSION_NUM >= 170000
-#define HnswTidStore TidStore
-#else
-#define HnswTidStore tidhash_hash
-#endif
-
 #define HNSW_MAX_DIM 2000
 #define HNSW_MAX_NNZ 1000
 
@@ -88,21 +78,6 @@ typedef Pointer Item;
 #define HnswPageGetOpaque(page)	((HnswPageOpaque) PageGetSpecialPointer(page))
 #define HnswPageGetMeta(page)	((HnswMetaPageData *) PageGetContents(page))
 
-#ifdef HNSW_BENCH
-#define HnswBench(name, code) \
-	do { \
-		instr_time	start; \
-		instr_time	duration; \
-		INSTR_TIME_SET_CURRENT(start); \
-		(code); \
-		INSTR_TIME_SET_CURRENT(duration); \
-		INSTR_TIME_SUBTRACT(duration, start); \
-		elog(INFO, "%s: %.3f ms", name, INSTR_TIME_GET_MILLISEC(duration)); \
-	} while (0)
-#else
-#define HnswBench(name, code) (code)
-#endif
-
 #if PG_VERSION_NUM >= 150000
 #define RandomDouble() pg_prng_double(&pg_global_prng_state)
 #define SeedRandom(seed) pg_prng_seed(&pg_global_prng_state, seed)
@@ -433,11 +408,10 @@ typedef struct HnswVacuumState
 	HnswSupport support;
 
 	/* Variables */
-	struct HnswTidStore *deleted;
+	struct tidhash_hash *deleted;
 	BufferAccessStrategy bas;
 	HnswNeighborTuple ntup;
 	HnswElementData highestPoint;
-	HnswElementData fallbackPoint;
 
 	/* Memory */
 	MemoryContext tmpCtx;
@@ -491,7 +465,7 @@ IndexBulkDeleteResult *hnswbulkdelete(IndexVacuumInfo *info, IndexBulkDeleteResu
 IndexBulkDeleteResult *hnswvacuumcleanup(IndexVacuumInfo *info, IndexBulkDeleteResult *stats);
 IndexScanDesc hnswbeginscan(Relation index, int nkeys, int norderbys);
 void		hnswrescan(IndexScanDesc scan, ScanKey keys, int nkeys, ScanKey orderbys, int norderbys);
-bool		hnswgettuple(IndexScanDesc scan, ScanDirection dir);
+IndexScanBatch hnswgetbatch(IndexScanDesc scan, IndexScanBatch priorbatch, ScanDirection dir);
 void		hnswendscan(IndexScanDesc scan);
 
 static inline HnswNeighborArray *

src/hnswscan.c

@@ -3,6 +3,7 @@
 #include <limits.h>
 
 #include "access/genam.h"
+#include "access/indexbatch.h"
 #include "access/relscan.h"
 #include "hnsw.h"
 #include "lib/pairingheap.h"
@@ -135,6 +136,11 @@ hnswbeginscan(Relation index, int nkeys, int norderbys)
 	double		maxMemory;
 
 	scan = RelationGetIndexScan(index, nkeys, norderbys);
+	scan->maxitemsbatch = hnsw_ef_search * HNSW_HEAPTIDS;
+	/* unused but must be > 0 */
+	scan->batch_index_opaque_static = MAXALIGN(1);
+	scan->batch_index_opaque_dyn = 0;
+	scan->batch_tuples_workspace = 0;
 
 	so = (HnswScanOpaque) palloc(sizeof(HnswScanOpaqueData));
 	so->typeInfo = HnswGetTypeInfo(index);
@@ -184,12 +190,13 @@ hnswrescan(IndexScanDesc scan, ScanKey keys, int nkeys, ScanKey orderbys, int no
 }
 
 /*
- * Fetch the next tuple in the given scan
+ * Fetch the next batch in the given scan
  */
-bool
+IndexScanBatch
-hnswgettuple(IndexScanDesc scan, ScanDirection dir)
+hnswgetbatch(IndexScanDesc scan, IndexScanBatch priorbatch, ScanDirection dir)
 {
 	HnswScanOpaque so = (HnswScanOpaque) scan->opaque;
+	IndexScanBatch batch = indexam_util_alloc_batch(scan);
 	MemoryContext oldCtx = MemoryContextSwitchTo(so->tmpCtx);
 
 	/*
@@ -245,6 +252,7 @@ hnswgettuple(IndexScanDesc scan, ScanDirection dir)
 		HnswSearchCandidate *sc;
 		HnswElement element;
 		ItemPointer heaptid;
+		int			nitems = 0;
 
 		if (list_length(so->w) == 0)
 		{
@@ -290,6 +298,8 @@ hnswgettuple(IndexScanDesc scan, ScanDirection dir)
 				break;
 		}
 
+		while (list_length(so->w) != 0)
+		{
 			sc = llast(so->w);
 			element = HnswPtrAccess(base, sc->element);
 
@@ -318,16 +328,34 @@ hnswgettuple(IndexScanDesc scan, ScanDirection dir)
 				so->previousDistance = sc->distance;
 			}
 
+			batch->items[nitems].tableTid = *heaptid;
+			batch->items[nitems].indexOffset = -1;
+			batch->items[nitems].tupleOffset = 0;
+			nitems++;
+
+			/* Keep batch size flexible */
+			if (nitems == scan->maxitemsbatch)
+				break;
+		}
+
+		/* Needed for strict iterative scans */
+		if (nitems == 0)
+			continue;
+
 		MemoryContextSwitchTo(oldCtx);
 
-		scan->xs_heaptid = *heaptid;
 		scan->xs_recheck = false;
 		scan->xs_recheckorderby = false;
-		return true;
+
+		batch->firstItem = 0;
+		batch->lastItem = nitems - 1;
+		batch->dir = ForwardScanDirection;
+		return batch;
 	}
 
 	MemoryContextSwitchTo(oldCtx);
-	return false;
+	indexam_util_release_batch(scan, batch);
+	return NULL;
 }
 
 /*

src/hnswutils.c

@@ -546,9 +546,6 @@ HnswLoadElementImpl(BlockNumber blkno, OffsetNumber offno, double *distance, Hns
 
 	Assert(HnswIsElementTuple(etup));
 
-	if (unlikely(etup->deleted))
-		elog(ERROR, "cannot load deleted element");
-
 	/* Calculate distance */
 	if (distance != NULL)
 	{

src/hnswvacuum.c

@@ -10,12 +10,6 @@
 #include "utils/memutils.h"
 #include "utils/rel.h"
 
-#if PG_VERSION_NUM >= 170000
-#include "access/tidstore.h"
-#include "miscadmin.h"
-#include "postmaster/autovacuum.h"
-#endif
-
 #if PG_VERSION_NUM >= 160000
 #include "varatt.h"
 #endif
@@ -28,13 +22,9 @@
  * Check if deleted list contains an index TID
  */
 static bool
-DeletedContains(HnswTidStore * deleted, ItemPointer indextid)
+DeletedContains(tidhash_hash * deleted, ItemPointer indextid)
 {
-#if PG_VERSION_NUM >= 170000
-	return TidStoreIsMember(deleted, indextid);
-#else
 	return tidhash_lookup(deleted, *indextid) != NULL;
-#endif
 }
 
 /*
@@ -47,20 +37,17 @@ RemoveHeapTids(HnswVacuumState * vacuumstate)
 {
 	BlockNumber blkno = HNSW_HEAD_BLKNO;
 	HnswElement highestPoint = &vacuumstate->highestPoint;
-	HnswElement fallbackPoint = &vacuumstate->fallbackPoint;
 	Relation	index = vacuumstate->index;
 	BufferAccessStrategy bas = vacuumstate->bas;
+	HnswElement entryPoint = HnswGetEntryPoint(vacuumstate->index);
 	IndexBulkDeleteResult *stats = vacuumstate->stats;
 
-	/* Store separately since HnswElement level is uint8 */
+	/* Store separately since highestPoint.level is uint8 */
 	int			highestLevel = -1;
-	int			fallbackLevel = -1;
 
-	/* Initialize highest point and fallback point */
+	/* Initialize highest point */
 	highestPoint->blkno = InvalidBlockNumber;
 	highestPoint->offno = InvalidOffsetNumber;
-	fallbackPoint->blkno = InvalidBlockNumber;
-	fallbackPoint->offno = InvalidOffsetNumber;
 
 	while (BlockNumberIsValid(blkno))
 	{
@@ -70,10 +57,6 @@ RemoveHeapTids(HnswVacuumState * vacuumstate)
 		OffsetNumber offno;
 		OffsetNumber maxoffno;
 		bool		updated = false;
-#if PG_VERSION_NUM >= 170000
-		OffsetNumber deletedoffs[MaxOffsetNumber];
-		int			ndeletedoffs = 0;
-#endif
 
 		vacuum_delay_point();
 
@@ -127,9 +110,6 @@ RemoveHeapTids(HnswVacuumState * vacuumstate)
 
 			if (!ItemPointerIsValid(&etup->heaptids[0]))
 			{
-#if PG_VERSION_NUM >= 170000
-				deletedoffs[ndeletedoffs++] = offno;
-#else
 				ItemPointerData ip;
 				bool		found;
 
@@ -138,38 +118,16 @@ RemoveHeapTids(HnswVacuumState * vacuumstate)
 
 				tidhash_insert(vacuumstate->deleted, ip, &found);
 				Assert(!found);
-#endif
 			}
-			else if (etup->level > highestLevel)
+			else if (etup->level > highestLevel && !(entryPoint != NULL && blkno == entryPoint->blkno && offno == entryPoint->offno))
 			{
-				if (BlockNumberIsValid(highestPoint->blkno))
+				/* Keep track of highest non-entry point */
-				{
-					/* Current highest point becomes fallback */
-					fallbackPoint->blkno = highestPoint->blkno;
-					fallbackPoint->offno = highestPoint->offno;
-					fallbackPoint->level = highestPoint->level;
-					fallbackLevel = highestLevel;
-				}
-
-				/* Keep track of highest point */
 				highestPoint->blkno = blkno;
 				highestPoint->offno = offno;
 				highestPoint->level = etup->level;
 				highestLevel = etup->level;
 			}
-			else if (etup->level > fallbackLevel)
-			{
-				/* Keep track of second highest point */
-				fallbackPoint->blkno = blkno;
-				fallbackPoint->offno = offno;
-				fallbackPoint->level = etup->level;
-				fallbackLevel = etup->level;
 		}
-		}
-
-#if PG_VERSION_NUM >= 170000
-		TidStoreSetBlockOffsets(vacuumstate->deleted, blkno, deletedoffs, ndeletedoffs);
-#endif
 
 		blkno = HnswPageGetOpaque(page)->nextblkno;
 
@@ -180,10 +138,6 @@ RemoveHeapTids(HnswVacuumState * vacuumstate)
 
 		UnlockReleaseBuffer(buf);
 	}
-
-#ifdef HNSW_MEMORY
-	elog(INFO, "memory: %zu KB", MemoryContextMemAllocated(CurrentMemoryContext, true) / 1024);
-#endif
 }
 
 /*
@@ -315,27 +269,12 @@ RepairGraphEntryPoint(HnswVacuumState * vacuumstate)
 		/* Get a shared lock */
 		LockPage(index, HNSW_UPDATE_LOCK, ShareLock);
 
-		/* Get latest entry point */
-		entryPoint = HnswGetEntryPoint(index);
-
-		/* Use fallback point if highest point is entry point */
-		if (entryPoint != NULL && entryPoint->blkno == highestPoint->blkno && entryPoint->offno == highestPoint->offno)
-		{
-			highestPoint = &vacuumstate->fallbackPoint;
-
-			if (!BlockNumberIsValid(highestPoint->blkno))
-				highestPoint = NULL;
-		}
-
-		if (highestPoint != NULL)
-		{
 		/* Load element */
 		HnswLoadElement(highestPoint, NULL, NULL, index, support, true, NULL);
 
 		/* Repair if needed */
 		if (NeedsUpdated(vacuumstate, highestPoint))
-				RepairGraphElement(vacuumstate, highestPoint, entryPoint);
+			RepairGraphElement(vacuumstate, highestPoint, HnswGetEntryPoint(index));
-		}
 
 		/* Release lock */
 		UnlockPage(index, HNSW_UPDATE_LOCK, ShareLock);
@@ -502,99 +441,6 @@ RepairGraph(HnswVacuumState * vacuumstate)
 		/* Reset memory context */
 		MemoryContextSwitchTo(oldCtx);
 		MemoryContextReset(vacuumstate->tmpCtx);
-
-#ifdef HNSW_VACUUM_PROGRESS
-		if (!BlockNumberIsValid(blkno) || ((blkno - HNSW_HEAD_BLKNO) % 1000 == 0 && blkno != HNSW_HEAD_BLKNO))
-		{
-			BlockNumber totalBlocks = RelationGetNumberOfBlocks(index);
-			BlockNumber currentBlocks = BlockNumberIsValid(blkno) ? blkno : totalBlocks;
-
-			elog(INFO, "hnsw vacuum progress: %.1f%%", 100.0 * currentBlocks / totalBlocks);
-		}
-#endif
-	}
-}
-
-/*
- * Confirm graph was repaired
- */
-static void
-ConfirmRepaired(HnswVacuumState * vacuumstate)
-{
-	BlockNumber blkno = HNSW_HEAD_BLKNO;
-	Relation	index = vacuumstate->index;
-	BufferAccessStrategy bas = vacuumstate->bas;
-
-	while (BlockNumberIsValid(blkno))
-	{
-		Buffer		buf;
-		Page		page;
-		OffsetNumber offno;
-		OffsetNumber maxoffno;
-
-		vacuum_delay_point();
-
-		buf = ReadBufferExtended(index, MAIN_FORKNUM, blkno, RBM_NORMAL, bas);
-		LockBuffer(buf, BUFFER_LOCK_SHARE);
-		page = BufferGetPage(buf);
-		maxoffno = PageGetMaxOffsetNumber(page);
-
-		/* Iterate over nodes */
-		for (offno = FirstOffsetNumber; offno <= maxoffno; offno = OffsetNumberNext(offno))
-		{
-			HnswElementTuple etup = (HnswElementTuple) PageGetItem(page, PageGetItemId(page, offno));
-			HnswNeighborTuple ntup;
-			Buffer		nbuf;
-			Page		npage;
-			BlockNumber neighborPage;
-			OffsetNumber neighborOffno;
-
-			/* Skip neighbor tuples */
-			if (!HnswIsElementTuple(etup))
-				continue;
-
-			/* Skip if being deleted */
-			if (!ItemPointerIsValid(&etup->heaptids[0]))
-				continue;
-
-			/* Get neighbor page */
-			neighborPage = ItemPointerGetBlockNumber(&etup->neighbortid);
-			neighborOffno = ItemPointerGetOffsetNumber(&etup->neighbortid);
-
-			if (neighborPage == blkno)
-			{
-				nbuf = buf;
-				npage = page;
-			}
-			else
-			{
-				nbuf = ReadBufferExtended(index, MAIN_FORKNUM, neighborPage, RBM_NORMAL, bas);
-				LockBuffer(nbuf, BUFFER_LOCK_SHARE);
-				npage = BufferGetPage(nbuf);
-			}
-
-			ntup = (HnswNeighborTuple) PageGetItem(npage, PageGetItemId(npage, neighborOffno));
-
-			/* Check neighbors */
-			for (int i = 0; i < ntup->count; i++)
-			{
-				ItemPointer indextid = &ntup->indextids[i];
-
-				if (!ItemPointerIsValid(indextid))
-					continue;
-
-				/* Check if in deleted list */
-				if (DeletedContains(vacuumstate->deleted, indextid))
-					elog(ERROR, "hnsw graph not repaired");
-			}
-
-			if (nbuf != buf)
-				UnlockReleaseBuffer(nbuf);
-		}
-
-		blkno = HnswPageGetOpaque(page)->nextblkno;
-
-		UnlockReleaseBuffer(buf);
 	}
 }
 
@@ -761,11 +607,7 @@ InitVacuumState(HnswVacuumState * vacuumstate, IndexVacuumInfo *info, IndexBulkD
 	HnswGetMetaPageInfo(index, &vacuumstate->m, NULL);
 
 	/* Create hash table */
-#if PG_VERSION_NUM >= 170000
-	vacuumstate->deleted = TidStoreCreateLocal((AmAutoVacuumWorkerProcess() && autovacuum_work_mem != -1) ? autovacuum_work_mem : maintenance_work_mem, true);
-#else
 	vacuumstate->deleted = tidhash_create(CurrentMemoryContext, 256, NULL);
-#endif
 }
 
 /*
@@ -774,11 +616,7 @@ InitVacuumState(HnswVacuumState * vacuumstate, IndexVacuumInfo *info, IndexBulkD
 static void
 FreeVacuumState(HnswVacuumState * vacuumstate)
 {
-#if PG_VERSION_NUM >= 170000
-	TidStoreDestroy(vacuumstate->deleted);
-#else
 	tidhash_destroy(vacuumstate->deleted);
-#endif
 	FreeAccessStrategy(vacuumstate->bas);
 	pfree(vacuumstate->ntup);
 	MemoryContextDelete(vacuumstate->tmpCtx);
@@ -796,16 +634,13 @@ hnswbulkdelete(IndexVacuumInfo *info, IndexBulkDeleteResult *stats,
 	InitVacuumState(&vacuumstate, info, stats, callback, callback_state);
 
 	/* Pass 1: Remove heap TIDs */
-	HnswBench("RemoveHeapTids", RemoveHeapTids(&vacuumstate));
+	RemoveHeapTids(&vacuumstate);
 
 	/* Pass 2: Repair graph */
-	HnswBench("RepairGraph", RepairGraph(&vacuumstate));
+	RepairGraph(&vacuumstate);
 
-	/* Pass 3: Confirm repaired */
+	/* Pass 3: Mark as deleted */
-	HnswBench("ConfirmRepaired", ConfirmRepaired(&vacuumstate));
+	MarkDeleted(&vacuumstate);
-
-	/* Pass 4: Mark as deleted */
-	HnswBench("MarkDeleted", MarkDeleted(&vacuumstate));
 
 	FreeVacuumState(&vacuumstate);
 

src/ivfbuild.c

@@ -399,7 +399,6 @@ InitBuildState(IvfflatBuildState * buildstate, Relation heap, Relation index, In
 
 	buildstate->slot = MakeSingleTupleTableSlot(buildstate->sortdesc, &TTSOpsVirtual);
 
-	/* TODO Ensure within maintenance_work_mem */
 	buildstate->centers = VectorArrayInit(buildstate->lists, buildstate->dimensions, buildstate->typeInfo->itemSize(buildstate->dimensions));
 	buildstate->listInfo = palloc(sizeof(ListInfo) * buildstate->lists);
 

src/ivfflat.c

@@ -175,6 +175,11 @@ ivfflatvalidate(Oid opclassoid)
 	return true;
 }
 
+static void
+ivfflatunguardbatch(IndexScanDesc scan, IndexScanBatch batch)
+{
+}
+
 /*
  * Define index handler
  *
@@ -196,6 +201,7 @@ ivfflathandler(PG_FUNCTION_ARGS)
 		.amconsistentequality = false,
 		.amconsistentordering = false,
 		.amcanbackward = false,
+		.amcanmarkpos = false,
 		.amcanunique = false,
 		.amcanmulticol = false,
 		.amoptionalkey = true,
@@ -228,11 +234,14 @@ ivfflathandler(PG_FUNCTION_ARGS)
 		.amadjustmembers = NULL,
 		.ambeginscan = ivfflatbeginscan,
 		.amrescan = ivfflatrescan,
-		.amgettuple = ivfflatgettuple,
+		.amgettuple = NULL,
+		.amgetbatch = ivfflatgetbatch,
+		.amunguardbatch = ivfflatunguardbatch,
+		.amkillitemsbatch = NULL,
+		.amgettransform = NULL,
 		.amgetbitmap = NULL,
 		.amendscan = ivfflatendscan,
-		.ammarkpos = NULL,
+		.amposreset = NULL,
-		.amrestrpos = NULL,
 		.amestimateparallelscan = NULL,
 		.aminitparallelscan = NULL,
 		.amparallelrescan = NULL,

src/ivfflat.h

@@ -344,7 +344,7 @@ IndexBulkDeleteResult *ivfflatbulkdelete(IndexVacuumInfo *info, IndexBulkDeleteR
 IndexBulkDeleteResult *ivfflatvacuumcleanup(IndexVacuumInfo *info, IndexBulkDeleteResult *stats);
 IndexScanDesc ivfflatbeginscan(Relation index, int nkeys, int norderbys);
 void		ivfflatrescan(IndexScanDesc scan, ScanKey keys, int nkeys, ScanKey orderbys, int norderbys);
-bool		ivfflatgettuple(IndexScanDesc scan, ScanDirection dir);
+IndexScanBatch ivfflatgetbatch(IndexScanDesc scan, IndexScanBatch priorbatch, ScanDirection dir);
 void		ivfflatendscan(IndexScanDesc scan);
 
 #endif

src/ivfscan.c

@@ -3,6 +3,7 @@
 #include <float.h>
 
 #include "access/genam.h"
+#include "access/indexbatch.h"
 #include "access/itup.h"
 #include "access/relscan.h"
 #include "access/tupdesc.h"
@@ -261,6 +262,11 @@ ivfflatbeginscan(Relation index, int nkeys, int norderbys)
 	MemoryContext oldCtx;
 
 	scan = RelationGetIndexScan(index, nkeys, norderbys);
+	scan->maxitemsbatch = 1000;
+	/* unused but must be > 0 */
+	scan->batch_index_opaque_static = MAXALIGN(1);
+	scan->batch_index_opaque_dyn = 0;
+	scan->batch_tuples_workspace = 0;
 
 	/* Get lists and dimensions from metapage */
 	IvfflatGetMetaPageInfo(index, &lists, &dimensions);
@@ -348,14 +354,16 @@ ivfflatrescan(IndexScanDesc scan, ScanKey keys, int nkeys, ScanKey orderbys, int
 }
 
 /*
- * Fetch the next tuple in the given scan
+ * Fetch the next batch in the given scan
  */
-bool
+IndexScanBatch
-ivfflatgettuple(IndexScanDesc scan, ScanDirection dir)
+ivfflatgetbatch(IndexScanDesc scan, IndexScanBatch priorbatch, ScanDirection dir)
 {
 	IvfflatScanOpaque so = (IvfflatScanOpaque) scan->opaque;
+	IndexScanBatch batch = indexam_util_alloc_batch(scan);
 	ItemPointer heaptid;
 	bool		isnull;
+	int			nitems = 0;
 
 	/*
 	 * Index can be used to scan backward, but Postgres doesn't support
@@ -393,17 +401,37 @@ ivfflatgettuple(IndexScanDesc scan, ScanDirection dir)
 	while (!tuplesort_gettupleslot(so->sortstate, true, false, so->mslot, NULL))
 	{
 		if (so->listIndex == so->maxProbes)
-			return false;
+		{
+			indexam_util_release_batch(scan, batch);
+			return NULL;
+		}
 
 		IvfflatBench("GetScanItems", GetScanItems(scan, so->value));
 	}
 
+	for (;;)
+	{
 		heaptid = (ItemPointer) DatumGetPointer(slot_getattr(so->mslot, 2, &isnull));
 
-	scan->xs_heaptid = *heaptid;
+		batch->items[nitems].tableTid = *heaptid;
+		batch->items[nitems].indexOffset = -1;
+		batch->items[nitems].tupleOffset = 0;
+		nitems++;
+
+		if (nitems == scan->maxitemsbatch)
+			break;
+
+		if (!tuplesort_gettupleslot(so->sortstate, true, false, so->mslot, NULL))
+			break;
+	}
+
 	scan->xs_recheck = false;
 	scan->xs_recheckorderby = false;
-	return true;
+
+	batch->firstItem = 0;
+	batch->lastItem = nitems - 1;
+	batch->dir = ForwardScanDirection;
+	return batch;
 }
 
 /*