v20-0002-Move-heapam_handler.c-index-scan-code-to-new-fil.patch

application/octet-stream

Filename: v20-0002-Move-heapam_handler.c-index-scan-code-to-new-fil.patch
Type: application/octet-stream
Part: 16
Message: Re: index prefetching

Patch

Format: format-patch
Series: patch v20-0002
Subject: Move heapam_handler.c index scan code to new file.
File+
src/backend/access/heap/heapam.c 0 161
src/backend/access/heap/heapam_handler.c 0 111
src/backend/access/heap/heapam_indexscan.c 292 0
src/backend/access/heap/Makefile 1 0
src/backend/access/heap/meson.build 1 0
src/include/access/heapam.h 12 3
From e82059b0944c97e22eb6c5d884f224b2a807bed1 Mon Sep 17 00:00:00 2001
From: Peter Geoghegan <pg@bowt.ie>
Date: Wed, 25 Mar 2026 00:22:17 -0400
Subject: [PATCH v20 02/17] Move heapam_handler.c index scan code to new file.

Move the heapam index fetch callbacks (index_fetch_begin,
index_fetch_reset, index_fetch_end, and index_fetch_tuple) into a new
dedicated file.  Also move heap_hot_search_buffer over.  This is a
purely mechanical move with no functional impact.

Upcoming work to add a slot-based table AM interface for index scans
will substantially expand this code.  Keeping it in heapam_handler.c
would clutter a file whose primary role is to wire up the TableAmRoutine
callbacks.  Bitmap heap scans and sequential scans would benefit from
similar separation in the future.

Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/bmbrkiyjxoal6o5xadzv5bveoynrt3x37wqch7w3jnwumkq2yo@b4zmtnrfs4mh
---
 src/include/access/heapam.h                |  15 +-
 src/backend/access/heap/Makefile           |   1 +
 src/backend/access/heap/heapam.c           | 161 ------------
 src/backend/access/heap/heapam_handler.c   | 111 --------
 src/backend/access/heap/heapam_indexscan.c | 292 +++++++++++++++++++++
 src/backend/access/heap/meson.build        |   1 +
 6 files changed, 306 insertions(+), 275 deletions(-)
 create mode 100644 src/backend/access/heap/heapam_indexscan.c

diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index 54067b828..cc90c821b 100644
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -366,9 +366,6 @@ extern bool heap_getnextslot_tidrange(TableScanDesc sscan,
 									  TupleTableSlot *slot);
 extern bool heap_fetch(Relation relation, Snapshot snapshot,
 					   HeapTuple tuple, Buffer *userbuf, bool keep_buf);
-extern bool heap_hot_search_buffer(ItemPointer tid, Relation relation,
-								   Buffer buffer, Snapshot snapshot, HeapTuple heapTuple,
-								   bool *all_dead, bool first_call);
 
 extern void heap_get_latest_tid(TableScanDesc sscan, ItemPointer tid);
 
@@ -431,6 +428,18 @@ extern void simple_heap_update(Relation relation, const ItemPointerData *otid,
 extern TransactionId heap_index_delete_tuples(Relation rel,
 											  TM_IndexDeleteOp *delstate);
 
+/* in heap/heapam_indexscan.c */
+extern IndexFetchTableData *heapam_index_fetch_begin(Relation rel, uint32 flags);
+extern void heapam_index_fetch_reset(IndexFetchTableData *scan);
+extern void heapam_index_fetch_end(IndexFetchTableData *scan);
+extern bool heap_hot_search_buffer(ItemPointer tid, Relation relation,
+								   Buffer buffer, Snapshot snapshot, HeapTuple heapTuple,
+								   bool *all_dead, bool first_call);
+extern bool heapam_index_fetch_tuple(struct IndexFetchTableData *scan,
+									 ItemPointer tid, Snapshot snapshot,
+									 TupleTableSlot *slot, bool *heap_continue,
+									 bool *all_dead);
+
 /* in heap/pruneheap.c */
 extern void heap_page_prune_opt(Relation relation, Buffer buffer,
 								Buffer *vmbuffer, bool rel_read_only);
diff --git a/src/backend/access/heap/Makefile b/src/backend/access/heap/Makefile
index 394534172..1d27ccb91 100644
--- a/src/backend/access/heap/Makefile
+++ b/src/backend/access/heap/Makefile
@@ -15,6 +15,7 @@ include $(top_builddir)/src/Makefile.global
 OBJS = \
 	heapam.o \
 	heapam_handler.o \
+	heapam_indexscan.o \
 	heapam_visibility.o \
 	heapam_xlog.o \
 	heaptoast.o \
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 6bff0032d..e06ce2db2 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -1764,167 +1764,6 @@ heap_fetch(Relation relation,
 	return false;
 }
 
-/*
- *	heap_hot_search_buffer	- search HOT chain for tuple satisfying snapshot
- *
- * On entry, *tid is the TID of a tuple (either a simple tuple, or the root
- * of a HOT chain), and buffer is the buffer holding this tuple.  We search
- * for the first chain member satisfying the given snapshot.  If one is
- * found, we update *tid to reference that tuple's offset number, and
- * return true.  If no match, return false without modifying *tid.
- *
- * heapTuple is a caller-supplied buffer.  When a match is found, we return
- * the tuple here, in addition to updating *tid.  If no match is found, the
- * contents of this buffer on return are undefined.
- *
- * If all_dead is not NULL, we check non-visible tuples to see if they are
- * globally dead; *all_dead is set true if all members of the HOT chain
- * are vacuumable, false if not.
- *
- * Unlike heap_fetch, the caller must already have pin and (at least) share
- * lock on the buffer; it is still pinned/locked at exit.
- */
-bool
-heap_hot_search_buffer(ItemPointer tid, Relation relation, Buffer buffer,
-					   Snapshot snapshot, HeapTuple heapTuple,
-					   bool *all_dead, bool first_call)
-{
-	Page		page = BufferGetPage(buffer);
-	TransactionId prev_xmax = InvalidTransactionId;
-	BlockNumber blkno;
-	OffsetNumber offnum;
-	bool		at_chain_start;
-	bool		valid;
-	bool		skip;
-	GlobalVisState *vistest = NULL;
-
-	/* If this is not the first call, previous call returned a (live!) tuple */
-	if (all_dead)
-		*all_dead = first_call;
-
-	blkno = ItemPointerGetBlockNumber(tid);
-	offnum = ItemPointerGetOffsetNumber(tid);
-	at_chain_start = first_call;
-	skip = !first_call;
-
-	/* XXX: we should assert that a snapshot is pushed or registered */
-	Assert(TransactionIdIsValid(RecentXmin));
-	Assert(BufferGetBlockNumber(buffer) == blkno);
-
-	/* Scan through possible multiple members of HOT-chain */
-	for (;;)
-	{
-		ItemId		lp;
-
-		/* check for bogus TID */
-		if (offnum < FirstOffsetNumber || offnum > PageGetMaxOffsetNumber(page))
-			break;
-
-		lp = PageGetItemId(page, offnum);
-
-		/* check for unused, dead, or redirected items */
-		if (!ItemIdIsNormal(lp))
-		{
-			/* We should only see a redirect at start of chain */
-			if (ItemIdIsRedirected(lp) && at_chain_start)
-			{
-				/* Follow the redirect */
-				offnum = ItemIdGetRedirect(lp);
-				at_chain_start = false;
-				continue;
-			}
-			/* else must be end of chain */
-			break;
-		}
-
-		/*
-		 * Update heapTuple to point to the element of the HOT chain we're
-		 * currently investigating. Having t_self set correctly is important
-		 * because the SSI checks and the *Satisfies routine for historical
-		 * MVCC snapshots need the correct tid to decide about the visibility.
-		 */
-		heapTuple->t_data = (HeapTupleHeader) PageGetItem(page, lp);
-		heapTuple->t_len = ItemIdGetLength(lp);
-		heapTuple->t_tableOid = RelationGetRelid(relation);
-		ItemPointerSet(&heapTuple->t_self, blkno, offnum);
-
-		/*
-		 * Shouldn't see a HEAP_ONLY tuple at chain start.
-		 */
-		if (at_chain_start && HeapTupleIsHeapOnly(heapTuple))
-			break;
-
-		/*
-		 * The xmin should match the previous xmax value, else chain is
-		 * broken.
-		 */
-		if (TransactionIdIsValid(prev_xmax) &&
-			!TransactionIdEquals(prev_xmax,
-								 HeapTupleHeaderGetXmin(heapTuple->t_data)))
-			break;
-
-		/*
-		 * When first_call is true (and thus, skip is initially false) we'll
-		 * return the first tuple we find.  But on later passes, heapTuple
-		 * will initially be pointing to the tuple we returned last time.
-		 * Returning it again would be incorrect (and would loop forever), so
-		 * we skip it and return the next match we find.
-		 */
-		if (!skip)
-		{
-			/* If it's visible per the snapshot, we must return it */
-			valid = HeapTupleSatisfiesVisibility(heapTuple, snapshot, buffer);
-			HeapCheckForSerializableConflictOut(valid, relation, heapTuple,
-												buffer, snapshot);
-
-			if (valid)
-			{
-				ItemPointerSetOffsetNumber(tid, offnum);
-				PredicateLockTID(relation, &heapTuple->t_self, snapshot,
-								 HeapTupleHeaderGetXmin(heapTuple->t_data));
-				if (all_dead)
-					*all_dead = false;
-				return true;
-			}
-		}
-		skip = false;
-
-		/*
-		 * If we can't see it, maybe no one else can either.  At caller
-		 * request, check whether all chain members are dead to all
-		 * transactions.
-		 *
-		 * Note: if you change the criterion here for what is "dead", fix the
-		 * planner's get_actual_variable_range() function to match.
-		 */
-		if (all_dead && *all_dead)
-		{
-			if (!vistest)
-				vistest = GlobalVisTestFor(relation);
-
-			if (!HeapTupleIsSurelyDead(heapTuple, vistest))
-				*all_dead = false;
-		}
-
-		/*
-		 * Check to see if HOT chain continues past this tuple; if so fetch
-		 * the next offnum and loop around.
-		 */
-		if (HeapTupleIsHotUpdated(heapTuple))
-		{
-			Assert(ItemPointerGetBlockNumber(&heapTuple->t_data->t_ctid) ==
-				   blkno);
-			offnum = ItemPointerGetOffsetNumber(&heapTuple->t_data->t_ctid);
-			at_chain_start = false;
-			prev_xmax = HeapTupleHeaderGetUpdateXid(heapTuple->t_data);
-		}
-		else
-			break;				/* end of chain */
-	}
-
-	return false;
-}
-
 /*
  *	heap_get_latest_tid -  get the latest tid of a specified tuple
  *
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index dc7db5885..07f07188d 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -75,117 +75,6 @@ heapam_slot_callbacks(Relation relation)
 }
 
 
-/* ------------------------------------------------------------------------
- * Index Scan Callbacks for heap AM
- * ------------------------------------------------------------------------
- */
-
-static IndexFetchTableData *
-heapam_index_fetch_begin(Relation rel, uint32 flags)
-{
-	IndexFetchHeapData *hscan = palloc0_object(IndexFetchHeapData);
-
-	hscan->xs_base.rel = rel;
-	hscan->xs_base.flags = flags;
-	hscan->xs_cbuf = InvalidBuffer;
-	hscan->xs_vmbuffer = InvalidBuffer;
-
-	return &hscan->xs_base;
-}
-
-static void
-heapam_index_fetch_reset(IndexFetchTableData *scan)
-{
-	IndexFetchHeapData *hscan = (IndexFetchHeapData *) scan;
-
-	if (BufferIsValid(hscan->xs_cbuf))
-	{
-		ReleaseBuffer(hscan->xs_cbuf);
-		hscan->xs_cbuf = InvalidBuffer;
-	}
-
-	if (BufferIsValid(hscan->xs_vmbuffer))
-	{
-		ReleaseBuffer(hscan->xs_vmbuffer);
-		hscan->xs_vmbuffer = InvalidBuffer;
-	}
-}
-
-static void
-heapam_index_fetch_end(IndexFetchTableData *scan)
-{
-	IndexFetchHeapData *hscan = (IndexFetchHeapData *) scan;
-
-	heapam_index_fetch_reset(scan);
-
-	pfree(hscan);
-}
-
-static bool
-heapam_index_fetch_tuple(struct IndexFetchTableData *scan,
-						 ItemPointer tid,
-						 Snapshot snapshot,
-						 TupleTableSlot *slot,
-						 bool *heap_continue, bool *all_dead)
-{
-	IndexFetchHeapData *hscan = (IndexFetchHeapData *) scan;
-	BufferHeapTupleTableSlot *bslot = (BufferHeapTupleTableSlot *) slot;
-	bool		got_heap_tuple;
-
-	Assert(TTS_IS_BUFFERTUPLE(slot));
-
-	/* We can skip the buffer-switching logic if we're in mid-HOT chain. */
-	if (!*heap_continue)
-	{
-		/* Switch to correct buffer if we don't have it already */
-		Buffer		prev_buf = hscan->xs_cbuf;
-
-		hscan->xs_cbuf = ReleaseAndReadBuffer(hscan->xs_cbuf,
-											  hscan->xs_base.rel,
-											  ItemPointerGetBlockNumber(tid));
-
-		/*
-		 * Prune page, but only if we weren't already on this page
-		 */
-		if (prev_buf != hscan->xs_cbuf)
-			heap_page_prune_opt(hscan->xs_base.rel, hscan->xs_cbuf,
-								&hscan->xs_vmbuffer,
-								hscan->xs_base.flags & SO_HINT_REL_READ_ONLY);
-	}
-
-	/* Obtain share-lock on the buffer so we can examine visibility */
-	LockBuffer(hscan->xs_cbuf, BUFFER_LOCK_SHARE);
-	got_heap_tuple = heap_hot_search_buffer(tid,
-											hscan->xs_base.rel,
-											hscan->xs_cbuf,
-											snapshot,
-											&bslot->base.tupdata,
-											all_dead,
-											!*heap_continue);
-	bslot->base.tupdata.t_self = *tid;
-	LockBuffer(hscan->xs_cbuf, BUFFER_LOCK_UNLOCK);
-
-	if (got_heap_tuple)
-	{
-		/*
-		 * Only in a non-MVCC snapshot can more than one member of the HOT
-		 * chain be visible.
-		 */
-		*heap_continue = !IsMVCCLikeSnapshot(snapshot);
-
-		slot->tts_tableOid = RelationGetRelid(scan->rel);
-		ExecStoreBufferHeapTuple(&bslot->base.tupdata, slot, hscan->xs_cbuf);
-	}
-	else
-	{
-		/* We've reached the end of the HOT chain. */
-		*heap_continue = false;
-	}
-
-	return got_heap_tuple;
-}
-
-
 /* ------------------------------------------------------------------------
  * Callbacks for non-modifying operations on individual tuples for heap AM
  * ------------------------------------------------------------------------
diff --git a/src/backend/access/heap/heapam_indexscan.c b/src/backend/access/heap/heapam_indexscan.c
new file mode 100644
index 000000000..c36b804d1
--- /dev/null
+++ b/src/backend/access/heap/heapam_indexscan.c
@@ -0,0 +1,292 @@
+/*-------------------------------------------------------------------------
+ *
+ * heapam_indexscan.c
+ *	  heap table plain index scan and index-only scan code
+ *
+ * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/access/heap/heapam_indexscan.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/heapam.h"
+#include "access/relscan.h"
+#include "storage/predicate.h"
+
+
+/* ------------------------------------------------------------------------
+ * Index Scan Callbacks for heap AM
+ * ------------------------------------------------------------------------
+ */
+
+IndexFetchTableData *
+heapam_index_fetch_begin(Relation rel, uint32 flags)
+{
+	IndexFetchHeapData *hscan = palloc0_object(IndexFetchHeapData);
+
+	hscan->xs_base.rel = rel;
+	hscan->xs_base.flags = flags;
+	hscan->xs_cbuf = InvalidBuffer;
+	hscan->xs_vmbuffer = InvalidBuffer;
+
+	return &hscan->xs_base;
+}
+
+void
+heapam_index_fetch_reset(IndexFetchTableData *scan)
+{
+	IndexFetchHeapData *hscan = (IndexFetchHeapData *) scan;
+
+	if (BufferIsValid(hscan->xs_cbuf))
+	{
+		ReleaseBuffer(hscan->xs_cbuf);
+		hscan->xs_cbuf = InvalidBuffer;
+	}
+
+	if (BufferIsValid(hscan->xs_vmbuffer))
+	{
+		ReleaseBuffer(hscan->xs_vmbuffer);
+		hscan->xs_vmbuffer = InvalidBuffer;
+	}
+}
+
+void
+heapam_index_fetch_end(IndexFetchTableData *scan)
+{
+	IndexFetchHeapData *hscan = (IndexFetchHeapData *) scan;
+
+	heapam_index_fetch_reset(scan);
+
+	pfree(hscan);
+}
+
+/*
+ *	heap_hot_search_buffer	- search HOT chain for tuple satisfying snapshot
+ *
+ * On entry, *tid is the TID of a tuple (either a simple tuple, or the root
+ * of a HOT chain), and buffer is the buffer holding this tuple.  We search
+ * for the first chain member satisfying the given snapshot.  If one is
+ * found, we update *tid to reference that tuple's offset number, and
+ * return true.  If no match, return false without modifying *tid.
+ *
+ * heapTuple is a caller-supplied buffer.  When a match is found, we return
+ * the tuple here, in addition to updating *tid.  If no match is found, the
+ * contents of this buffer on return are undefined.
+ *
+ * If all_dead is not NULL, we check non-visible tuples to see if they are
+ * globally dead; *all_dead is set true if all members of the HOT chain
+ * are vacuumable, false if not.
+ *
+ * Unlike heap_fetch, the caller must already have pin and (at least) share
+ * lock on the buffer; it is still pinned/locked at exit.
+ */
+bool
+heap_hot_search_buffer(ItemPointer tid, Relation relation, Buffer buffer,
+					   Snapshot snapshot, HeapTuple heapTuple,
+					   bool *all_dead, bool first_call)
+{
+	Page		page = BufferGetPage(buffer);
+	TransactionId prev_xmax = InvalidTransactionId;
+	BlockNumber blkno;
+	OffsetNumber offnum;
+	bool		at_chain_start;
+	bool		valid;
+	bool		skip;
+	GlobalVisState *vistest = NULL;
+
+	/* If this is not the first call, previous call returned a (live!) tuple */
+	if (all_dead)
+		*all_dead = first_call;
+
+	blkno = ItemPointerGetBlockNumber(tid);
+	offnum = ItemPointerGetOffsetNumber(tid);
+	at_chain_start = first_call;
+	skip = !first_call;
+
+	/* XXX: we should assert that a snapshot is pushed or registered */
+	Assert(TransactionIdIsValid(RecentXmin));
+	Assert(BufferGetBlockNumber(buffer) == blkno);
+
+	/* Scan through possible multiple members of HOT-chain */
+	for (;;)
+	{
+		ItemId		lp;
+
+		/* check for bogus TID */
+		if (offnum < FirstOffsetNumber || offnum > PageGetMaxOffsetNumber(page))
+			break;
+
+		lp = PageGetItemId(page, offnum);
+
+		/* check for unused, dead, or redirected items */
+		if (!ItemIdIsNormal(lp))
+		{
+			/* We should only see a redirect at start of chain */
+			if (ItemIdIsRedirected(lp) && at_chain_start)
+			{
+				/* Follow the redirect */
+				offnum = ItemIdGetRedirect(lp);
+				at_chain_start = false;
+				continue;
+			}
+			/* else must be end of chain */
+			break;
+		}
+
+		/*
+		 * Update heapTuple to point to the element of the HOT chain we're
+		 * currently investigating. Having t_self set correctly is important
+		 * because the SSI checks and the *Satisfies routine for historical
+		 * MVCC snapshots need the correct tid to decide about the visibility.
+		 */
+		heapTuple->t_data = (HeapTupleHeader) PageGetItem(page, lp);
+		heapTuple->t_len = ItemIdGetLength(lp);
+		heapTuple->t_tableOid = RelationGetRelid(relation);
+		ItemPointerSet(&heapTuple->t_self, blkno, offnum);
+
+		/*
+		 * Shouldn't see a HEAP_ONLY tuple at chain start.
+		 */
+		if (at_chain_start && HeapTupleIsHeapOnly(heapTuple))
+			break;
+
+		/*
+		 * The xmin should match the previous xmax value, else chain is
+		 * broken.
+		 */
+		if (TransactionIdIsValid(prev_xmax) &&
+			!TransactionIdEquals(prev_xmax,
+								 HeapTupleHeaderGetXmin(heapTuple->t_data)))
+			break;
+
+		/*
+		 * When first_call is true (and thus, skip is initially false) we'll
+		 * return the first tuple we find.  But on later passes, heapTuple
+		 * will initially be pointing to the tuple we returned last time.
+		 * Returning it again would be incorrect (and would loop forever), so
+		 * we skip it and return the next match we find.
+		 */
+		if (!skip)
+		{
+			/* If it's visible per the snapshot, we must return it */
+			valid = HeapTupleSatisfiesVisibility(heapTuple, snapshot, buffer);
+			HeapCheckForSerializableConflictOut(valid, relation, heapTuple,
+												buffer, snapshot);
+
+			if (valid)
+			{
+				ItemPointerSetOffsetNumber(tid, offnum);
+				PredicateLockTID(relation, &heapTuple->t_self, snapshot,
+								 HeapTupleHeaderGetXmin(heapTuple->t_data));
+				if (all_dead)
+					*all_dead = false;
+				return true;
+			}
+		}
+		skip = false;
+
+		/*
+		 * If we can't see it, maybe no one else can either.  At caller
+		 * request, check whether all chain members are dead to all
+		 * transactions.
+		 *
+		 * Note: if you change the criterion here for what is "dead", fix the
+		 * planner's get_actual_variable_range() function to match.
+		 */
+		if (all_dead && *all_dead)
+		{
+			if (!vistest)
+				vistest = GlobalVisTestFor(relation);
+
+			if (!HeapTupleIsSurelyDead(heapTuple, vistest))
+				*all_dead = false;
+		}
+
+		/*
+		 * Check to see if HOT chain continues past this tuple; if so fetch
+		 * the next offnum and loop around.
+		 */
+		if (HeapTupleIsHotUpdated(heapTuple))
+		{
+			Assert(ItemPointerGetBlockNumber(&heapTuple->t_data->t_ctid) ==
+				   blkno);
+			offnum = ItemPointerGetOffsetNumber(&heapTuple->t_data->t_ctid);
+			at_chain_start = false;
+			prev_xmax = HeapTupleHeaderGetUpdateXid(heapTuple->t_data);
+		}
+		else
+			break;				/* end of chain */
+
+	}
+
+	return false;
+}
+
+bool
+heapam_index_fetch_tuple(struct IndexFetchTableData *scan,
+						 ItemPointer tid,
+						 Snapshot snapshot,
+						 TupleTableSlot *slot,
+						 bool *heap_continue, bool *all_dead)
+{
+	IndexFetchHeapData *hscan = (IndexFetchHeapData *) scan;
+	BufferHeapTupleTableSlot *bslot = (BufferHeapTupleTableSlot *) slot;
+	bool		got_heap_tuple;
+
+	Assert(TTS_IS_BUFFERTUPLE(slot));
+
+	/* We can skip the buffer-switching logic if we're in mid-HOT chain. */
+	if (!*heap_continue)
+	{
+		/* Switch to correct buffer if we don't have it already */
+		Buffer		prev_buf = hscan->xs_cbuf;
+
+		hscan->xs_cbuf = ReleaseAndReadBuffer(hscan->xs_cbuf,
+											  hscan->xs_base.rel,
+											  ItemPointerGetBlockNumber(tid));
+
+		/*
+		 * Prune page, but only if we weren't already on this page
+		 */
+		if (prev_buf != hscan->xs_cbuf)
+			heap_page_prune_opt(hscan->xs_base.rel, hscan->xs_cbuf,
+								&hscan->xs_vmbuffer,
+								hscan->xs_base.flags & SO_HINT_REL_READ_ONLY);
+	}
+
+	/* Obtain share-lock on the buffer so we can examine visibility */
+	LockBuffer(hscan->xs_cbuf, BUFFER_LOCK_SHARE);
+	got_heap_tuple = heap_hot_search_buffer(tid,
+											hscan->xs_base.rel,
+											hscan->xs_cbuf,
+											snapshot,
+											&bslot->base.tupdata,
+											all_dead,
+											!*heap_continue);
+	bslot->base.tupdata.t_self = *tid;
+	LockBuffer(hscan->xs_cbuf, BUFFER_LOCK_UNLOCK);
+
+	if (got_heap_tuple)
+	{
+		/*
+		 * Only in a non-MVCC snapshot can more than one member of the HOT
+		 * chain be visible.
+		 */
+		*heap_continue = !IsMVCCLikeSnapshot(snapshot);
+
+		slot->tts_tableOid = RelationGetRelid(scan->rel);
+		ExecStoreBufferHeapTuple(&bslot->base.tupdata, slot, hscan->xs_cbuf);
+	}
+	else
+	{
+		/* We've reached the end of the HOT chain. */
+		*heap_continue = false;
+	}
+
+	return got_heap_tuple;
+}
diff --git a/src/backend/access/heap/meson.build b/src/backend/access/heap/meson.build
index 92ab8be3d..00ec07d7f 100644
--- a/src/backend/access/heap/meson.build
+++ b/src/backend/access/heap/meson.build
@@ -3,6 +3,7 @@
 backend_sources += files(
   'heapam.c',
   'heapam_handler.c',
+  'heapam_indexscan.c',
   'heapam_visibility.c',
   'heapam_xlog.c',
   'heaptoast.c',
-- 
2.53.0