Remove some more "snapshot too old" vestiges.

Commit f691f5b8 removed the logic, but left behind some now-useless
Snapshot arguments to various AM-internal functions, and missed a couple
of comments.

Reported-by: Peter Geoghegan <pg@bowt.ie>
Discussion: https://postgr.es/m/CAH2-Wznj9qSNXZ1P1uWTUD_FeaTezbUazb416EPwi4Qr_jR_6A%40mail.gmail.com

16 files changed, 56 insertions, 85 deletions

diff --git a/contrib/amcheck/verify_nbtree.c b/contrib/amcheck/verify_nbtree.c
index 94a9759322e..dbb83d80f81 100644
--- a/contrib/amcheck/verify_nbtree.c
+++ b/contrib/amcheck/verify_nbtree.c
@@ -2694,7 +2694,7 @@ bt_rootdescend(BtreeCheckState *state, IndexTuple itup)
 	 */
 	Assert(state->readonly && state->rootdescend);
 	exists = false;
-	stack = _bt_search(state->rel, NULL, key, &lbuf, BT_READ, NULL);
+	stack = _bt_search(state->rel, NULL, key, &lbuf, BT_READ);
 
 	if (BufferIsValid(lbuf))
 	{
diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index d4fec654bb6..a7538f32c2e 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -169,7 +169,7 @@ brininsert(Relation idxRel, Datum *values, bool *nulls,
 	MemoryContext oldcxt = CurrentMemoryContext;
 	bool		autosummarize = BrinGetAutoSummarize(idxRel);
 
-	revmap = brinRevmapInitialize(idxRel, &pagesPerRange, NULL);
+	revmap = brinRevmapInitialize(idxRel, &pagesPerRange);
 
 	/*
 	 * origHeapBlk is the block number where the insertion occurred.  heapBlk
@@ -202,7 +202,7 @@ brininsert(Relation idxRel, Datum *values, bool *nulls,
 
 			lastPageTuple =
 				brinGetTupleForHeapBlock(revmap, lastPageRange, &buf, &off,
-										 NULL, BUFFER_LOCK_SHARE, NULL);
+										 NULL, BUFFER_LOCK_SHARE);
 			if (!lastPageTuple)
 			{
 				bool		recorded;
@@ -222,7 +222,7 @@ brininsert(Relation idxRel, Datum *values, bool *nulls,
 		}
 
 		brtup = brinGetTupleForHeapBlock(revmap, heapBlk, &buf, &off,
-										 NULL, BUFFER_LOCK_SHARE, NULL);
+										 NULL, BUFFER_LOCK_SHARE);
 
 		/* if range is unsummarized, there's nothing to do */
 		if (!brtup)
@@ -332,8 +332,7 @@ brinbeginscan(Relation r, int nkeys, int norderbys)
 	scan = RelationGetIndexScan(r, nkeys, norderbys);
 
 	opaque = palloc_object(BrinOpaque);
-	opaque->bo_rmAccess = brinRevmapInitialize(r, &opaque->bo_pagesPerRange,
-											   scan->xs_snapshot);
+	opaque->bo_rmAccess = brinRevmapInitialize(r, &opaque->bo_pagesPerRange);
 	opaque->bo_bdesc = brin_build_desc(r);
 	scan->opaque = opaque;
 
@@ -537,8 +536,7 @@ bringetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
 		MemoryContextResetAndDeleteChildren(perRangeCxt);
 
 		tup = brinGetTupleForHeapBlock(opaque->bo_rmAccess, heapBlk, &buf,
-									   &off, &size, BUFFER_LOCK_SHARE,
-									   scan->xs_snapshot);
+									   &off, &size, BUFFER_LOCK_SHARE);
 		if (tup)
 		{
 			gottuple = true;
@@ -880,7 +878,7 @@ brinbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 	/*
 	 * Initialize our state, including the deformed tuple state.
 	 */
-	revmap = brinRevmapInitialize(index, &pagesPerRange, NULL);
+	revmap = brinRevmapInitialize(index, &pagesPerRange);
 	state = initialize_brin_buildstate(index, revmap, pagesPerRange);
 
 	/*
@@ -1458,8 +1456,7 @@ summarize_range(IndexInfo *indexInfo, BrinBuildState *state, Relation heapRel,
 		 * the same.)
 		 */
 		phtup = brinGetTupleForHeapBlock(state->bs_rmAccess, heapBlk, &phbuf,
-										 &offset, &phsz, BUFFER_LOCK_SHARE,
-										 NULL);
+										 &offset, &phsz, BUFFER_LOCK_SHARE);
 		/* the placeholder tuple must exist */
 		if (phtup == NULL)
 			elog(ERROR, "missing placeholder tuple");
@@ -1496,7 +1493,7 @@ brinsummarize(Relation index, Relation heapRel, BlockNumber pageRange,
 	Buffer		buf;
 	BlockNumber startBlk;
 
-	revmap = brinRevmapInitialize(index, &pagesPerRange, NULL);
+	revmap = brinRevmapInitialize(index, &pagesPerRange);
 
 	/* determine range of pages to process */
 	heapNumBlocks = RelationGetNumberOfBlocks(heapRel);
@@ -1537,7 +1534,7 @@ brinsummarize(Relation index, Relation heapRel, BlockNumber pageRange,
 		CHECK_FOR_INTERRUPTS();
 
 		tup = brinGetTupleForHeapBlock(revmap, startBlk, &buf, &off, NULL,
-									   BUFFER_LOCK_SHARE, NULL);
+									   BUFFER_LOCK_SHARE);
 		if (tup == NULL)
 		{
 			/* no revmap entry for this heap range. Summarize it. */
diff --git a/src/backend/access/brin/brin_revmap.c b/src/backend/access/brin/brin_revmap.c
index 956dd927656..fcea10ccdb4 100644
--- a/src/backend/access/brin/brin_revmap.c
+++ b/src/backend/access/brin/brin_revmap.c
@@ -68,8 +68,7 @@ static void revmap_physical_extend(BrinRevmap *revmap);
  * brinRevmapTerminate when caller is done with it.
  */
 BrinRevmap *
-brinRevmapInitialize(Relation idxrel, BlockNumber *pagesPerRange,
-					 Snapshot snapshot)
+brinRevmapInitialize(Relation idxrel, BlockNumber *pagesPerRange)
 {
 	BrinRevmap *revmap;
 	Buffer		meta;
@@ -194,8 +193,7 @@ brinSetHeapBlockItemptr(Buffer buf, BlockNumber pagesPerRange,
  */
 BrinTuple *
 brinGetTupleForHeapBlock(BrinRevmap *revmap, BlockNumber heapBlk,
-						 Buffer *buf, OffsetNumber *off, Size *size, int mode,
-						 Snapshot snapshot)
+						 Buffer *buf, OffsetNumber *off, Size *size, int mode)
 {
 	Relation	idxRel = revmap->rm_irel;
 	BlockNumber mapBlk;
@@ -339,7 +337,7 @@ brinRevmapDesummarizeRange(Relation idxrel, BlockNumber heapBlk)
 	OffsetNumber regOffset;
 	ItemId		lp;
 
-	revmap = brinRevmapInitialize(idxrel, &pagesPerRange, NULL);
+	revmap = brinRevmapInitialize(idxrel, &pagesPerRange);
 
 	revmapBlk = revmap_get_blkno(revmap, heapBlk);
 	if (!BlockNumberIsValid(revmapBlk))
diff --git a/src/backend/access/common/toast_internals.c b/src/backend/access/common/toast_internals.c
index 588825ed85d..371515395a5 100644
--- a/src/backend/access/common/toast_internals.c
+++ b/src/backend/access/common/toast_internals.c
@@ -636,8 +636,7 @@ toast_close_indexes(Relation *toastidxs, int num_indexes, LOCKMODE lock)
  *
  *	Initialize an appropriate TOAST snapshot.  We must use an MVCC snapshot
  *	to initialize the TOAST snapshot; since we don't know which one to use,
- *	just use the oldest one.  This is safe: at worst, we will get a "snapshot
- *	too old" error that might have been avoided otherwise.
+ *	just use the oldest one.
  */
 void
 init_toast_snapshot(Snapshot toast_snapshot)
diff --git a/src/backend/access/gin/ginbtree.c b/src/backend/access/gin/ginbtree.c
index 7d097c75e05..06e97a7fbb8 100644
--- a/src/backend/access/gin/ginbtree.c
+++ b/src/backend/access/gin/ginbtree.c
@@ -78,7 +78,7 @@ ginTraverseLock(Buffer buffer, bool searchMode)
  */
 GinBtreeStack *
 ginFindLeafPage(GinBtree btree, bool searchMode,
-				bool rootConflictCheck, Snapshot snapshot)
+				bool rootConflictCheck)
 {
 	GinBtreeStack *stack;
 
diff --git a/src/backend/access/gin/gindatapage.c b/src/backend/access/gin/gindatapage.c
index 9caeac164a9..344e1c5e6bd 100644
--- a/src/backend/access/gin/gindatapage.c
+++ b/src/backend/access/gin/gindatapage.c
@@ -1917,7 +1917,7 @@ ginInsertItemPointers(Relation index, BlockNumber rootBlkno,
 	{
 		/* search for the leaf page where the first item should go to */
 		btree.itemptr = insertdata.items[insertdata.curitem];
-		stack = ginFindLeafPage(&btree, false, true, NULL);
+		stack = ginFindLeafPage(&btree, false, true);
 
 		ginInsertValue(&btree, stack, &insertdata, buildStats);
 	}
@@ -1927,8 +1927,7 @@ ginInsertItemPointers(Relation index, BlockNumber rootBlkno,
  * Starts a new scan on a posting tree.
  */
 GinBtreeStack *
-ginScanBeginPostingTree(GinBtree btree, Relation index, BlockNumber rootBlkno,
-						Snapshot snapshot)
+ginScanBeginPostingTree(GinBtree btree, Relation index, BlockNumber rootBlkno)
 {
 	GinBtreeStack *stack;
 
@@ -1936,7 +1935,7 @@ ginScanBeginPostingTree(GinBtree btree, Relation index, BlockNumber rootBlkno,
 
 	btree->fullScan = true;
 
-	stack = ginFindLeafPage(btree, true, false, snapshot);
+	stack = ginFindLeafPage(btree, true, false);
 
 	return stack;
 }
diff --git a/src/backend/access/gin/ginget.c b/src/backend/access/gin/ginget.c
index 10d2bb89008..88d8d0c04b1 100644
--- a/src/backend/access/gin/ginget.c
+++ b/src/backend/access/gin/ginget.c
@@ -67,7 +67,7 @@ moveRightIfItNeeded(GinBtreeData *btree, GinBtreeStack *stack, Snapshot snapshot
  */
 static void
 scanPostingTree(Relation index, GinScanEntry scanEntry,
-				BlockNumber rootPostingTree, Snapshot snapshot)
+				BlockNumber rootPostingTree)
 {
 	GinBtreeData btree;
 	GinBtreeStack *stack;
@@ -75,7 +75,7 @@ scanPostingTree(Relation index, GinScanEntry scanEntry,
 	Page		page;
 
 	/* Descend to the leftmost leaf page */
-	stack = ginScanBeginPostingTree(&btree, index, rootPostingTree, snapshot);
+	stack = ginScanBeginPostingTree(&btree, index, rootPostingTree);
 	buffer = stack->buffer;
 
 	IncrBufferRefCount(buffer); /* prevent unpin in freeGinBtreeStack */
@@ -244,8 +244,7 @@ collectMatchBitmap(GinBtreeData *btree, GinBtreeStack *stack,
 			PredicateLockPage(btree->index, rootPostingTree, snapshot);
 
 			/* Collect all the TIDs in this entry's posting tree */
-			scanPostingTree(btree->index, scanEntry, rootPostingTree,
-							snapshot);
+			scanPostingTree(btree->index, scanEntry, rootPostingTree);
 
 			/*
 			 * We lock again the entry page and while it was unlocked insert
@@ -344,7 +343,7 @@ restartScanEntry:
 	ginPrepareEntryScan(&btreeEntry, entry->attnum,
 						entry->queryKey, entry->queryCategory,
 						ginstate);
-	stackEntry = ginFindLeafPage(&btreeEntry, true, false, snapshot);
+	stackEntry = ginFindLeafPage(&btreeEntry, true, false);
 	page = BufferGetPage(stackEntry->buffer);
 
 	/* ginFindLeafPage() will have already checked snapshot age. */
@@ -419,7 +418,7 @@ restartScanEntry:
 			needUnlock = false;
 
 			stack = ginScanBeginPostingTree(&entry->btree, ginstate->index,
-											rootPostingTree, snapshot);
+											rootPostingTree);
 			entry->buffer = stack->buffer;
 
 			/*
@@ -652,7 +651,7 @@ startScan(IndexScanDesc scan)
  */
 static void
 entryLoadMoreItems(GinState *ginstate, GinScanEntry entry,
-				   ItemPointerData advancePast, Snapshot snapshot)
+				   ItemPointerData advancePast)
 {
 	Page		page;
 	int			i;
@@ -697,7 +696,7 @@ entryLoadMoreItems(GinState *ginstate, GinScanEntry entry,
 						   OffsetNumberNext(GinItemPointerGetOffsetNumber(&advancePast)));
 		}
 		entry->btree.fullScan = false;
-		stack = ginFindLeafPage(&entry->btree, true, false, snapshot);
+		stack = ginFindLeafPage(&entry->btree, true, false);
 
 		/* we don't need the stack, just the buffer. */
 		entry->buffer = stack->buffer;
@@ -807,7 +806,7 @@ entryLoadMoreItems(GinState *ginstate, GinScanEntry entry,
  */
 static void
 entryGetItem(GinState *ginstate, GinScanEntry entry,
-			 ItemPointerData advancePast, Snapshot snapshot)
+			 ItemPointerData advancePast)
 {
 	Assert(!entry->isFinished);
 
@@ -938,7 +937,7 @@ entryGetItem(GinState *ginstate, GinScanEntry entry,
 			/* If we've processed the current batch, load more items */
 			while (entry->offset >= entry->nlist)
 			{
-				entryLoadMoreItems(ginstate, entry, advancePast, snapshot);
+				entryLoadMoreItems(ginstate, entry, advancePast);
 
 				if (entry->isFinished)
 				{
@@ -989,7 +988,7 @@ entryGetItem(GinState *ginstate, GinScanEntry entry,
  */
 static void
 keyGetItem(GinState *ginstate, MemoryContext tempCtx, GinScanKey key,
-		   ItemPointerData advancePast, Snapshot snapshot)
+		   ItemPointerData advancePast)
 {
 	ItemPointerData minItem;
 	ItemPointerData curPageLossy;
@@ -1036,7 +1035,7 @@ keyGetItem(GinState *ginstate, MemoryContext tempCtx, GinScanKey key,
 		 */
 		if (ginCompareItemPointers(&entry->curItem, &advancePast) <= 0)
 		{
-			entryGetItem(ginstate, entry, advancePast, snapshot);
+			entryGetItem(ginstate, entry, advancePast);
 			if (entry->isFinished)
 				continue;
 		}
@@ -1111,7 +1110,7 @@ keyGetItem(GinState *ginstate, MemoryContext tempCtx, GinScanKey key,
 
 		if (ginCompareItemPointers(&entry->curItem, &advancePast) <= 0)
 		{
-			entryGetItem(ginstate, entry, advancePast, snapshot);
+			entryGetItem(ginstate, entry, advancePast);
 			if (entry->isFinished)
 				continue;
 		}
@@ -1334,8 +1333,7 @@ scanGetItem(IndexScanDesc scan, ItemPointerData advancePast,
 			}
 
 			/* Fetch the next item for this key that is > advancePast. */
-			keyGetItem(&so->ginstate, so->tempCtx, key, advancePast,
-					   scan->xs_snapshot);
+			keyGetItem(&so->ginstate, so->tempCtx, key, advancePast);
 
 			if (key->isFinished)
 				return false;
diff --git a/src/backend/access/gin/gininsert.c b/src/backend/access/gin/gininsert.c
index 56968b95acf..b4d216d4c6a 100644
--- a/src/backend/access/gin/gininsert.c
+++ b/src/backend/access/gin/gininsert.c
@@ -192,7 +192,7 @@ ginEntryInsert(GinState *ginstate,
 	ginPrepareEntryScan(&btree, attnum, key, category, ginstate);
 	btree.isBuild = (buildStats != NULL);
 
-	stack = ginFindLeafPage(&btree, false, false, NULL);
+	stack = ginFindLeafPage(&btree, false, false);
 	page = BufferGetPage(stack->buffer);
 
 	if (btree.findItem(&btree, stack))
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index 1a05adfa61c..b3c24d68f02 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -2865,10 +2865,6 @@ lazy_cleanup_one_index(Relation indrel, IndexBulkDeleteResult *istat,
  * in effect in any case.  lazy_scan_prune makes the optimistic assumption
  * that any LP_DEAD items it encounters will always be LP_UNUSED by the time
  * we're called.
- *
- * Also don't attempt it if we are doing early pruning/vacuuming, because a
- * scan which cannot find a truncated heap page cannot determine that the
- * snapshot is too old to read that page.
  */
 static bool
 should_attempt_truncation(LVRelState *vacrel)
diff --git a/src/backend/access/nbtree/nbtinsert.c b/src/backend/access/nbtree/nbtinsert.c
index d33f814a938..9cff4f29313 100644
--- a/src/backend/access/nbtree/nbtinsert.c
+++ b/src/backend/access/nbtree/nbtinsert.c
@@ -378,7 +378,7 @@ _bt_search_insert(Relation rel, Relation heaprel, BTInsertState insertstate)
 
 	/* Cannot use optimization -- descend tree, return proper descent stack */
 	return _bt_search(rel, heaprel, insertstate->itup_key, &insertstate->buf,
-					  BT_WRITE, NULL);
+					  BT_WRITE);
 }
 
 /*
@@ -2165,7 +2165,7 @@ _bt_insert_parent(Relation rel,
 					 BlockNumberIsValid(RelationGetTargetBlock(rel))));
 
 			/* Find the leftmost page at the next level up */
-			pbuf = _bt_get_endpoint(rel, opaque->btpo_level + 1, false, NULL);
+			pbuf = _bt_get_endpoint(rel, opaque->btpo_level + 1, false);
 			/* Set up a phony stack entry pointing there */
 			stack = &fakestack;
 			stack->bts_blkno = BufferGetBlockNumber(pbuf);
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index 6558aea42ba..b7660a459e2 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -1962,8 +1962,7 @@ _bt_pagedel(Relation rel, Buffer leafbuf, BTVacState *vstate)
 				itup_key = _bt_mkscankey(rel, targetkey);
 				/* find the leftmost leaf page with matching pivot/high key */
 				itup_key->pivotsearch = true;
-				stack = _bt_search(rel, NULL, itup_key, &sleafbuf, BT_READ,
-								   NULL);
+				stack = _bt_search(rel, NULL, itup_key, &sleafbuf, BT_READ);
 				/* won't need a second lock or pin on leafbuf */
 				_bt_relbuf(rel, sleafbuf);
 
diff --git a/src/backend/access/nbtree/nbtsearch.c b/src/backend/access/nbtree/nbtsearch.c
index 1799089fb45..17ad89749d5 100644
--- a/src/backend/access/nbtree/nbtsearch.c
+++ b/src/backend/access/nbtree/nbtsearch.c
@@ -43,7 +43,7 @@ static bool _bt_steppage(IndexScanDesc scan, ScanDirection dir);
 static bool _bt_readnextpage(IndexScanDesc scan, BlockNumber blkno, ScanDirection dir);
 static bool _bt_parallel_readpage(IndexScanDesc scan, BlockNumber blkno,
 								  ScanDirection dir);
-static Buffer _bt_walk_left(Relation rel, Buffer buf, Snapshot snapshot);
+static Buffer _bt_walk_left(Relation rel, Buffer buf);
 static bool _bt_endpoint(IndexScanDesc scan, ScanDirection dir);
 static inline void _bt_initialize_more_data(BTScanOpaque so, ScanDirection dir);
 
@@ -83,10 +83,6 @@ _bt_drop_lock_and_maybe_pin(IndexScanDesc scan, BTScanPos sp)
  * which is locked and pinned.  No locks are held on the parent pages,
  * however!
  *
- * If the snapshot parameter is not NULL, "old snapshot" checking will take
- * place during the descent through the tree.  This is not needed when
- * positioning for an insert or delete, so NULL is used for those cases.
- *
  * The returned buffer is locked according to access parameter.  Additionally,
  * access = BT_WRITE will allow an empty root page to be created and returned.
  * When access = BT_READ, an empty index will result in *bufP being set to
@@ -98,7 +94,7 @@ _bt_drop_lock_and_maybe_pin(IndexScanDesc scan, BTScanPos sp)
  */
 BTStack
 _bt_search(Relation rel, Relation heaprel, BTScanInsert key, Buffer *bufP,
-		   int access, Snapshot snapshot)
+		   int access)
 {
 	BTStack		stack_in = NULL;
 	int			page_access = BT_READ;
@@ -138,7 +134,7 @@ _bt_search(Relation rel, Relation heaprel, BTScanInsert key, Buffer *bufP,
 		 * opportunity to finish splits of internal pages too.
 		 */
 		*bufP = _bt_moveright(rel, heaprel, key, *bufP, (access == BT_WRITE),
-							  stack_in, page_access, snapshot);
+							  stack_in, page_access);
 
 		/* if this is a leaf page, we're done */
 		page = BufferGetPage(*bufP);
@@ -198,8 +194,7 @@ _bt_search(Relation rel, Relation heaprel, BTScanInsert key, Buffer *bufP,
 		 * but before we acquired a write lock.  If it has, we may need to
 		 * move right to its new sibling.  Do that.
 		 */
-		*bufP = _bt_moveright(rel, heaprel, key, *bufP, true, stack_in, BT_WRITE,
-							  snapshot);
+		*bufP = _bt_moveright(rel, heaprel, key, *bufP, true, stack_in, BT_WRITE);
 	}
 
 	return stack_in;
@@ -235,10 +230,6 @@ _bt_search(Relation rel, Relation heaprel, BTScanInsert key, Buffer *bufP,
  * On entry, we have the buffer pinned and a lock of the type specified by
  * 'access'.  If we move right, we release the buffer and lock and acquire
  * the same on the right sibling.  Return value is the buffer we stop at.
- *
- * If the snapshot parameter is not NULL, "old snapshot" checking will take
- * place during the descent through the tree.  This is not needed when
- * positioning for an insert or delete, so NULL is used for those cases.
  */
 Buffer
 _bt_moveright(Relation rel,
@@ -247,8 +238,7 @@ _bt_moveright(Relation rel,
 			  Buffer buf,
 			  bool forupdate,
 			  BTStack stack,
-			  int access,
-			  Snapshot snapshot)
+			  int access)
 {
 	Page		page;
 	BTPageOpaque opaque;
@@ -1373,7 +1363,7 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
 	 * Use the manufactured insertion scan key to descend the tree and
 	 * position ourselves on the target leaf page.
 	 */
-	stack = _bt_search(rel, NULL, &inskey, &buf, BT_READ, scan->xs_snapshot);
+	stack = _bt_search(rel, NULL, &inskey, &buf, BT_READ);
 
 	/* don't need to keep the stack around... */
 	_bt_freestack(stack);
@@ -1392,8 +1382,7 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
 		if (IsolationIsSerializable())
 		{
 			PredicateLockRelation(rel, scan->xs_snapshot);
-			stack = _bt_search(rel, NULL, &inskey, &buf, BT_READ,
-							   scan->xs_snapshot);
+			stack = _bt_search(rel, NULL, &inskey, &buf, BT_READ);
 			_bt_freestack(stack);
 		}
 
@@ -2113,8 +2102,7 @@ _bt_readnextpage(IndexScanDesc scan, BlockNumber blkno, ScanDirection dir)
 			}
 
 			/* Step to next physical page */
-			so->currPos.buf = _bt_walk_left(rel, so->currPos.buf,
-											scan->xs_snapshot);
+			so->currPos.buf = _bt_walk_left(rel, so->currPos.buf);
 
 			/* if we're physically at end of index, return failure */
 			if (so->currPos.buf == InvalidBuffer)
@@ -2205,7 +2193,7 @@ _bt_parallel_readpage(IndexScanDesc scan, BlockNumber blkno, ScanDirection dir)
  * again if it's important.
  */
 static Buffer
-_bt_walk_left(Relation rel, Buffer buf, Snapshot snapshot)
+_bt_walk_left(Relation rel, Buffer buf)
 {
 	Page		page;
 	BTPageOpaque opaque;
@@ -2320,8 +2308,7 @@ _bt_walk_left(Relation rel, Buffer buf, Snapshot snapshot)
  * The returned buffer is pinned and read-locked.
  */
 Buffer
-_bt_get_endpoint(Relation rel, uint32 level, bool rightmost,
-				 Snapshot snapshot)
+_bt_get_endpoint(Relation rel, uint32 level, bool rightmost)
 {
 	Buffer		buf;
 	Page		page;
@@ -2417,7 +2404,7 @@ _bt_endpoint(IndexScanDesc scan, ScanDirection dir)
 	 * version of _bt_search().  We don't maintain a stack since we know we
 	 * won't need it.
 	 */
-	buf = _bt_get_endpoint(rel, 0, ScanDirectionIsBackward(dir), scan->xs_snapshot);
+	buf = _bt_get_endpoint(rel, 0, ScanDirectionIsBackward(dir));
 
 	if (!BufferIsValid(buf))
 	{
diff --git a/src/backend/access/spgist/spgscan.c b/src/backend/access/spgist/spgscan.c
index 17cab0087fe..8c00b724db2 100644
--- a/src/backend/access/spgist/spgscan.c
+++ b/src/backend/access/spgist/spgscan.c
@@ -815,7 +815,7 @@ spgTestLeafTuple(SpGistScanOpaque so,
  */
 static void
 spgWalk(Relation index, SpGistScanOpaque so, bool scanWholeIndex,
-		storeRes_func storeRes, Snapshot snapshot)
+		storeRes_func storeRes)
 {
 	Buffer		buffer = InvalidBuffer;
 	bool		reportedSome = false;
@@ -949,7 +949,7 @@ spggetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
 	so->tbm = tbm;
 	so->ntids = 0;
 
-	spgWalk(scan->indexRelation, so, true, storeBitmap, scan->xs_snapshot);
+	spgWalk(scan->indexRelation, so, true, storeBitmap);
 
 	return so->ntids;
 }
@@ -1070,8 +1070,7 @@ spggettuple(IndexScanDesc scan, ScanDirection dir)
 		}
 		so->iPtr = so->nPtrs = 0;
 
-		spgWalk(scan->indexRelation, so, false, storeGettuple,
-				scan->xs_snapshot);
+		spgWalk(scan->indexRelation, so, false, storeGettuple);
 
 		if (so->nPtrs == 0)
 			break;				/* must have completed scan */
diff --git a/src/include/access/brin_revmap.h b/src/include/access/brin_revmap.h
index 75323630e07..79726051a4a 100644
--- a/src/include/access/brin_revmap.h
+++ b/src/include/access/brin_revmap.h
@@ -24,7 +24,7 @@
 typedef struct BrinRevmap BrinRevmap;
 
 extern BrinRevmap *brinRevmapInitialize(Relation idxrel,
-										BlockNumber *pagesPerRange, Snapshot snapshot);
+										BlockNumber *pagesPerRange);
 extern void brinRevmapTerminate(BrinRevmap *revmap);
 
 extern void brinRevmapExtend(BrinRevmap *revmap,
@@ -35,7 +35,7 @@ extern void brinSetHeapBlockItemptr(Buffer buf, BlockNumber pagesPerRange,
 									BlockNumber heapBlk, ItemPointerData tid);
 extern BrinTuple *brinGetTupleForHeapBlock(BrinRevmap *revmap,
 										   BlockNumber heapBlk, Buffer *buf, OffsetNumber *off,
-										   Size *size, int mode, Snapshot snapshot);
+										   Size *size, int mode);
 extern bool brinRevmapDesummarizeRange(Relation idxrel, BlockNumber heapBlk);
 
 #endif							/* BRIN_REVMAP_H */
diff --git a/src/include/access/gin_private.h b/src/include/access/gin_private.h
index 6da64928b66..76b99232015 100644
--- a/src/include/access/gin_private.h
+++ b/src/include/access/gin_private.h
@@ -202,7 +202,7 @@ typedef struct
  */
 
 extern GinBtreeStack *ginFindLeafPage(GinBtree btree, bool searchMode,
-									  bool rootConflictCheck, Snapshot snapshot);
+									  bool rootConflictCheck);
 extern Buffer ginStepRight(Buffer buffer, Relation index, int lockmode);
 extern void freeGinBtreeStack(GinBtreeStack *stack);
 extern void ginInsertValue(GinBtree btree, GinBtreeStack *stack,
@@ -230,7 +230,7 @@ extern void GinPageDeletePostingItem(Page page, OffsetNumber offset);
 extern void ginInsertItemPointers(Relation index, BlockNumber rootBlkno,
 								  ItemPointerData *items, uint32 nitem,
 								  GinStatsData *buildStats);
-extern GinBtreeStack *ginScanBeginPostingTree(GinBtree btree, Relation index, BlockNumber rootBlkno, Snapshot snapshot);
+extern GinBtreeStack *ginScanBeginPostingTree(GinBtree btree, Relation index, BlockNumber rootBlkno);
 extern void ginDataFillRoot(GinBtree btree, Page root, BlockNumber lblkno, Page lpage, BlockNumber rblkno, Page rpage);
 
 /*
diff --git a/src/include/access/nbtree.h b/src/include/access/nbtree.h
index 8891fa79734..f5c66964ca0 100644
--- a/src/include/access/nbtree.h
+++ b/src/include/access/nbtree.h
@@ -1231,16 +1231,15 @@ extern void _bt_pendingfsm_finalize(Relation rel, BTVacState *vstate);
  * prototypes for functions in nbtsearch.c
  */
 extern BTStack _bt_search(Relation rel, Relation heaprel, BTScanInsert key,
-						  Buffer *bufP, int access, Snapshot snapshot);
+						  Buffer *bufP, int access);
 extern Buffer _bt_moveright(Relation rel, Relation heaprel, BTScanInsert key,
 							Buffer buf, bool forupdate, BTStack stack,
-							int access, Snapshot snapshot);
+							int access);
 extern OffsetNumber _bt_binsrch_insert(Relation rel, BTInsertState insertstate);
 extern int32 _bt_compare(Relation rel, BTScanInsert key, Page page, OffsetNumber offnum);
 extern bool _bt_first(IndexScanDesc scan, ScanDirection dir);
 extern bool _bt_next(IndexScanDesc scan, ScanDirection dir);
-extern Buffer _bt_get_endpoint(Relation rel, uint32 level, bool rightmost,
-							   Snapshot snapshot);
+extern Buffer _bt_get_endpoint(Relation rel, uint32 level, bool rightmost);
 
 /*
  * prototypes for functions in nbtutils.c