Modify BufferGetPage() to prepare for "snapshot too old" feature

This patch is a no-op patch which is intended to reduce the chances
of failures of omission once the functional part of the "snapshot
too old" patch goes in.  It adds parameters for snapshot, relation,
and an enum to specify whether the snapshot age check needs to be
done for the page at this point.  This initial patch passes NULL
for the first two new parameters and BGP_NO_SNAPSHOT_TEST for the
third.  The follow-on patch will change the places where the test
needs to be made.

1 files changed, 62 insertions, 46 deletions

diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 34ba385748f..66b23540fe2 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -394,7 +394,7 @@ heapgetpage(HeapScanDesc scan, BlockNumber page)
 	 */
 	LockBuffer(buffer, BUFFER_LOCK_SHARE);
 
-	dp = (Page) BufferGetPage(buffer);
+	dp = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 	lines = PageGetMaxOffsetNumber(dp);
 	ntup = 0;
 
@@ -537,7 +537,7 @@ heapgettup(HeapScanDesc scan,
 
 		LockBuffer(scan->rs_cbuf, BUFFER_LOCK_SHARE);
 
-		dp = (Page) BufferGetPage(scan->rs_cbuf);
+		dp = BufferGetPage(scan->rs_cbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 		lines = PageGetMaxOffsetNumber(dp);
 		/* page and lineoff now reference the physically next tid */
 
@@ -582,7 +582,7 @@ heapgettup(HeapScanDesc scan,
 
 		LockBuffer(scan->rs_cbuf, BUFFER_LOCK_SHARE);
 
-		dp = (Page) BufferGetPage(scan->rs_cbuf);
+		dp = BufferGetPage(scan->rs_cbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 		lines = PageGetMaxOffsetNumber(dp);
 
 		if (!scan->rs_inited)
@@ -616,7 +616,7 @@ heapgettup(HeapScanDesc scan,
 			heapgetpage(scan, page);
 
 		/* Since the tuple was previously fetched, needn't lock page here */
-		dp = (Page) BufferGetPage(scan->rs_cbuf);
+		dp = BufferGetPage(scan->rs_cbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 		lineoff = ItemPointerGetOffsetNumber(&(tuple->t_self));
 		lpp = PageGetItemId(dp, lineoff);
 		Assert(ItemIdIsNormal(lpp));
@@ -745,7 +745,7 @@ heapgettup(HeapScanDesc scan,
 
 		LockBuffer(scan->rs_cbuf, BUFFER_LOCK_SHARE);
 
-		dp = (Page) BufferGetPage(scan->rs_cbuf);
+		dp = BufferGetPage(scan->rs_cbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 		lines = PageGetMaxOffsetNumber((Page) dp);
 		linesleft = lines;
 		if (backward)
@@ -832,7 +832,7 @@ heapgettup_pagemode(HeapScanDesc scan,
 			lineindex = scan->rs_cindex + 1;
 		}
 
-		dp = (Page) BufferGetPage(scan->rs_cbuf);
+		dp = BufferGetPage(scan->rs_cbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 		lines = scan->rs_ntuples;
 		/* page and lineindex now reference the next visible tid */
 
@@ -875,7 +875,7 @@ heapgettup_pagemode(HeapScanDesc scan,
 			page = scan->rs_cblock;		/* current page */
 		}
 
-		dp = (Page) BufferGetPage(scan->rs_cbuf);
+		dp = BufferGetPage(scan->rs_cbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 		lines = scan->rs_ntuples;
 
 		if (!scan->rs_inited)
@@ -908,7 +908,7 @@ heapgettup_pagemode(HeapScanDesc scan,
 			heapgetpage(scan, page);
 
 		/* Since the tuple was previously fetched, needn't lock page here */
-		dp = (Page) BufferGetPage(scan->rs_cbuf);
+		dp = BufferGetPage(scan->rs_cbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 		lineoff = ItemPointerGetOffsetNumber(&(tuple->t_self));
 		lpp = PageGetItemId(dp, lineoff);
 		Assert(ItemIdIsNormal(lpp));
@@ -1027,7 +1027,7 @@ heapgettup_pagemode(HeapScanDesc scan,
 
 		heapgetpage(scan, page);
 
-		dp = (Page) BufferGetPage(scan->rs_cbuf);
+		dp = BufferGetPage(scan->rs_cbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 		lines = scan->rs_ntuples;
 		linesleft = lines;
 		if (backward)
@@ -1871,7 +1871,7 @@ heap_fetch(Relation relation,
 	 * Need share lock on buffer to examine tuple commit status.
 	 */
 	LockBuffer(buffer, BUFFER_LOCK_SHARE);
-	page = BufferGetPage(buffer);
+	page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 	/*
 	 * We'd better check for out-of-range offnum in case of VACUUM since the
@@ -1986,7 +1986,7 @@ heap_hot_search_buffer(ItemPointer tid, Relation relation, Buffer buffer,
 					   Snapshot snapshot, HeapTuple heapTuple,
 					   bool *all_dead, bool first_call)
 {
-	Page		dp = (Page) BufferGetPage(buffer);
+	Page		dp = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 	TransactionId prev_xmax = InvalidTransactionId;
 	OffsetNumber offnum;
 	bool		at_chain_start;
@@ -2200,7 +2200,7 @@ heap_get_latest_tid(Relation relation,
 		 */
 		buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(&ctid));
 		LockBuffer(buffer, BUFFER_LOCK_SHARE);
-		page = BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		/*
 		 * Check for bogus item number.  This is not treated as an error
@@ -2418,10 +2418,12 @@ heap_insert(Relation relation, HeapTuple tup, CommandId cid,
 	RelationPutHeapTuple(relation, buffer, heaptup,
 						 (options & HEAP_INSERT_SPECULATIVE) != 0);
 
-	if (PageIsAllVisible(BufferGetPage(buffer)))
+	if (PageIsAllVisible(BufferGetPage(buffer, NULL, NULL,
+									   BGP_NO_SNAPSHOT_TEST)))
 	{
 		all_visible_cleared = true;
-		PageClearAllVisible(BufferGetPage(buffer));
+		PageClearAllVisible(BufferGetPage(buffer, NULL, NULL,
+										  BGP_NO_SNAPSHOT_TEST));
 		visibilitymap_clear(relation,
 							ItemPointerGetBlockNumber(&(heaptup->t_self)),
 							vmbuffer);
@@ -2446,7 +2448,8 @@ heap_insert(Relation relation, HeapTuple tup, CommandId cid,
 		xl_heap_insert xlrec;
 		xl_heap_header xlhdr;
 		XLogRecPtr	recptr;
-		Page		page = BufferGetPage(buffer);
+		Page		page = BufferGetPage(buffer, NULL, NULL,
+										 BGP_NO_SNAPSHOT_TEST);
 		uint8		info = XLOG_HEAP_INSERT;
 		int			bufflags = 0;
 
@@ -2705,7 +2708,7 @@ heap_multi_insert(Relation relation, HeapTuple *tuples, int ntuples,
 		buffer = RelationGetBufferForTuple(relation, heaptuples[ndone]->t_len,
 										   InvalidBuffer, options, bistate,
 										   &vmbuffer, NULL);
-		page = BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		/* NO EREPORT(ERROR) from here till changes are logged */
 		START_CRIT_SECTION();
@@ -3019,7 +3022,7 @@ heap_delete(Relation relation, ItemPointer tid,
 
 	block = ItemPointerGetBlockNumber(tid);
 	buffer = ReadBuffer(relation, block);
-	page = BufferGetPage(buffer);
+	page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 	/*
 	 * Before locking the buffer, pin the visibility map page if it appears to
@@ -3509,7 +3512,7 @@ heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,
 
 	block = ItemPointerGetBlockNumber(otid);
 	buffer = ReadBuffer(relation, block);
-	page = BufferGetPage(buffer);
+	page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 	/*
 	 * Before locking the buffer, pin the visibility map page if it appears to
@@ -4110,17 +4113,22 @@ l2:
 	oldtup.t_data->t_ctid = heaptup->t_self;
 
 	/* clear PD_ALL_VISIBLE flags */
-	if (PageIsAllVisible(BufferGetPage(buffer)))
+	if (PageIsAllVisible(BufferGetPage(buffer, NULL, NULL,
+									   BGP_NO_SNAPSHOT_TEST)))
 	{
 		all_visible_cleared = true;
-		PageClearAllVisible(BufferGetPage(buffer));
+		PageClearAllVisible(BufferGetPage(buffer, NULL, NULL,
+										  BGP_NO_SNAPSHOT_TEST));
 		visibilitymap_clear(relation, BufferGetBlockNumber(buffer),
 							vmbuffer);
 	}
-	if (newbuf != buffer && PageIsAllVisible(BufferGetPage(newbuf)))
+	if (newbuf != buffer &&
+		PageIsAllVisible(BufferGetPage(newbuf, NULL, NULL,
+									   BGP_NO_SNAPSHOT_TEST)))
 	{
 		all_visible_cleared_new = true;
-		PageClearAllVisible(BufferGetPage(newbuf));
+		PageClearAllVisible(BufferGetPage(newbuf, NULL, NULL,
+										  BGP_NO_SNAPSHOT_TEST));
 		visibilitymap_clear(relation, BufferGetBlockNumber(newbuf),
 							vmbuffer_new);
 	}
@@ -4151,9 +4159,12 @@ l2:
 								 all_visible_cleared_new);
 		if (newbuf != buffer)
 		{
-			PageSetLSN(BufferGetPage(newbuf), recptr);
+			PageSetLSN(BufferGetPage(newbuf, NULL, NULL,
+									 BGP_NO_SNAPSHOT_TEST),
+					   recptr);
 		}
-		PageSetLSN(BufferGetPage(buffer), recptr);
+		PageSetLSN(BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST),
+				   recptr);
 	}
 
 	END_CRIT_SECTION();
@@ -4517,7 +4528,7 @@ heap_lock_tuple(Relation relation, HeapTuple tuple,
 	*buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(tid));
 	LockBuffer(*buffer, BUFFER_LOCK_EXCLUSIVE);
 
-	page = BufferGetPage(*buffer);
+	page = BufferGetPage(*buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 	lp = PageGetItemId(page, ItemPointerGetOffsetNumber(tid));
 	Assert(ItemIdIsNormal(lp));
 
@@ -5695,7 +5706,8 @@ l4:
 		{
 			xl_heap_lock_updated xlrec;
 			XLogRecPtr	recptr;
-			Page		page = BufferGetPage(buf);
+			Page		page = BufferGetPage(buf, NULL, NULL,
+											 BGP_NO_SNAPSHOT_TEST);
 
 			XLogBeginInsert();
 			XLogRegisterBuffer(0, buf, REGBUF_STANDARD);
@@ -5802,7 +5814,7 @@ heap_finish_speculative(Relation relation, HeapTuple tuple)
 
 	buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(&(tuple->t_self)));
 	LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
-	page = (Page) BufferGetPage(buffer);
+	page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 	offnum = ItemPointerGetOffsetNumber(&(tuple->t_self));
 	if (PageGetMaxOffsetNumber(page) >= offnum)
@@ -5896,7 +5908,7 @@ heap_abort_speculative(Relation relation, HeapTuple tuple)
 
 	block = ItemPointerGetBlockNumber(tid);
 	buffer = ReadBuffer(relation, block);
-	page = BufferGetPage(buffer);
+	page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 	LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
 
@@ -6043,7 +6055,7 @@ heap_inplace_update(Relation relation, HeapTuple tuple)
 
 	buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(&(tuple->t_self)));
 	LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
-	page = (Page) BufferGetPage(buffer);
+	page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 	offnum = ItemPointerGetOffsetNumber(&(tuple->t_self));
 	if (PageGetMaxOffsetNumber(page) >= offnum)
@@ -7298,7 +7310,8 @@ log_heap_update(Relation reln, Buffer oldbuf,
 	uint16		prefixlen = 0,
 				suffixlen = 0;
 	XLogRecPtr	recptr;
-	Page		page = BufferGetPage(newbuf);
+	Page		page = BufferGetPage(newbuf, NULL, NULL,
+									 BGP_NO_SNAPSHOT_TEST);
 	bool		need_tuple_data = RelationIsLogicallyLogged(reln);
 	bool		init;
 	int			bufflags;
@@ -7747,7 +7760,8 @@ heap_xlog_clean(XLogReaderState *record)
 										   &buffer);
 	if (action == BLK_NEEDS_REDO)
 	{
-		Page		page = (Page) BufferGetPage(buffer);
+		Page		page = BufferGetPage(buffer, NULL, NULL,
+										 BGP_NO_SNAPSHOT_TEST);
 		OffsetNumber *end;
 		OffsetNumber *redirected;
 		OffsetNumber *nowdead;
@@ -7853,7 +7867,7 @@ heap_xlog_visible(XLogReaderState *record)
 		 * XLOG record's LSN, we mustn't mark the page all-visible, because
 		 * the subsequent update won't be replayed to clear the flag.
 		 */
-		page = BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		PageSetAllVisible(page);
 
@@ -7879,7 +7893,8 @@ heap_xlog_visible(XLogReaderState *record)
 	if (XLogReadBufferForRedoExtended(record, 0, RBM_ZERO_ON_ERROR, false,
 									  &vmbuffer) == BLK_NEEDS_REDO)
 	{
-		Page		vmpage = BufferGetPage(vmbuffer);
+		Page		vmpage = BufferGetPage(vmbuffer, NULL, NULL,
+										   BGP_NO_SNAPSHOT_TEST);
 		Relation	reln;
 
 		/* initialize the page if it was read as zeros */
@@ -7946,7 +7961,8 @@ heap_xlog_freeze_page(XLogReaderState *record)
 
 	if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
 	{
-		Page		page = BufferGetPage(buffer);
+		Page		page = BufferGetPage(buffer, NULL, NULL,
+										 BGP_NO_SNAPSHOT_TEST);
 		xl_heap_freeze_tuple *tuples;
 
 		tuples = (xl_heap_freeze_tuple *) XLogRecGetBlockData(record, 0, NULL);
@@ -8033,7 +8049,7 @@ heap_xlog_delete(XLogReaderState *record)
 
 	if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
 	{
-		page = BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		if (PageGetMaxOffsetNumber(page) >= xlrec->offnum)
 			lp = PageGetItemId(page, xlrec->offnum);
@@ -8116,7 +8132,7 @@ heap_xlog_insert(XLogReaderState *record)
 	if (XLogRecGetInfo(record) & XLOG_HEAP_INIT_PAGE)
 	{
 		buffer = XLogInitBufferForRedo(record, 0);
-		page = BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 		PageInit(page, BufferGetPageSize(buffer), 0);
 		action = BLK_NEEDS_REDO;
 	}
@@ -8127,7 +8143,7 @@ heap_xlog_insert(XLogReaderState *record)
 		Size		datalen;
 		char	   *data;
 
-		page = BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		if (PageGetMaxOffsetNumber(page) + 1 < xlrec->offnum)
 			elog(PANIC, "invalid max offset number");
@@ -8232,7 +8248,7 @@ heap_xlog_multi_insert(XLogReaderState *record)
 	if (isinit)
 	{
 		buffer = XLogInitBufferForRedo(record, 0);
-		page = BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 		PageInit(page, BufferGetPageSize(buffer), 0);
 		action = BLK_NEEDS_REDO;
 	}
@@ -8248,7 +8264,7 @@ heap_xlog_multi_insert(XLogReaderState *record)
 		tupdata = XLogRecGetBlockData(record, 0, &len);
 		endptr = tupdata + len;
 
-		page = (Page) BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		for (i = 0; i < xlrec->ntuples; i++)
 		{
@@ -8399,7 +8415,7 @@ heap_xlog_update(XLogReaderState *record, bool hot_update)
 									  &obuffer);
 	if (oldaction == BLK_NEEDS_REDO)
 	{
-		page = BufferGetPage(obuffer);
+		page = BufferGetPage(obuffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 		offnum = xlrec->old_offnum;
 		if (PageGetMaxOffsetNumber(page) >= offnum)
 			lp = PageGetItemId(page, offnum);
@@ -8446,7 +8462,7 @@ heap_xlog_update(XLogReaderState *record, bool hot_update)
 	else if (XLogRecGetInfo(record) & XLOG_HEAP_INIT_PAGE)
 	{
 		nbuffer = XLogInitBufferForRedo(record, 0);
-		page = (Page) BufferGetPage(nbuffer);
+		page = BufferGetPage(nbuffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 		PageInit(page, BufferGetPageSize(nbuffer), 0);
 		newaction = BLK_NEEDS_REDO;
 	}
@@ -8479,7 +8495,7 @@ heap_xlog_update(XLogReaderState *record, bool hot_update)
 		recdata = XLogRecGetBlockData(record, 0, &datalen);
 		recdata_end = recdata + datalen;
 
-		page = BufferGetPage(nbuffer);
+		page = BufferGetPage(nbuffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		offnum = xlrec->new_offnum;
 		if (PageGetMaxOffsetNumber(page) + 1 < offnum)
@@ -8609,7 +8625,7 @@ heap_xlog_confirm(XLogReaderState *record)
 
 	if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
 	{
-		page = BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		offnum = xlrec->offnum;
 		if (PageGetMaxOffsetNumber(page) >= offnum)
@@ -8645,7 +8661,7 @@ heap_xlog_lock(XLogReaderState *record)
 
 	if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
 	{
-		page = (Page) BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		offnum = xlrec->offnum;
 		if (PageGetMaxOffsetNumber(page) >= offnum)
@@ -8695,7 +8711,7 @@ heap_xlog_lock_updated(XLogReaderState *record)
 
 	if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
 	{
-		page = BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		offnum = xlrec->offnum;
 		if (PageGetMaxOffsetNumber(page) >= offnum)
@@ -8734,7 +8750,7 @@ heap_xlog_inplace(XLogReaderState *record)
 	{
 		char	   *newtup = XLogRecGetBlockData(record, 0, &newlen);
 
-		page = BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		offnum = xlrec->offnum;
 		if (PageGetMaxOffsetNumber(page) >= offnum)