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, 20 insertions, 17 deletions

diff --git a/src/backend/access/nbtree/nbtxlog.c b/src/backend/access/nbtree/nbtxlog.c
index f8691bbc44a..e49aad44a93 100644
--- a/src/backend/access/nbtree/nbtxlog.c
+++ b/src/backend/access/nbtree/nbtxlog.c
@@ -89,7 +89,7 @@ _bt_restore_meta(XLogReaderState *record, uint8 block_id)
 	Assert(len == sizeof(xl_btree_metadata));
 	Assert(BufferGetBlockNumber(metabuf) == BTREE_METAPAGE);
 	xlrec = (xl_btree_metadata *) ptr;
-	metapg = BufferGetPage(metabuf);
+	metapg = BufferGetPage(metabuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 	_bt_pageinit(metapg, BufferGetPageSize(metabuf));
 
@@ -130,7 +130,8 @@ _bt_clear_incomplete_split(XLogReaderState *record, uint8 block_id)
 
 	if (XLogReadBufferForRedo(record, block_id, &buf) == BLK_NEEDS_REDO)
 	{
-		Page		page = (Page) BufferGetPage(buf);
+		Page		page = BufferGetPage(buf, NULL, NULL,
+										 BGP_NO_SNAPSHOT_TEST);
 		BTPageOpaque pageop = (BTPageOpaque) PageGetSpecialPointer(page);
 
 		Assert((pageop->btpo_flags & BTP_INCOMPLETE_SPLIT) != 0);
@@ -167,7 +168,7 @@ btree_xlog_insert(bool isleaf, bool ismeta, XLogReaderState *record)
 		Size		datalen;
 		char	   *datapos = XLogRecGetBlockData(record, 0, &datalen);
 
-		page = BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		if (PageAddItem(page, (Item) datapos, datalen, xlrec->offnum,
 						false, false) == InvalidOffsetNumber)
@@ -224,7 +225,7 @@ btree_xlog_split(bool onleft, bool isroot, XLogReaderState *record)
 	/* Reconstruct right (new) sibling page from scratch */
 	rbuf = XLogInitBufferForRedo(record, 1);
 	datapos = XLogRecGetBlockData(record, 1, &datalen);
-	rpage = (Page) BufferGetPage(rbuf);
+	rpage = BufferGetPage(rbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 	_bt_pageinit(rpage, BufferGetPageSize(rbuf));
 	ropaque = (BTPageOpaque) PageGetSpecialPointer(rpage);
@@ -266,7 +267,8 @@ btree_xlog_split(bool onleft, bool isroot, XLogReaderState *record)
 		 * but it helps debugging.  See also _bt_restore_page(), which does
 		 * the same for the right page.
 		 */
-		Page		lpage = (Page) BufferGetPage(lbuf);
+		Page		lpage = BufferGetPage(lbuf, NULL, NULL,
+										  BGP_NO_SNAPSHOT_TEST);
 		BTPageOpaque lopaque = (BTPageOpaque) PageGetSpecialPointer(lpage);
 		OffsetNumber off;
 		Item		newitem = NULL;
@@ -368,7 +370,8 @@ btree_xlog_split(bool onleft, bool isroot, XLogReaderState *record)
 
 		if (XLogReadBufferForRedo(record, 2, &buffer) == BLK_NEEDS_REDO)
 		{
-			Page		page = (Page) BufferGetPage(buffer);
+			Page		page = BufferGetPage(buffer, NULL, NULL,
+											 BGP_NO_SNAPSHOT_TEST);
 			BTPageOpaque pageop = (BTPageOpaque) PageGetSpecialPointer(page);
 
 			pageop->btpo_prev = rightsib;
@@ -476,7 +479,7 @@ btree_xlog_vacuum(XLogReaderState *record)
 
 		ptr = XLogRecGetBlockData(record, 0, &len);
 
-		page = (Page) BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		if (len > 0)
 		{
@@ -570,7 +573,7 @@ btree_xlog_delete_get_latestRemovedXid(XLogReaderState *record)
 	if (!BufferIsValid(ibuffer))
 		return InvalidTransactionId;
 	LockBuffer(ibuffer, BT_READ);
-	ipage = (Page) BufferGetPage(ibuffer);
+	ipage = BufferGetPage(ibuffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 	/*
 	 * Loop through the deleted index items to obtain the TransactionId from
@@ -597,7 +600,7 @@ btree_xlog_delete_get_latestRemovedXid(XLogReaderState *record)
 			return InvalidTransactionId;
 		}
 		LockBuffer(hbuffer, BUFFER_LOCK_SHARE);
-		hpage = (Page) BufferGetPage(hbuffer);
+		hpage = BufferGetPage(hbuffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		/*
 		 * Look up the heap tuple header that the index tuple points at by
@@ -693,7 +696,7 @@ btree_xlog_delete(XLogReaderState *record)
 	 */
 	if (XLogReadBufferForRedo(record, 0, &buffer) == BLK_NEEDS_REDO)
 	{
-		page = (Page) BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		if (XLogRecGetDataLen(record) > SizeOfBtreeDelete)
 		{
@@ -745,7 +748,7 @@ btree_xlog_mark_page_halfdead(uint8 info, XLogReaderState *record)
 		OffsetNumber nextoffset;
 		BlockNumber rightsib;
 
-		page = (Page) BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 		pageop = (BTPageOpaque) PageGetSpecialPointer(page);
 
 		poffset = xlrec->poffset;
@@ -769,7 +772,7 @@ btree_xlog_mark_page_halfdead(uint8 info, XLogReaderState *record)
 
 	/* Rewrite the leaf page as a halfdead page */
 	buffer = XLogInitBufferForRedo(record, 0);
-	page = (Page) BufferGetPage(buffer);
+	page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 	_bt_pageinit(page, BufferGetPageSize(buffer));
 	pageop = (BTPageOpaque) PageGetSpecialPointer(page);
@@ -825,7 +828,7 @@ btree_xlog_unlink_page(uint8 info, XLogReaderState *record)
 	/* Fix left-link of right sibling */
 	if (XLogReadBufferForRedo(record, 2, &buffer) == BLK_NEEDS_REDO)
 	{
-		page = (Page) BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 		pageop = (BTPageOpaque) PageGetSpecialPointer(page);
 		pageop->btpo_prev = leftsib;
 
@@ -840,7 +843,7 @@ btree_xlog_unlink_page(uint8 info, XLogReaderState *record)
 	{
 		if (XLogReadBufferForRedo(record, 1, &buffer) == BLK_NEEDS_REDO)
 		{
-			page = (Page) BufferGetPage(buffer);
+			page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 			pageop = (BTPageOpaque) PageGetSpecialPointer(page);
 			pageop->btpo_next = rightsib;
 
@@ -853,7 +856,7 @@ btree_xlog_unlink_page(uint8 info, XLogReaderState *record)
 
 	/* Rewrite target page as empty deleted page */
 	buffer = XLogInitBufferForRedo(record, 0);
-	page = (Page) BufferGetPage(buffer);
+	page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 	_bt_pageinit(page, BufferGetPageSize(buffer));
 	pageop = (BTPageOpaque) PageGetSpecialPointer(page);
@@ -882,7 +885,7 @@ btree_xlog_unlink_page(uint8 info, XLogReaderState *record)
 		IndexTupleData trunctuple;
 
 		buffer = XLogInitBufferForRedo(record, 3);
-		page = (Page) BufferGetPage(buffer);
+		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 		_bt_pageinit(page, BufferGetPageSize(buffer));
 		pageop = (BTPageOpaque) PageGetSpecialPointer(page);
@@ -926,7 +929,7 @@ btree_xlog_newroot(XLogReaderState *record)
 	Size		len;
 
 	buffer = XLogInitBufferForRedo(record, 0);
-	page = (Page) BufferGetPage(buffer);
+	page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
 
 	_bt_pageinit(page, BufferGetPageSize(buffer));
 	pageop = (BTPageOpaque) PageGetSpecialPointer(page);