Revert no-op changes to BufferGetPage()

The reverted changes were intended to force a choice of whether any
newly-added BufferGetPage() calls needed to be accompanied by a
test of the snapshot age, to support the "snapshot too old"
feature.  Such an accompanying test is needed in about 7% of the
cases, where the page is being used as part of a scan rather than
positioning for other purposes (such as DML or vacuuming).  The
additional effort required for back-patching, and the doubt whether
the intended benefit would really be there, have indicated it is
best just to rely on developers to do the right thing based on
comments and existing usage, as we do with many other conventions.

This change should have little or no effect on generated executable
code.

Motivated by the back-patching pain of Tom Lane and Robert Haas

1 files changed, 17 insertions, 20 deletions

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