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, 39 insertions, 39 deletions

diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index 9ba61d5fe1..390bd1a219 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -130,7 +130,7 @@ _bt_getroot(Relation rel, int access)
 		rootlevel = metad->btm_fastlevel;
 
 		rootbuf = _bt_getbuf(rel, rootblkno, BT_READ);
-		rootpage = BufferGetPage(rootbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		rootpage = BufferGetPage(rootbuf);
 		rootopaque = (BTPageOpaque) PageGetSpecialPointer(rootpage);
 
 		/*
@@ -156,7 +156,7 @@ _bt_getroot(Relation rel, int access)
 	}
 
 	metabuf = _bt_getbuf(rel, BTREE_METAPAGE, BT_READ);
-	metapg = BufferGetPage(metabuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	metapg = BufferGetPage(metabuf);
 	metaopaque = (BTPageOpaque) PageGetSpecialPointer(metapg);
 	metad = BTPageGetMeta(metapg);
 
@@ -213,7 +213,7 @@ _bt_getroot(Relation rel, int access)
 		 */
 		rootbuf = _bt_getbuf(rel, P_NEW, BT_WRITE);
 		rootblkno = BufferGetBlockNumber(rootbuf);
-		rootpage = BufferGetPage(rootbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		rootpage = BufferGetPage(rootbuf);
 		rootopaque = (BTPageOpaque) PageGetSpecialPointer(rootpage);
 		rootopaque->btpo_prev = rootopaque->btpo_next = P_NONE;
 		rootopaque->btpo_flags = (BTP_LEAF | BTP_ROOT);
@@ -295,7 +295,7 @@ _bt_getroot(Relation rel, int access)
 		for (;;)
 		{
 			rootbuf = _bt_relandgetbuf(rel, rootbuf, rootblkno, BT_READ);
-			rootpage = BufferGetPage(rootbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+			rootpage = BufferGetPage(rootbuf);
 			rootopaque = (BTPageOpaque) PageGetSpecialPointer(rootpage);
 
 			if (!P_IGNORE(rootopaque))
@@ -360,7 +360,7 @@ _bt_gettrueroot(Relation rel)
 	rel->rd_amcache = NULL;
 
 	metabuf = _bt_getbuf(rel, BTREE_METAPAGE, BT_READ);
-	metapg = BufferGetPage(metabuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	metapg = BufferGetPage(metabuf);
 	metaopaque = (BTPageOpaque) PageGetSpecialPointer(metapg);
 	metad = BTPageGetMeta(metapg);
 
@@ -397,7 +397,7 @@ _bt_gettrueroot(Relation rel)
 	for (;;)
 	{
 		rootbuf = _bt_relandgetbuf(rel, rootbuf, rootblkno, BT_READ);
-		rootpage = BufferGetPage(rootbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		rootpage = BufferGetPage(rootbuf);
 		rootopaque = (BTPageOpaque) PageGetSpecialPointer(rootpage);
 
 		if (!P_IGNORE(rootopaque))
@@ -446,7 +446,7 @@ _bt_getrootheight(Relation rel)
 		BTPageOpaque metaopaque;
 
 		metabuf = _bt_getbuf(rel, BTREE_METAPAGE, BT_READ);
-		metapg = BufferGetPage(metabuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		metapg = BufferGetPage(metabuf);
 		metaopaque = (BTPageOpaque) PageGetSpecialPointer(metapg);
 		metad = BTPageGetMeta(metapg);
 
@@ -501,7 +501,7 @@ _bt_getrootheight(Relation rel)
 void
 _bt_checkpage(Relation rel, Buffer buf)
 {
-	Page		page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	Page		page = BufferGetPage(buf);
 
 	/*
 	 * ReadBuffer verifies that every newly-read page passes
@@ -616,7 +616,7 @@ _bt_getbuf(Relation rel, BlockNumber blkno, int access)
 			buf = ReadBuffer(rel, blkno);
 			if (ConditionalLockBuffer(buf))
 			{
-				page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+				page = BufferGetPage(buf);
 				if (_bt_page_recyclable(page))
 				{
 					/*
@@ -674,7 +674,7 @@ _bt_getbuf(Relation rel, BlockNumber blkno, int access)
 			UnlockRelationForExtension(rel, ExclusiveLock);
 
 		/* Initialize the new page before returning it */
-		page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		page = BufferGetPage(buf);
 		Assert(PageIsNew(page));
 		_bt_pageinit(page, BufferGetPageSize(buf));
 	}
@@ -789,7 +789,7 @@ _bt_delitems_vacuum(Relation rel, Buffer buf,
 					OffsetNumber *itemnos, int nitems,
 					BlockNumber lastBlockVacuumed)
 {
-	Page		page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	Page		page = BufferGetPage(buf);
 	BTPageOpaque opaque;
 
 	/* No ereport(ERROR) until changes are logged */
@@ -862,7 +862,7 @@ _bt_delitems_delete(Relation rel, Buffer buf,
 					OffsetNumber *itemnos, int nitems,
 					Relation heapRel)
 {
-	Page		page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	Page		page = BufferGetPage(buf);
 	BTPageOpaque opaque;
 
 	/* Shouldn't be called unless there's something to do */
@@ -931,7 +931,7 @@ _bt_is_page_halfdead(Relation rel, BlockNumber blk)
 	bool		result;
 
 	buf = _bt_getbuf(rel, blk, BT_READ);
-	page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	page = BufferGetPage(buf);
 	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 
 	result = P_ISHALFDEAD(opaque);
@@ -991,7 +991,7 @@ _bt_lock_branch_parent(Relation rel, BlockNumber child, BTStack stack,
 	parent = stack->bts_blkno;
 	poffset = stack->bts_offset;
 
-	page = BufferGetPage(pbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	page = BufferGetPage(pbuf);
 	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 	maxoff = PageGetMaxOffsetNumber(page);
 
@@ -1035,7 +1035,7 @@ _bt_lock_branch_parent(Relation rel, BlockNumber child, BTStack stack,
 				BTPageOpaque lopaque;
 
 				lbuf = _bt_getbuf(rel, leftsib, BT_READ);
-				lpage = BufferGetPage(lbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+				lpage = BufferGetPage(lbuf);
 				lopaque = (BTPageOpaque) PageGetSpecialPointer(lpage);
 
 				/*
@@ -1126,7 +1126,7 @@ _bt_pagedel(Relation rel, Buffer buf)
 
 	for (;;)
 	{
-		page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		page = BufferGetPage(buf);
 		opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 
 		/*
@@ -1231,7 +1231,7 @@ _bt_pagedel(Relation rel, Buffer buf)
 					Page		lpage;
 
 					lbuf = _bt_getbuf(rel, leftsib, BT_READ);
-					lpage = BufferGetPage(lbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+					lpage = BufferGetPage(lbuf);
 					lopaque = (BTPageOpaque) PageGetSpecialPointer(lpage);
 
 					/*
@@ -1332,7 +1332,7 @@ _bt_mark_page_halfdead(Relation rel, Buffer leafbuf, BTStack stack)
 	IndexTuple	itup;
 	IndexTupleData trunctuple;
 
-	page = BufferGetPage(leafbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	page = BufferGetPage(leafbuf);
 	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 
 	Assert(!P_RIGHTMOST(opaque) && !P_ISROOT(opaque) && !P_ISDELETED(opaque) &&
@@ -1385,7 +1385,7 @@ _bt_mark_page_halfdead(Relation rel, Buffer leafbuf, BTStack stack)
 	 * contents.  The test on the next-child downlink is known to sometimes
 	 * fail in the field, though.
 	 */
-	page = BufferGetPage(topparent, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	page = BufferGetPage(topparent);
 	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 
 #ifdef USE_ASSERT_CHECKING
@@ -1417,7 +1417,7 @@ _bt_mark_page_halfdead(Relation rel, Buffer leafbuf, BTStack stack)
 	 * to copy the right sibling's downlink over the target downlink, and then
 	 * delete the following item.
 	 */
-	page = BufferGetPage(topparent, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	page = BufferGetPage(topparent);
 	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 
 	itemid = PageGetItemId(page, topoff);
@@ -1432,7 +1432,7 @@ _bt_mark_page_halfdead(Relation rel, Buffer leafbuf, BTStack stack)
 	 * highest internal page in the branch we're deleting.  We use the tid of
 	 * the high key to store it.
 	 */
-	page = BufferGetPage(leafbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	page = BufferGetPage(leafbuf);
 	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 	opaque->btpo_flags |= BTP_HALF_DEAD;
 
@@ -1469,7 +1469,7 @@ _bt_mark_page_halfdead(Relation rel, Buffer leafbuf, BTStack stack)
 		XLogRegisterBuffer(0, leafbuf, REGBUF_WILL_INIT);
 		XLogRegisterBuffer(1, topparent, REGBUF_STANDARD);
 
-		page = BufferGetPage(leafbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		page = BufferGetPage(leafbuf);
 		opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 		xlrec.leftblk = opaque->btpo_prev;
 		xlrec.rightblk = opaque->btpo_next;
@@ -1478,9 +1478,9 @@ _bt_mark_page_halfdead(Relation rel, Buffer leafbuf, BTStack stack)
 
 		recptr = XLogInsert(RM_BTREE_ID, XLOG_BTREE_MARK_PAGE_HALFDEAD);
 
-		page = BufferGetPage(topparent, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		page = BufferGetPage(topparent);
 		PageSetLSN(page, recptr);
-		page = BufferGetPage(leafbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		page = BufferGetPage(leafbuf);
 		PageSetLSN(page, recptr);
 	}
 
@@ -1525,7 +1525,7 @@ _bt_unlink_halfdead_page(Relation rel, Buffer leafbuf, bool *rightsib_empty)
 	ItemPointer leafhikey;
 	BlockNumber nextchild;
 
-	page = BufferGetPage(leafbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	page = BufferGetPage(leafbuf);
 	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 
 	Assert(P_ISLEAF(opaque) && P_ISHALFDEAD(opaque));
@@ -1551,7 +1551,7 @@ _bt_unlink_halfdead_page(Relation rel, Buffer leafbuf, bool *rightsib_empty)
 
 		/* fetch the block number of the topmost parent's left sibling */
 		buf = _bt_getbuf(rel, target, BT_READ);
-		page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		page = BufferGetPage(buf);
 		opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 		leftsib = opaque->btpo_prev;
 		targetlevel = opaque->btpo.level;
@@ -1589,7 +1589,7 @@ _bt_unlink_halfdead_page(Relation rel, Buffer leafbuf, bool *rightsib_empty)
 	if (leftsib != P_NONE)
 	{
 		lbuf = _bt_getbuf(rel, leftsib, BT_WRITE);
-		page = BufferGetPage(lbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		page = BufferGetPage(lbuf);
 		opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 		while (P_ISDELETED(opaque) || opaque->btpo_next != target)
 		{
@@ -1603,7 +1603,7 @@ _bt_unlink_halfdead_page(Relation rel, Buffer leafbuf, bool *rightsib_empty)
 				return false;
 			}
 			lbuf = _bt_getbuf(rel, leftsib, BT_WRITE);
-			page = BufferGetPage(lbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+			page = BufferGetPage(lbuf);
 			opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 		}
 	}
@@ -1616,7 +1616,7 @@ _bt_unlink_halfdead_page(Relation rel, Buffer leafbuf, bool *rightsib_empty)
 	 * empty page.
 	 */
 	LockBuffer(buf, BT_WRITE);
-	page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	page = BufferGetPage(buf);
 	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 
 	/*
@@ -1660,7 +1660,7 @@ _bt_unlink_halfdead_page(Relation rel, Buffer leafbuf, bool *rightsib_empty)
 	 */
 	rightsib = opaque->btpo_next;
 	rbuf = _bt_getbuf(rel, rightsib, BT_WRITE);
-	page = BufferGetPage(rbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	page = BufferGetPage(rbuf);
 	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 	if (opaque->btpo_prev != target)
 		elog(ERROR, "right sibling's left-link doesn't match: "
@@ -1684,13 +1684,13 @@ _bt_unlink_halfdead_page(Relation rel, Buffer leafbuf, bool *rightsib_empty)
 	 */
 	if (leftsib == P_NONE && rightsib_is_rightmost)
 	{
-		page = BufferGetPage(rbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		page = BufferGetPage(rbuf);
 		opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 		if (P_RIGHTMOST(opaque))
 		{
 			/* rightsib will be the only one left on the level */
 			metabuf = _bt_getbuf(rel, BTREE_METAPAGE, BT_WRITE);
-			metapg = BufferGetPage(metabuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+			metapg = BufferGetPage(metabuf);
 			metad = BTPageGetMeta(metapg);
 
 			/*
@@ -1721,12 +1721,12 @@ _bt_unlink_halfdead_page(Relation rel, Buffer leafbuf, bool *rightsib_empty)
 	 */
 	if (BufferIsValid(lbuf))
 	{
-		page = BufferGetPage(lbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		page = BufferGetPage(lbuf);
 		opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 		Assert(opaque->btpo_next == target);
 		opaque->btpo_next = rightsib;
 	}
-	page = BufferGetPage(rbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	page = BufferGetPage(rbuf);
 	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 	Assert(opaque->btpo_prev == target);
 	opaque->btpo_prev = leftsib;
@@ -1754,7 +1754,7 @@ _bt_unlink_halfdead_page(Relation rel, Buffer leafbuf, bool *rightsib_empty)
 	 * will continue to do so, holding back RecentGlobalXmin, for the duration
 	 * of that scan.
 	 */
-	page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	page = BufferGetPage(buf);
 	opaque = (BTPageOpaque) PageGetSpecialPointer(page);
 	opaque->btpo_flags &= ~BTP_HALF_DEAD;
 	opaque->btpo_flags |= BTP_DELETED;
@@ -1826,18 +1826,18 @@ _bt_unlink_halfdead_page(Relation rel, Buffer leafbuf, bool *rightsib_empty)
 		{
 			PageSetLSN(metapg, recptr);
 		}
-		page = BufferGetPage(rbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		page = BufferGetPage(rbuf);
 		PageSetLSN(page, recptr);
-		page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		page = BufferGetPage(buf);
 		PageSetLSN(page, recptr);
 		if (BufferIsValid(lbuf))
 		{
-			page = BufferGetPage(lbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+			page = BufferGetPage(lbuf);
 			PageSetLSN(page, recptr);
 		}
 		if (target != leafblkno)
 		{
-			page = BufferGetPage(leafbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+			page = BufferGetPage(leafbuf);
 			PageSetLSN(page, recptr);
 		}
 	}