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, 16 insertions, 32 deletions

diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index 999e71cafc..996363c2de 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -211,8 +211,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 				bool markfollowright)
 {
 	BlockNumber blkno = BufferGetBlockNumber(buffer);
-	Page		page = BufferGetPage(buffer, NULL, NULL,
-									 BGP_NO_SNAPSHOT_TEST);
+	Page		page = BufferGetPage(buffer);
 	bool		is_leaf = (GistPageIsLeaf(page)) ? true : false;
 	XLogRecPtr	recptr;
 	int			i;
@@ -317,9 +316,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 
 			dist->buffer = buffer;
 			dist->block.blkno = BufferGetBlockNumber(buffer);
-			dist->page =
-				PageGetTempPageCopySpecial(BufferGetPage(buffer, NULL, NULL,
-														 BGP_NO_SNAPSHOT_TEST));
+			dist->page = PageGetTempPageCopySpecial(BufferGetPage(buffer));
 
 			/* clean all flags except F_LEAF */
 			GistPageGetOpaque(dist->page)->flags = (is_leaf) ? F_LEAF : 0;
@@ -331,7 +328,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 			/* Allocate new page */
 			ptr->buffer = gistNewBuffer(rel);
 			GISTInitBuffer(ptr->buffer, (is_leaf) ? F_LEAF : 0);
-			ptr->page = BufferGetPage(ptr->buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+			ptr->page = BufferGetPage(ptr->buffer);
 			ptr->block.blkno = BufferGetBlockNumber(ptr->buffer);
 		}
 
@@ -357,10 +354,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 			int			i;
 
 			rootpg.buffer = buffer;
-			rootpg.page =
-				PageGetTempPageCopySpecial(BufferGetPage(rootpg.buffer,
-														 NULL, NULL,
-														 BGP_NO_SNAPSHOT_TEST));
+			rootpg.page = PageGetTempPageCopySpecial(BufferGetPage(rootpg.buffer));
 			GistPageGetOpaque(rootpg.page)->flags = 0;
 
 			/* Prepare a vector of all the downlinks */
@@ -468,11 +462,8 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		 * The first page in the chain was a temporary working copy meant to
 		 * replace the old page. Copy it over the old page.
 		 */
-		PageRestoreTempPage(dist->page, BufferGetPage(dist->buffer,
-													  NULL, NULL,
-													  BGP_NO_SNAPSHOT_TEST));
-		dist->page = BufferGetPage(dist->buffer, NULL, NULL,
-								   BGP_NO_SNAPSHOT_TEST);
+		PageRestoreTempPage(dist->page, BufferGetPage(dist->buffer));
+		dist->page = BufferGetPage(dist->buffer);
 
 		/* Write the WAL record */
 		if (RelationNeedsWAL(rel))
@@ -563,8 +554,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 	 */
 	if (BufferIsValid(leftchildbuf))
 	{
-		Page		leftpg = BufferGetPage(leftchildbuf, NULL, NULL,
-										   BGP_NO_SNAPSHOT_TEST);
+		Page		leftpg = BufferGetPage(leftchildbuf);
 
 		GistPageSetNSN(leftpg, recptr);
 		GistClearFollowRight(leftpg);
@@ -624,8 +614,7 @@ gistdoinsert(Relation r, IndexTuple itup, Size freespace, GISTSTATE *giststate)
 			gistcheckpage(state.r, stack->buffer);
 		}
 
-		stack->page = BufferGetPage(stack->buffer, NULL, NULL,
-									BGP_NO_SNAPSHOT_TEST);
+		stack->page = (Page) BufferGetPage(stack->buffer);
 		stack->lsn = PageGetLSN(stack->page);
 		Assert(!RelationNeedsWAL(state.r) || !XLogRecPtrIsInvalid(stack->lsn));
 
@@ -710,8 +699,7 @@ gistdoinsert(Relation r, IndexTuple itup, Size freespace, GISTSTATE *giststate)
 					LockBuffer(stack->buffer, GIST_UNLOCK);
 					LockBuffer(stack->buffer, GIST_EXCLUSIVE);
 					xlocked = true;
-					stack->page = BufferGetPage(stack->buffer, NULL, NULL,
-												BGP_NO_SNAPSHOT_TEST);
+					stack->page = (Page) BufferGetPage(stack->buffer);
 
 					if (PageGetLSN(stack->page) != stack->lsn)
 					{
@@ -775,8 +763,7 @@ gistdoinsert(Relation r, IndexTuple itup, Size freespace, GISTSTATE *giststate)
 				LockBuffer(stack->buffer, GIST_UNLOCK);
 				LockBuffer(stack->buffer, GIST_EXCLUSIVE);
 				xlocked = true;
-				stack->page = BufferGetPage(stack->buffer, NULL, NULL,
-											BGP_NO_SNAPSHOT_TEST);
+				stack->page = (Page) BufferGetPage(stack->buffer);
 				stack->lsn = PageGetLSN(stack->page);
 
 				if (stack->blkno == GIST_ROOT_BLKNO)
@@ -866,7 +853,7 @@ gistFindPath(Relation r, BlockNumber child, OffsetNumber *downlinkoffnum)
 		buffer = ReadBuffer(r, top->blkno);
 		LockBuffer(buffer, GIST_SHARE);
 		gistcheckpage(r, buffer);
-		page = BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		page = (Page) BufferGetPage(buffer);
 
 		if (GistPageIsLeaf(page))
 		{
@@ -954,8 +941,7 @@ gistFindCorrectParent(Relation r, GISTInsertStack *child)
 	GISTInsertStack *parent = child->parent;
 
 	gistcheckpage(r, parent->buffer);
-	parent->page = BufferGetPage(parent->buffer, NULL, NULL,
-								 BGP_NO_SNAPSHOT_TEST);
+	parent->page = (Page) BufferGetPage(parent->buffer);
 
 	/* here we don't need to distinguish between split and page update */
 	if (child->downlinkoffnum == InvalidOffsetNumber ||
@@ -996,8 +982,7 @@ gistFindCorrectParent(Relation r, GISTInsertStack *child)
 			parent->buffer = ReadBuffer(r, parent->blkno);
 			LockBuffer(parent->buffer, GIST_EXCLUSIVE);
 			gistcheckpage(r, parent->buffer);
-			parent->page = BufferGetPage(parent->buffer, NULL, NULL,
-										 BGP_NO_SNAPSHOT_TEST);
+			parent->page = (Page) BufferGetPage(parent->buffer);
 		}
 
 		/*
@@ -1021,8 +1006,7 @@ gistFindCorrectParent(Relation r, GISTInsertStack *child)
 		while (ptr)
 		{
 			ptr->buffer = ReadBuffer(r, ptr->blkno);
-			ptr->page = BufferGetPage(ptr->buffer, NULL, NULL,
-									  BGP_NO_SNAPSHOT_TEST);
+			ptr->page = (Page) BufferGetPage(ptr->buffer);
 			ptr = ptr->parent;
 		}
 
@@ -1044,7 +1028,7 @@ static IndexTuple
 gistformdownlink(Relation rel, Buffer buf, GISTSTATE *giststate,
 				 GISTInsertStack *stack)
 {
-	Page		page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	Page		page = BufferGetPage(buf);
 	OffsetNumber maxoff;
 	OffsetNumber offset;
 	IndexTuple	downlink = NULL;
@@ -1125,7 +1109,7 @@ gistfixsplit(GISTInsertState *state, GISTSTATE *giststate)
 		GISTPageSplitInfo *si = palloc(sizeof(GISTPageSplitInfo));
 		IndexTuple	downlink;
 
-		page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+		page = BufferGetPage(buf);
 
 		/* Form the new downlink tuples to insert to parent */
 		downlink = gistformdownlink(state->r, buf, giststate, stack);