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, 15 insertions, 24 deletions

diff --git a/src/backend/access/spgist/spgdoinsert.c b/src/backend/access/spgist/spgdoinsert.c
index b780bfea44d..f090ca528b1 100644
--- a/src/backend/access/spgist/spgdoinsert.c
+++ b/src/backend/access/spgist/spgdoinsert.c
@@ -451,7 +451,7 @@ moveLeafs(Relation index, SpGistState *state,
 	/* Find a leaf page that will hold them */
 	nbuf = SpGistGetBuffer(index, GBUF_LEAF | (isNulls ? GBUF_NULLS : 0),
 						   size, &xlrec.newPage);
-	npage = BufferGetPage(nbuf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	npage = BufferGetPage(nbuf);
 	nblkno = BufferGetBlockNumber(nbuf);
 	Assert(nblkno != current->blkno);
 
@@ -1037,8 +1037,7 @@ doPickSplit(Relation index, SpGistState *state,
 		nodePageSelect = (uint8 *) palloc(sizeof(uint8) * out.nNodes);
 
 		curspace = currentFreeSpace;
-		newspace = PageGetExactFreeSpace
-			(BufferGetPage(newLeafBuffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST));
+		newspace = PageGetExactFreeSpace(BufferGetPage(newLeafBuffer));
 		for (i = 0; i < out.nNodes; i++)
 		{
 			if (leafSizes[i] <= curspace)
@@ -1071,9 +1070,7 @@ doPickSplit(Relation index, SpGistState *state,
 
 			/* Repeat the node assignment process --- should succeed now */
 			curspace = currentFreeSpace;
-			newspace = PageGetExactFreeSpace
-				(BufferGetPage(newLeafBuffer, NULL, NULL,
-							   BGP_NO_SNAPSHOT_TEST));
+			newspace = PageGetExactFreeSpace(BufferGetPage(newLeafBuffer));
 			for (i = 0; i < out.nNodes; i++)
 			{
 				if (leafSizes[i] <= curspace)
@@ -1204,9 +1201,7 @@ doPickSplit(Relation index, SpGistState *state,
 			it->nextOffset = InvalidOffsetNumber;
 
 		/* Insert it on page */
-		newoffset = SpGistPageAddNewItem(state,
-										 BufferGetPage(leafBuffer, NULL, NULL,
-													   BGP_NO_SNAPSHOT_TEST),
+		newoffset = SpGistPageAddNewItem(state, BufferGetPage(leafBuffer),
 										 (Item) it, it->size,
 										 &startOffsets[leafPageSelect[i]],
 										 false);
@@ -1280,8 +1275,7 @@ doPickSplit(Relation index, SpGistState *state,
 		/* Repoint "current" at the new inner tuple */
 		current->buffer = newInnerBuffer;
 		current->blkno = BufferGetBlockNumber(current->buffer);
-		current->page = BufferGetPage(current->buffer, NULL, NULL,
-									  BGP_NO_SNAPSHOT_TEST);
+		current->page = BufferGetPage(current->buffer);
 		xlrec.offnumInner = current->offnum =
 			SpGistPageAddNewItem(state, current->page,
 								 (Item) innerTuple, innerTuple->size,
@@ -1397,22 +1391,24 @@ doPickSplit(Relation index, SpGistState *state,
 		/* Update page LSNs on all affected pages */
 		if (newLeafBuffer != InvalidBuffer)
 		{
-			Page		page = BufferGetPage(newLeafBuffer, NULL, NULL,
-											 BGP_NO_SNAPSHOT_TEST);
+			Page		page = BufferGetPage(newLeafBuffer);
+
 			PageSetLSN(page, recptr);
 		}
 
 		if (saveCurrent.buffer != InvalidBuffer)
 		{
-			Page		page = BufferGetPage(saveCurrent.buffer, NULL, NULL,
-											 BGP_NO_SNAPSHOT_TEST);
+			Page		page = BufferGetPage(saveCurrent.buffer);
+
 			PageSetLSN(page, recptr);
 		}
 
 		PageSetLSN(current->page, recptr);
 
 		if (parent->buffer != InvalidBuffer)
+		{
 			PageSetLSN(parent->page, recptr);
+		}
 	}
 
 	END_CRIT_SECTION();
@@ -1582,8 +1578,7 @@ spgAddNodeAction(Relation index, SpGistState *state,
 									newInnerTuple->size + sizeof(ItemIdData),
 										  &xlrec.newPage);
 		current->blkno = BufferGetBlockNumber(current->buffer);
-		current->page = BufferGetPage(current->buffer, NULL, NULL,
-									  BGP_NO_SNAPSHOT_TEST);
+		current->page = BufferGetPage(current->buffer);
 
 		/*
 		 * Let's just make real sure new current isn't same as old.  Right now
@@ -1798,9 +1793,7 @@ spgSplitNodeAction(Relation index, SpGistState *state,
 	{
 		postfixBlkno = BufferGetBlockNumber(newBuffer);
 		xlrec.offnumPostfix = postfixOffset =
-			SpGistPageAddNewItem(state,
-								 BufferGetPage(newBuffer, NULL, NULL,
-											   BGP_NO_SNAPSHOT_TEST),
+			SpGistPageAddNewItem(state, BufferGetPage(newBuffer),
 								 (Item) postfixTuple, postfixTuple->size,
 								 NULL, false);
 		MarkBufferDirty(newBuffer);
@@ -1847,8 +1840,7 @@ spgSplitNodeAction(Relation index, SpGistState *state,
 
 		if (newBuffer != InvalidBuffer)
 		{
-			PageSetLSN(BufferGetPage(newBuffer, NULL, NULL,
-									 BGP_NO_SNAPSHOT_TEST), recptr);
+			PageSetLSN(BufferGetPage(newBuffer), recptr);
 		}
 	}
 
@@ -1992,8 +1984,7 @@ spgdoinsert(Relation index, SpGistState *state,
 			/* inner tuple can be stored on the same page as parent one */
 			current.buffer = parent.buffer;
 		}
-		current.page = BufferGetPage(current.buffer, NULL, NULL,
-									 BGP_NO_SNAPSHOT_TEST);
+		current.page = BufferGetPage(current.buffer);
 
 		/* should not arrive at a page of the wrong type */
 		if (isnull ? !SpGistPageStoresNulls(current.page) :