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, 10 insertions, 19 deletions

diff --git a/src/backend/storage/freespace/freespace.c b/src/backend/storage/freespace/freespace.c
index 25aeb3b7b89..2ffa8ff24d0 100644
--- a/src/backend/storage/freespace/freespace.c
+++ b/src/backend/storage/freespace/freespace.c
@@ -253,7 +253,7 @@ XLogRecordPageWithFreeSpace(RelFileNode rnode, BlockNumber heapBlk,
 	buf = XLogReadBufferExtended(rnode, FSM_FORKNUM, blkno, RBM_ZERO_ON_ERROR);
 	LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 
-	page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	page = BufferGetPage(buf);
 	if (PageIsNew(page))
 		PageInit(page, BLCKSZ, 0);
 
@@ -280,8 +280,7 @@ GetRecordedFreeSpace(Relation rel, BlockNumber heapBlk)
 	buf = fsm_readbuf(rel, addr, false);
 	if (!BufferIsValid(buf))
 		return 0;
-	cat = fsm_get_avail(BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST),
-						slot);
+	cat = fsm_get_avail(BufferGetPage(buf), slot);
 	ReleaseBuffer(buf);
 
 	return fsm_space_cat_to_avail(cat);
@@ -328,9 +327,7 @@ FreeSpaceMapTruncateRel(Relation rel, BlockNumber nblocks)
 		if (!BufferIsValid(buf))
 			return;				/* nothing to do; the FSM was already smaller */
 		LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
-		fsm_truncate_avail(BufferGetPage(buf, NULL, NULL,
-										 BGP_NO_SNAPSHOT_TEST),
-						   first_removed_slot);
+		fsm_truncate_avail(BufferGetPage(buf), first_removed_slot);
 		MarkBufferDirtyHint(buf, false);
 		UnlockReleaseBuffer(buf);
 
@@ -580,9 +577,8 @@ fsm_readbuf(Relation rel, FSMAddress addr, bool extend)
 	 * headers, for example.
 	 */
 	buf = ReadBufferExtended(rel, FSM_FORKNUM, blkno, RBM_ZERO_ON_ERROR, NULL);
-	if (PageIsNew(BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST)))
-		PageInit(BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST),
-				 BLCKSZ, 0);
+	if (PageIsNew(BufferGetPage(buf)))
+		PageInit(BufferGetPage(buf), BLCKSZ, 0);
 	return buf;
 }
 
@@ -661,7 +657,7 @@ fsm_set_and_search(Relation rel, FSMAddress addr, uint16 slot,
 	buf = fsm_readbuf(rel, addr, true);
 	LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 
-	page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	page = BufferGetPage(buf);
 
 	if (fsm_set_avail(page, slot, newValue))
 		MarkBufferDirtyHint(buf, false);
@@ -705,9 +701,7 @@ fsm_search(Relation rel, uint8 min_cat)
 									(addr.level == FSM_BOTTOM_LEVEL),
 									false);
 			if (slot == -1)
-				max_avail =
-					fsm_get_max_avail(BufferGetPage(buf, NULL, NULL,
-													BGP_NO_SNAPSHOT_TEST));
+				max_avail = fsm_get_max_avail(BufferGetPage(buf));
 			UnlockReleaseBuffer(buf);
 		}
 		else
@@ -789,7 +783,7 @@ fsm_vacuum_page(Relation rel, FSMAddress addr, bool *eof_p)
 	else
 		*eof_p = false;
 
-	page = BufferGetPage(buf, NULL, NULL, BGP_NO_SNAPSHOT_TEST);
+	page = BufferGetPage(buf);
 
 	/*
 	 * Recurse into children, and fix the information stored about them at
@@ -816,17 +810,14 @@ fsm_vacuum_page(Relation rel, FSMAddress addr, bool *eof_p)
 			if (fsm_get_avail(page, slot) != child_avail)
 			{
 				LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
-				fsm_set_avail(BufferGetPage(buf, NULL, NULL,
-											BGP_NO_SNAPSHOT_TEST),
-							  slot, child_avail);
+				fsm_set_avail(BufferGetPage(buf), slot, child_avail);
 				MarkBufferDirtyHint(buf, false);
 				LockBuffer(buf, BUFFER_LOCK_UNLOCK);
 			}
 		}
 	}
 
-	max_avail = fsm_get_max_avail(BufferGetPage(buf, NULL, NULL,
-												BGP_NO_SNAPSHOT_TEST));
+	max_avail = fsm_get_max_avail(BufferGetPage(buf));
 
 	/*
 	 * Reset the next slot pointer. This encourages the use of low-numbered