From: Robert Haas <rhaas@postgresql.org>
Date: Thu, 25 Jul 2013 20:16:42 +0000 (-0400)
Subject: pgstattuple: Use SnapshotDirty, not SnapshotNow.
X-Git-Url: http://git.postgresql.org/gitweb/?a=commitdiff_plain;h=80c79ab2a8d63bc6c83269b29c1ba993c8077d3a;p=users%2Fbernd%2Fpostgres.git

pgstattuple: Use SnapshotDirty, not SnapshotNow.

Tuples belonging to uncommitted transactions should not be
counted as dead.

This is arguably a bug fix that should be back-patched, but
as no one ever noticed until it came time to try to get rid
of SnapshotNow, I'm only doing this in master for now.
---

diff --git a/contrib/pgstattuple/pgstattuple.c b/contrib/pgstattuple/pgstattuple.c
index 7f41ec3ad9..f9ba0a6c21 100644
--- a/contrib/pgstattuple/pgstattuple.c
+++ b/contrib/pgstattuple/pgstattuple.c
@@ -278,9 +278,11 @@ pgstat_heap(Relation rel, FunctionCallInfo fcinfo)
 	Buffer		buffer;
 	pgstattuple_type stat = {0};
 	BufferAccessStrategy bstrategy;
+	SnapshotData SnapshotDirty;
 
 	/* Disable syncscan because we assume we scan from block zero upwards */
 	scan = heap_beginscan_strat(rel, SnapshotAny, 0, NULL, true, false);
+	InitDirtySnapshot(SnapshotDirty);
 
 	nblocks = scan->rs_nblocks; /* # blocks to be scanned */
 
@@ -296,7 +298,7 @@ pgstat_heap(Relation rel, FunctionCallInfo fcinfo)
 		/* must hold a buffer lock to call HeapTupleSatisfiesVisibility */
 		LockBuffer(scan->rs_cbuf, BUFFER_LOCK_SHARE);
 
-		if (HeapTupleSatisfiesVisibility(tuple, SnapshotNow, scan->rs_cbuf))
+		if (HeapTupleSatisfiesVisibility(tuple, &SnapshotDirty, scan->rs_cbuf))
 		{
 			stat.tuple_len += tuple->t_len;
 			stat.tuple_count++;