Repair possible failure to update hint bits back to disk, per

http://archives.postgresql.org/pgsql-hackers/2004-10/msg00464.php.
This fix is intended to be permanent: it moves the responsibility for
calling SetBufferCommitInfoNeedsSave() into the tqual.c routines,
eliminating the requirement for callers to test whether t_infomask changed.
Also, tighten validity checking on buffer IDs in bufmgr.c --- several
routines were paranoid about out-of-range shared buffer numbers but not
about out-of-range local ones, which seems a tad pointless.

1 files changed, 9 insertions, 2 deletions

diff --git a/contrib/pgstattuple/pgstattuple.c b/contrib/pgstattuple/pgstattuple.c
index bfe37eb9ed6..e2fab7863eb 100644
--- a/contrib/pgstattuple/pgstattuple.c
+++ b/contrib/pgstattuple/pgstattuple.c
@@ -1,5 +1,5 @@
 /*
- * $PostgreSQL: pgsql/contrib/pgstattuple/pgstattuple.c,v 1.16 2004/08/29 05:06:37 momjian Exp $
+ * $PostgreSQL: pgsql/contrib/pgstattuple/pgstattuple.c,v 1.17 2004/10/15 22:39:38 tgl Exp $
  *
  * Copyright (c) 2001,2002	Tatsuo Ishii
  *
@@ -134,7 +134,10 @@ pgstattuple_real(Relation rel)
 	/* scan the relation */
 	while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
 	{
-		if (HeapTupleSatisfiesNow(tuple->t_data))
+		/* must hold a buffer lock to call HeapTupleSatisfiesNow */
+		LockBuffer(scan->rs_cbuf, BUFFER_LOCK_SHARE);
+
+		if (HeapTupleSatisfiesNow(tuple->t_data, scan->rs_cbuf))
 		{
 			tuple_len += tuple->t_len;
 			tuple_count++;
@@ -145,6 +148,8 @@ pgstattuple_real(Relation rel)
 			dead_tuple_count++;
 		}
 
+		LockBuffer(scan->rs_cbuf, BUFFER_LOCK_UNLOCK);
+
 		/*
 		 * To avoid physically reading the table twice, try to do the
 		 * free-space scan in parallel with the heap scan.	However,
@@ -156,7 +161,9 @@ pgstattuple_real(Relation rel)
 		while (block <= tupblock)
 		{
 			buffer = ReadBuffer(rel, block);
+			LockBuffer(buffer, BUFFER_LOCK_SHARE);
 			free_space += PageGetFreeSpace((Page) BufferGetPage(buffer));
+			LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
 			ReleaseBuffer(buffer);
 			block++;
 		}