Be careful to get share lock on each page before computing its free space.

ITAGAKI Takahiro

diff --git a/contrib/pgstattuple/pgstattuple.c b/contrib/pgstattuple/pgstattuple.c
index e3dae87593229be188bb4acfe454fda819b4f851..48194e3a6e86b247d86cf588229ec43bbcc698ef 100644 (file)
--- a/contrib/pgstattuple/pgstattuple.c
+++ b/contrib/pgstattuple/pgstattuple.c
@@ -1,5 +1,5 @@
 /*
- * $PostgreSQL: pgsql/contrib/pgstattuple/pgstattuple.c,v 1.30 2007/09/20 17:56:30 tgl Exp $
+ * $PostgreSQL: pgsql/contrib/pgstattuple/pgstattuple.c,v 1.31 2007/10/22 17:29:35 tgl Exp $
  *
  * Copyright (c) 2001,2002 Tatsuo Ishii
  *
@@ -291,8 +291,7 @@ pgstat_heap(Relation rel, FunctionCallInfo fcinfo)
            buffer = ReadBuffer(rel, block);
            LockBuffer(buffer, BUFFER_LOCK_SHARE);
            stat.free_space += PageGetHeapFreeSpace((Page) BufferGetPage(buffer));
-           LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
-           ReleaseBuffer(buffer);
+           UnlockReleaseBuffer(buffer);
            block++;
        }
    }
@@ -301,8 +300,9 @@ pgstat_heap(Relation rel, FunctionCallInfo fcinfo)
    while (block < nblocks)
    {
        buffer = ReadBuffer(rel, block);
+       LockBuffer(buffer, BUFFER_LOCK_SHARE);
        stat.free_space += PageGetHeapFreeSpace((Page) BufferGetPage(buffer));
-       ReleaseBuffer(buffer);
+       UnlockReleaseBuffer(buffer);
        block++;
    }