From 1d15afda136deef870aa9f70c795b9062ea23b67 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 29 Jun 2001 16:34:49 +0000
Subject: [PATCH] Fix longstanding error in VACUUM: sometimes would examine a
 buffer page after writing/unpinning it.  An actual failure is unlikely,
 unless the system is tremendously short of buffers ... but a bug is a bug.

---
 src/backend/commands/vacuum.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 694d0e8bbc1..8c4f9985e3f 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.189 2001/03/25 23:23:58 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.189.2.1 2001/06/29 16:34:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -577,7 +577,6 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
 				maxoff;
 	bool		pgchanged,
 				tupgone,
-				dobufrel,
 				notup;
 	char	   *relname;
 	VacPage		vacpage,
@@ -876,15 +875,6 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
 			}
 		}
 
-		if (pgchanged)
-		{
-			WriteBuffer(buf);
-			dobufrel = false;
-			changed_pages++;
-		}
-		else
-			dobufrel = true;
-
 		if (tempPage != (Page) NULL)
 		{						/* Some tuples are gone */
 			PageRepairFragmentation(tempPage, NULL);
@@ -900,8 +890,15 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
 			free_size += vacpage->free;
 			reap_page(vacuum_pages, vacpage);
 		}
-		if (dobufrel)
+
+		if (pgchanged)
+		{
+			WriteBuffer(buf);
+			changed_pages++;
+		}
+		else
 			ReleaseBuffer(buf);
+
 		if (notup)
 			empty_end_pages++;
 		else
-- 
2.39.5