It occurred to me that if we elog(ERROR) during VACUUM, the vacuum activity hint will not be reset. This will result in all subsequent I/O by the current backend being treated by the bufmgr as though it resulted from VACUUM. While elog(ERROR) during VACUUM is not a common occurrence, I don't think it's wise to assume it is impossible.

Attached is a patch which resets the vacuum activity hint in AbortTransaction().

Barring any objections, I intend to apply this to REL8_0_STABLE and HEAD sometime on Monday.

Index: src/backend/access/transam/xact.c
RCS file: /Users/neilc/local/cvs/pgsql/src/backend/access/transam/xact.c,v
retrieving revision 1.195
diff -c -r1.195 xact.c
*** src/backend/access/transam/xact.c	31 Dec 2004 21:59:29 -0000	1.195
--- src/backend/access/transam/xact.c	22 Jan 2005 12:07:16 -0000
*** 32,37 ****
--- 32,38 ----
  #include "executor/spi.h"
  #include "libpq/be-fsstubs.h"
  #include "miscadmin.h"
+ #include "storage/buf_internals.h"
  #include "storage/fd.h"
  #include "storage/proc.h"
  #include "storage/sinval.h"
*** 1606,1611 ****
--- 1607,1621 ----
+ 	/*
+ 	 * Reset the VACUUM activity hint. If we did elog(ERROR) during
+ 	 * VACUUM, this might still be set to true, so reset it here. For
+ 	 * the sake of correctness, we make sure to reset the flag fairly
+ 	 * early, before we've done any I/O that may be required for txn
+ 	 * abort.
+ 	 */
+ 	StrategyHintVacuum(false);
  	/* Clean up buffer I/O and buffer context locks, too */

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