From 2910ccefb454759a9f598996a4be9505b388e824 Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Sat, 30 Jun 2007 04:08:05 +0000
Subject: [PATCH] Avoid crash in interrupted autovacuum worker, caused by
leaving the current memory context pointing at a context not long lived
enough.
Also, create a fake PortalContext where to store the vac_context, if only
to avoid having it be a top-level memory context.
---
src/backend/postmaster/autovacuum.c | 48 ++++++++++++++++++++---------
1 file changed, 33 insertions(+), 15 deletions(-)
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 2739e2484f..e1fff7e6f8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -55,7 +55,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.52 2007/06/29 17:07:39 alvherre Exp $
+ * $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.53 2007/06/30 04:08:05 alvherre Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1427,8 +1427,8 @@ AutoVacWorkerMain(int argc, char *argv[])
pqsignal(SIGHUP, SIG_IGN);
/*
- * Presently, SIGINT will lead to autovacuum shutdown, because that's how
- * we handle ereport(ERROR). It could be improved however.
+ * SIGINT is used to signal cancelling the current table's vacuum;
+ * SIGTERM means abort and exit cleanly, and SIGQUIT means abandon ship.
*/
pqsignal(SIGINT, StatementCancelHandler);
pqsignal(SIGTERM, die);
@@ -1513,6 +1513,7 @@ AutoVacWorkerMain(int argc, char *argv[])
/* insert into the running list */
SHMQueueInsertBefore(&AutoVacuumShmem->av_runningWorkers,
&MyWorkerInfo->wi_links);
+
/*
* remove from the "starting" pointer, so that the launcher can start
* a new worker if required
@@ -1560,13 +1561,6 @@ AutoVacWorkerMain(int argc, char *argv[])
ereport(DEBUG1,
(errmsg("autovacuum: processing database \"%s\"", dbname)));
- /* Create the memory context where cross-transaction state is stored */
- AutovacMemCxt = AllocSetContextCreate(TopMemoryContext,
- "AV worker",
- ALLOCSET_DEFAULT_MINSIZE,
- ALLOCSET_DEFAULT_INITSIZE,
- ALLOCSET_DEFAULT_MAXSIZE);
-
/* And do an appropriate amount of work */
recentXid = ReadNewTransactionId();
do_autovacuum();
@@ -1787,6 +1781,18 @@ do_autovacuum(void)
PgStat_StatDBEntry *dbentry;
BufferAccessStrategy bstrategy;
+ /*
+ * StartTransactionCommand and CommitTransactionCommand will automatically
+ * switch to other contexts. We need this one to keep the list of
+ * relations to vacuum/analyze across transactions.
+ */
+ AutovacMemCxt = AllocSetContextCreate(TopMemoryContext,
+ "AV worker",
+ ALLOCSET_DEFAULT_MINSIZE,
+ ALLOCSET_DEFAULT_INITSIZE,
+ ALLOCSET_DEFAULT_MAXSIZE);
+ MemoryContextSwitchTo(AutovacMemCxt);
+
/*
* may be NULL if we couldn't find an entry (only happens if we
* are forcing a vacuum for anti-wrap purposes).
@@ -1825,11 +1831,7 @@ do_autovacuum(void)
ReleaseSysCache(tuple);
- /*
- * StartTransactionCommand and CommitTransactionCommand will automatically
- * switch to other contexts. We need this one to keep the list of
- * relations to vacuum/analyze across transactions.
- */
+ /* StartTransactionCommand changed elsewhere */
MemoryContextSwitchTo(AutovacMemCxt);
/* The database hash where pgstat keeps shared relations */
@@ -1932,6 +1934,16 @@ do_autovacuum(void)
*/
bstrategy = GetAccessStrategy(BAS_VACUUM);
+ /*
+ * create a memory context to act as fake PortalContext, so that the
+ * contexts created in the vacuum code are cleaned up for each table.
+ */
+ PortalContext = AllocSetContextCreate(AutovacMemCxt,
+ "Autovacuum Portal",
+ ALLOCSET_DEFAULT_INITSIZE,
+ ALLOCSET_DEFAULT_MINSIZE,
+ ALLOCSET_DEFAULT_MAXSIZE);
+
/*
* Perform operations on collected tables.
*/
@@ -1996,6 +2008,7 @@ next_worker:
* FIXME we ignore the possibility that the table was finished being
* vacuumed in the last 500ms (PGSTAT_STAT_INTERVAL). This is a bug.
*/
+ MemoryContextSwitchTo(AutovacMemCxt);
tab = table_recheck_autovac(relid);
if (tab == NULL)
{
@@ -2026,6 +2039,9 @@ next_worker:
autovac_balance_cost();
LWLockRelease(AutovacuumLock);
+ /* clean up memory before each iteration */
+ MemoryContextResetAndDeleteChildren(PortalContext);
+
/*
* We will abort vacuuming the current table if we are interrupted, and
* continue with the next one in schedule; but if anything else
@@ -2035,6 +2051,7 @@ next_worker:
PG_TRY();
{
/* have at it */
+ MemoryContextSwitchTo(TopTransactionContext);
autovacuum_do_vac_analyze(tab->at_relid,
tab->at_dovacuum,
tab->at_doanalyze,
@@ -2063,6 +2080,7 @@ next_worker:
AbortOutOfAnyTransaction();
FlushErrorState();
+ MemoryContextResetAndDeleteChildren(PortalContext);
/* restart our transaction for the following operations */
StartTransactionCommand();
--
2.40.0