From 1832cefda116f5bb3ef842a5be4434d29f036bec Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 28 Aug 2006 19:38:09 +0000
Subject: [PATCH] Fix pgstat_report_waiting() to not dump core if called before
pgstat_bestart() has been called; else any lock-block occurring during
InitPostgres() is disastrous. I believe this explains recent wasp regression
failure; at least it explains the crash I got while trying to duplicate the
problem. I also made pgstat_report_activity() safe against the same
scenario, just in case. The report_waiting hazard was created by my patch of
19-Aug to include waiting status in pg_stat_activity.
---
src/backend/postmaster/pgstat.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index a37d9fa349f..715de0071c1 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -13,7 +13,7 @@
*
* Copyright (c) 2001-2006, PostgreSQL Global Development Group
*
- * $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.137 2006/08/19 01:36:24 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.138 2006/08/28 19:38:09 tgl Exp $
* ----------
*/
#include "postgres.h"
@@ -1384,7 +1384,7 @@ pgstat_bestart(void)
static void
pgstat_beshutdown_hook(int code, Datum arg)
{
- volatile PgBackendStatus *beentry;
+ volatile PgBackendStatus *beentry = MyBEEntry;
pgstat_report_tabstat();
@@ -1393,7 +1393,6 @@ pgstat_beshutdown_hook(int code, Datum arg)
* st_changecount before and after. We use a volatile pointer here
* to ensure the compiler doesn't try to get cute.
*/
- beentry = MyBEEntry;
beentry->st_changecount++;
beentry->st_procpid = 0; /* mark invalid */
@@ -1413,11 +1412,11 @@ pgstat_beshutdown_hook(int code, Datum arg)
void
pgstat_report_activity(const char *cmd_str)
{
- volatile PgBackendStatus *beentry;
+ volatile PgBackendStatus *beentry = MyBEEntry;
TimestampTz start_timestamp;
int len;
- if (!pgstat_collect_querystring)
+ if (!pgstat_collect_querystring || !beentry)
return;
/*
@@ -1434,7 +1433,6 @@ pgstat_report_activity(const char *cmd_str)
* st_changecount before and after. We use a volatile pointer here
* to ensure the compiler doesn't try to get cute.
*/
- beentry = MyBEEntry;
beentry->st_changecount++;
beentry->st_activity_start_timestamp = start_timestamp;
@@ -1450,14 +1448,17 @@ pgstat_report_activity(const char *cmd_str)
* pgstat_report_waiting() -
*
* Called from lock manager to report beginning or end of a lock wait.
+ *
+ * NB: this *must* be able to survive being called before MyBEEntry has been
+ * initialized.
* ----------
*/
void
pgstat_report_waiting(bool waiting)
{
- volatile PgBackendStatus *beentry;
+ volatile PgBackendStatus *beentry = MyBEEntry;
- if (!pgstat_collect_querystring)
+ if (!pgstat_collect_querystring || !beentry)
return;
/*
@@ -1465,8 +1466,6 @@ pgstat_report_waiting(bool waiting)
* may modify, there seems no need to bother with the st_changecount
* protocol. The update must appear atomic in any case.
*/
- beentry = MyBEEntry;
-
beentry->st_waiting = waiting;
}
--
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