From 1358466a8c918f14f48ea60d60db96ae7eba5045 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 8 Jun 2006 23:55:48 +0000
Subject: [PATCH] Fix bootstrap.c so that database startup process and bgwriter
properly release LWLocks during a panic exit. This avoids the possible
self-deadlock pointed out by Qingqing Zhou. Also, I noted that an error
during LoadFreeSpaceMap() or BuildFlatFiles() would result in exit(0) which
would leave the postmaster thinking all is well. Added a critical section to
ensure such errors don't allow startup to proceed.
Backpatched to 8.1. The 8.0 code is a bit different and I'm not sure if the
problem exists there; given we've not seen this reported from the field, I'm
going to be conservative about backpatching any further.
---
src/backend/bootstrap/bootstrap.c | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 5dfda5a427d..bc60d533ae4 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -8,7 +8,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/bootstrap/bootstrap.c,v 1.215 2006/05/10 23:18:39 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/bootstrap/bootstrap.c,v 1.216 2006/06/08 23:55:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -55,6 +55,7 @@ extern char *optarg;
static void usage(void);
static void bootstrap_signals(void);
+static void ShutdownDummyProcess(int code, Datum arg);
static hashnode *AddStr(char *str, int strlength, int mderef);
static Form_pg_attribute AllocateAttribute(void);
static int CompHash(char *str, int len);
@@ -395,6 +396,9 @@ BootstrapMain(int argc, char *argv[])
/* finish setting up bufmgr.c */
InitBufferPoolBackend();
+
+ /* register a shutdown callback for LWLock cleanup */
+ on_shmem_exit(ShutdownDummyProcess, 0);
}
/*
@@ -417,8 +421,14 @@ BootstrapMain(int argc, char *argv[])
case BS_XLOG_STARTUP:
bootstrap_signals();
StartupXLOG();
+ /*
+ * These next two functions don't consider themselves critical,
+ * but we'd best PANIC anyway if they fail.
+ */
+ START_CRIT_SECTION();
LoadFreeSpaceMap();
BuildFlatFiles(false);
+ END_CRIT_SECTION();
proc_exit(0); /* startup done */
case BS_XLOG_BGWRITER:
@@ -552,6 +562,19 @@ bootstrap_signals(void)
}
}
+/*
+ * Begin shutdown of a dummy process. This is approximately the equivalent
+ * of ShutdownPostgres() in postinit.c. We can't run transactions in a
+ * dummy process, so most of the work of AbortTransaction() is not needed,
+ * but we do need to make sure we've released any LWLocks we are holding.
+ * (This is only critical during an error exit.)
+ */
+static void
+ShutdownDummyProcess(int code, Datum arg)
+{
+ LWLockReleaseAll();
+}
+
/* ----------------
* error handling / abort routines
* ----------------
--
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