From: Robert Haas <rhaas@postgresql.org>
Date: Thu, 26 Jul 2012 13:18:32 +0000 (-0400)
Subject: Log a better message when canceling autovacuum.
X-Git-Tag: REL9_1_5~22
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a1195a5c26c316b46a6c4a8268116b6deeab2d72;p=postgresql

Log a better message when canceling autovacuum.

The old message was at DEBUG2, so typically it didn't show up in the
log at all.  As a result, in most cases where autovacuum was canceled,
the only information that was logged was the table being vacuumed,
with no indication as to what problem caused the cancel.  Crank up
the level to LOG and add some more details to assist with debugging.

Back-patch all the way, per discussion on pgsql-hackers.
---

diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 6ea2fed0b8..ffab85f665 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -1033,12 +1033,29 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 				!(autovac->vacuumFlags & PROC_VACUUM_FOR_WRAPAROUND))
 			{
 				int			pid = autovac->pid;
+				StringInfoData locktagbuf;
+				StringInfoData logbuf;		/* errdetail for server log */
+
+				initStringInfo(&locktagbuf);
+				initStringInfo(&logbuf);
+				DescribeLockTag(&locktagbuf, &lock->tag);
+				appendStringInfo(&logbuf,
+					  _("Process %d waits for %s on %s"),
+						 MyProcPid,
+						 GetLockmodeName(lock->tag.locktag_lockmethodid,
+										 lockmode),
+						 locktagbuf.data);
+
+				/* release lock as quickly as possible */
+				LWLockRelease(ProcArrayLock);
 
-				elog(DEBUG2, "sending cancel to blocking autovacuum PID %d",
-					 pid);
+				ereport(LOG,
+						(errmsg("sending cancel to blocking autovacuum PID %d",
+							pid),
+						 errdetail_log("%s", logbuf.data)));
 
-				/* don't hold the lock across the kill() syscall */
-				LWLockRelease(ProcArrayLock);
+				pfree(logbuf.data);
+				pfree(locktagbuf.data);
 
 				/* send the autovacuum worker Back to Old Kent Road */
 				if (kill(pid, SIGINT) < 0)