mirrors/postgres
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix UNLISTEN to fall out quickly if the current backend has never executed

Browse Source 
any LISTEN command.  This is more important than it used to be because
DISCARD ALL invokes UNLISTEN.  Connection-pooled applications making heavy
use of DISCARD ALL were seeing significant contention for pg_listener,
as reported by Matteo Beccati.  It seems unlikely that clients using LISTEN
would use pooled connections, so this simple tweak seems sufficient,
especially since the pg_listener implementation is slated to go away soon
anyway.

Back-patch to 8.3, where DISCARD ALL was introduced.
This commit is contained in:
Tom Lane 2009-02-13 17:12:04 +00:00
parent 30735adfe4
commit ca5646fc82
1 changed files with 9 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
src/backend/commands/async.c
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/async.c,v 1.145 2009/01/01 17:23:37 momjian Exp $
* $PostgreSQL: pgsql/src/backend/commands/async.c,v 1.146 2009/02/13 17:12:04 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -277,6 +277,10 @@ Async_Unlisten(const char *relname)
if (Trace_notify)
elog(DEBUG1, "Async_Unlisten(%s,%d)", relname, MyProcPid);
/* If we couldn't possibly be listening, no need to queue anything */
if (pendingActions == NIL && !unlistenExitRegistered)
return;
queue_listen(LISTEN_UNLISTEN, relname);
}
@ -291,6 +295,10 @@ Async_UnlistenAll(void)
if (Trace_notify)
elog(DEBUG1, "Async_UnlistenAll(%d)", MyProcPid);
/* If we couldn't possibly be listening, no need to queue anything */
if (pendingActions == NIL && !unlistenExitRegistered)
return;
queue_listen(LISTEN_UNLISTEN_ALL, "");
}