diff options
| author | Tom Lane | 2009-02-13 17:12:04 +0000 |
|---|---|---|
| committer | Tom Lane | 2009-02-13 17:12:04 +0000 |
| commit | 5d2a33cc53db4d1996c81ab09c879ab8e5f31acb (patch) | |
| tree | edafafe6fb25a6d54633be2de6859e0f4bcbcc59 | |
| parent | 9697aaab2fdebcaa1107bdf918c3fec8378b3b24 (diff) | |
Fix UNLISTEN to fall out quickly if the current backend has never executed
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.
| -rw-r--r-- | src/backend/commands/async.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index a6b93e5910..d410b2d47d 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -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, ""); } |