diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2004-05-23 03:50:45 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2004-05-23 03:50:45 +0000 |
| commit | ebfc56d3fb41d914c799555a1f4c9d1a72379e9f (patch) | |
| tree | 7fb674efed5b26eb9a11b0e77733b2c8e7eaf642 /src/include/commands/async.h | |
| parent | 4d86ae42600c42834a55371630416e98593b7b11 (diff) | |
| download | postgresql-ebfc56d3fb41d914c799555a1f4c9d1a72379e9f.tar.gz postgresql-ebfc56d3fb41d914c799555a1f4c9d1a72379e9f.zip | |
Handle impending sinval queue overflow by means of a separate signal
(SIGUSR1, which we have not been using recently) instead of piggybacking
on SIGUSR2-driven NOTIFY processing. This has several good results:
the processing needed to drain the sinval queue is a lot less than the
processing needed to answer a NOTIFY; there's less contention since we
don't have a bunch of backends all trying to acquire exclusive lock on
pg_listener; backends that are sitting inside a transaction block can
still drain the queue, whereas NOTIFY processing can't run if there's
an open transaction block. (This last is a fairly serious issue that
I don't think we ever recognized before --- with clients like JDBC that
tend to sit with open transaction blocks, the sinval queue draining
mechanism never really worked as intended, probably resulting in a lot
of useless cache-reset overhead.) This is the last of several proposed
changes in response to Philip Warner's recent report of sinval-induced
performance problems.
Diffstat (limited to 'src/include/commands/async.h')
| -rw-r--r-- | src/include/commands/async.h | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/src/include/commands/async.h b/src/include/commands/async.h index bbfb24086e0..6429895fbdc 100644 --- a/src/include/commands/async.h +++ b/src/include/commands/async.h @@ -6,7 +6,7 @@ * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/commands/async.h,v 1.23 2003/11/29 22:40:59 pgsql Exp $ + * $PostgreSQL: pgsql/src/include/commands/async.h,v 1.24 2004/05/23 03:50:45 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -25,15 +25,14 @@ extern void AtCommit_Notify(void); extern void AtAbort_Notify(void); /* signal handler for inbound notifies (SIGUSR2) */ -extern void Async_NotifyHandler(SIGNAL_ARGS); +extern void NotifyInterruptHandler(SIGNAL_ARGS); /* * enable/disable processing of inbound notifies directly from signal handler. * The enable routine first performs processing of any inbound notifies that - * have occurred since the last disable. These are meant to be called ONLY - * from the appropriate places in PostgresMain(). + * have occurred since the last disable. */ extern void EnableNotifyInterrupt(void); -extern void DisableNotifyInterrupt(void); +extern bool DisableNotifyInterrupt(void); #endif /* ASYNC_H */ |