From 5df64f298d2863c9fb39437abb3ae6f988aedc0a Mon Sep 17 00:00:00 2001 From: Alvaro Herrera Date: Wed, 8 Apr 2015 13:19:49 -0300 Subject: [PATCH] Fix autovacuum launcher shutdown sequence It was previously possible to have the launcher re-execute its main loop before shutting down if some other signal was received or an error occurred after getting SIGTERM, as reported by Qingqing Zhou. While investigating, Tom Lane further noticed that if autovacuum had been disabled in the config file, it would misbehave by trying to start a new worker instead of bailing out immediately -- it would consider itself as invoked in emergency mode. Fix both problems by checking the shutdown flag in a few more places. These problems have existed since autovacuum was introduced, so backpatch all the way back. --- src/backend/postmaster/autovacuum.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c index db46134979..be4cd1d9f1 100644 --- a/src/backend/postmaster/autovacuum.c +++ b/src/backend/postmaster/autovacuum.c @@ -507,6 +507,10 @@ AutoVacLauncherMain(int argc, char *argv[]) /* Now we can allow interrupts again */ RESUME_INTERRUPTS(); + /* if in shutdown mode, no need for anything further; just go away */ + if (got_SIGTERM) + goto shutdown; + /* * Sleep at least 1 second after any error. We don't want to be * filling the error logs as fast as we can. @@ -542,10 +546,14 @@ AutoVacLauncherMain(int argc, char *argv[]) SetConfigOption("default_transaction_isolation", "read committed", PGC_SUSET, PGC_S_OVERRIDE); - /* in emergency mode, just start a worker and go away */ + /* + * In emergency mode, just start a worker (unless shutdown was requested) + * and go away. + */ if (!AutoVacuumingActive()) { - do_start_worker(); + if (!got_SIGTERM) + do_start_worker(); proc_exit(0); /* done */ } @@ -560,7 +568,8 @@ AutoVacLauncherMain(int argc, char *argv[]) */ rebuild_database_list(InvalidOid); - for (;;) + /* loop until shutdown request */ + while (!got_SIGTERM) { struct timeval nap; TimestampTz current_time = 0; @@ -758,6 +767,7 @@ AutoVacLauncherMain(int argc, char *argv[]) } /* Normal exit from the autovac launcher is here */ +shutdown: ereport(LOG, (errmsg("autovacuum launcher shutting down"))); AutoVacuumShmem->av_launcherpid = 0;