Have autovacuum workers listen to SIGHUP, too

They have historically ignored it, but it's been said to be useful at
times to change their settings mid-flight.

Author: Michael Paquier

diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 080c3e62df8f6e7c167ce8a424719e29f4497ec1..b2d37e5d4799c3c582e1c7d2d458864c51723ec1 100644 (file)
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -311,7 +311,7 @@ static PgStat_StatTabEntry *get_pgstat_tabentry_relid(Oid relid, bool isshared,
                                                  PgStat_StatDBEntry *shared,
                                                  PgStat_StatDBEntry *dbentry);
 static void autovac_report_activity(autovac_table *tab);
-static void avl_sighup_handler(SIGNAL_ARGS);
+static void av_sighup_handler(SIGNAL_ARGS);
 static void avl_sigusr2_handler(SIGNAL_ARGS);
 static void avl_sigterm_handler(SIGNAL_ARGS);
 static void autovac_refresh_stats(void);
@@ -419,7 +419,7 @@ AutoVacLauncherMain(int argc, char *argv[])
         * backend, so we use the same signal handling.  See equivalent code in
         * tcop/postgres.c.
         */
-       pqsignal(SIGHUP, avl_sighup_handler);
+       pqsignal(SIGHUP, av_sighup_handler);
        pqsignal(SIGINT, StatementCancelHandler);
        pqsignal(SIGTERM, avl_sigterm_handler);
 
@@ -1329,7 +1329,7 @@ AutoVacWorkerFailed(void)
 
 /* SIGHUP: set flag to re-read config file at next convenient time */
 static void
-avl_sighup_handler(SIGNAL_ARGS)
+av_sighup_handler(SIGNAL_ARGS)
 {
        int                     save_errno = errno;
 
@@ -1460,11 +1460,8 @@ AutoVacWorkerMain(int argc, char *argv[])
         * Set up signal handlers.  We operate on databases much like a regular
         * backend, so we use the same signal handling.  See equivalent code in
         * tcop/postgres.c.
-        *
-        * Currently, we don't pay attention to postgresql.conf changes that
-        * happen during a single daemon iteration, so we can ignore SIGHUP.
         */
-       pqsignal(SIGHUP, SIG_IGN);
+       pqsignal(SIGHUP, av_sighup_handler);
 
        /*
         * SIGINT is used to signal canceling the current table's vacuum; SIGTERM
@@ -2163,6 +2160,22 @@ do_autovacuum(void)
 
                CHECK_FOR_INTERRUPTS();
 
+               /*
+                * Check for config changes before processing each collected table.
+                */
+               if (got_SIGHUP)
+               {
+                       got_SIGHUP = false;
+                       ProcessConfigFile(PGC_SIGHUP);
+
+                       /*
+                        * You might be tempted to bail out if we see autovacuum is now
+                        * disabled.  Must resist that temptation -- this might be a
+                        * for-wraparound emergency worker, in which case that would be
+                        * entirely inappropriate.
+                        */
+               }
+
                /*
                 * hold schedule lock from here until we're sure that this table still
                 * needs vacuuming.  We also need the AutovacuumLock to walk the