Reduce the maximum sleep interval in the autovac launcher to 1 second,

so that it responds to SIGQUIT reasonably promptly even on machines where
SA_RESTART signals restart a sleep from scratch.  (This whole area could
stand some rethinking, but for now make it work like the other processes
do.)  Also some marginal stylistic cleanups.

diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index a00f6d708d2ce8820ab87e9db55337520d0c7e14..aa674e54f9200f9aec1236c822bd8f965a462f6c 100644 (file)
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -55,7 +55,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.54 2007/07/01 02:20:59 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.55 2007/07/01 18:30:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -99,10 +99,6 @@
 #include "utils/syscache.h"
 
 
-static volatile sig_atomic_t got_SIGUSR1 = false;
-static volatile sig_atomic_t got_SIGHUP = false;
-static volatile sig_atomic_t avlauncher_shutdown_request = false;
-
 /*
  * GUC parameters
  */
@@ -121,13 +117,15 @@ int                       autovacuum_vac_cost_limit;
 int                    Log_autovacuum = -1;
 
 
-/* maximum sleep duration in the launcher, in seconds */
-#define AV_SLEEP_QUANTUM 10
-
 /* Flags to tell if we are in an autovacuum process */
 static bool am_autovacuum_launcher = false;
 static bool am_autovacuum_worker = false;
 
+/* Flags set by signal handlers */
+static volatile sig_atomic_t got_SIGHUP = false;
+static volatile sig_atomic_t got_SIGUSR1 = false;
+static volatile sig_atomic_t got_SIGTERM = false;
+
 /* Comparison point for determining whether freeze_max_age is exceeded */
 static TransactionId recentXid;
 
@@ -291,7 +289,7 @@ static PgStat_StatTabEntry *get_pgstat_tabentry_relid(Oid relid, bool isshared,
 static void autovac_report_activity(VacuumStmt *vacstmt, Oid relid);
 static void avl_sighup_handler(SIGNAL_ARGS);
 static void avl_sigusr1_handler(SIGNAL_ARGS);
-static void avlauncher_shutdown(SIGNAL_ARGS);
+static void avl_sigterm_handler(SIGNAL_ARGS);
 static void avl_quickdie(SIGNAL_ARGS);
 
 
@@ -411,7 +409,7 @@ AutoVacLauncherMain(int argc, char *argv[])
        pqsignal(SIGHUP, avl_sighup_handler);
 
        pqsignal(SIGINT, SIG_IGN);
-       pqsignal(SIGTERM, avlauncher_shutdown);
+       pqsignal(SIGTERM, avl_sigterm_handler);
        pqsignal(SIGQUIT, avl_quickdie);
        pqsignal(SIGALRM, SIG_IGN);
 
@@ -544,23 +542,27 @@ AutoVacLauncherMain(int argc, char *argv[])
                                                                 INVALID_OFFSET, false, &nap);
 
                /*
-                * Sleep for a while according to schedule.  We only sleep in
-                * AV_SLEEP_QUANTUM second intervals, in order to promptly notice
-                * postmaster death.
+                * Sleep for a while according to schedule.
+                *
+                * On some platforms, signals won't interrupt the sleep.  To ensure we
+                * respond reasonably promptly when someone signals us, break down the
+                * sleep into 1-second increments, and check for interrupts after each
+                * nap.
                 */
                while (nap.tv_sec > 0 || nap.tv_usec > 0)
                {
                        uint32  sleeptime;
 
-                       sleeptime = nap.tv_usec;
-                       nap.tv_usec = 0;
-
                        if (nap.tv_sec > 0)
                        {
-                               sleeptime += Min(nap.tv_sec, AV_SLEEP_QUANTUM) * 1000000;
-                               nap.tv_sec -= Min(nap.tv_sec, AV_SLEEP_QUANTUM);
+                               sleeptime = 1000000;
+                               nap.tv_sec--;
+                       }
+                       else
+                       {
+                               sleeptime = nap.tv_usec;
+                               nap.tv_usec = 0;
                        }
-                       
                        pg_usleep(sleeptime);
 
                        /*
@@ -570,12 +572,12 @@ AutoVacLauncherMain(int argc, char *argv[])
                        if (!PostmasterIsAlive(true))
                                exit(1);
 
-                       if (avlauncher_shutdown_request || got_SIGHUP || got_SIGUSR1)
+                       if (got_SIGTERM || got_SIGHUP || got_SIGUSR1)
                                break;
                }
 
                /* the normal shutdown case */
-               if (avlauncher_shutdown_request)
+               if (got_SIGTERM)
                        break;
 
                if (got_SIGHUP)
@@ -788,7 +790,7 @@ launcher_determine_sleep(bool canlaunch, bool recursing, struct timeval *nap)
         * We only recurse once.  rebuild_database_list should always return times
         * in the future, but it seems best not to trust too much on that.
         */
-       if (nap->tv_sec == 0L && nap->tv_usec == 0 && !recursing)
+       if (nap->tv_sec == 0 && nap->tv_usec == 0 && !recursing)
        {
                rebuild_database_list(InvalidOid);
                launcher_determine_sleep(canlaunch, true, nap);
@@ -796,9 +798,9 @@ launcher_determine_sleep(bool canlaunch, bool recursing, struct timeval *nap)
        }
 
        /* 100ms is the smallest time we'll allow the launcher to sleep */
-       if (nap->tv_sec <= 0L && nap->tv_usec <= 100000)
+       if (nap->tv_sec <= 0 && nap->tv_usec <= 100000)
        {
-               nap->tv_sec = 0L;
+               nap->tv_sec = 0;
                nap->tv_usec = 100000;  /* 100 ms */
        }
 }
@@ -1276,10 +1278,11 @@ avl_sigusr1_handler(SIGNAL_ARGS)
        got_SIGUSR1 = true;
 }
 
+/* SIGTERM: time to die */
 static void
-avlauncher_shutdown(SIGNAL_ARGS)
+avl_sigterm_handler(SIGNAL_ARGS)
 {
-       avlauncher_shutdown_request = true;
+       got_SIGTERM = true;
 }
 
 /*