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authorAlvaro Herrera2015-06-19 15:44:36 +0000
committerAlvaro Herrera2015-06-19 15:44:36 +0000
commitda1a9d0f5bed1f93908be9233a4fef39b988e505 (patch)
tree23976a4d424ca1f0ceb236ec821667d197022c9d
parentbe87143fe90adf8862791aeddd76151e88ce5603 (diff)
Clamp autovacuum launcher sleep time to 5 minutes
This avoids the problem that it might go to sleep for an unreasonable amount of time in unusual conditions like the server clock moving backwards an unreasonable amount of time. (Simply moving the server clock forward again doesn't solve the problem unless you wake up the autovacuum launcher manually, say by sending it SIGHUP). Per trouble report from Prakash Itnal in https://www.postgresql.org/message-id/CAHC5u79-UqbapAABH2t4Rh2eYdyge0Zid-X=Xz-ZWZCBK42S0Q@mail.gmail.com Analyzed independently by Haribabu Kommi and Tom Lane.
-rw-r--r--src/backend/postmaster/autovacuum.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 5b69959444..45d00abed4 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -128,6 +128,7 @@ int Log_autovacuum_min_duration = -1;
/* the minimum allowed time between two awakenings of the launcher */
#define MIN_AUTOVAC_SLEEPTIME 100.0 /* milliseconds */
+#define MAX_AUTOVAC_SLEEPTIME 300 /* seconds */
/* Flags to tell if we are in an autovacuum process */
static bool am_autovacuum_launcher = false;
@@ -844,6 +845,15 @@ launcher_determine_sleep(bool canlaunch, bool recursing, struct timeval * nap)
nap->tv_sec = 0;
nap->tv_usec = MIN_AUTOVAC_SLEEPTIME * 1000;
}
+
+ /*
+ * If the sleep time is too large, clamp it to an arbitrary maximum (plus
+ * any fractional seconds, for simplicity). This avoids an essentially
+ * infinite sleep in strange cases like the system clock going backwards a
+ * few years.
+ */
+ if (nap->tv_sec > MAX_AUTOVAC_SLEEPTIME)
+ nap->tv_sec = MAX_AUTOVAC_SLEEPTIME;
}
/*