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authorAlvaro Herrera <alvherre@alvh.no-ip.org>2015-06-19 12:44:34 -0300
committerAlvaro Herrera <alvherre@alvh.no-ip.org>2015-06-19 12:44:34 -0300
commit5ac77a276311a7373950020973967d8d62e20d38 (patch)
tree2d11f84b7833c8b985cfada63872f91e818b9a84 /src
parent6199b1f90c5c3b800fa4d647e333c194ae4ee933 (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.
Diffstat (limited to 'src')
-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 8a6531a7b2c..682863b97a2 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;
@@ -873,6 +874,15 @@ 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;
}
/*