From: Robert Haas Date: Wed, 22 Jun 2011 02:32:30 +0000 (-0400) Subject: Make deadlock_timeout PGC_SUSET rather than PGC_SIGHUP. X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=7095003cbef630fe29c2299cc819fd37c691d0b0;p=pg-rex%2Fsyncrep.git Make deadlock_timeout PGC_SUSET rather than PGC_SIGHUP. This allows deadlock_timeout to be reduced for transactions that are particularly likely to be involved in a deadlock, thus detecting it more quickly. It is also potentially useful as a poor-man's deadlock priority mechanism: a transaction with a high deadlock_timeout is less likely to be chosen as the victim than one with a low deadlock_timeout. Since that could be used to game the system, we make this PGC_SUSET rather than PGC_USERSET. At some point, it might be worth thinking about a more explicit priority mechanism, since using this is far from fool-proof. But let's see whether there's enough use case to justify the additional work before we go down that route. Noah Misch, reviewed by Shigeru Hanada --- diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 794aef4e6a..3f6986fc1b 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -5266,7 +5266,8 @@ dynamic_library_path = 'C:\tools\postgresql;H:\my_project\lib;$libdir' practice. On a heavily loaded server you might want to raise it. Ideally the setting should exceed your typical transaction time, so as to improve the odds that a lock will be released before - the waiter decides to check for deadlock. + the waiter decides to check for deadlock. Only superusers can change + this setting. diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 1c6f197748..6e85cb5335 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -1532,8 +1532,8 @@ static struct config_int ConfigureNamesInt[] = }, { - /* This is PGC_SIGHUP so all backends have the same value. */ - {"deadlock_timeout", PGC_SIGHUP, LOCK_MANAGEMENT, + /* This is PGC_SUSET to prevent hiding from log_lock_waits. */ + {"deadlock_timeout", PGC_SUSET, LOCK_MANAGEMENT, gettext_noop("Sets the time to wait on a lock before checking for deadlock."), NULL, GUC_UNIT_MS