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| author | Robert Haas <rhaas@postgresql.org> | 2011-06-21 22:32:30 -0400 |
|---|---|---|
| committer | Robert Haas <rhaas@postgresql.org> | 2011-06-21 22:36:59 -0400 |
| commit | 7095003cbef630fe29c2299cc819fd37c691d0b0 (patch) | |
| tree | a248a40965cb734062621bc037e941429c74bc88 | |
| parent | 8f9fe6edce358f7904e0db119416b4d1080a83aa (diff) | |
| download | postgresql-7095003cbef630fe29c2299cc819fd37c691d0b0.tar.gz | |
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
| -rw-r--r-- | doc/src/sgml/config.sgml | 3 | ||||
| -rw-r--r-- | src/backend/utils/misc/guc.c | 4 |
2 files changed, 4 insertions, 3 deletions
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. </para> <para> 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 |