Re: lock_timeout GUC patch - Review

From: Boszormenyi Zoltan <zb(at)cybertec(dot)at>
To: Marc Cousin <cousinmarc(at)gmail(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: lock_timeout GUC patch - Review
Date: 2010-08-02 11:25:48
Views: Raw Message | Whole Thread | Download mbox | Resend email
Lists: pgsql-hackers

Marc Cousin írta:
> The Thursday 29 July 2010 13:55:38, Boszormenyi Zoltan wrote :
>> I fixed this by adding CheckLockTimeout() function that works like
>> CheckStatementTimeout() and ensuring that the same start time is
>> used for both deadlock_timeout and lock_timeout if both are active.
>> The preference of errors if their timeout values are equal is:
>> statement_timeout > lock_timeout > deadlock_timeout
> As soon as lock_timeout is bigger than deadlock_timeout, it doesn't
> work, with this new version.
> Keeping the deadlock_timeout to 1s, when lock_timeout >= 1001,
> lock_timeout doesn't trigger anymore.

I missed one case when the lock_timeout_active should have been set
but the timer must not have been re-set, this caused the problem.
I blame the hot weather and having no air conditioning. The second is
now fixed. :-)

I also added one line in autovacuum.c to disable lock_timeout,
in case it's globally set in postgresq.conf as per Alvaro's comment.

Also, I made sure that only one or two timeout causes (one of
and lock_timeout in the first case or statement_timeout plus one of the
other two)
can be active at a time. Previously I was able to trigger a segfault
with the default
1sec deadlock_timeout and lock_timeout = 999 or 1001. Effectively, the
clock resolution makes the lock_timeout and deadlock_timeout equal and
RemoveFromWaitQueue() was called twice. This way it's a lot more robust.

Best regards,
Zoltán Böszörményi

Attachment Content-Type Size
5-pg91-locktimeout-19-ctxdiff.patch text/x-patch 40.1 KB

In response to


Browse pgsql-hackers by date

  From Date Subject
Next Message Robert Haas 2010-08-02 11:32:05 Re: Synchronous replication
Previous Message Fujii Masao 2010-08-02 11:06:28 Re: Synchronous replication