Re: postgres deadlocks

On Wed, Jul 25, 2001 at 05:38:06PM -0400, Joseph Shraibman wrote:
> My postgres deadlocked again today. Logs indicated that before the
> nightly vacuum -z everything was fine, but after it was locked. The
> postgres.log contained the end of the vacuum which appeared to be
> consistant with the other vacuums in the log. A ps showed no vacuuming
> processes, but it did show one 'idle in transaction'. This problem last
> happened in Februrary when I was using 7.0.3.
>
> select version();
> version
> ---------------------------------------------------------------------
> PostgreSQL 7.1.2 on i686-pc-linux-gnu, compiled by GCC egcs-2.91.66
> (1 row)
>
>
> [root(at)p1 /var/log] ps ax | grep postgres
> 16973 ? S 0:36 postgres: user2 owl 127.0.0.1 idle
> 17105 ? S 0:01 postgres: user2 owl 127.0.0.1 idle
> 17122 ? S 1:51 postgres: user2 owl 127.0.0.1 idle
> 17302 ? S 1:19 postgres: user2 owl 127.0.0.1 UPDATE waiting
> 17453 ? S 0:32 postgres: user2 owl 127.0.0.1 idle
> 18202 ? S 0:03 postgres: user2 owl 127.0.0.1 idle
> 18351 ? S 0:12 postgres: user2 owl 127.0.0.1 idle in
> transaction
> 18352 ? S 0:00 postgres: user2 owl 127.0.0.1 idle
> 7137 ? S 0:00 postgres: user2 owl 127.0.0.1 idle
>
> --
> Joseph Shraibman
> jks(at)selectacast(dot)net
> Increase signal to noise ratio. http://www.targabot.com
>
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster

Whenever I've seen something like this it's turned out to be a deadlock
between the process in the transaction and the transaction (UPDATE in this
case) waiting.

I think it's generally bad for a client to be idle in a transaction?

Stephen