Re: Deadlocks ? - Mailing list pgsql-admin

From Tino Schwarze
Subject Re: Deadlocks ?
Date
Msg-id 20080513193048.GA15701@easy2.in-chemnitz.de
Whole thread Raw
In response to Deadlocks ?  (kevin kempter <kevin@kevinkempterllc.com>)
Responses Re: Deadlocks ?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-admin
On Tue, May 13, 2008 at 01:18:24PM -0600, kevin kempter wrote:

> we seem to be getting deadlock quite a lot. We have a python process
> that does the following and we keep getting deadlocks. Is this a real
> deadlock or maybe a wait condition? Any help in debugging / resolving
> this would be much appreciated.

An easy way to avoid deadlocks is to lock tables always in the same
order.

> cursor.execute("lock player_log_uuid in share update exclusive mode")
>
>
> >Traceback (most recent call last):
> >  File "StatsParser.py", line 740, in InsertData
> >    cursor.execute("lock player_log_uuid in share update exclusive
> >mode")
> >ProgrammingError: deadlock detected
> >DETAIL:  Process 23098 waits for ShareUpdateExclusiveLock on
> >relation 428126 of database 427376; blocked by process 23916.
> >Process 23916 waits for ShareLock on transaction 46802680; blocked
> >by process 23098.

I've never figured out how to resolve the "lock on transaction" to
something understandable...

HTH,

Tino.

--
"What we resist, persists." (Zen saying)

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