Re: Misunderstanding deadlocks

From: pgsql-general-owner(at)postgresql(dot)org [mailto:pgsql-general-owner(at)postgresql(dot)org] On Behalf Of snacktime
Sent: Thursday, October 16, 2014 1:02 PM
To: pgsql-general(at)postgresql(dot)org
Subject: [GENERAL] Misunderstanding deadlocks

I'm confused about how deadlock detection and breaking deadlocks works. Googling around it seems that the server should be detecting deadlocks and aborting one of the queries.

But I'm getting occasional deadlocks that literally hang forever. I'm assuming they are deadlocks because they show up when running the queries I got from this url:

https://wiki.postgresql.org/wiki/Lock_Monitoring

I'm running postgres 9.3 on ubuntu, configuration is the default.

Chris

Deadlocks don’t “hang forever”.
Postgres is pretty good at discovering deadlocks.
Do you see circular dependency in your locks?
The fact that some query hangs forever only means that some resource that this query is looking for was not released by some other connection (user locked some object and went for a coffee break ☺

Regards,
Igor Neyman