Re: Lock problem

On Wed, Apr 2, 2014 at 11:00 AM, Victor Sterpu <victor@caido.ro> wrote:
> All my transactions have commit or rollback.

Well, you have to verify that.  There's a couple of ways to do it.
Probably the most direct is to:
1. Make sure database is logging pids in log_line_prefix (this is a
good idea all around)
2. turn on all statement logging (be advised: this can eat a lot of
log space and slow down the server).

Those two changes do not require a restart.   A pg_ctl reload should
be sufficient.

Once you can do that, you should be able to locate database sessions
per pg_stat_activity that are 'idle in transaction' for a long time
without activity (anything over a second or so should be suspicious).
That will give the pid which you can then use to grep through the
statement log.

Common culprits are:
*) Dubious connection pooling solutions (php pconnect comes to mind)
*) Bad error handling logic in application (say, badly handled thrown exception)

merlin