Re: 2PC-induced lockup - Mailing list pgsql-hackers

From tomas@tuxteam.de
Subject Re: 2PC-induced lockup
Date
Msg-id 20070711040713.GA19967@www.trapp.net
Whole thread Raw
In response to Re: 2PC-induced lockup  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: 2PC-induced lockup  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
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On Tue, Jul 10, 2007 at 10:41:31AM -0400, Tom Lane wrote:
> Peter Eisentraut <peter_e@gmx.net> writes:
> > The following command sequence appears to lock up the database system:
> > BEGIN;
> > LOCK pg_authid;
> > PREPARE TRANSACTION 'foo';
> > \q
> 
> > After that you can't connect anymore, even in single-user mode.  The
> > only way I could find is to clear out the pg_twophase directory, but
> > I'm not sure whether it is safe to do that.
> 
> > Should this be prevented somehow, and is there a better recovery path?
> 
> AFAICS this is just one of many ways in which a superuser can shoot
> himself in the foot; I'm not eager to try to prevent it.
> 
> Right offhand, clearing pg_twophase while the system is stopped should
> be safe enough.

It might make sense then to clear the pg_twophase directory on DB
startup. Nobody would expect the locks to persist a database restart --
or am I way off?

Regards
- -- tomás
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