Re: URGENT: Out of disk space pg_xlog

ohp(at)pyrenet(dot)fr wrote:
> On Fri, 22 Dec 2006, Tom Lane wrote:
>
> > Date: Fri, 22 Dec 2006 13:14:18 -0500
> > From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
> > To: Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>
> > Cc: Jeremy Haile <jhaile(at)fastmail(dot)fm>, pgsql-performance(at)postgresql(dot)org
> > Subject: Re: [PERFORM] URGENT: Out of disk space pg_xlog
> >
> > "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> writes:
> > > As I understand it, the log space accumulates for the oldest transaction
> > > which is still running, and all transactions which started after it.
> >
> > No, pg_xlog can be truncated as soon as a checkpoint occurs.
>
> Even for currently running transactions ?
>
> My understanding was that checkpoint was syncing data files for commited
> transactions.

No, it syncs data files for all transactions, even those currently
running.

> What happens to pg_xlogs when a transaction updates M of rows/tables and
> runs for hours?

They get recycled as the update goes.

--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.