Re: URGENT: Out of disk space pg_xlog

Thanks for your reply.

I learnt something again!
On Fri, 22 Dec 2006, Alvaro Herrera wrote:

> Date: Fri, 22 Dec 2006 17:25:43 -0300
> From: Alvaro Herrera <alvherre(at)commandprompt(dot)com>
> To: ohp(at)pyrenet(dot)fr
> Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>,
> Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>,
> Jeremy Haile <jhaile(at)fastmail(dot)fm>, pgsql-performance(at)postgresql(dot)org
> Subject: Re: [PERFORM] 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.
>
>

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