Re: New 8.4 hot standby feature

On Wednesday 28 January 2009 18:35:18 Gabi Julien wrote:
> On Tuesday 27 January 2009 21:47:36 you wrote:
> > Hi,
> >
> > On Wed, Jan 28, 2009 at 4:28 AM, Gabi Julien <gabi(dot)julien(at)broadsign(dot)com>
>
> wrote:
> > > Yes, the logs are shipped every minute but the recevory is 3 or 4 times
> > > longer.
> >
> > Are you disabling full_page_writes? It may slow down recovery several
> > times.
>
> It looks like you found my problem. Everything I needed to know is
> described here:
>
> http://www.postgresql.org/docs/8.3/interactive/wal-configuration.html
>
> Setting checkpoint_timeout to 55 seconds speeds up the recovery to the
> level I want. Ironically, it makes the pg_last_recovered_xact_timestamp()
> function more reliable too on how up to date the replica is. I am not sure
> that I can take this for granted however.

This is a good question actually. If I set the checkpoint_timeout to
something less then the archive_timeout, can I take this for granted the fact
that pg_last_recovered_xact_timestamp() will always accurately tell me how up
to date the replica is?