Re: how to delay sync by a set time, hour or day?

On 20 Nov 2014 06:11, "John Smith" <jayzee(dot)smith(at)gmail(dot)com> wrote:
>
> On 11/19/14, Michael Paquier <michael(dot)paquier(at)gmail(dot)com> wrote:
> > On Wed, Nov 19, 2014 at 8:37 AM, John Smith <jayzee(dot)smith(at)gmail(dot)com>
wrote:
> >>
> >> i want to setup a standby slave that listens 24/7 but only syncs when
told
> >> to.
> >>
> >> setting "pause_at_recovery_target (boolean)" in recovery.conf on slave
> >> doesn't help since docs say it only "specifies whether recovery should
> >> pause when the recovery target is reached."
> >>
> >> also "recovery_target = 'immediate'" is the only value allowed.
> >>
> >> i want to delay sync by a set time, hour or day.
> >>
> >> how?
> >> http://www.postgresql.org/docs/9.3/static/recovery-target-settings.html
> >
> > Aren't pg_xlog_replay_pause and pg_xlog_replay_resume what you are
looking
> > for?
> >
http://www.postgresql.org/docs/devel/static/functions-admin.html#FUNCTIONS-RECOVERY-CONTROL
> > --
> > Michael
> >
>
> can i use "pg_start_backup('name');" and "pg_stop_backup();"? how
> would they work ie if i stop backup, make changes to master, copy
> master's /data/ to slave and restart backup, slave should catch-up
> with master, right?
>
> is this the same if i use "pg_xlog_replay_pause()" and
> "pg_xlog_replay_resume()".
>
> when would i use "pg_stop_backup();" over "pg_xlog_replay_pause()",
> aside from user restrictions.
>

These are two different functions with different purpose. pg_stop_backup
marks the stop of a backup process (and not the recovery or restore
process). It makes postgres flush the wal to archives and reset other stuff
that pg_start_backup would have done in order to mark the begining of a
backup process. What you are probably trying to do is stop at a point
during recovery- either while restoring from a backup or during a recovery
on a standby db. If later is your case then use the suggested
pg_xlog_replay_pause.

> thanks, jzs
>
>
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