Re: replication slots replicated to standbys?

On 22 August 2016 at 10:31, Michael Paquier <michael(dot)paquier(at)gmail(dot)com>
wrote:

> On Sun, Aug 21, 2016 at 1:24 PM, Craig Ringer
> <craig(dot)ringer(at)2ndquadrant(dot)com> wrote:
> > On 21 Aug 2016 12:36 AM, "Bruce Momjian" <bruce(at)momjian(dot)us> wrote:
> >> Seems like another good idea to use pg_basebackup rather than manually
> >> doing base backups; Magnus has been saying this for a while.
> >
> > The main time that's an issue is when you're rsync'ing to save bandwidth,
> > using CoW volume snapshots, etc. pg_basebackup becomes totally
> impractical
> > on big systems.
>
> Yes, and that's not fun. Particularly when the backup takes so long
> that WAL has already been recycled... Replication slots help here but
> the partitions dedicated to pg_xlog have their limit as well.
>

We can and probably should allow XLogReader to invoke restore_command to
fetch WAL, read it, and discard/recycle it again. This would greatly
alleviate the pain of indefinite xlog retention.

It's a pain to do so while recovery.conf is its own separate magic though,
not part of postgresql.conf.

I have no plans to work on this at this time.

--
Craig Ringer http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services