Re: Turning recovery.conf into GUCs

On 2014-11-24 12:02:52 -0800, Josh Berkus wrote:
> On 11/24/2014 09:24 AM, Jaime Casanova wrote:
> >> ... I don't honestly think we need a 4th method for promotion.
> >>
> >
> > this is not for promotion, this is to force postgres to start in
> > recovery mode and read recovery configuration parameters.
> >
> >> The main reason to want a "we're in recovery file" is for PITR rather
> >> than for replication, where it has a number of advantages as a method,
> >> the main one being that recovery.conf is unlikely to be overwritten by
> >> the contents of the backup.
> >>
> >
> > only that you need to start in recovery mode to start replication
>
> Right, but my point is that having a trigger file *is not necessary for
> replication, only for PITR* -- and maybe not necessary even for PITR.
> That is, in a streaming replication configuration, having a
> "standby_mode = on|off" parameter is 100% sufficient to control
> replication with the small detail that "pg_ctl promote" needs to set it
> in pg.auto.conf or conf.d.
>
> And, now, having given it some thought, I'm going to argue that it's not
> required for PITR either, provided that we can use the auto.conf method.
>
> Before I go into my ideas, though, what does the current patch do
> regarding non-replication PITR?

Guys. We aren't rereading the GUCs in the relevant places. It's also
decidedly nontrivial to make standby_mode PGC_SIGHUP. Don't make this
patch more complex than it has to be. That's what stalled it the last
times round.

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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