Re: Turning recovery.conf into GUCs

On 2014-11-21 10:59:23 -0800, Josh Berkus wrote:
> On 11/21/2014 10:54 AM, Stephen Frost wrote:
> > * Josh Berkus (josh@agliodbs.com) wrote:
> >>> Either way, from the code it is clear that we only stay in recovery if
> >>> standby_mode is directly turned on.  This makes the whole check for a
> >>> specially named file unnecessary, IMO: we should just check the value of
> >>> standby_mode (which is off by default).
> >>
> >> So, what happens when someone does "pg_ctl promote"?  Somehow
> >> standby_mode needs to get set to "off".  Maybe we write "standby_mode =
> >> off" to postgresql.auto.conf?
> > 
> > Uhh, and then not work for the sane folks who disable
> > postgresql.auto.conf?  No thanks..
> 
> Other ideas then, without reverting to the old system?  Being able to
> promote servers over port 5432 will be a huge advantage for
> container-based systems, so I don't want to give that up as a feature.

Why is a trigger file making that impossible? Adding the code from
pg_ctl promote into a SQL callable function is a couple minutes worth of
work?

A guc alone won't work very well - standby_mode is checked in specific
places, you can't just turn that off and expect that that'd result in
speedy promotion. And it'd break people using scripts pg_standby. And it also
has other effects.

So, no.

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services