Re: (replication) Detecting if server a slave, or a master in recovery

On Mon, 2011-09-12 at 17:09 +1000, Toby Corkindale wrote:
> On 12/09/11 16:54, Toby Corkindale wrote:
> > Hi,
> > What is the correct way to tell what mode a replicated Pg server is
> > currently in, via a database connection?
> >
> > I can take a guess if it's the master or a slave by using the
> > pg_current_xlog_location() and pg_last_xlog_replay_location() functions.
> >
> > However it occurs to me that a master server, which has been roughly
> > rebooted and is replaying its WAL files will probably give the same
> > response as a slave, when I call the current_xlog_location().
> >
> >
> > What is the best method for determining whether you're connected to the
> > master or slave database?
>
>
> It's disappointing that I can't query standby_mode in psql.
> ie.
> SHOW standby_mode;
>

I agree. Actually, you can't get the value of any parameter set in
recovery.conf. But Fuji Masao seems to work on it: he posted a patch to
unite recovery.conf and postgresql.conf (see "unite recovery.conf and
postgresql.conf" thread on pgsql-hackers). And I guess it'll help us
querying these parameters' values.

--
Guillaume
http://blog.guillaume.lelarge.info
http://www.dalibo.com