Re: Hot Standby remaining issues - Mailing list pgsql-hackers

From Simon Riggs
Subject Re: Hot Standby remaining issues
Date
Msg-id 1259772113.13774.23386.camel@ebony
Whole thread Raw
In response to Re: Hot Standby remaining issues  (Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>)
Responses Re: Hot Standby remaining issues
List pgsql-hackers
On Tue, 2009-12-01 at 20:26 +0200, Heikki Linnakangas wrote:
> Simon Riggs wrote:
> > commit 02c3eadb766201db084b668daa271db4a900adc9
> > Author: Simon Riggs <sriggs@ebony.(none)>
> > Date:   Sat Nov 28 06:23:33 2009 +0000
> > 
> >     Added wal_standby_info GUC to turn RM_STANDBY_ID messages on/off.
> >     Various comments added also.
> > 
> 
> This patch makes it unsafe to start hot standby mode from a shutdown
> checkpoint, because we don't know if wal_standby_info was enabled in the
> master.

> I still don't think we need the GUC. 

If that's a good plan we can remove it in late beta. Let's keep it there
for now.

> But for future-proofing, perhaps we
> should add a flag to shutdown checkpoint records, indicating whether
> it's safe to start hot standby from it. That way, if we decide to add a
> GUC like that at a later stage, we don't need to change the on-disk format.

OK, I understand this now. Taken me a while, even though obvious now I
see.

-- Simon Riggs           www.2ndQuadrant.com



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