Re: Hot Standby on git

On Fri, 2009-10-02 at 11:26 +0300, Heikki Linnakangas wrote:
> Simon Riggs wrote:
> > On Fri, 2009-10-02 at 10:43 +0300, Heikki Linnakangas wrote:
> > 
> >> It seems dangerous to write a WAL record after the shutdown checkpoint.
> >> It will be overwritten by subsequent startup, which is a recipe for trouble.
> > 
> > I've said its a corner case and not worth spending time on. I'm putting
> > it in at your request. If it's not correct before and not correct after,
> > where exactly do you want it?
> 
> I don't know. Perhaps it should go between the REDO pointer of the
> shutdown checkpoint and the checkpoint record itself. Or maybe the
> information should be included in the checkpoint record itself.

I've implemented this but it requires us to remove two checks - one at
shutdown and one at startup on a shutdown checkpoint. I'm not happy
doing that and would like to put them back.

I'd rather just skip this for now. It's a minor case anyway and there's
nothing stopping writing their own RunningXactData records with a
function, if it is needed. I can add a function for that.

-- Simon Riggs           www.2ndQuadrant.com