Re: [PATCHES] Restartable Recovery

On Sun, 2006-07-16 at 15:33 -0400, Tom Lane wrote:
> Simon Riggs <simon@2ndquadrant.com> writes:
> > On Sun, 2006-07-16 at 12:40 -0400, Tom Lane wrote:
> >> A compromise that might be good enough is to add an rmgr routine defined
> >> as "bool is_idle(void)" that tests whether the rmgr has any open state
> >> to worry about.  Then, recovery checkpoints are done only if all rmgrs
> >> say they are idle.  
> 
> > Perhaps that should be extended to say whether there are any
> > non-idempotent changes made in the last checkpoint period. That might
> > cover a wider set of potential actions.
> 
> Perhaps best to call it safe_to_checkpoint(), and not pre-judge what
> reasons the rmgr might have for not wanting to restart here.

You read my mind.

> If we are only going to do a recovery checkpoint at every Nth checkpoint
> record, then occasionally having to skip one seems no big problem ---
> just do it at the first subsequent record that is safe.

Got it.

--  Simon Riggs EnterpriseDB          http://www.enterprisedb.com