Re: [PATCHES] Restartable Recovery

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.

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.
        regards, tom lane