Re: Hot standby, pausing recovery

Simon Riggs wrote:
> On Fri, 2009-10-16 at 09:33 +0300, Heikki Linnakangas wrote:
>> If you pause recovery, and then continue, we reset to "target none"
>> mode, even if a stopping point was set previously.
>
> Yes, currently. Resetting the target mode will do what you want, rather
> than continue.
>
>> That doesn't seem right to me.
>
> We can define these things various ways and I'm happy to change it to be
> the way people find most intuitive and useful. You're the first person
> to give me feedback on how these things should work, so I'm happy to
> hear how you would like it to work.

Thinking about the interface a bit more: pg_recovery_advance() isn't
very useful except for debugging hot standby itself. Normal users don't
care about individual WAL records, since the effect of record X isn't
visible until the transaction commit record anyway. A function to
advance to next *commit* record would make a lot more sense, allowing
you to step through transactions one at a time.

A function to step forward X minutes would be useful too.

At this point, I'd like to cut out all those control functions to
pause/stop at various points from the patch. They're not required for
Hot Standby, and the less stuff I have to review right now the better.
Don't get me wrong, I absolutely love those functions, it's a great
feature that I do want to get in before release, but we need more
discussion on the exact set of functions and how they should work.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com