Re: Streaming replication, and walsender during recovery

On Fri, Jan 29, 2010 at 5:41 PM, Simon Riggs <simon@2ndquadrant.com> wrote:
>> To improve the situation, I think that we need to use
>> checkpoint_segment/timeout as a trigger of restartpoint, regardless
>> of the checkpoint record. Though I'm not sure that is possible and
>> should be included in v9.0.
>
> Yes, that is a simple change. I think it is needed now.

On second thought, it's difficult to force restartpoint without
a checkpoint record. A recovery always needs to start from a
checkpoint redo location. Otherwise a torn page might be caused
because a full-page image has not been replayed. So restartpoint
will not start without a checkpoint record.

But at least we might have to change the bgwriter so as to use
not only checkpoint_timeout but also checkpoint_segments as a
trigger of restartpoint. It would be useful for people who want
to control the cycle of checkpoint by using only checkpoint_segments.

Regards,

-- 
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center