Re: [COMMITTERS] pgsql: Basic Recovery Control functions for use in Hot Standby. Pause,

On Wed, Feb 9, 2011 at 2:02 PM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>> Why did you change the default to on? This would surprise people who are
>> used to PITR.
>
> You pointed out that the code did not match the documented default. So I
> made them match according to the docs.

Well, I meant changing the docs rather than the code.

> Making it pause at target by default is more natural behaviour, even if
> it is a change of behaviour. It can waste a lot of time if it leaves
> recovery at the wrong point so I don't see the change as a bad one? Only
> PITR is affected, not replication or standalone operation.

I agree that new option is useful to reduce the waste of time as you described.
But I'm still not sure that the change of default behavior is better.
Because I can
easily imagine the case where a user feels confused about the pause of PITR
when he starts PITR as he did in previous version. It would take some time for
him to learn what to do in that situation (i.e., execute pg_xlog_replay_resume).

On the second thought, I think it's useful to emit the NOTICE message when
recovery reaches the pause point, as follows.

NOTICE: Recovery will not complete until pg_xlog_replay_resume() is called.

Regards,

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