Re: Stefan's bug (was: max_standby_delay considered harmful)

On Tue, May 18, 2010 at 3:24 PM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> On Tue, 2010-05-18 at 15:09 +0900, Fujii Masao wrote:
>> On Tue, May 18, 2010 at 2:26 PM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>> > On Tue, 2010-05-18 at 12:02 +0900, Fujii Masao wrote:
>> >> On Mon, May 17, 2010 at 9:01 PM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>> >> >> (1)
>> >> >> Smart or fast shutdown requested in PM_STARTUP state always removes
>> >> >> the backup_label file if it exists. But it might be still required
>> >> >> for subsequent recovery. I changed your patch so that additionally
>> >> >> the postmaster skips deleting the backup_label in that case.
>> >> >
>> >> > Don't like the name NeedBackupLabel seems too specific. That really
>> >> > corresponds to "we were in recovery". We should have a couple of
>> >> > super-states that correspond to am in recovery/am not in recovery so we
>> >> > can drive it from that.
>> >>
>> >> ISTM that we can use XLogCtl->SharedRecoveryInProgress for that.
>> >> Is this OK?
>> >
>> > That can change state at any time. Would that work?
>>
>> Yes. XLogCtl->SharedRecoveryInProgress is set to TRUE only when
>> XLogCtl structure is initialized (i.e., XLOGShmemInit), and it's
>> set to FALSE only at the end of recovery.
>
> You should be using RecoveryInProgress()

Isn't access to a bool variable atomic?

And I think that postmaster should not take any locks since its
deadlock would cause a fatal situation. No?

Regards,

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