Re: pg_receivexlog --status-interval add fsync feedback

> On 09/05/2014 08:51 AM, furuyao(at)pm(dot)nttdata(dot)co(dot)jp wrote:
> >>> Thanks for the review!
> >>>
> >>> I understand the attention message wasn't appropriate.
> >>>
> >>> To report the write location, even If you do not specify a
> >>> replication
> >> slot.
> >>> So the fix only appended messages.
> >>>
> >>> There was a description of the flush location section of '-S'
> >>> option, but I intended to catch eye more and added a message.
> >>>
> >>> Is it better to make specification of the -S option indispensable?
> >>
> >> The patch cannot be applied to HEAD cleanly. Could you update the
> patch?
> >
> > Thank you for pointing out.
> > Updated the patch.
>
> I don't understand what this patch does. When would you want to use the
> new --reply-fsync option? Is there any reason *not* to use it? In other
> words, do we need an option for this, couldn't you just always send the
> feedback message after fsync?

Thanks for the comment.

--reply-fsync option is intended for use in synchronous mode.

By specifying -F option and --slot option, process calls fsync() when it received the WAL, and flush location would be set in feedback message.

Interval of sending feedback message depends on -s option in this state, so in the case of synchronous mode, waiting for feedback message would occure.

therefore, --reply-fsync option is necessary. because it can send the feedback message after fsync without waiting for the interval of -s option.

The reason for not sending the feedback message after fsync without waiting for the interval of -s option always, is to answer the needs who want to use fsync only (NOT using synchronous mode).

Regards,

--
Furuya Osamu