Re: Use durable_unlink for .ready and .done files for WAL segment removal

On September 27, 2018 10:23:31 PM PDT, Michael Paquier <michael(at)paquier(dot)xyz> wrote:
>On Thu, Sep 27, 2018 at 08:40:26PM -0700, Andres Freund wrote:
>> On 2018-09-28 12:28:27 +0900, Michael Paquier wrote:
>>> While reviewing the archiving code, I have bumped into the fact that
>>> XLogArchiveCleanup() thinks that it is safe to do only a plain
>unlink()
>>> for .ready and .done files when removing a past segment. I don't
>think
>>> that it is a smart move, as on a subsequent crash we may still see
>>> those, but the related segment would have gone away. This is not
>really
>>> a problem for .done files, but it could confuse the archiver to see
>some
>>> .ready files about things that have already gone away.
>>
>> Isn't that window fundamentally there anyway?
>
>Sure. However the point I would like to make is that if we have the
>possibility to reduce this window, then we should.

It's not free though. I don't think this is as clear cut as you make it sound.

Andres
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