| From: | Andres Freund <andres(at)anarazel(dot)de> |
|---|---|
| To: | "Bossart, Nathan" <bossartn(at)amazon(dot)com> |
| Cc: | Michael Paquier <michael(at)paquier(dot)xyz>, Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>, "pgsql-hackers(at)lists(dot)postgresql(dot)org" <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Use durable_unlink for .ready and .done files for WAL segment removal |
| Date: | 2018-11-27 20:45:57 |
| Message-ID: | 20181127204557.yitbyophzgknpdsw@alap3.anarazel.de |
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| Lists: | pgsql-hackers |
Hi,
On 2018-11-27 20:43:06 +0000, Bossart, Nathan wrote:
> I don't have exact figures to share, but yes, a huge number of calls
> to sync_file_range() and fsync() can use up a lot of time. Presumably
> Postgres processes files individually instead of using sync() because
> sync() may return before writing is done. Also, sync() would affect
> non-Postgres files. However, it looks like Linux actually does wait
> for writing to complete before returning from sync() [0].
sync() has absolutely no way to report errors. So, we're never going to
be able to use it. Besides, even postgres' temp files would be a good
reason to not use it.
Greetings,
Andres Freund
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