On 11/27/18, 2:46 PM, "Andres Freund" <andres@anarazel.de> wrote:
> 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.
Ah, I see. Thanks for clarifying.
Nathan