Re: Use pg_pwritev_with_retry() instead of write() in dir_open_for_write() to avoid partial writes? - Mailing list pgsql-hackers

From Nathan Bossart
Subject Re: Use pg_pwritev_with_retry() instead of write() in dir_open_for_write() to avoid partial writes?
Date
Msg-id 20220926215531.GA1342693@nathanxps13
Whole thread Raw
In response to Re: Use pg_pwritev_with_retry() instead of write() in dir_open_for_write() to avoid partial writes?  (Thomas Munro <thomas.munro@gmail.com>)
List pgsql-hackers
On Tue, Sep 27, 2022 at 10:37:38AM +1300, Thomas Munro wrote:
> I don't think so, that's an extra kernel call.  I think I'll just have
> to revert part of my recent change that removed the pg_ prefix from
> those function names in our code, and restore the comment that warns
> you about the portability hazard (I thought it went away with HP-UX
> 10, where we were literally calling lseek() before every write()).
> The majority of users of these functions don't intermix them with
> calls to read()/write(), so they don't care about the file position,
> so I think it's just something we'll have to continue to be mindful of
> in the places that do.

Ah, you're right, it's probably best to avoid the extra system call for the
majority of callers that don't care about the file position.  I retract my
previous message.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com



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