Horton

Re: Use pg_pwritev_with_retry() instead of write() in dir_open_for_write() to avoid partial writes?

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Nathan Bossart <nathandbossart@gmail.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-10-30T23:31:08Z
Lists: pgsql-hackers 
On Sun, Oct 30, 2022 at 03:44:32PM +0100, Alvaro Herrera wrote:
> So I'm kinda proposing that we only do the forward struct initialization
> dance when it really saves on things -- in particular, when it helps
> avoid or reduce massive indirect header inclusion.

Sure.

>  extern ssize_t pg_pwritev_with_retry(int fd,
> -                                     const struct iovec *iov,
> +                                     const iovec *iov,
>                                       int iovcnt,
>                                       off_t offset);

However this still needs to be defined as a struct, no?
--
Michael

Commits

  1. Revise pg_pwrite_zeros()

  2. Use pg_pwrite_zeros() in walmethods.c

  3. Introduce pg_pwrite_zeros() in fileutils.c

  4. Move pg_pwritev_with_retry() to src/common/file_utils.c

  5. Restore pg_pread and friends.

  6. Remove dead pread and pwrite replacement code.