Horton

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

Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>

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From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Nathan Bossart <nathandbossart@gmail.com>, Michael Paquier <michael@paquier.xyz>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-09-27T12:03:33Z
Lists: pgsql-hackers 
On Tue, Sep 27, 2022 at 3:01 PM Thomas Munro <thomas.munro@gmail.com> wrote:
>
> Something like the attached.

Isn't it also better to add notes in win32pread.c and win32pwrite.c
about the callers doing lseek(SEEK_SET) if they wish to and Windows
implementations changing file position? We can also add a TODO item
about replacing pg_ versions with pread and friends someday when
Windows fixes the issue? Having it in the commit and include/port.h is
good, but the comments in win32pread.c and win32pwrite.c make life
easier IMO. Otherwise, the patch LGTM.

--
Bharath Rupireddy
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com

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.