Horton

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: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-08-05T10:25:26Z
Lists: pgsql-hackers 
Hi,

I noticed that dir_open_for_write() in walmethods.c uses write() for
WAL file initialization (note that this code is used by pg_receivewal
and pg_basebackup) as opposed to core using pg_pwritev_with_retry() in
XLogFileInitInternal() to avoid partial writes. Do we need to fix
this?

Thoughts?

-- 
Bharath Rupireddy
RDS Open Source Databases: https://aws.amazon.com/rds/postgresql/

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.