Avoid creating archive status ".ready" files too early
WAL records may span multiple segments, but XLogWrite() does not
wait for the entire record to be written out to disk before
creating archive status files. Instead, as soon as the last WAL page of
the segment is written, the archive status file is created, and the
archiver may process it. If PostgreSQL crashes before it is able to
write and flush the rest of the record (in the next WAL segment), the
wrong version of the first segment file lingers in the archive, which
causes operations such as point-in-time restores to fail.
To fix this, keep track of records that span across segments and ensure
that segments are only marked ready-for-archival once such records have
been completely written to disk.
This has always been wrong, so backpatch all the way back.
Author: Nathan Bossart <bossartn@amazon.com>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: Ryo Matsumura <matsumura.ryo@fujitsu.com>
Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru>
Discussion: https://postgr.es/m/CBDDFA01-6E40-46BB-9F98-9340F4379505@amazon.com
Branch
------
REL_12_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/5065aeafb0b7593c04d3bc5bc2a86037f32143fc
Modified Files
--------------
src/backend/access/transam/xlog.c | 216 +++++++++++++++++++++++++++++++++++--
src/backend/postmaster/walwriter.c | 7 ++
src/include/access/xlog.h | 1 +
src/include/access/xlogdefs.h | 1 +
4 files changed, 215 insertions(+), 10 deletions(-)