The attached 010_zero.pl, when run as part of the pg_waldump test suite, fails
at today's master (c36b636) and v15 (1bc19df). It passes at v14 (5a32af3).
Command "pg_waldump --start 0/01000000 --end 0/01000100" fails as follows:
pg_waldump: error: WAL segment size must be a power of two between 1 MB and 1 GB, but the WAL file
"000000010000000000000002"header specifies 0 bytes
Where it fails, the server has created an all-zeros WAL file under that name.
Where it succeeds, that file doesn't exist at all. Two decisions to make:
- Should a clean server shutdown ever leave an all-zeros WAL file? I think
yes, it's okay to let that happen.
- Should "pg_waldump --start $X --end $Y" open files not needed for the
requested range? I think no.
Bisect of master got:
30a53b7 Wed Mar 8 16:56:37 2023 +0100 Allow tailoring of ICU locales with custom rules
Doesn't fail at $(git merge-base REL_15_STABLE master). Bisect of v15 got:
811203d Sat Aug 6 11:50:23 2022 -0400 Fix data-corruption hazard in WAL-logged CREATE DATABASE.
I suspect those are innocent. They changed the exact WAL content, which I
expect somehow caused creation of segment 2.
Oddly, I find only one other report of this:
https://www.postgresql.org/message-id/CAJ6DU3HiJ5FHbqPua19jAD%3DwLgiXBTjuHfbmv1jCOaNOpB3cCQ%40mail.gmail.com
Thanks,
nm