Horton

Re: pg_verify_checksums and -fno-strict-aliasing

Michael Banck <michael.banck@credativ.de>

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From: Michael Banck <michael.banck@credativ.de>
To: Magnus Hagander <magnus@hagander.net>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: Fabien COELHO <coelho@cri.ensmp.fr>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2018-08-30T20:28:21Z
Lists: pgsql-hackers 
Hi,

Am Donnerstag, den 30.08.2018, 21:35 +0200 schrieb Magnus Hagander:
> So if I get you  right, you're saying the attached patch should be all
> that's needed? 

I tried to do some similar changes but neither what you proposed nor
what I came up with actually fixes the checksum failures, though they
silence the warning at -Wall level.

Could well be I'm doing something wrong, so it would be cool if somebody
could reproduce this first. In principle, it should be enough to run
'make clean && make CLFAGS=-O2' in the src/bin/pg_verify_checksums
subdirectory in order to get a broken executable.


Michael

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Commits

  1. Avoid using potentially-under-aligned page buffers.

  2. Code review for pg_verify_checksums.c.

  3. Make checksum_impl.h safe to compile with -fstrict-aliasing.