Horton

Re: pg_verify_checksums and -fno-strict-aliasing

Magnus Hagander <magnus@hagander.net>

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From: Magnus Hagander <magnus@hagander.net>
To: Michael Paquier <michael@paquier.xyz>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Fabien COELHO <coelho@cri.ensmp.fr>, Michael Banck <michael.banck@credativ.de>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2018-08-30T20:07:38Z
Lists: pgsql-hackers 
On Thu, Aug 30, 2018 at 10:02 PM, Michael Paquier <michael@paquier.xyz>
wrote:

> On Thu, Aug 30, 2018 at 09:35:33PM +0200, Magnus Hagander wrote:
> > Should we make it a separate test in pg_verify_checksums, or should we
> > piggyback on the pg_basebackup tests (which AFAICT is the only ones that
> > create a cluster with checksums enabled at all, and thus is the only
> > codepath that actually uses the backend checksum code at all, which I
> think
> > is an even worse thing to have no tests of)
>
> This should be a separate suite.  And FWIW, we only use pg_regress to
> make sure that an already-initialized data folder has the correct,
> secure authentication set.  So creating a node with checksums enabled is
> just that:
> $node->init(extra => ['--data-checksums']);
>
> [... 20 minutes later ...]
> Attached is a basic test suite ;)
>

Haha, nice timing :)

I wonder if your tests that pg_control has picked things up belong more in
the tests of initdb itself?

Do you think there is value in testing against a non-checksum cluster? I
guess there's some point to it. I think testing actual corruption (like my
version of the tests) is more valuable, but perhaps we should just do both?

-- 
 Magnus Hagander
 Me: https://www.hagander.net/ <http://www.hagander.net/>
 Work: https://www.redpill-linpro.com/ <http://www.redpill-linpro.com/>

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.