Horton

Re: Offline enabling/disabling of data checksums

Michael Banck <michael.banck@credativ.de>

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From: Michael Banck <michael.banck@credativ.de>
To: Magnus Hagander <magnus@hagander.net>
Cc: Michael Paquier <michael@paquier.xyz>, Fabien COELHO <coelho@cri.ensmp.fr>, Sergei Kornilov <sk@zsrv.org>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2019-03-13T11:09:24Z
Lists: pgsql-hackers

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Hi,

Am Mittwoch, den 13.03.2019, 11:47 +0100 schrieb Magnus Hagander:
> On Wed, Mar 13, 2019 at 11:41 AM Michael Banck <michael.banck@credativ.de> wrote:
> > I propose we re-read the control file for the enable case after we
> > finished operating on all files and (i) check the instance is still
> > offline and (ii) update the checksums version from there. That should be
> > a small but worthwhile change that could be done anyway.
> 
> In (i) you need to also check that is' not offline *again*. Somebody
> could start *and* stop the database while pg_checksums is running. But
> that should hopefully be enough to check the time field?

Good point.

> > Also, I suggest to maybe add a notice in verbose mode that we are
> > syncing the data directory - otherwise the user might wonder what's
> > going on at 100% done, though I haven't seen a large delay in my tests
> > so far.
> 
> Seems like a good idea -- there certainly could be a substantial delay
> there depending on data size and underlying storage.

The attached patch should do the above, on top of Michael's last
patchset.


Michael

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Commits

  1. Reorganize Notes section in documentation of pg_checksums

  2. Add option -N/--no-sync to pg_checksums

  3. Add options to enable and disable checksums in pg_checksums

  4. Refactor more code logic to update the control file

  5. Rename pg_verify_checksums to pg_checksums

  6. Fix cross-version compatibility checks of pg_verify_checksums

  7. Add routine able to update the control file to src/common/