Horton

Re: Offline enabling/disabling of data checksums

Bernd Helmle <mailings@oopsware.de>

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From: Bernd Helmle <mailings@oopsware.de>
To: Fabien COELHO <coelho@cri.ensmp.fr>, Michael Banck <michael.banck@credativ.de>
Cc: Magnus Hagander <magnus@hagander.net>, Michael Paquier <michael@paquier.xyz>, Postgres hackers <pgsql-hackers@postgresql.org>
Date: 2019-01-08T14:39:30Z
Lists: pgsql-hackers 
Am Dienstag, den 08.01.2019, 15:09 +0100 schrieb Fabien COELHO:
> > The question is how to reliably do this in an acceptable way? Just
> > faking a postmaster.pid sounds pretty hackish to me, do you have
> > any
> > suggestions here?
> 
> Adding a new state to ControlFileData which would prevent it from 
> starting?

But then you have to make sure the control flag gets cleared in any
case pg_verify_checksums crashes somehow or gets SIGKILL'ed ...

Setting the checksum flag is done after having finished all blocks, so
there is no problem. But we need to set this new flag before and reset
it afterwards, so in between strange things can happen (as the various
calls to exit() within error handling illustrates). 

Bernd.

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/