Horton

Re: Offline enabling/disabling of data checksums

Fabien COELHO <coelho@cri.ensmp.fr>

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From: Fabien COELHO <coelho@cri.ensmp.fr>
To: Michael Paquier <michael@paquier.xyz>
Cc: Michael Banck <michael.banck@credativ.de>, Postgres hackers <pgsql-hackers@postgresql.org>
Date: 2019-03-17T09:01:20Z
Lists: pgsql-hackers

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Bonjour Michaël-san,

> Yes, that would be nice, for now I have focused.  For pg_resetwal yes
> we could do it easily.  Would you like to send a patch?

Here is a proposal for "pg_resetwal".

The implementation basically removes a lot of copy paste and calls the 
new update_controlfile function instead. I like removing useless code:-)

The reserwal implementation was doing a rm/create cycle, which was leaving 
a small window for losing the controlfile. Not neat.

I do not see the value of *not* fsyncing the control file when writing it, 
as it is by definition very precious, so I added a fsync. The server side 
branch uses the backend available "pg_fsync", which complies with server 
settings there and can do nothing if fsync is disabled.

Maybe the two changes could be committed separately.

-- 
Fabien.

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/