Re: Offline enabling/disabling of data checksums

Michael Banck <michael.banck@credativ.de>

From: Michael Banck <michael.banck@credativ.de>

To: Magnus Hagander <magnus@hagander.net>, Sergei Kornilov <sk@zsrv.org>

Cc: Michael Paquier <michael@paquier.xyz>, Fabien COELHO <coelho@cri.ensmp.fr>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>

Date: 2019-03-13T15:51:23Z

Lists: pgsql-hackers

Hi,

Am Mittwoch, den 13.03.2019, 12:43 +0100 schrieb Magnus Hagander:
> I think this is dangerous enough that it needs to be enforced and not
> documented.

Changing the cluster ID might have some other side-effects, I think
there are several cloud-native 3rd party solutions that use the cluster
ID as some kind of unique identifier for an instance. It might not be an
issue in practise, but then again, it might break other stuff down the
road.

Another possibility would be to extend the replication protocol's 
IDENTIFY_SYSTEM command to also report the checksum version so that the
standby can check against the local control file on startup. But I am
not sure we can easily extend IDENTIFY_SYSTEM this way nor whether we
should for this rather corner-casey thing?


Michael

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Commits

Reorganize Notes section in documentation of pg_checksums
- a7cc52370b2b 12.0 landed
Add option -N/--no-sync to pg_checksums
- e0090c869008 12.0 landed
Add options to enable and disable checksums in pg_checksums
- ed308d783790 12.0 landed
Refactor more code logic to update the control file
- 8b938d36f744 12.0 landed
Rename pg_verify_checksums to pg_checksums
- 6dd263cfaa84 12.0 landed
Fix cross-version compatibility checks of pg_verify_checksums
- 501f58359b59 11.3 landed
- c9ae7f704c67 12.0 landed
Add routine able to update the control file to src/common/
- ce6afc6823fb 12.0 landed