From: | Jim Nasby <Jim(dot)Nasby(at)BlueTreble(dot)com> |
---|---|
To: | Magnus Hagander <magnus(at)hagander(dot)net>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Online enabling of page level checksums |
Date: | 2017-01-22 22:59:44 |
Message-ID: | 710eb8a7-5497-e005-2fce-79feaa11bfc5@BlueTreble.com |
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Lists: | pgsql-hackers |
On 1/22/17 5:13 AM, Magnus Hagander wrote:
> If the system is interrupted before the background worker is done, it
> starts over from the beginning. Previously touched blocks will be read
> and verified, but not written (because their checksum is already
> correct). This will take time, but not re-generate the WAL.
Another option would be to store a watermark of the largest block ID
that had been verified for each relation/fork. That would be used to
determine if checksums could be trusted, and more usefully would allow
you to start where you left off if the verification process got interrupted.
> I think the actual functions and background worker could go in an
> extension that's installed and loaded only by those who need it. But the
> core functionality of being able to have "checksum in progress" would
> have to be in the core codebase.
If it was in contrib I think that'd be fine.
--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com
855-TREBLE2 (855-873-2532)
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