Re: Online enabling of checksums

Magnus Hagander <magnus@hagander.net>

From: Magnus Hagander <magnus@hagander.net>
To: Michael Banck <michael.banck@credativ.de>
Cc: Daniel Gustafsson <daniel@yesql.se>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>, Greg Stark <stark@mit.edu>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2018-03-05T10:09:02Z
Lists: pgsql-hackers
On Mon, Mar 5, 2018 at 10:43 AM, Michael Banck <michael.banck@credativ.de>
wrote:

> Hi,
>
> Am Sonntag, den 04.03.2018, 23:30 +0100 schrieb Daniel Gustafsson:
> > Agreed.  Looking at our current error messages, “in file” is
> conventionally
> > followed by the filename.  I do however think “calculated” is better than
> > “expected” since it conveys clearly that the compared checksum is
> calculated by
> > pg_verify_checksum and not read from somewhere.
> >
> > How about something like this?
> >
> > _(“%s: checksum mismatch in file \”%s\”, block %d: calculated %X, found
> %X”),
> >       progname, fn, blockno, csum, header->pd_checksum);
>
> I still find that confusing, but maybe it's just me. I thought the one
> in the pageheader is the "expected" checksum, and we compare the "found"
> or "computed/calculated" (in the page itself) against it.
>
> I had the same conversation with an external tool author, by the way:
>

Maybe we should just say "on disk" for the one that's on disk, would that
break the confusion? So "calculated %X, found %X on disk"?

-- 
 Magnus Hagander
 Me: https://www.hagander.net/ <http://www.hagander.net/>
 Work: https://www.redpill-linpro.com/ <http://www.redpill-linpro.com/>

Commits

  1. Online enabling and disabling of data checksums

  2. Deactive flapping checksum isolation tests.

  3. Add support for coordinating record typmods among parallel workers.