Re: Checksum errors in pg_stat_database

On Sun, Dec 11, 2022 at 08:48:15PM -0500, Tom Lane wrote:
> I think a stats table indexed solely by relfilenode wouldn't be a great
> idea, because you'd lose all the stats about a table as soon as you
> do vacuum full/cluster/rewriting-alter-table/etc.  Can we create two
> index structures over the same stats table entries, so you can look
> up by either relfilenode or OID?  I'm not quite sure how to manage
> rewrites, where you transiently have two relfilenodes for "the
> same" table ... maybe we could allow multiple pointers to the same
> stats entry??

FWIW, I am not sure that I would care much if we were to dropped the
stats associated to a relfilenode on a rewrite.  In terms of checksum
failures, tuples are deformed so if there is one checksum failure a
rewrite would just not happen.  The potential complexity is not really
appealing compared to the implementation simplicity and its gains, and
rewrites are lock-heavy so I'd like to think that people avoid them
(cough)..
--
Michael