Re: amcheck verification for GiST and GIN

Thank you, v5 didn't find any issues at all. One thing: for my 29 indexes,
the tool generated output 3.5 GiB. I guess many INFO messages should be
downgraded to something like DEBUG1?

On Fri, Jul 30, 2021 at 2:35 AM Heikki Linnakangas <hlinnaka(at)iki(dot)fi> wrote:

> On 29/07/2021 21:34, Nikolay Samokhvalov wrote:
> > I was trying to check a bunch of GINs on some production after switching
> > from Ubuntu 16.04 to 18.04 and got many errors. So decided to check for
> > 16.04 first (that is still used on prod for that DB), without any
> > OS/glibc changes.
> >
> > On 16.04, I still saw errors and it was not really expected because this
> > should mean that production is corrupted too. So, REINDEX should fix it.
> > But it didn't -- see output below. I cannot give data and thinking how
> > to create a synthetic demo of this. Any suggestions?
> >
> > And is this a sign that the tool is wrong rather that we have a real
> > corruption cases? (I assume if we did, we would see no errors after
> > REINDEXing -- of course, if GIN itself doesn't have bugs).
> >
> > Env: Ubuntu 16.04 (so, glibc 2.27), Postgres 12.7, patch from Heikki
> > slightly adjusted to work with PG12 (
> > https://gitlab.com/postgres/postgres/-/merge_requests/5
> > <https://gitlab.com/postgres/postgres/-/merge_requests/5>) snippet used
> > to run amcheck:
> > https://gitlab.com/-/snippets/2001962
> > <https://gitlab.com/-/snippets/2001962> (see file #3)
>
> Almost certainly the tool is wrong. We went back and forth a few times
> with Pawel, fixing various bugs in the amcheck patch at this thread:
>
> https://www.postgresql.org/message-id/9fdbb584-1e10-6a55-ecc2-9ba8b5dca1cf%40iki.fi.
>
> Can you try again with the latest patch version from that thread,
> please? That's v5-0001-Amcheck-for-GIN-13stable.patch.
>
> - Heikki
>