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
