Re: BUG #16593: pg_upgrade make corrupt UK indexes

On Wed, Aug 26, 2020 at 09:49:00AM +0200, Magnus Hagander wrote:
>
>
> On Wed, Aug 26, 2020 at 7:38 AM Nick Cleaton <nick(at)cleaton(dot)net> wrote:
>
> On Tue, 25 Aug 2020 at 23:55, PG Bug reporting form <noreply(at)postgresql(dot)org
> > wrote:
>
> We upgrade from 9.6 Centos7 to 12.3 Centos 8
>
>
> This from https://www.postgresql.org/docs/12/amcheck.html#id-1.11.7.11.9
> might be relevent:
>
> > Comparisons of datums of a collatable type like text must be immutable
> (just as all comparisons used for B-Tree index scans must be immutable),
> which implies that operating system collation rules must never change.
> Though rare, updates to operating system collation rules can cause these
> issues. More commonly, an inconsistency in the collation order between a
> master server and a standby server is implicated, possibly because the
> major operating system version in use is inconsistent
>
>
> And in particular also see https://wiki.postgresql.org/wiki/Locale_data_changes
> , which shows that the step from Centos7 to Centos8 is one that causes this
> problem. You need to reindex all text/varchar indexes when you  make that
> upgrade.

And we should have a script ready for people to do this. :-)

--
Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
EnterpriseDB https://enterprisedb.com

The usefulness of a cup is in its emptiness, Bruce Lee