Re: Move defaults toward ICU in 16?

pá 17. 2. 2023 v 18:02 odesílatel Jeff Davis <pgsql(at)j-davis(dot)com> napsal:

> On Fri, 2023-02-17 at 00:06 -0800, Jeff Davis wrote:
> > On Tue, 2023-02-14 at 09:59 -0800, Andres Freund wrote:
> > > I am saying that pg_upgrade should be able to deal with the
> > > difference. The
> > > details of how to implement that, don't matter that much.
> >
> > To clarify, you're saying that pg_upgrade should simply update
> > pg_database to set the new databases' collation fields equal to that
> > of
> > the old cluster?
>
> Thinking about this more, it's not clear to me if this would be in
> scope for pg_upgrade or not. If pg_upgrade is fixing up the new cluster
> rather than checking for compatibility, why doesn't it just take over
> and do the initdb for the new cluster itself? That would be less
> confusing for users, and avoid some weirdness (like, if you drop the
> database "postgres" on the original, why does it reappear after an
> upgrade?).
>
> Someone might want to do something interesting to the new cluster
> before the upgrade, but it's not clear from the docs what would be both
> useful and safe.
>

Today I tested icu for Czech sorting. It is a little bit slower, but not
too much, but it produces partially different results.

select row_number() over (order by nazev collate "cs-x-icu"), nazev from
obce
except select row_number() over (order by nazev collate "cs_CZ"), nazev
from obce;

returns a not empty set. So minimally for Czech collate, an index rebuild
is necessary

Regards

Pavel

>
> Regards,
> Jeff Davis
>
>
>
>