Re: Order changes in PG16 since ICU introduction - Mailing list pgsql-hackers

On Fri, Apr 21, 2023 at 07:14:13PM +0200, Peter Eisentraut wrote:
> On 21.04.23 19:09, Sandro Santilli wrote:
> > On Fri, Apr 21, 2023 at 11:48:51AM -0400, Tom Lane wrote:
> > > "Regina Obe" <lr@pcorp.us> writes:
> > > 
> > > > https://trac.osgeo.org/postgis/ticket/5375
> > > 
> > > If they actually are using locale C, I would say this is a bug.
> > > That should designate memcmp sorting and nothing else.
> > 
> > Sounds like a bug to me. This is happening with a PostgreSQL cluster
> > created and served by a build of commit c04c6c5d6f :
> > 
> >    =# select version();
> >    PostgreSQL 16devel on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 11.3.0-1ubuntu1~22.04) 11.3.0, 64-bit
> >    =# show lc_collate;
> >    C
> >    =# select '+' < '-';
> >    f
> 
> If the database is created with locale provider ICU, then lc_collate does
> not apply here, so the result might be correct (depending on what locale you
> have set).

The database is created by a perl script which starts like this:

  $ENV{"LC_ALL"} = "C";
  $ENV{"LANG"} = "C";

And then runs:

  createdb --encoding=UTF-8 --template=template0 --lc-collate=C 

Should we tweak anything else to make the results predictable ?

--strk;