Re: Wrong results with postgres_fdw and merge anti join from RHEL 7.9 to RHEL 8.7

On 4/5/23 15:46, Jim Mlodgenski wrote:
>
>
> On Wed, Apr 5, 2023 at 2:41 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us
> <mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us>> wrote:
>
> "Daniel Westermann (DWE)" <daniel(dot)westermann(at)dbi-services(dot)com
> <mailto:daniel(dot)westermann(at)dbi-services(dot)com>> writes:
> > I am not sure if this qualifies as  bug, but anyway:
>
> > Source instance: PostgreSQL 13.7 on RHEL 7.9
> > Target instance PostgreSQL 13.7 on RHEL 8.7
>
>
> glibc on those 2 versions of RHEL have very different ideas of what the
> sort order should be. Try running the following and you'll likely see
> different results on RHEL 7.9 vs 8.7
>
> CREATE TABLE t1 (c1 varchar PRIMARY KEY);
> INSERT INTO t1 VALUES ('1-a'), ('1a'), ('1-aa');
> SELECT * FROM t1 ORDER BY c1;

Yep -- RHEL 7.9 is glibc 2.17 (likely -326) and 8.7 is glibc 2.28 (-211
seems to be latest), and they are well known to sort differently even
for "common" characters (e.g. "-")

--
Joe Conway
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com