Re: Determining Indexes to Rebuild on new libc

On Thu, Aug 4, 2022 at 10:03 AM Jim Mlodgenski <jimmy76(at)gmail(dot)com> wrote:

>
> I don't think you can make that assumption with the UUID data. Try this
> simple example and you can see the sort order changes on the newer OS and
> can lead to duplicates on your primary key if you don't reindex after the
> upgrade.
>
> CREATE TABLE t1 (c1 varchar PRIMARY KEY);
> INSERT INTO t1 VALUES ('1-a'), ('1a'), ('1-aa');
> SELECT * FROM t1 ORDER BY c1;
>
>
Looks like you're right. Testing with PG 12.11 pgdg packages for their
respective Ubuntu versions:

18.04:
testdb=# SELECT * FROM t1 ORDER BY c1;
c1
------
1a
1-a
1-aa
(3 rows)

22.04:
testdb=# SELECT * FROM t1 ORDER BY c1;
c1
------
1-a
1a
1-aa
(3 rows)

So it looks like we'd have to rebuild any UUID index to be safe anyway,
which are used a lot for identifiers. *sadness intensifies*

--
Don Seiler
www.seiler.us