Re: Order dependency in function test

On Thu, Apr 8, 2021 at 3:34 PM Magnus Hagander <magnus(at)hagander(dot)net> wrote:
>
> Looking at https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=prion&dt=2021-04-08%2009%3A43%3A13
> which broke with the patch to add pg_wait_backend_termination().
>
> AFAICT the change is that the order of rows coming back from "SELECT
> routine_name, sequence_name FROM
> information_schema.routine_sequence_usage" has changed. This test was
> added in f40c6969d0e ("Routine usage information schema tables"),
>
> It does not change consistently, as it works fine on my machine and
> has also passed on other buildfarm animals (including other archs and
> compilers).
>
> My guess is that maybe the query plan is different, ending up with a
> different order, since there is no explicit ORDER BY in the query.
>
> Is there a particular thing we want to check on it that requires it to
> run without ORDER BY, or should we add one to solve the problem? Or,
> of course, am I completely misunderstanding it? :)

The buildfarm failure is due to lack of ORDER BY clause. Upon
searching in that file, I found below statements are returning more
than one row but doesn't have ORDER BY clause which can make output
quite unstable.

SELECT routine_name, sequence_name FROM
information_schema.routine_sequence_usage;
SELECT routine_name, table_name, column_name FROM
information_schema.routine_column_usage;
SELECT routine_name, table_name FROM information_schema.routine_table_usage;
SELECT * FROM functest_sri1();
SELECT * FROM functest_sri2();
TABLE sometable;

I added a ORDER BY 1 clause for each of the above statements and
replaced TABLE sometable; with SELECT * FROM sometable ORDER BY 1;

Here's the patch.

With Regards,
Bharath Rupireddy.
EnterpriseDB: http://www.enterprisedb.com