Re: BUG #16583: merge join on tables with different DB collation behind postgres_fdw fails

On Wed, Mar 3, 2021 at 1:42 PM Neil Chen <carpenter.nail.cz@gmail.com>
wrote:

> The following review has been posted through the commitfest application:
> make installcheck-world:  tested, passed
> Implements feature:       tested, passed
> Spec compliant:           not tested
> Documentation:            tested, passed
>
> Greetings,
> I learned about the patch and read your discussions. I'm not sure why this
> patch has not been discussed now. In short, I think it's beneficial to
> submit it as a temporary solution.
> Another thing I want to know is whether these codes can be simplified:
> -       if (state > outer_cxt->state)
> +       if (collation == outer_cxt->collation &&
> +               ((state == FDW_COLLATE_UNSAFE &&
> +                 outer_cxt->state == FDW_COLLATE_SAFE) ||
> +                (state == FDW_COLLATE_SAFE &&
> +                 outer_cxt->state == FDW_COLLATE_UNSAFE)))
> +       {
> +               outer_cxt->state = FDW_COLLATE_SAFE;
> +       }
> +       else if (state > outer_cxt->state)
>
> If the state is determined by the collation, when the collations are
> equal, do we just need to judge the state not equal to FDW_COLLATE_NONE?


The patch is failing the regression, @Tom Lane <tgl@sss.pgh.pa.us> can you
please take a look at that.

https://cirrus-ci.com/task/4593497492684800

============== running regression test queries ==============
test postgres_fdw ... FAILED 2782 ms
============== shutting down postmaster ==============
======================
1 of 1 tests failed.
======================
The differences that caused some tests to fail can be viewed in the
file "/tmp/cirrus-ci-build/contrib/postgres_fdw/regression.diffs". A copy
of the test summary that you see
above is saved in the file
"/tmp/cirrus-ci-build/contrib/postgres_fdw/regression.out".


-- 
Ibrar Ahmed