Re: BUG #18568: BUG: Result wrong when do group by on partition table!

Tender Wang <tndrwang@gmail.com> 于2024年10月23日周三 14:25写道：

>
>
> And I found some codes only use equal not check the collation, for
> example, in match_expr_to_partition_keys():
> if (equal(lfirst(lc), expr))
> lfirst(lc) is partkeys.
> I thinks other codes assume that the collation of partexprs in RelOptInfo
> is same with pg_partitioned_table. But it is not.
>
>
It seems that only partition pruning logic not only does equal() but also
checks the collation match. I find below codes in
match_clause_to_partition_key():

/*
* Partition key match also requires collation match.  There may be
* multiple partkeys with the same expression but different
* collations, so failure is NOMATCH.
*/
if (!PartCollMatchesExprColl(partcoll, opclause->inputcollid))
    return PARTCLAUSE_NOMATCH;

Others only do equal(), as far as I know.

I tried the patch I provided in [1], and the regression test cases all
passed.


[1]
https://www.postgresql.org/message-id/CAHewXNnKLrZYG4iqaYw%3DuB3XWRrYRZHo7VtcMsbUEbdbajQg2Q%40mail.gmail.com

-- 
Thanks,
Tender Wang