Re: postgres_fdw aggregate pushdown for group by with expressions - Mailing list pgsql-general

> On 3 Mar 2024, at 18:42, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> =?utf-8?Q?Micha=C5=82_K=C5=82eczek?= <michal@kleczek.org> writes:
>> I’ve performed some more tests and it seems expressions with “extract” function are not pushed down at all -
>
> Yeah :-(.  I traced through this, and it seems it's a collation
> problem.  Internally, that call looks like
>     extract('year'::text, date_column)
> The text constant is marked as having collation "default", which means
> that extract() is marked as having input collation "default", and then
> it falls foul of this rule:
[snip]

Thanks for explanation - I have a follow-up question.

Does that mean that *any* expression containing text constants is not going to be pushed down??
That would be a really serious issues I’d say.

—
Michal