On Tue, 27 Aug 2024 at 14:03, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Yeah, I got that same result by bisecting. It seems like it's
> somehow related to the cast to information_schema.sql_identifier:
> we are able to get rid of that normally but seem to fail to do so
> in this query.
In case it saves you a bit of time, I stripped as much of the
unrelated stuff out as I could and got:
create table t (a name, b int);
explain select * from (select a::varchar,b from (select distinct a,b
from t) st) t right join t t2 on t.b=t2.b where t.a='test';
getting rid of the cast or swapping to INNER JOIN rather than RIGHT
JOIN means that qual_is_pushdown_safe() gets a Var rather than a
PlaceHolderVar.
David