postgres scanner not work on partition table

The full table copy operation performed by the DuckDB PostgreSQL extension on partitioned tables, such as
```
SELECT *
FROM pg.sch.tb a
left join b on a.x=b.x
where a.dt=current_date
```
, checks the process for full table copy. Under what conditions is it pushed down?
now, this sql need like this:
```
with a as (select * from postgres_query('pg',$$select * from sch.tb$$))
select * from a
left join b on a.x=b.x
```