Boolean partition constraint behaving strangely

Hi,

I have an issue with a table partitioned by one boolean column. The
query planner only seems to skip the non matching table if expired
(the column I use for the partition) is true.

Here is a simple example:

CREATE TABLE mos (type_id INTEGER UNIQUE, expired boolean);
CREATE TABLE mos_expired_1 ( CHECK ( expired = true ) ) INHERITS
(mos);
CREATE TABLE mos_active_1 ( CHECK ( expired = false ) ) INHERITS
(mos);
INSERT INTO mos_expired_1 (type_id,expired) VALUES(1, true);
INSERT INTO mos_active_1 (type_id,expired) VALUES(2, false);

EXPLAIN SELECT * from mos where expired = true;

Result (cost=0.00..66.60 rows=2330 width=5)
-> Append (cost=0.00..66.60 rows=2330 width=5)
-> Seq Scan on mos (cost=0.00..33.30 rows=1165 width=5)
Filter: expired
-> Seq Scan on mos_expired_1 mos (cost=0.00..33.30 rows=1165
width=5)
Filter: expired

EXPLAIN SELECT * from mos where expired = false;

Result (cost=0.00..99.90 rows=3495 width=5)
-> Append (cost=0.00..99.90 rows=3495 width=5)
-> Seq Scan on mos (cost=0.00..33.30 rows=1165 width=5)
Filter: (NOT expired)
-> Seq Scan on mos_expired_1 mos (cost=0.00..33.30 rows=1165
width=5)
Filter: (NOT expired)
-> Seq Scan on mos_active_1 mos (cost=0.00..33.30 rows=1165
width=5)
Filter: (NOT expired)

I would really like to know if I am missing something or it's a query
planner issue.

--
Dominik Sander