The following bug has been logged online:

Bug reference: 1681
Logged by: fremaux
Email address: benjamin.fremaux (AT) sofrecom (DOT) com
PostgreSQL version: 7.2.2
Operating system: Linux kernel 2.4.6.19-mdk
Description: Selection problem
Details:

following query :
SELECT list.group_artifact_id, list.name
FROM artifact_group_list list
WHERE (list.group_artifact_id=167)

returns 2 lines where the first list.group_artifact_id equals "165". The
problem is that the only lines that have to be returned are the ones with
list.group_artifact_id=167

---------------------------(end of broadcast)---------------------------
TIP 9: the planner will ignore your desire to choose an index scan if your
joining column's datatypes do not match