subselect requires offset 0 for good performance.

Howdy. I seem to have inherited this problem:

http://www.postgresql.org/message-id/EF524E81-B815-4122-A337-7E50BCED514E@silentmedia.com

Basically a subselect with no offset is resulting in really poor
performance with 120s queries but adding an offset 0 to the inner sub
select results in 0.5s query times, and I get the same output.

The original answer Robert Haas asks for a self contained test case.

I am running 8.4.15 and can try 8.4.17 if some patch has been applied
to it to address this issue. I just want to know should I

A: upgrade to 8.4.17
or
B: create a self contained test case.

--
To understand recursion, one must first understand recursion.