Optimizer generates bad plans.

While adding schema support to the JDBC Driver, I came across a query
which occasionally generates some spectacularly bad plans. I have
attached the query and explain analyze outputs against today's cvs head
for queries that take between 9 and 845941 msec. In the JDBC Driver I
will specify a reasonable join order using explicit JOINs, but I thought
someone might be interested in a test case for the optimizer.

Kris Jurka

The query tries to determine what foreign keys exists between the
following tables.

create table people (id int4 primary key, name text);
create table policy (id int4 primary key, name text);
create table users (id int4 primary key, people_id int4,
policy_id int4,
CONSTRAINT people FOREIGN KEY (people_id) references people(id),
constraint policy FOREIGN KEY (policy_id) references policy(id));