Problem with nested query

Hello,

I have quite strange problem with nested query.

mails=> explain INSERT INTO member(email)
mails-> select distinct email
mails-> FROM iaddress
mails-> WHERE NOT EXISTS (
mails(> SELECT email
mails(> FROM member
mails(> WHERE member.email=iaddress.email);
NOTICE: QUERY PLAN:

Unique (cost=1869591274.28..1869591274.28 rows=0 width=12)
-> Sort (cost=1869591274.28..1869591274.28 rows=1 width=12)
-> Seq Scan on iaddress (cost=0.00..1869591274.27 rows=1 width=12)
SubPlan
-> Seq Scan on member (cost=0.00..10226.27 rows=1 width=12)

EXPLAIN

As far as you can see it uses sequence scan for inner select. This is quite
strange as if I do this select with a constant it will use index scan:

mails=> explain SELECT email
mails-> FROM member
mails-> WHERE member.email='test';
NOTICE: QUERY PLAN:

Index Scan using ix_member_email on member (cost=0.00..4.76 rows=1 width=12)

EXPLAIN

Additional data.

mails=> select count(*) from iaddress;
count
-------
58742
(1 row)

mails=> select count(*) from member;
count
--------
219648
(1 row)

There is an index member(email).
PostgreSQL 7.0.2.

Any ideas?

--
Sincerely Yours,
Denis Perchine

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