PostgreSQL 8.0.1 problem

Hi:

I want migrate to PostgreSQL 8.0.1 for Windows from PostgreSQL 7.4.1, but I
have a big problem.

In 7.4.1 I have a large view with nested views. It lasts 1 minute and 20
seconds to finish. In 8.0.1 for Windows it lasts.... I don't know. One
hour, two hour, one day... I always cancel the view because it lasts
forever.

Shared buffers and work mem in 8.0.1 are greater than those of 7.4.1. So I
think this isn't a memory problem. Furthermore, the 8.0.1 server has double
RAM than 7.4 server. The "simples" views work right. But when I run the
large view the problem appears.

The database was migrated with pg_dumpall (8.0.1 version) and restored with
psql (8.0.1 version).

Please, I need help.

Thanks in advance.

Indibil

postscript: Sorry for my poor english.