>> we have performance problems running several queries pon postgres 8.4 .
>> Using the previous version (8.3) our queries performs well
>> (The queries are quite complex, consisting of several sub-queries and
>> various spatial functions).
Two things that frequently bite people during an upgrade:
1. Forgetting to ANALYZE the database after reload. Autovacuum would
probably fix that for you eventually, but it's better to just issue one
manually.
2. Creating the new database with the wrong locale. I see a bunch of
LIKE operators in the query plans you show later, so I'm wondering if
you went from C locale to a non-C locale and that defeated LIKE
optimizations that used to work.
regards, tom lane
