On 26.01.2011 16:46, Felix Schmidt @ Oracle wrote:
> Everybody,
>
> I'm interested in the query optimizer of PostgreSQL DB. Where could I
> find useful documentation or could you send me a pointer in the source code?
The relevant source code is in src/backend/optimizer directory. If you
google around, you'll find introductory presentations, but I can't
recommend any particular one.
> What kind of parallelism does PostgreSQL use for operators, like
> selection or join?
The short answer is "none". Each PostgreSQL backend is a one
single-threaded process, one query will only utilize one CPU
(http://wiki.postgresql.org/wiki/FAQ#How_does_PostgreSQL_use_CPU_resources.3F).
If you search the archives, you'll find discussion on how it might one
day be improved, but nothing concrete has been done.
-- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com
