Обсуждение: Query Optimizer + Parallel Operators
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? What kind of parallelism does PostgreSQL use for operators, like selection or join? Thank you - felix
Felix, > 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? > > What kind of parallelism does PostgreSQL use for operators, like > selection or join? Normally we're very helpful with this kind of information ... it's all public after all ... but I have to say that the domain you're e-mailing from makes it a little hard to give you a direct answer. Could you maybe give us a little information about what you want this information for? -- -- Josh Berkus PostgreSQL Experts Inc. http://www.pgexperts.com
This is kinda scary .....
Oracle guy asking for PostgreSQL documentation and internals of the optimizer.
On Thu, Jan 27, 2011 at 12:14 AM, Josh Berkus <josh@agliodbs.com> wrote:
Felix,Normally we're very helpful with this kind of information ... it's all
> 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?
>
> What kind of parallelism does PostgreSQL use for operators, like
> selection or join?
public after all ... but I have to say that the domain you're e-mailing
from makes it a little hard to give you a direct answer.
Could you maybe give us a little information about what you want this
information for?
--
-- Josh Berkus
PostgreSQL Experts Inc.
http://www.pgexperts.com
--
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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