Re: Utilizing multiple cores for one query

> > I wonder whether the current versions of postgres (i.e. either 8.2 or 8.3)
> > are able to utilize multiple cores for the execution of a single query?
> Nope.

I see, thanks for the clarification.

Btw, in this thread: http://archives.postgresql.org/pgsql-performance/2007-10/msg00159.php

the following is said:

>You can determine what runs in parellel based on the
>indentation of the output.
>Items at the same indentation level under the same
>"parent" line will run in parallel

Wouldn't this offer some opportunities for running things on multiple cores? Based on the above, many people already seem to think that PG is able to utilize multiple cores for 1 query. Of course, it can be easily "proved" that this does not happen by simply watching at the CPU utilization graphs when executing a query. Nevertheless, those people may wonder why (some of) those items that already run in parallel not actually run in parallel using multiple cores?

> Currently, the only way to parallelize a query in Postgres is to use pgpool-II.
>
> http://pgpool.projects.postgresql.org/

Yes, I noticed this project before. At the time it was not really clear how stable and/or how well supported this is. It indeed seems to support parallel queries automatically by being able to rewrite standard queries. It does seem it needs different DB nodes and is thus probably not able to use multiple cores of a single DBMS. Also, I could not really find how well pgpool-II is doing at making judgments of the level of parallelization it's going to use. E.g. when there are 16 nodes in the system with a currently low utilization, a single query may be split into 16 pieces. On the other hand, when 8 of these nodes are heavily utilized, splitting to 8 pieces might be better. etc.

Anyway, are there any plans for postgresql to support parallelizing queries natively?

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