Ühel kenal päeval, N, 2007-07-12 kell 14:00, kirjutas Hannu Krosing:
> Ühel kenal päeval, K, 2007-07-11 kell 19:08, kirjutas Greg Smith:
> > On Wed, 11 Jul 2007, Narasimha Rao P.A wrote:
> >
> > > Does postgreSQL support distributive query processing
> >
> > Not internally. It's possible in some situations to split queries up
> > across multiple nodes using add-on software. pgpool-II, available at
> > http://pgfoundry.org/projects/pgpool/ provides an implementation of
> > distributed queries if your table has a type of key such that you split
> > across it, but it's relatively immature software
>
> Actually it is not "immature" at all, it is used 24/7 doing tens of
> thousands of queries per second :P
uups, I thought you were talking about plproxy ver.2
http://pgfoundry.org/projects/plproxy
all my ranting is about it, not pgpool II, which is indeed quite new
project ;)
> But it is limited (by design) in what it can do - it is meant to run a
> postgresql _function_ on one or more db hosts based on parameter
> hash(es).
>
> This can be used as a tool to construct a system which does distributed
> queries, and also to distribute load on small OLTP queries over a set of
> databases.
>
> > and you would have to
> > look at it very carefully to see if that parallel query implementation
> > could fit your needs.
>
> It has no parallel query implementation by itself (other than a special
> running the same SQL on a set of hosts and merging the results), but you
> definitely can progrem on using pgpool.
>
> If you need something to distribute queries over a number of hosts
> automatically, there is a commercial data warehousing product (based on
> postgresql) available from greenplum, which does exactly this:
>
> http://www.greenplum.com/index.php?page=greenplum-database
>
>
> > --
> > * Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD
> >
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> > TIP 6: explain analyze is your friend
>
>
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