Thread: doubt

doubt

From
"Narasimha Rao P.A"
Date:
Does postgreSQL support distributive query processing<br /><p><hr size="1" /> Get the freedom to save as many mails as
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Re: doubt

From
"Joshua D. Drake"
Date:
Narasimha Rao P.A wrote:
> Does postgreSQL support distributive query processing

No.

> 
> Get the freedom to save as many mails as you wish. Click here to know 
> how. 
> <http://in.rd.yahoo.com/tagline_mail_5/*http://help.yahoo.com/l/in/yahoo/mail/yahoomail/tools/tools-08.html/> 
> 


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Re: doubt

From
Greg Smith
Date:
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 and you would have to 
look at it very carefully to see if that parallel query implementation 
could fit your needs.

--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD


Re: doubt

From
Hannu Krosing
Date:
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

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
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 6: explain analyze is your friend



Re: doubt

From
Hannu Krosing
Date:
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
> > 
> > ---------------------------(end of broadcast)---------------------------
> > TIP 6: explain analyze is your friend
> 
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 6: explain analyze is your friend