RE: Re:partitioning

You can get significant benefit from hash partitioning if you have 2 or more tables that are equi-partitioned. The benefit comes when you join the tables together -- you get partition-wise joining! In effect, you perform multiple small table joins instead of 1 join of 2 large tables!

This works for any partitioning scheme!

Kevin
-----Original Message-----
From: root_at_fatcity.com [mailto:root_at_fatcity.com]On Behalf Of Jonathan Lewis
Sent: Thursday, March 20, 2003 11:49 AM
To: Multiple recipients of list ORACLE-L Subject: Re: Re:partitioning

I wouldn't really expect to get any
significant benefit from partition
elimination when using hash partitions.

In fact, apart from the administrative
convenience, I think the only benefit
is likely to come from partition wise
joins using partition iterators.

Can you give us any details of the
problems you are having - or a
Metalink reference we can get
access to ?

Regards

Jonathan Lewis
http://www.jlcomp.demon.co.uk

One-day tutorials:
(see http://www.jlcomp.demon.co.uk/tutorial.html )

____UK_______April 8th
____UK_______April 22nd
____Denmark May 21-23rd
____USA_(FL)_May 2nd

Three-day seminar:
(see http://www.jlcomp.demon.co.uk/seminar.html )

____UK_(Manchester)_May
____USA_(CA, TX)_August

The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html

• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: 20 March 2003 14:23

> As we have discovered, hash partitioning does not
> always give you partition elimination nor does CBO
> always work as expected. One of our DBAs has a tar
> open with Oracle on this issue and we are finding that
> no one appears to understand the complete
> ramifications of using hash partitions when a query is
> run against large data sets.
>

--
Please see the official ORACLE-L FAQ: http://www.orafaq.net
--
Author: Jonathan Lewis
  INET: jonathan_at_jlcomp.demon.co.uk

Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
San Diego, California        -- Mailing list and web hosting services
---------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may