Re: Partitioning

From: Sakthi , Raj <rajan_sakthi_at_yahoo.com>
Date: Tue, 19 Nov 2002 14:35:23 -0800
Message-ID: <F001.00507500.20021119143523@fatcity.com>

Rishi,
In hash partitioning you have to select the number of partitions equal to the power of 2. i.e. 2,4,8,16 so on.
Your problem of skewed partition size is well documented in hash partitioning if you don't choose correct number of partitions.
Please refer to JLewis Book. He deals with this very well and from practical stand point.

http://www.amazon.com/exec/obidos/ASIN/0201715848/jlcomp/102-6448893-9036931

Check his site too

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

HTH Cheers
RS

P.S.: Listers ...I am back..:) ( I know....I know...you all say who noticed ya gone man..!! )

• Rishi.Jain_at_VerizonWireless.com wrote:
  > We have a table with around 80 million rows. The
  > table has been partitioned
  > by hash as there is no clear way of partitioning
  > depending on range etc..
  > The data is very unevenly distributed in these
  > partitions. Some of them even
  > have 3 times the number of rows as compared to the
  > other partitions.
  > This application is being ported from Informix to
  > Oracle (9i R2). In
  > informix the dba's had partitioned the table based
  > on a function . He was
  > taking the mod of the number ( dividing by 10 ) .
  > The values were then
  > placed in either of the 10 partitions ranging from
  > 0 - 9. This really gave
  > us very good distribution of data .Can we achieve
  > something similar in 9i
  > with list partitioning.
  >
  >
  > TIA
  >
  > Rishi
  > --
  > Please see the official ORACLE-L FAQ:
  > http://www.orafaq.com
  > --
  > Author:
  > INET: Rishi.Jain_at_VerizonWireless.com
  >
  > Fat City Network Services -- 858-538-5051
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Sakthi , Raj
  INET: rajan_sakthi_at_yahoo.com

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Received on Tue Nov 19 2002 - 16:35:23 CST