RE: Keep pool

  • From: "Lex de Haan" <lex.de.haan@xxxxxxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Fri, 12 Mar 2004 13:22:01 +0100

MessageOK -- so it is all about avoiding row chaining... I think I would
still try to choose one block size for your database, and take some chaining
for granted. the problem with multiple block sizes is that you have to
segment your available SGA memory, resulting in less efficiency and more
maintenance. It is a great feature, but it was never intended as a
performance feature, although the thought may seem appealing. It is meant to
open up transportable tablespaces possibilities.

are the rows of these wide tables all fixed length? and are all columns
defined as NOT NULL? maybe the 8KB block size would be good enough ... and
the advantages of a single block size would outweigh the disadvantages of
some chaining. after all, reading a single 16 KB block is not that much
cheaper than reading two 8 KB blocks, certainly not when part of a
multi-block I/O scan ...

cheers,
Lex.
  -----Original Message-----
  From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx]On Behalf Of George Leonard
  Sent: vrijdag 12 maart 2004 13:08
  To: oracle-l@xxxxxxxxxxxxx
  Subject: RE: Keep pool


  hi there
  firstly the database was created as a 8k block size, I have always found
this a very good block size to use.

  but I do have some very wide tables and I mean very wide that just ended
up better on a 16K block. so I am using /oracle9 feature of mutiple block
sizes depended on data requirements.


  George



  ________________________________________________



  George Leonard
  Oracle Database Administrator
  Dimension Data (Pty) Ltd
  (Reg. No. 1987/006597/07)
  Tel: (+27 11) 575 0573
  Fax: (+27 11) 576 0573
  E-mail:george.leonard@xxxxxxxxxxxxx
  Web:   http://www.didata.co.za



  You Have The Obligation to Inform One Honestly of the risk, And As a
Person
  You Are Committed to Educate Yourself to the Total Risk In Any Activity!
  Once Informed & Totally Aware of the Risk,
  Every Fool Has the Right to Kill or Injure Themselves as They See Fit!





    -----Original Message-----
    From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Lex de Haan
    Sent: 12 March 2004 14:04 PM
    To: oracle-l@xxxxxxxxxxxxx
    Subject: RE: Keep pool


    Hi George,

    as far as I know, this is impossible. may I ask why you have two
different block sizes in a single database?

    kind regards,

    Lex.
      -----Original Message-----
      From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx]On Behalf Of George Leonard
      Sent: vrijdag 12 maart 2004 12:52
      To: oracle-l@xxxxxxxxxxxxx
      Subject: Keep pool


      Hi all

      I have a mix of 8K and 16K tablespaces.

      As such I have configured a 8K and 16K cache pool via:db_cache_size
and
      db_16k_cache_size.
      I have thus far configured a kep pool via db_keep_cache_size, but I am
      guessing this will only be used for the default block size being 8K.

      How do I configure (what si the parameter name) for a 16K keep pool ?

      thanks

      George

      ________________________________________________

      George Leonard
      Oracle Database Administrator
      Dimension Data (Pty) Ltd
      (Reg. No. 1987/006597/07)
      Tel: (+27 11) 575 0573
      Fax: (+27 11) 576 0573
      E-mail:george.leonard@xxxxxxxxxxxxx
      Web: http://www.didata.co.za

      You Have The Obligation to Inform One Honestly of the risk, And As a
      Person
      You Are Committed to Educate Yourself to the Total Risk In Any
Activity!
      Once Informed & Totally Aware of the Risk,
      Every Fool Has the Right to Kill or Injure Themselves as They See Fit!
      This e-mail is sent on the Terms and Conditions that can be accessed
by Clicking on this link http://www.vodacom.net/legal/email.asp "
  This e-mail is sent on the Terms and Conditions that can be accessed by
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