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Re: Oracle Compress Option

From: Tanel Poder <>
Date: Thu, 25 Sep 2003 06:34:40 -0800
Message-ID: <>

RE: Oracle Compress OptionHm, interesting...

How does your active-active config work, do you have write activity on all nodes? I'd be interested in any performance issues you had or currently have... Have you partitioned your application or data usage somehow? What kind of interconnect you're using?


  Waleed, I get your point ...

  We have 6 RAC instances that run active-active ... and compared to availability requirements, we (incl management) decided that disk is cheap.

  I guess it is relative ...


  Rajendra dot Jamadagni at nospamespn dot com   All Views expressed in this email are strictly personal.   QOTD: Any clod can have facts, having an opinion is an art !     -----Original Message-----
    From: Khedr, Waleed [mailto:Waleed.Khedr_at_FMR.COM]     Sent: Thursday, September 25, 2003 9:35 AM     To: Multiple recipients of list ORACLE-L     Subject: RE: Oracle Compress Option

    Disk is not cheap if you pay for high availability configuration. I compress historical data on daily basis and was able to save 70 percent of the disk space. Imagine the amount of savings for five TB.

    Two major issues:

  1. Oracle says updates will be slow on compressed tables, but I say don't even try to update a compressed table, uncompress first otherwise you will end up with a segment that is not good at all for scattered reads.
  2. You can not add columns to the table when it's compressed, so if you compressed a big table and need a new column you need to recreate the table without compression. So adding many extra columns before compression is a good idea.

    It's mainly good for data warehouses applications.



      -----Original Message-----
      From: Jamadagni, Rajendra []
      Sent: Thursday, September 25, 2003 9:05 AM
      To: Multiple recipients of list ORACLE-L
      Subject: RE: Oracle Compress Option

      I think 9202 doesn't like to export compressed tables in direct mode ... so watch out for that ... I implemented, tested and next day reverted back to regular tables due to this export issue. Disk is cheap.

      A BAARF party member wannabe !! 
      Rajendra dot Jamadagni at nospamespn dot com 
      All Views expressed in this email are strictly personal. 
      QOTD: Any clod can have facts, having an opinion is an art ! 

      -----Original Message----- 
      From: Mogens Nørgaard [] 
      Sent: Wednesday, September 24, 2003 10:05 PM 
      To: Multiple recipients of list ORACLE-L 
      Subject: Re: Oracle Compress Option 

      "Compress to impress?" by Julian Dyke is a good presentation on this 
      topic (see for instance 

      I do have the article - 202 K with no compression, 147 K with 
      compression :). 

      Let me know if you're interested, and I'll email it directly to you. 

      Mogens wrote: 

>Does anybody has any experience with Oracle 9I compression option. I did some test on 9202 with a table of more 14 million rows. Table has total 7 indexes. Surprising both table and indexes are using more space after compression. Before compression space used is 13064MB and after compression 13184MB. In both the cases I did export from source table and stored in two different tablespaces. Any insight on that and any disadvantages of using that.

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Author: Tanel Poder

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Received on Thu Sep 25 2003 - 09:34:40 CDT

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