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  1. #1
    Join Date
    Jul 2006
    Pune , India

    Unanswered: After Reorg , More Space Utilized !!

    i have done a backup on a databse 3 days ago and the size of the backup image was 4.93 GB. However yesteday i scheduled it for reorg on tables and indexes after the results of
    i used following commands :

    Reorg table eone.tabname;
    Reorg indexes all for table eone.tabname;

    However To my surprise the backup image of today is 6.14 GB. In the meantime no work was performed on that database.
    How does reorg is increasing the size of image when the main purpose of reorg is to recover the wasted space.

    --Rahul Singh

  2. #2
    Join Date
    May 2003
    One of the purposes of a reorg is reclaim wasted space, but there are other purposes also.

    A reorg restores percent free on the table and indexes. The default is 10% free unless you change it.

    The purpose of percent free is to allow space for maintaining the correct order in the rows in the table when an insert takes place, according to the clustering index. If you don't have a clustering index, or the table is defined with append option (to always insert new rows at the end) then you could set percent free to zero on the table.

    Percent free on indexes is more complicated since indexes always need to be in the exact order specified. However, if you had an index on a timestamp column and the value always had the current timestamp on insert, then you might be better off with percent free zero on such an index.
    M. A. Feldman
    IBM Certified DBA on DB2 for Linux, UNIX, and Windows
    IBM Certified DBA on DB2 for z/OS and OS/390

  3. #3
    Join Date
    Sep 2003
    A better measure of REORG is to see how many free pages and used pages there are before and after the REORG. I am guessing backup copies each tablespace upto the Highwater mark; since you used the same tablespace for reorg, I wonder if that pushed up the Highwater mark!

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