sort_area_size in oracle 10g
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  1. #1
    Join Date
    Dec 2011
    Posts
    5

    sort_area_size in oracle 10g

    Hello,
    I'm working on oracle 10g,
    In order to understand the effect of sort_area-size, I changed its value to 2048 bytes

    alter system set SORT_AREA_SIZE = 2048 deferred;

    and after some reading I saw that I should also change the value of workarea_size_policy parameter to manual in order to see the effects of changing the first parameter so I did:

    alter system set workarea_size_policy= manual;

    and I verified that the tow parameters have the new values.

    then I ran a sort query from one session and I monitored the sort activity from another session, by running these scripts:

    SELECT NAME,VALUE FROM V$SYSSTAT WHERE UPPER(NAME) LIKE '%SORT%';

    select tablespace_name,total_extents,total_blocks, used_extents from v$sort_segment;


    In fact, I couldn't really notice the differences after assigning the value 41943040 to the sort_area_size parameters!!

    So I would really like to help me to understand the effect of this parameter and how I can verify this effect in practice?

    thank you
    Baraa

  2. #2
    Join Date
    Mar 2006
    Location
    Charlotte, NC
    Posts
    865
    well, are you are on 10g why to worry with manual allocation when you have a automated option? check pga_aggregate_target parameter in 10g. It will do every thing for you.

    Regards,
    Vijay Tummala

    Try hard to get what you like OR you will be forced to like what you get.

  3. #3
    Join Date
    Dec 2011
    Posts
    5
    I want to understand the effect (the real use) of such parameters to understand really the use of each of them

    Thanks to help me in that,
    Regards
    Baraa

  4. #4
    Join Date
    Mar 2007
    Location
    Ft. Lauderdale, FL
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    3,554
    Quote Originally Posted by Ro2a.M View Post
    I want to understand the effect (the real use) of such parameters to understand really the use of each of them
    How about reading Oracle documentation? Let me quote: 'SORT_AREA_SIZE specifies (in bytes) the maximum amount of memory Oracle will use for a sort. After the sort is complete, but before the rows are returned, Oracle releases all of the memory allocated for the sort, except the amount specified by the SORT_AREA_RETAINED_SIZE parameter. After the last row is returned, Oracle releases the remainder of the memory.' (*)

    (*) http://docs.oracle.com/cd/B13789_01/...tparams200.htm
    Pablo (Paul) Berzukov

    Author of Understanding Database Administration available at amazon and other bookstores.

    Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.

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