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Thread: Bufferpool read

  1. #1
    Join Date
    Sep 2002
    Posts
    456

    Arrow Unanswered: Bufferpool read

    Hello Guys,

    We have a situation: users are working with application which is connect to DB2 UDB V7.2 database. They can insert/update/delete data through their application. Optionally we have a load process which can dump the data in the database. Now the problem is whenever the load process dumps the data, its not visible to the users until we do an instance restart or wait a day or so.
    Another DBA in the company is suggesting it's because of the bufferpool as the old data is still in memory new rows are not read so stopping the instance will flush the data from memory or just wait enough time that new pages are read into it!!!

    I don't agree; as far I think rows from the bufferpool are only read if they are exactly the same as requested otherwise new rows are read into the bufferpool!!

    Please comment, otherwise we have to look at other alternatives to fix this situation(load might not be working correctly; this load is part of a utility provided by another company and we don't know how this load is working)

    dollar

  2. #2
    Join Date
    Aug 2001
    Location
    UK
    Posts
    4,650

    Re: Bufferpool read

    I agree with you on the point of bufferpools ..

    But I do not understand why the LOAD holds the database for a day ...

    I will suggest that you go through application snapshot to see what the third party product is actually doing ... this will enable to figure-out why you cannot access the data that long .... Also, try getting support from that company ...

    Cheers

    Sathyaram

    Last edited by sathyaram_s; 03-05-03 at 14:35.

  3. #3
    Join Date
    Jul 2002
    Location
    ATL
    Posts
    170

    Re: Bufferpool read

    It Looks like your application is inserting the data and not commiting it.
    There might be two reasons why you guys are able to see the data
    after two days
    1.Data be flushed out of bufferpool when there are enough dirty pages.
    2Application is commiting only when it is terminated.
    I would check the application what kind of commitcount it is doing and what kind of isolation level it is using.
    Also check the config parameter CHNGPGS_THRESH (lower thr better)

    Good Luck
    Prasad

    Originally posted by dollar489
    Hello Guys,

    We have a situation: users are working with application which is connect to DB2 UDB V7.2 database. They can insert/update/delete data through their application. Optionally we have a load process which can dump the data in the database. Now the problem is whenever the load process dumps the data, its not visible to the users until we do an instance restart or wait a day or so.
    Another DBA in the company is suggesting it's because of the bufferpool as the old data is still in memory new rows are not read so stopping the instance will flush the data from memory or just wait enough time that new pages are read into it!!!

    I don't agree; as far I think rows from the bufferpool are only read if they are exactly the same as requested otherwise new rows are read into the bufferpool!!

    Please comment, otherwise we have to look at other alternatives to fix this situation(load might not be working correctly; this load is part of a utility provided by another company and we don't know how this load is working)

    dollar

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