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  1. #1
    Join Date
    Mar 2006
    Location
    Tuticorin, India
    Posts
    103

    Unanswered: db_heap_top - 0 value

    Env: DB2 V8.2/AIX 5.3

    /tmp> db2 " select db_heap_top from table(snapshot_database('',-1)) db"

    DB_HEAP_TOP
    --------------------
    0

    1 record(s) selected.

    /tmp > db2 get snapshot for database on ccapro | grep -i heap
    Total Shared Sort heap allocated = 0
    Shared Sort heap high water mark = 0


    What does this mean? I am unable to comprehend this pls advice.

  2. #2
    Join Date
    Jun 2003
    Location
    Toronto, Canada
    Posts
    5,516
    Provided Answers: 1
    I'm assuming the snapshot monitors are enabled. Shared sort heap is used for, well, shared sorts in a partitioned database or when the intra-partition parallelism is enabled. If you don't have parallel plan execution you won't have any parallel sorts either.

    Regarding the database heap watermark being 0, I think it might be just another case of the buggy snapshot functions.
    ---
    "It does not work" is not a valid problem statement.

  3. #3
    Join Date
    Mar 2006
    Location
    Tuticorin, India
    Posts
    103
    Yes, All the switches are turned on. There is more than 75+ active database connection but it shows as 0.

    The same snap function returns valid results on another comparable databases.

  4. #4
    Join Date
    May 2007
    Location
    somewhere in dbforums
    Posts
    221
    Quote Originally Posted by db2udbgirl
    db2 " select db_heap_top from table(snapshot_database('',-1)) db"

    DB_HEAP_TOP
    --------------------
    0

    1 record(s) selected.

    Does snapshot_database give wrong results for all or only for DB_HEAP_TOP

    Quote Originally Posted by db2udbgirl
    /tmp > db2 get snapshot for database on ccapro | grep -i heap
    Total Shared Sort heap allocated = 0
    Shared Sort heap high water mark = 0
    As nick said... this seems to be buggy
    IBM Certified Database Associate, DB2 9 for LUW

  5. #5
    Join Date
    May 2003
    Location
    USA
    Posts
    5,737
    I quit using the snapshot functions because they are terribly buggy, especially in V8. I need accurate information and they just don't seem to work properly.

    If I ever did start using them again, I would have to run tests against the traditional get snapshots to see if the results were the same before I accepted the results.

    A lot of this stuff is being added to DB2 for them to claim it is easy to administer versus the competition (like the Health Monitor). They are shoving the stuff out the door before they have it working, and I want no part of any of that until it is fully debugged.
    M. A. Feldman
    IBM Certified DBA on DB2 for Linux, UNIX, and Windows
    IBM Certified DBA on DB2 for z/OS and OS/390

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