Cbo
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  1. #1
    Join Date
    Jul 2001
    Posts
    181

    Cbo

    If query's are suddenly running slowly, could it be because we analyze tables estimate statistics 60%. Is there problem once you exceed that estaimation. Hope this makes sense

  2. #2
    Join Date
    Sep 2000
    Location
    Chennai, India
    Posts
    865
    You could run/automate a compute statistics every day using ... and see the outcome.
    Code:
    exec dbms_stats.gather_schema_stats(ownname => 'SCOTT', cascade => TRUE);

  3. #3
    Join Date
    Aug 2002
    Location
    Colorado Springs
    Posts
    5,253
    Use tkprof to find out what wait events are slowing you down.

    Preserve a number of key queries and their execution plans, so that in future you can look for changes.

    run ...

    ALTER TABLE my_table MONITORING;

    ... to allow DBMS_STATS to decide whether a table needs re-analyzing. COMPUTE every day is overkill i think.

    Make a record of any parameter changes.
    David Aldridge,
    "The Oracle Sponge"

    Senior Manager, Business Intelligence Development
    XM Satellite Radio
    Washington, DC

    Oracle ACE

  4. #4
    Join Date
    Aug 2002
    Location
    Bangalore, India
    Posts
    405
    Originally posted by slimdave
    Use tkprof to find out what wait events are slowing you down.

    ???!!!
    -nagarjuna

  5. #5
    Join Date
    Aug 2002
    Location
    Colorado Springs
    Posts
    5,253
    Originally posted by nagarjuna
    ???!!!
    Yes, combined with ...

    alter session set events '10046 trace name context forever, level 12';

    ... of course, rather than the regular sql_trace=true
    David Aldridge,
    "The Oracle Sponge"

    Senior Manager, Business Intelligence Development
    XM Satellite Radio
    Washington, DC

    Oracle ACE

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