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Thread: tracing

  1. #1
    Join Date
    Dec 2003
    Location
    Belgium
    Posts
    48

    Question Unanswered: tracing

    hello,

    I want to know if statistics are running on the database, how can I found out this?

    In my execution plan the optimizer goal is choose, what does this mean, is this rule based or cost based? Also it gives me 0 rows in the execution plan, although the result gave me 15 rows. (I can also see 15 in my fetch row)

    database is 92010 on linux redhat

    can anyone give me more explanation of why it is giving no rows

    thanks

  2. #2
    Join Date
    Jul 2003
    Posts
    2,296
    as the schema owner run:

    select table_name, last_analyzed from user_tables;

    this definitely sounds like you have not analyzed your tables recently.
    you need to create a proc to analyze the appropriate schema(s) at a periodic interval (create database job). I personally analyze all my tables and indexes nightly. This might be overkill, but I constantly compare plans from dev to production and I need to be sure all environments have been analyzed recently.
    - The_Duck
    you can lead someone to something but they will never learn anything ...

  3. #3
    Join Date
    Oct 2003
    Location
    Slovakia
    Posts
    482
    Originally posted by The_Duck
    as the schema owner run:

    select table_name, last_analyzed from user_tables;

    this definitely sounds like you have not analyzed your tables recently.
    you need to create a proc to analyze the appropriate schema(s) at a periodic interval (create database job). I personally analyze all my tables and indexes nightly. This might be overkill, but I constantly compare plans from dev to production and I need to be sure all environments have been analyzed recently.
    For analysis use dbms_stats package.
    Examples at:
    http://www.dba-oracle.com/art_builder_dbms_stats.htm
    or http://tahiti.oracle.com

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