Re: Oracle Performance

RE: Oracle PerformanceThat is Interesting, If I argued is because it could 
confuse a newbie,
he could understand: "Why don't you use rule, is better than cbo" 
  ----- Original Message ----- 
  From: Whittle Jerome Contr NCI 
  To: oracle-l@xxxxxxxxxxxxx 
  Cc: jreyes@xxxxxxxxxxxxxxxx 
  Sent: Thursday, March 11, 2004 4:43 PM
  Subject: RE: Oracle Performance


  Maybe I wasn't clear enough. I use the Rule hint for troubleshooting. If it 
works much faster with the Rule hint, obviously something else needs 
investigating like analyzing tables or using histograms. If using Rule is 
slower, that also gives me some ideas. If using Rule doesn't make any 
difference and the SQL is still slow, maybe there needs to be an index or some 
other way of writing the SQL.

  Using the Rule hint is a good, quick troubleshooting method but not normally 
the fix. 

  Jerry Whittle 
  ASIFICS DBA 
  NCI Information Systems Inc. 
  jerome.whittle@xxxxxxxxxxxx 
  618-622-4145 

    -----Original Message----- 
    From:   Juan Cachito Reyes Pacheco [SMTP:jreyes@xxxxxxxxxxxxxxxx] 

    Honestly I don't agree with this, I don't think there is any need to use 
rule, in Oracle 9i, CBO works 
    perfectly with this kind of situation, the problem must be find and fixed. 

      ----- Original Message ----- 
      From: Whittle Jerome Contr NCI <mailto:Jerome.Whittle@xxxxxxxxxxxx> 

      You have 5 indexes of which 3 have the fields in your SQL. You may be 
better off with one index on the COD_IMPORTACION, COD_NIVEL_CALIDAD, and 
NRO_FACTURACION fields. After creating the index, analyze the table before 
running your sql.

      You might also just want to try to use the Rule hint. It's usually one of 
the first things I try with slow SQL. If it runs much faster with the Rule 
hint, something is going on to confuse the CBO.

      SELECT /*+ RULE */ COUNT(NRO_FACTURACION) .... 

      Jerry Whittle
      ASIFICS DBA
      NCI Information Systems Inc.
      jerome.whittle@xxxxxxxxxxxx
      618-622-4145 

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