Re: Oracle Performance
- From: "Juan Cachito Reyes Pacheco" <jreyes@xxxxxxxxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 11 Mar 2004 20:30:22 -0400
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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