RE: Query Tuning Help

David,

  I would probably not try to tune a query to make it use an index but tune a query to make it run faster - I have had recently a nice example, a join between a 500K row table and two 2K row tables (returning about 2K rows too) was running faster with FTS (followed by hash joins) on _ALL_ tables than when using the primary key of the big table (it was about twice as fast). Try avoiding prejudices...

Otherwise, no, the calculation cannot cause the problem in that case.

I would also get all columns in the SELECT list from the same table, just in case.

HTH, SF

>----- ------- Original Message ------- -----
>From: David Wagoner <dwagoner_at_arsenaldigital.com>
>To: Multiple recipients of list ORACLE-L
><ORACLE-L_at_fatcity.com>
>Sent: Mon, 27 Oct 2003 07:34:26
>
>I'm trying to tune the following query to use an
>index on the FILE_DTS
>column, rather than a FTS on the CLASS_CONFIG table
>(~350,000 rows).
>
>SELECT a2.class_config_id, a1.schedule_name
>FROM class_config a2, class_schedule a1
>WHERE a2.class_config_id = a1.class_config_id
>AND to_date(a2.file_dts, 'mmddyyhh24miss') >
>SYSDATE - 35
>
>
>I created a function-based index on FILE_DTS, like
>this:
>
>CREATE INDEX CLASS_CONFIG_FILE_DTS_FX_IDX ON
>CLASS_CONFIG to_date(file_dts,
>'mmddyyhh24miss')
>
>and analyzed the table, but the explain plan still
>shows a FTS. I can
>change the query to something simpler and get it to
>use the new index, but I
>assume the calculation (> SYSDATE - 35) is causing
>the problem. Any
>suggestions?
>
>
>Best regards,
>
>David B. Wagoner
>Database Administrator
>Arsenal Digital Solutions
>Web: http://www.arsenaldigital.com
>
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Regards,

Stephane Faroult
Oriole

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Author: Stephane Faroult
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