How can I see the optimized SQL by CBO [message #141468] |
Mon, 10 October 2005 07:45 |
vgs2005
Messages: 123 Registered: April 2005
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Senior Member |
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If I write a very complex SQL statement, I know that CBO makes it optimized sometimes by rewriting the query internally. How do I actually see this 'optmized' query?
thanks in advance..
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Re: How can I see the optimized SQL by CBO [message #141482 is a reply to message #141468] |
Mon, 10 October 2005 08:23 |
Frank Naude
Messages: 4581 Registered: April 1998
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Senior Member |
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Hi,
Oracle doesn't change the physical query syntax, it just picks the optimal execution plan (or the plan it thinks is optimal). You can look at the plan by running an EXPLAIN PLAN (check the SQL Reference Guide for details).
One exception is when your create Materialized Views and enable Oracle's QUERY REWRITE feature. In such a case you need to enable SQL TRACING to see the rewritten statements.
Best regards.
Frank
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