Method R Discussion GroupMethod R helps developers, DBAs, and decision-makers optimize Oracle-based software in every phase of the software life cycle. |
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What use is explain plan now that we have STAT lines?
Becky Goodman   Tuesday, February 26, 2008
In some ways I guess you could say "Not much!" The stat lines certainly give us more information then the explain plan does. However there are times where the query can't be run, or it's not piratical to run. Maybe the query takes hours to run and you'd like to do some testing right now. Using explain plan can give you a clue as to are you doing the right or wrong thing with a query. Also it can reveal issues with the CBO's estimates. If you know your data very well, you might be able to see in the explain plan that it's miscalculating the cardinality of a step. And with this maybe you can fix the problem before you actually run the statement.
Even with all this I just said, I agree with you 100%. Given a choice, I'd take the stat lines over an explain plan every time.
Ric Van Dyke Wednesday, February 27, 2008 |
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