Hint

Finding Query Block names for a SQL that you can't modify...

Submitted by dave on Tue, 07/20/2010 - 12:36

I recently had an issue where a query being submitted to the database had a large change in performance. I could attribute the change to a recent change in object statistics, but the query wasn't behaving because of a combination of a view, subquery, UNION, and LIKE operators. After spending too much time on this statement I decided to hint it to make it perform like it did before the most recent stats change.

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Documented Hints available in 11.2...

Submitted by dave on Wed, 11/25/2009 - 11:53

As I get deeper into tuning with Statistics and the CBO I have been paying a lot more attention to hints.

In the past I always tried to avoid hints. After working with the CBO and staistics in recent versions I believe they are necessary at times to give guidance to the CBO.

The Oracle Database SQL Language Reference has a comprehensive list of hints included in the documentation of SQL Comments. The list for 11g is available here: link.

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