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Why Does Optimizer Hate My SQL?

About the Talk

April 15, 2010 11:00 AM

Billund, Denmark

Billund, Denmark

This presentation is to explore various SQL performance issues encountered in the real world and to discuss the root cause for those SQL performance issues. 1. Review of cardinality, selectivity, and histograms. A must for every performance tuner to completely understand these concepts. 2. What to look for in a 10053 trace. How to effectively use 10053 trace files to identify the root cause of a SQL performance issue. 3. Bind peeking issues. 4. Effective use of system statistics to combat optimizer discrepencies. 5. Index efficiency and indices on non-selective columns. 6. Nulls and indices. 7. Issues with few hints such as ORDERED, INDEX, etc. Use of profiles and outlines to resolve these issues. 8. Subquery transformation and few optimizer features related to sub query transformation. 9. Predicate based first_k_rows mode. 10. Correlation issues.

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