Articles & Content
Topic: 2007 EU
Subtopic: DB2 for LUW
DATE: 2007-11-7 (13:30 - 14:30)
SPEAKERS: John Hornibrook (IBM Toronto Lab)
The query optimizer and the query execution plans (QEPs) it generates are key to the performance of the RDBMS. But query optimization is often a mysterious process and the choices made by the query optimizercan be difficult to understand. If you've ever wondered how an SQL statement gets optimized and how query executionplans are created, this presentation is for you. Using many QEP examples displayed with the Explain facility,this presentation will cover a variety of optimization topics including query rewrite and cardinality estimationand the cost model.
EXP. LEVEL: Intermediate
What is query optimization and why it is important
How queries are rewritten
How filtering, cardinalities and costs are computed
How access plans are chosen to optimize index access and different data organization schemes such as database and range partitioning and multidimensional clustering.
How to interpret Explain facility output
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