Chapter 3. Introduction to IBM DB2 Universal Database 69
3.3 The DB2 query optimizer
The query optimizer is the key component in the performance of any Enterprise Database
Server. IBM has made more than a 25-year investment in enhancements to the DB2
cost-based, rule-driven optimizer with the goal of keeping it the best in the industry. A major
component of this effort is the implementation of the Starburst extensible optimizer in DB2
UDB. This allows IBM to add new intelligence to the optimizer without having to modify the
entire query-compilation process.
As DB2 UDB is enhanced with new features and functionality, the optimizer performance
improves. An example is extending the optimizer to understand OLAP SQL extensions and
multiple levels ...
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