Comparing real-time cardinality to the optimizer cardinality estimates

A tool to aid in tuning queries

From the developerWorks archives

Samir Kapoor, Sudharsan Selvarajah, and Kaarel Truuvert

Date archived: January 13, 2017 | First published: December 15, 2005

Evaluating real time cardinality in IBM® DB2® Universal Database ™ (DB2 UDB) versus the estimated cardinality in the access plan can help DBAs make various decisions to improve query performance. Here are all the details to create count queries to evaluate real-time cardinalities at certain operators in an access plan.

This content is no longer being updated or maintained. The full article is provided "as is" in a PDF file. Given the rapid evolution of technology, some steps and illustrations may have changed.



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