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Exploiting Indexes and Influencing DB2 Usage (F10)

Topic: DB2 for z/OS

Subtopic: 2010



DATE: 2010-11-10 (11:00 - 12:00)
SPEAKERS: Susan Lawson (YLA), Dan Luksetich (YLA)

For high performance DB2 applications it is not only important we understand how DB2 is optimizing its access to the data but how well we are utilizing our indexes. We spend a lot of time building and maintaining indexes, so lets use them wisely! Filtering as much as possible, as soon as possible is key to achieving high performance in our applications and the more we can filter via the indexes the better. We will first cover index design issues and query performance topics, such as best use of index matching predicates, and index screening. We will then turn our attention to influencing DB2 to use particular indexes. Having accurate catalog statistics and coding proper predicates gives DB2 an excellent opportunity to properly choose the appropriate index for each query. There are situations, however, in which we may know more than DB2. Such things include the common input values, the organization on input files to our processes, and the sequence of statements within a process. Knowing these things we may find ourselves in situations in which we may want to influence DB2 towards the utilization of a particular index.

EXP. LEVEL: Intermediate

OBJECTIVES:

Overview of Index Utilization in DB2

Discuss Reasons for Indexes

Show How DB2 Matches Predicates

Discuss how to Influence Index Selection

Discuss SQL Techniques for Influening Index Selection



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