DB2 & IMS

• The presence of heuristics or best practices. There should be simple, straightforward methods of implementing tasks, including standards and best practices.

With these objectives in mind, this article takes an in-depth look at the following five tuning strategies:

• SQL tuning involves SQL review and knowledge of potential access paths, table and index data distribution, and statistics.

• Resource constraint tuning is an analysis of possible trade-offs among CPU, elapsed time, I/O, memory, network traffic, and other resources.

• Application tuning focuses attention on suites of programs that access particular tables, batch windows, and online service levels.

• Object tuning concentrates on the general definitions and configurations of tables, indexes, stored procedures, and other database objects.

• System tuning deals with the DB2 DBMS infrastructure that supports all of these strategies.

How do you tell what kinds of tuning are most needed in your environment? First, let’s discuss typical symptoms.

SQL issues always exist, although specific symptoms may be difficult to detect. Typical causes range from poor coding techniques, poor understanding of SQL coding standards, lack of understanding of the data model, and so forth.

Resource constraint issues commonly arise when a need is felt for additional CPU or DASD, or Service Level Agreements (SLAs) aren’t being met.

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