Figure 9 12   RUNSTATS command options

DB2 UDB comes with a very powerful query optimization algorithm. This 

cost based algorithm will attempt to determine the cheapest way to perform a 

query against a database. Items such as the database configuration, database 

physical layout, table relationships, and data distribution are all considered when

finding

the optimal access plan for a query. To check the current execution plan, 

you can use the Explain utility.

9.5.6  Configuration Advisor

The Configuration Advisor wizard is a GUI tool that can be helpful in preparing 

the DB2 initial configuration. The wizard requests information about the 

database, its data, and the purpose of the system, and then recommends new 

configuration parameters for the database and the instance.

To invoke this wizard from the DB2 Control Center, expand the object tree until 

you find the database that you want to tune. Select the icon for the database, 

right click and select 

Configuration Advisor

. Through several dialog windows 

the wizard collects information about the percentage of memory dedicated to 

DB2, type of workload, number of statements per transaction, transaction 

throughput, trade off between recovery and database performance, number of 

 Chapter 9. Testing and tuning 

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