DB2 10.5 for Linux, UNIX, and Windows

XML schema for the global OPTGUIDELINES element

The OPTGUIDELINES element defines the global optimization guidelines for the optimization profile.

It is defined by the complex type globalOptimizationGuidelinesType.
XML Schema

   <xs:complexType name="globalOptimizationGuidelinesType">
      <xs:sequence>
         <xs:group ref="MQTOptimizationChoices"/>
         <xs:group ref="computationalPartitionGroupOptimizationChoices"/>
         <xs:group ref="generalRequest"/>
         <xs:group ref="mqtEnforcementRequest"/>
      </xs:sequence>
   </xs:complexType>

Description

Global optimization guidelines can be defined with elements from the groups MQTOptimizationChoices, computationalPartitionGroupChoices, or generalRequest.
  • MQTOptimizationChoices group elements can be used to influence MQT substitution.
  • computationalPartitionGroupOptimizationChoices group elements can be used to influence computational partition group optimization, which involves the dynamic redistribution of data read from remote data sources. It applies only to partitioned federated database configurations.
  • The generalRequest group elements are not specific to a particular phase of the optimization process, and can be used to change the optimizer's search space. They can be specified globally or at the statement level.
  • MQT enforcement requests specify semantically matchable materialized query tables (MQTs) whose use in access plans should be enforced regardless of cost estimates.