DB2 Version 9.7 for Linux, UNIX, and Windows

XML schema for general optimization guidelines

The generalRequest group defines guidelines that are not specific to a particular phase of the optimization process, and can be used to change the optimizer's search space.

<!--************************************************************************************* --> \
<!-- Choices of general request elements.                                                 --> \
<!-- REOPT can be used to override the setting of the REOPT bind option.                  --> \
<!-- DPFXMLMOVEMENT can be used to affect the optimizer's plan when moving XML documents  --> \
<!-- between database partitions. The allowed value can be REFERENCE or COMBINATION. The  --> \
<!-- default value is NONE.                                                               --> \
<!--************************************************************************************* --> \
<xs:group name="generalRequest"> 
   <xs:sequence> 
      <xs:element name="REOPT" type="reoptType" minOccurs="0" maxOccurs="1"/>
      <xs:element name="DEGREE" type="degreeType" minOccurs="0" maxOccurs="1"/>
      <xs:element name="QRYOPT" type="qryoptType" minOccurs="0" maxOccurs="1"/>
      <xs:element name="RTS" type="rtsType" minOccurs="0" maxOccurs="1"/>
      <xs:element name="DPFXMLMOVEMENT" type="dpfXMLMovementType" minOccurs="0" maxOccurs="1"/>
   </xs:sequence>
</xs:group>

Note: General optimization guidelines can be specified at both the global and statement levels. The description and syntax of general optimization guideline elements is the same for both global optimization guidelines and statement-level optimization guidelines.

Description

General request elements can be used to define general optimization guidelines, which affect the optimization search space and hence, can affect the applicability of rewrite and cost-based optimization guidelines.