Package org.apache.vxquery.compiler.rewriter.rules

Class PushChildIntoDataScanRule

java.lang.Object

org.apache.vxquery.compiler.rewriter.rules.AbstractUsedVariablesProcessingRule

org.apache.vxquery.compiler.rewriter.rules.PushChildIntoDataScanRule

All Implemented Interfaces:

org.apache.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule

public class PushChildIntoDataScanRule
extends AbstractUsedVariablesProcessingRule

The rule searches for an unnest operator immediately following a data scan operator.

 Before

   plan__parent
   UNNEST( $v2 : child( $v1 ) )
   DATASCAN( $source : $v1 )
   plan__child

   Where $v1 is not used in plan__parent.

 After

   plan__parent
   DATASCAN( $source : $v1 )
   plan__child

   $source is encoded with the child parameters.
 

Author:

prestonc

Field Summary

Fields inherited from class org.apache.vxquery.compiler.rewriter.rules.AbstractUsedVariablesProcessingRule

hasRun, usedVariables

Constructor Summary

Constructors

Constructor	Description
PushChildIntoDataScanRule()

Method Summary

Modifier and Type	Method	Description
protected boolean	processOperator(org.apache.commons.lang3.mutable.Mutable<org.apache.hyracks.algebricks.core.algebra.base.ILogicalOperator> opRef, org.apache.hyracks.algebricks.core.algebra.base.IOptimizationContext context)

Methods inherited from class org.apache.vxquery.compiler.rewriter.rules.AbstractUsedVariablesProcessingRule

rewritePost, rewritePre, rewritePreTrackingUsedVariables

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PushChildIntoDataScanRule

public PushChildIntoDataScanRule()

Method Detail

processOperator

protected boolean processOperator(org.apache.commons.lang3.mutable.Mutable<org.apache.hyracks.algebricks.core.algebra.base.ILogicalOperator> opRef,
                                  org.apache.hyracks.algebricks.core.algebra.base.IOptimizationContext context)
                           throws org.apache.hyracks.algebricks.common.exceptions.AlgebricksException

Specified by:

processOperator in class AbstractUsedVariablesProcessingRule

Throws:

org.apache.hyracks.algebricks.common.exceptions.AlgebricksException