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

Class ConsolidateDescandantChild

java.lang.Object

org.apache.vxquery.compiler.rewriter.rules.ConsolidateDescandantChild

All Implemented Interfaces:

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

public class ConsolidateDescandantChild
extends Object
implements org.apache.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule

The rule searches for assign operator with an aggregate function expression immediately following an aggregate operator with a sequence expression. XQuery aggregate functions are implemented in both scalar (one XDM Instance input as a sequence) and iterative (a stream of XDM Instances each one is single object).

 Before 
 
   plan__parent
   UNNEST( $v3 : fn:child( args[$v1], args[$filter]  ) )
   UNNEST( $v1 : fn:descandant( args[$v0] ) )
   plan__child
   
 After
 
   plan__parent
   UNNEST( $v3 : fn:descandant( args[$v0], args[$filter] ) )
   plan__child
 
 
 

Author:

shivanimall

Constructor Summary

Constructors

Constructor	Description
ConsolidateDescandantChild()

Method Summary

Modifier and Type	Method	Description
boolean	rewritePost(org.apache.commons.lang3.mutable.Mutable<org.apache.hyracks.algebricks.core.algebra.base.ILogicalOperator> opRef, org.apache.hyracks.algebricks.core.algebra.base.IOptimizationContext context)
boolean	rewritePre(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 java.lang.Object

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

Constructor Detail

ConsolidateDescandantChild

public ConsolidateDescandantChild()

Method Detail

rewritePre

public boolean rewritePre(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:

rewritePre in interface org.apache.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule

Throws:

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

rewritePost

public boolean rewritePost(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:

rewritePost in interface org.apache.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule

Throws:

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