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

Class EliminateUnnestAggregateSequencesRule

java.lang.Object

org.apache.vxquery.compiler.rewriter.rules.EliminateUnnestAggregateSequencesRule

All Implemented Interfaces:

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

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

The rule searches for unnest followed by an aggregate operator with a sequence function and converts the aggregate operator to an assign.

 Before
 
   plan__parent
   UNNEST( $v2 : iterate( $v1 ) )
   AGGREGATE( $v1 : sequence( $v0 ) )
   plan__child
   
   where plan__parent does not use $v1 and $v0 is defined in plan__child.
   
 After
 
   plan__parent
   UNNEST( $v2 : iterate( $v1 ) )
   ASSIGN( $v1 : $v0 )
   plan__child
 

Author:

prestonc

Constructor Summary

Constructors

Constructor	Description
EliminateUnnestAggregateSequencesRule()

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

EliminateUnnestAggregateSequencesRule

public EliminateUnnestAggregateSequencesRule()

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)

Specified by:

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