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

Class EliminateSubplanForSingleItemsRule

java.lang.Object

org.apache.vxquery.compiler.rewriter.rules.EliminateSubplanForSingleItemsRule

All Implemented Interfaces:

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

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

The rule searches for subplans that only have one item per tuple.

 Before
 
   %PARENT_PLAN
   SUBPLAN{
     AGGREGATE($v2, sequence(%expression($v1)) )
     UNNEST($v1, iterate($v0) )
     NESTEDTUPLESOURCE
   }
   %CHILD_PLAN
 
   Where |$v0| == 1
 
 After 
 
   %PARENT_PLAN
   ASSIGN($v2, %expression($v0) )
   %CHILD_PLAN
 

Author:

prestonc

Constructor Summary

Constructors

Constructor	Description
EliminateSubplanForSingleItemsRule()

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

EliminateSubplanForSingleItemsRule

public EliminateSubplanForSingleItemsRule()

Method Detail

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

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