org.apache.hadoop.hive.ql.optimizer

Class ConstantPropagateProcCtx

java.lang.Object

org.apache.hadoop.hive.ql.optimizer.ConstantPropagateProcCtx

All Implemented Interfaces:

NodeProcessorCtx

public class ConstantPropagateProcCtx
extends Object
implements NodeProcessorCtx

This class implements the processor context for Constant Propagate. ConstantPropagateProcCtx keeps track of propagated constants in a column->const map for each operator, enabling constants to be revolved across operators.

Constructor Summary

Constructors

Constructor and Description
ConstantPropagateProcCtx()

Method Summary

Methods

Modifier and Type	Method and Description
void	addOpToDelete(Operator<? extends Serializable> op)
Map<Operator<? extends Serializable>,Map<ColumnInfo,ExprNodeDesc>>	getOpToConstantExprs()
List<Operator<? extends Serializable>>	getOpToDelete()
Map<ColumnInfo,ExprNodeDesc>	getPropagatedConstants(Operator<? extends Serializable> op) Get propagated constant map from parents.

Methods inherited from class java.lang.Object

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

Constructor Detail

ConstantPropagateProcCtx

public ConstantPropagateProcCtx()

Method Detail

getOpToConstantExprs

public Map<Operator<? extends Serializable>,Map<ColumnInfo,ExprNodeDesc>> getOpToConstantExprs()

getPropagatedConstants

public Map<ColumnInfo,ExprNodeDesc> getPropagatedConstants(Operator<? extends Serializable> op)

Get propagated constant map from parents. Traverse all parents of current operator, if there is propagated constant (determined by assignment expression like column=constant value), resolve the column using RowResolver and add it to current constant map.

Parameters:

op - operator getting the propagated constants.

Returns:

map of ColumnInfo to ExprNodeDesc. The values of that map must be either ExprNodeConstantDesc or ExprNodeNullDesc.

addOpToDelete

public void addOpToDelete(Operator<? extends Serializable> op)

getOpToDelete

public List<Operator<? extends Serializable>> getOpToDelete()