org.apache.pig.newplan.logical.rules
Class ColumnPruneHelper

java.lang.Object
  extended by org.apache.pig.newplan.logical.rules.ColumnPruneHelper

public class ColumnPruneHelper
extends Object

Helper class used by ColumnMapKeyPrune to figure out what columns can be pruned. It doesn't make any changes to the operator plan


Field Summary
protected static String INPUTUIDS
           
static String OUTPUTUIDS
           
protected static String REQUIREDCOLS
           
 
Constructor Summary
ColumnPruneHelper(OperatorPlan currentPlan)
           
 
Method Summary
 boolean check()
           
protected  Set<Integer> getColumns(LogicalSchema schema, Set<Long> uids)
           
 OperatorPlan reportChanges()
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

INPUTUIDS

protected static final String INPUTUIDS
See Also:
Constant Field Values

OUTPUTUIDS

public static final String OUTPUTUIDS
See Also:
Constant Field Values

REQUIREDCOLS

protected static final String REQUIREDCOLS
See Also:
Constant Field Values
Constructor Detail

ColumnPruneHelper

public ColumnPruneHelper(OperatorPlan currentPlan)
Method Detail

check

public boolean check()
              throws FrontendException
Throws:
FrontendException

getColumns

protected Set<Integer> getColumns(LogicalSchema schema,
                                  Set<Long> uids)
                           throws FrontendException
Throws:
FrontendException

reportChanges

public OperatorPlan reportChanges()


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