org.apache.phoenix.compile

Class OrderPreservingTracker

java.lang.Object

org.apache.phoenix.compile.OrderPreservingTracker

public class OrderPreservingTracker
extends Object

Determines if the natural key order of the rows returned by the scan will match the order of the expressions. For GROUP BY, if order is preserved we can use an optimization during server-side aggregation to do the aggregation on-the-fly versus keeping track of each distinct group. We can only do this optimization if all the rows for each group will be contiguous. For ORDER BY, we can drop the ORDER BY statement if the order is preserved.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	OrderPreservingTracker.Info
static class	OrderPreservingTracker.Ordering

Constructor Summary

Constructors

Constructor and Description
OrderPreservingTracker(StatementContext context, GroupByCompiler.GroupBy groupBy, OrderPreservingTracker.Ordering ordering, int nNodes)
OrderPreservingTracker(StatementContext context, GroupByCompiler.GroupBy groupBy, OrderPreservingTracker.Ordering ordering, int nNodes, TupleProjector projector)

Method Summary

Modifier and Type	Method and Description
List<Expression>	getExpressionsFromOrderPreservingTrackInfos()
int	getOrderPreservingColumnCount()
boolean	isOrderPreserving()
boolean	isReverse()
void	track(Expression node)
void	track(Expression node, SortOrder sortOrder, Boolean isNullsLast)

Methods inherited from class java.lang.Object

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

Constructor Detail

OrderPreservingTracker

public OrderPreservingTracker(StatementContext context,
                              GroupByCompiler.GroupBy groupBy,
                              OrderPreservingTracker.Ordering ordering,
                              int nNodes)

OrderPreservingTracker

public OrderPreservingTracker(StatementContext context,
                              GroupByCompiler.GroupBy groupBy,
                              OrderPreservingTracker.Ordering ordering,
                              int nNodes,
                              TupleProjector projector)

Method Detail

track

public void track(Expression node)

track

public void track(Expression node,
                  SortOrder sortOrder,
                  Boolean isNullsLast)

getOrderPreservingColumnCount

public int getOrderPreservingColumnCount()

getExpressionsFromOrderPreservingTrackInfos

public List<Expression> getExpressionsFromOrderPreservingTrackInfos()

isOrderPreserving

public boolean isOrderPreserving()

isReverse

public boolean isReverse()