Class QueryOptimizer.LimitPushDown

java.lang.Object

com.loomcache.server.query.QueryOptimizer.LimitPushDown

All Implemented Interfaces:

QueryOptimizer.OptimizationRule

Enclosing class:

QueryOptimizer

public static final class QueryOptimizer.LimitPushDown
extends Object
implements QueryOptimizer.OptimizationRule

Limit push-down optimization: pushes LIMIT closer to the scan when possible.

Constructor Summary

Constructors

Constructor	Description
LimitPushDown()

Method Summary

Modifier and Type	Method	Description
QueryPlan	apply(QueryPlan plan, @Nullable QueryOptimizer.TableStatistics stats, Map<String, MapIndex<?,?>> availableIndexes)	Applies this optimization rule to the given query plan.
String	name()	Gets the name of this optimization rule.

Methods inherited from class Object

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

Constructor Details

LimitPushDown

public LimitPushDown()

Method Details

name

public String name()

Description copied from interface: QueryOptimizer.OptimizationRule

Gets the name of this optimization rule.

Specified by:

name in interface QueryOptimizer.OptimizationRule

apply

public QueryPlan apply(QueryPlan plan,
 @Nullable QueryOptimizer.TableStatistics stats,
 Map<String, MapIndex<?,?>> availableIndexes)

Description copied from interface: QueryOptimizer.OptimizationRule

Applies this optimization rule to the given query plan.

Specified by:

apply in interface QueryOptimizer.OptimizationRule

Parameters:

plan - the original query plan

stats - table statistics (if available)

availableIndexes - available indexes for the table

Returns:

optimized query plan, or original if optimization cannot be applied