io.prestosql.sql.planner.iterative.rule

Class RemoveRedundantDistinctLimit

java.lang.Object

io.prestosql.sql.planner.iterative.rule.RemoveRedundantDistinctLimit

All Implemented Interfaces:

Rule<DistinctLimitNode>

public class RemoveRedundantDistinctLimit
extends Object
implements Rule<DistinctLimitNode>

Replace DistinctLimit node 1. With a empty ValuesNode when count is 0 2. With a Distinct node when the subplan is guaranteed to produce fewer rows than count 3. With its source when the subplan produces only one row

Nested Class Summary

Nested classes/interfaces inherited from interface io.prestosql.sql.planner.iterative.Rule

Rule.Context, Rule.Result

Constructor Summary

Constructors

Constructor and Description
RemoveRedundantDistinctLimit()

Method Summary

Modifier and Type	Method and Description
Rule.Result	apply(DistinctLimitNode node, Captures captures, Rule.Context context)
Pattern<DistinctLimitNode>	getPattern() Returns a pattern to which plan nodes this rule applies.

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.prestosql.sql.planner.iterative.Rule

isEnabled

Constructor Detail

RemoveRedundantDistinctLimit

public RemoveRedundantDistinctLimit()

Method Detail

getPattern

public Pattern<DistinctLimitNode> getPattern()

Description copied from interface: Rule

Returns a pattern to which plan nodes this rule applies.

Specified by:

getPattern in interface Rule<DistinctLimitNode>

apply

public Rule.Result apply(DistinctLimitNode node,
                         Captures captures,
                         Rule.Context context)

Specified by:

apply in interface Rule<DistinctLimitNode>