Package io.trino.sql.planner.iterative.rule

Class MergeLimitWithTopN

java.lang.Object

io.trino.sql.planner.iterative.rule.MergeLimitWithTopN

All Implemented Interfaces:

Rule<LimitNode>

public class MergeLimitWithTopN
extends Object
implements Rule<LimitNode>

This rule handles both LimitNode with ties and LimitNode without ties. In the case of LimitNode with ties, the LimitNode is removed if only its row count equals or exceeds TopNNode's row count:

     - Limit (5, with ties)
        - TopN (3)
 

is transformed into:

     - TopN (3)
 

In the case of LimitNode without ties, the LimitNode is removed, and the TopNNode's row count is updated to minimum row count of both nodes:

     - Limit (3)
        - TopN (5)
 

is transformed into:

     - TopN (3)
 

Nested Class Summary

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

Rule.Context, Rule.Result

Constructor Summary

Constructors

Constructor	Description
MergeLimitWithTopN()

Method Summary

Modifier and Type	Method	Description
Rule.Result	apply(LimitNode parent, Captures captures, Rule.Context context)
Pattern<LimitNode>	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.trino.sql.planner.iterative.Rule

isEnabled

Constructor Details

MergeLimitWithTopN

public MergeLimitWithTopN()

Method Details

getPattern

public Pattern<LimitNode> getPattern()

Description copied from interface: Rule

Returns a pattern to which plan nodes this rule applies.

Specified by:

getPattern in interface Rule<LimitNode>

apply

public Rule.Result apply(LimitNode parent,
 Captures captures,
 Rule.Context context)

Specified by:

apply in interface Rule<LimitNode>