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

Class GatherPartialTopN

java.lang.Object

io.trino.sql.planner.iterative.rule.GatherPartialTopN

All Implemented Interfaces:

Rule<ExchangeNode>

public class GatherPartialTopN
extends Object
implements Rule<ExchangeNode>

Adds local round-robin and gathering exchange on top of partial TopN to limit the task output size. Replaces plans like:

 exchange(remote)
   - topn(partial)
 

with

  exchange(remote)
      - topn(partial)
          - exchange(local, gather)
              - topn(partial)
                  - local_exchange(round_robin)
                      - topn(partial)
 

Nested Class Summary

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

Rule.Context, Rule.Result

Constructor Summary

Constructors

Constructor	Description
GatherPartialTopN()

Method Summary

Modifier and Type	Method	Description
Rule.Result	apply(ExchangeNode node, Captures captures, Rule.Context context)
Pattern<ExchangeNode>	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

GatherPartialTopN

public GatherPartialTopN()

Method Details

getPattern

public Pattern<ExchangeNode> getPattern()

Description copied from interface: Rule

Returns a pattern to which plan nodes this rule applies.

Specified by:

getPattern in interface Rule<ExchangeNode>

apply

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

Specified by:

apply in interface Rule<ExchangeNode>