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

Class RemoveEmptyUnionBranches

java.lang.Object

io.trino.sql.planner.iterative.rule.RemoveEmptyUnionBranches

All Implemented Interfaces:

Rule<UnionNode>

public class RemoveEmptyUnionBranches
extends Object
implements Rule<UnionNode>

Removes branches from a UnionNode that are guaranteed to produce 0 rows. If there's only one branch left, it replaces the UnionNode with a projection to preserve the outputs of the union. If all branches are empty, it replaces the UnionNode with an empty ValuesNode

Nested Class Summary

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

Rule.Context, Rule.Result

Constructor Summary

Constructors

Constructor	Description
RemoveEmptyUnionBranches()

Method Summary

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

RemoveEmptyUnionBranches

public RemoveEmptyUnionBranches()

Method Details

getPattern

public Pattern<UnionNode> getPattern()

Description copied from interface: Rule

Returns a pattern to which plan nodes this rule applies.

Specified by:

getPattern in interface Rule<UnionNode>

apply

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

Specified by:

apply in interface Rule<UnionNode>