Package io.prestosql.sql.planner.iterative.rule

Class PruneApplySourceColumns

java.lang.Object

io.prestosql.sql.planner.iterative.rule.PruneApplySourceColumns

All Implemented Interfaces:

Rule<ApplyNode>

public class PruneApplySourceColumns
extends Object
implements Rule<ApplyNode>

This rule restricts outputs of ApplyNode's subquery to include only the symbols needed for subqueryAssignments. Symbols from the subquery are not produced at ApplyNode's output. They are only used for the assignments. Transforms:

 - Apply
      correlation: [corr_symbol]
      assignments:
          result_1 -> a in subquery_symbol_1,
          result_2 -> b > ALL subquery_symbol_2
    - Input (a, b, corr_symbol)
    - Subquery (subquery_symbol_1, subquery_symbol_2, subquery_symbol_3)
 

Into:

 - Apply
      correlation: [corr_symbol]
      assignments:
          result_1 -> a in subquery_symbol_1,
          result_2 -> b > ALL subquery_symbol_2
    - Input (a, b, corr_symbol)
    - Project
          subquery_symbol_1 -> subquery_symbol_1
          subquery_symbol_2 -> subquery_symbol_2
        - Subquery (subquery_symbol_1, subquery_symbol_2, subquery_symbol_3)
 

Note: ApplyNode's input symbols are produced on ApplyNode's output. They cannot be pruned without outer context.

Nested Class Summary

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

Rule.Context, Rule.Result

Constructor Summary

Constructors

Constructor	Description
PruneApplySourceColumns()

Method Summary

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

PruneApplySourceColumns

public PruneApplySourceColumns()

Method Detail

getPattern

public Pattern<ApplyNode> getPattern()

Description copied from interface: Rule

Returns a pattern to which plan nodes this rule applies.

Specified by:

getPattern in interface Rule<ApplyNode>

apply

public Rule.Result apply(ApplyNode applyNode,
                         Captures captures,
                         Rule.Context context)

Specified by:

apply in interface Rule<ApplyNode>