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

Class TransformCorrelatedGlobalAggregationWithProjection

java.lang.Object

io.prestosql.sql.planner.iterative.rule.TransformCorrelatedGlobalAggregationWithProjection

All Implemented Interfaces:

Rule<CorrelatedJoinNode>

public class TransformCorrelatedGlobalAggregationWithProjection
extends Object
implements Rule<CorrelatedJoinNode>

This rule decorrelates a correlated subquery of LEFT or INNER correlated join with: - single global aggregation, or - global aggregation over distinct operator (grouped aggregation with no aggregation assignments)

In the case of single aggregation, it transforms:

 - CorrelatedJoin LEFT or INNER (correlation: [c], filter: true, output: a, x, y)
      - Input (a, c)
      - Project (x <- f(count), y <- f'(agg))
           - Aggregation global
             count <- count(*)
             agg <- agg(b)
                - Source (b) with correlated filter (b > c)
 

Into:

 - Project (a <- a, x <- f(count), y <- f'(agg))
      - Aggregation (group by [a, c, unique])
        count <- count(*) mask(non_null)
        agg <- agg(b) mask(non_null)
           - LEFT join (filter: b > c)
                - UniqueId (unique)
                     - Input (a, c)
                - Project (non_null <- TRUE)
                     - Source (b) decorrelated
 

In the case of global aggregation over distinct operator, it transforms:

 - CorrelatedJoin LEFT or INNER (correlation: [c], filter: true, output: a, x, y)
      - Input (a, c)
      - Project (x <- f(count), y <- f'(agg))
           - Aggregation global
             count <- count(*)
             agg <- agg(b)
                - Aggregation "distinct operator" group by [b]
                     - Source (b) with correlated filter (b > c)
 

Into:

 - Project (a <- a, x <- f(count), y <- f'(agg))
      - Aggregation (group by [a, c, unique])
        count <- count(*) mask(non_null)
        agg <- agg(b) mask(non_null)
           - Aggregation "distinct operator" group by [a, c, unique, non_null, b]
                - LEFT join (filter: b > c)
                     - UniqueId (unique)
                          - Input (a, c)
                     - Project (non_null <- TRUE)
                          - Source (b) decorrelated
 

Nested Class Summary

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

Rule.Context, Rule.Result

Constructor Summary

Constructors

Constructor	Description
TransformCorrelatedGlobalAggregationWithProjection(Metadata metadata)

Method Summary

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

TransformCorrelatedGlobalAggregationWithProjection

public TransformCorrelatedGlobalAggregationWithProjection(Metadata metadata)

Method Detail

getPattern

public Pattern<CorrelatedJoinNode> getPattern()

Description copied from interface: Rule

Returns a pattern to which plan nodes this rule applies.

Specified by:

getPattern in interface Rule<CorrelatedJoinNode>

apply

public Rule.Result apply(CorrelatedJoinNode correlatedJoinNode,
                         Captures captures,
                         Rule.Context context)

Specified by:

apply in interface Rule<CorrelatedJoinNode>