org.apache.calcite.rel.rules

Class ProjectToWindowRule.WindowedAggRelSplitter

java.lang.Object

org.apache.calcite.rel.rules.CalcRelSplitter

org.apache.calcite.rel.rules.ProjectToWindowRule.WindowedAggRelSplitter

Enclosing class:

ProjectToWindowRule

static class ProjectToWindowRule.WindowedAggRelSplitter
extends CalcRelSplitter

Splitter that distinguishes between windowed aggregation expressions (calls to RexOver) and ordinary expressions.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.calcite.rel.rules.CalcRelSplitter

CalcRelSplitter.RelType

Field Summary

Fields

Modifier and Type	Field and Description
private static CalcRelSplitter.RelType[]	REL_TYPES

Fields inherited from class org.apache.calcite.rel.rules.CalcRelSplitter

program, relBuilder

Constructor Summary

Constructors

Constructor and Description
WindowedAggRelSplitter(Calc calc, RelBuilder relBuilder)

Method Summary

Modifier and Type	Method and Description
private DirectedGraph<Integer,DefaultEdge>	createGraphFromExpression(List<RexNode> exprs)
protected List<Set<Integer>>	getCohorts() Returns a list of sets of expressions that should be on the same level.
private List<Integer>	getRank(DirectedGraph<Integer,DefaultEdge> graph)
private boolean	isDependent(DirectedGraph<Integer,DefaultEdge> graph, List<Integer> rank, int ordinal1, int ordinal2)

Methods inherited from class org.apache.calcite.rel.rules.CalcRelSplitter

canImplement, execute, handle

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

REL_TYPES

private static final CalcRelSplitter.RelType[] REL_TYPES

Constructor Detail

WindowedAggRelSplitter

WindowedAggRelSplitter(Calc calc,
                       RelBuilder relBuilder)

Method Detail

getCohorts

protected List<Set<Integer>> getCohorts()

Description copied from class: CalcRelSplitter

Returns a list of sets of expressions that should be on the same level.

For example, if this method returns { {3, 5}, {4, 7} }, it means that expressions 3 and 5, should be on the same level, and expressions 4 and 7 should be on the same level. The two cohorts do not need to be on the same level.

The list is best effort. If it is not possible to arrange that the expressions in a cohort are on the same level, the CalcRelSplitter.execute() method will still succeed.

The default implementation of this method returns the empty list; expressions will be put on the most suitable level. This is generally the lowest possible level, except for literals, which are placed at the level where they are used.

Overrides:

getCohorts in class CalcRelSplitter

Returns:

List of cohorts, that is sets of expressions, that the splitting algorithm should attempt to place on the same level

isDependent

private boolean isDependent(DirectedGraph<Integer,DefaultEdge> graph,
                            List<Integer> rank,
                            int ordinal1,
                            int ordinal2)

getRank

private List<Integer> getRank(DirectedGraph<Integer,DefaultEdge> graph)

createGraphFromExpression

private DirectedGraph<Integer,DefaultEdge> createGraphFromExpression(List<RexNode> exprs)