public class CalcRelSplitter
extends java.lang.Object
Calc
with multiple RexCall
sub-expressions that
cannot all be implemented by a single concrete RelNode
.
This is a copy of CalcRelSplitter
modified to
work with Beam. TODO(CALCITE-4538) consider contributing these changes back upstream.
For example, the Java and Fennel calculator do not implement an identical set of operators. The Calc can be used to split a single Calc with mixed Java- and Fennel-only operators into a tree of Calc object that can each be individually implemented by either Java or Fennel.and splits it into several Calc instances.
Currently the splitter is only capable of handling two "rel types". That is, it can deal with Java vs. Fennel Calcs, but not Java vs. Fennel vs. some other type of Calc.
See ProjectToWindowRule
for an example of how this class is used.
Modifier and Type | Class and Description |
---|---|
static class |
CalcRelSplitter.RelType
Type of relational expression.
|
Modifier and Type | Field and Description |
---|---|
protected org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.rex.RexProgram |
program |
protected org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.tools.RelBuilder |
relBuilder |
Constructor and Description |
---|
CalcRelSplitter(org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.rel.core.Calc calc,
org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.tools.RelBuilder relBuilder,
CalcRelSplitter.RelType[] relTypes)
Constructs a CalcRelSplitter.
|
Modifier and Type | Method and Description |
---|---|
protected boolean |
canImplement(org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.rel.logical.LogicalCalc rel,
java.lang.String relTypeName)
Returns whether a relational expression can be implemented solely in a given
CalcRelSplitter.RelType . |
org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.rel.RelNode |
execute() |
protected java.util.List<java.util.Set<java.lang.Integer>> |
getCohorts()
Returns a list of sets of expressions that should be on the same level.
|
protected org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.rel.RelNode |
handle(org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.rel.RelNode rel)
Opportunity to further refine the relational expression created for a given level.
|
protected final org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.rex.RexProgram program
protected final org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.tools.RelBuilder relBuilder
public CalcRelSplitter(org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.rel.core.Calc calc, org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.tools.RelBuilder relBuilder, CalcRelSplitter.RelType[] relTypes)
calc
- Calc to splitrelTypes
- Array of rel types, e.g. {Java, Fennel}. Must be distinct.public org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.rel.RelNode execute()
protected org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.rel.RelNode handle(org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.rel.RelNode rel)
protected boolean canImplement(org.apache.beam.vendor.calcite.v1_28_0.org.apache.calcite.rel.logical.LogicalCalc rel, java.lang.String relTypeName)
CalcRelSplitter.RelType
.rel
- Calculation relational expressionrelTypeName
- Name of a CalcRelSplitter.RelType
protected java.util.List<java.util.Set<java.lang.Integer>> getCohorts()
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 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.