org.apache.calcite.rel.metadata

Class RelMdExpressionLineage

java.lang.Object

org.apache.calcite.rel.metadata.RelMdExpressionLineage

All Implemented Interfaces:

MetadataHandler<BuiltInMetadata.ExpressionLineage>

public class RelMdExpressionLineage
extends Object
implements MetadataHandler<BuiltInMetadata.ExpressionLineage>

Default implementation of RelMetadataQuery.getExpressionLineage(org.apache.calcite.rel.RelNode, org.apache.calcite.rex.RexNode) for the standard logical algebra.

The goal of this provider is to infer the lineage for the given expression.

The output expressions might contain references to columns produced by TableScan operators (RexTableInputRef). In turn, each TableScan operator is identified uniquely by a RexTableInputRef.RelTableRef containing its qualified name and an identifier.

If the lineage cannot be inferred, we return null.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	RelMdExpressionLineage.RexReplacer Replaces expressions with their equivalences.

Field Summary

Fields

Modifier and Type	Field and Description
static RelMetadataProvider	SOURCE

Constructor Summary

Constructors

Modifier	Constructor and Description
private	RelMdExpressionLineage()

Method Summary

Modifier and Type	Method and Description
private static Set<RexNode>	createAllPossibleExpressions(RexBuilder rexBuilder, RexNode expr, ImmutableBitSet predFieldsUsed, Map<RexInputRef,Set<RexNode>> mapping, Map<RexInputRef,RexNode> singleMapping)
protected static Set<RexNode>	createAllPossibleExpressions(RexBuilder rexBuilder, RexNode expr, Map<RexInputRef,Set<RexNode>> mapping) Given an expression, it will create all equivalent expressions resulting from replacing all possible combinations of references in the mapping by the corresponding expressions.
private static void	createExpressions(RexBuilder rexBuilder, RexNode expr, ImmutableBitSet predFieldsUsed, Map<RexInputRef,Set<RexNode>> mapping, Map<RexInputRef,RexNode> singleMapping, Set<RexNode> result)
MetadataDef<BuiltInMetadata.ExpressionLineage>	getDef()
Set<RexNode>	getExpressionLineage(Aggregate rel, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from Aggregate.
Set<RexNode>	getExpressionLineage(Exchange rel, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from Exchange.
Set<RexNode>	getExpressionLineage(Filter rel, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from Filter.
Set<RexNode>	getExpressionLineage(HepRelVertex rel, RelMetadataQuery mq, RexNode outputExpression)
Set<RexNode>	getExpressionLineage(Join rel, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from Join.
Set<RexNode>	getExpressionLineage(Project rel, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from Project.
Set<RexNode>	getExpressionLineage(RelNode rel, RelMetadataQuery mq, RexNode outputExpression)
Set<RexNode>	getExpressionLineage(RelSubset rel, RelMetadataQuery mq, RexNode outputExpression)
Set<RexNode>	getExpressionLineage(Sort rel, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from Sort.
Set<RexNode>	getExpressionLineage(TableScan rel, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from TableScan.
Set<RexNode>	getExpressionLineage(Union rel, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from Union.

Methods inherited from class java.lang.Object

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

Field Detail

SOURCE

public static final RelMetadataProvider SOURCE

Constructor Detail

RelMdExpressionLineage

private RelMdExpressionLineage()

Method Detail

getDef

public MetadataDef<BuiltInMetadata.ExpressionLineage> getDef()

Specified by:

getDef in interface MetadataHandler<BuiltInMetadata.ExpressionLineage>

getExpressionLineage

public Set<RexNode> getExpressionLineage(RelNode rel,
                                         RelMetadataQuery mq,
                                         RexNode outputExpression)

getExpressionLineage

public Set<RexNode> getExpressionLineage(HepRelVertex rel,
                                         RelMetadataQuery mq,
                                         RexNode outputExpression)

getExpressionLineage

public Set<RexNode> getExpressionLineage(RelSubset rel,
                                         RelMetadataQuery mq,
                                         RexNode outputExpression)

getExpressionLineage

public Set<RexNode> getExpressionLineage(TableScan rel,
                                         RelMetadataQuery mq,
                                         RexNode outputExpression)

Expression lineage from TableScan.

We extract the fields referenced by the expression and we express them using RexTableInputRef.

getExpressionLineage

public Set<RexNode> getExpressionLineage(Aggregate rel,
                                         RelMetadataQuery mq,
                                         RexNode outputExpression)

Expression lineage from Aggregate.

If the expression references grouping sets or aggregate function results, we cannot extract the lineage and we return null.

getExpressionLineage

public Set<RexNode> getExpressionLineage(Join rel,
                                         RelMetadataQuery mq,
                                         RexNode outputExpression)

Expression lineage from Join.

We only extract the lineage for INNER joins.

getExpressionLineage

public Set<RexNode> getExpressionLineage(Union rel,
                                         RelMetadataQuery mq,
                                         RexNode outputExpression)

Expression lineage from Union.

For Union operator, we might be able to extract multiple origins for the references in the given expression.

getExpressionLineage

public Set<RexNode> getExpressionLineage(Project rel,
                                         RelMetadataQuery mq,
                                         RexNode outputExpression)

Expression lineage from Project.

getExpressionLineage

public Set<RexNode> getExpressionLineage(Filter rel,
                                         RelMetadataQuery mq,
                                         RexNode outputExpression)

Expression lineage from Filter.

getExpressionLineage

public Set<RexNode> getExpressionLineage(Sort rel,
                                         RelMetadataQuery mq,
                                         RexNode outputExpression)

Expression lineage from Sort.

getExpressionLineage

public Set<RexNode> getExpressionLineage(Exchange rel,
                                         RelMetadataQuery mq,
                                         RexNode outputExpression)

Expression lineage from Exchange.

createAllPossibleExpressions

protected static Set<RexNode> createAllPossibleExpressions(RexBuilder rexBuilder,
                                                           RexNode expr,
                                                           Map<RexInputRef,Set<RexNode>> mapping)

Given an expression, it will create all equivalent expressions resulting from replacing all possible combinations of references in the mapping by the corresponding expressions.

Parameters:

rexBuilder - rexBuilder

expr - expression

mapping - mapping

Returns:

set of resulting expressions equivalent to the input expression

createAllPossibleExpressions

private static Set<RexNode> createAllPossibleExpressions(RexBuilder rexBuilder,
                                                         RexNode expr,
                                                         ImmutableBitSet predFieldsUsed,
                                                         Map<RexInputRef,Set<RexNode>> mapping,
                                                         Map<RexInputRef,RexNode> singleMapping)

createExpressions

private static void createExpressions(RexBuilder rexBuilder,
                                      RexNode expr,
                                      ImmutableBitSet predFieldsUsed,
                                      Map<RexInputRef,Set<RexNode>> mapping,
                                      Map<RexInputRef,RexNode> singleMapping,
                                      Set<RexNode> result)