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.

Field Summary

Fields

Modifier and Type	Field and Description
static RelMetadataProvider	SOURCE

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	RelMdExpressionLineage()

Method Summary

Modifier and Type	Method and Description
protected static @Nullable 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.
MetadataDef<BuiltInMetadata.ExpressionLineage>	getDef()
@Nullable Set<RexNode>	getExpressionLineage(Aggregate rel, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from Aggregate.
@Nullable Set<RexNode>	getExpressionLineage(Calc calc, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from Calc.
@Nullable Set<RexNode>	getExpressionLineage(Exchange rel, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from Exchange.
@Nullable Set<RexNode>	getExpressionLineage(Filter rel, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from Filter.
@Nullable Set<RexNode>	getExpressionLineage(Join rel, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from Join.
@Nullable Set<RexNode>	getExpressionLineage(Project rel, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from Project.
@Nullable Set<RexNode>	getExpressionLineage(RelNode rel, RelMetadataQuery mq, RexNode outputExpression)
@Nullable Set<RexNode>	getExpressionLineage(RelSubset rel, RelMetadataQuery mq, RexNode outputExpression)
@Nullable Set<RexNode>	getExpressionLineage(Sort rel, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from Sort.
@Nullable Set<RexNode>	getExpressionLineage(TableModify rel, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from TableModify.
@Nullable Set<RexNode>	getExpressionLineage(TableScan rel, RelMetadataQuery mq, RexNode outputExpression) Expression lineage from TableScan.
@Nullable 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

Methods inherited from interface org.apache.calcite.rel.metadata.MetadataHandler

handlerMethods

Field Detail

SOURCE

public static final RelMetadataProvider SOURCE

Constructor Detail

RelMdExpressionLineage

protected RelMdExpressionLineage()

Method Detail

getDef

public MetadataDef<BuiltInMetadata.ExpressionLineage> getDef()

Specified by:

getDef in interface MetadataHandler<BuiltInMetadata.ExpressionLineage>

getExpressionLineage

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

getExpressionLineage

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

getExpressionLineage

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

Expression lineage from Join.

We only extract the lineage for INNER joins.

getExpressionLineage

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

Expression lineage from Project.

getExpressionLineage

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

Expression lineage from Filter.

getExpressionLineage

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

Expression lineage from Sort.

getExpressionLineage

public @Nullable Set<RexNode> getExpressionLineage(TableModify rel,
                                                   RelMetadataQuery mq,
                                                   RexNode outputExpression)

Expression lineage from TableModify.

getExpressionLineage

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

Expression lineage from Exchange.

getExpressionLineage

public @Nullable Set<RexNode> getExpressionLineage(Calc calc,
                                                   RelMetadataQuery mq,
                                                   RexNode outputExpression)

Expression lineage from Calc.

createAllPossibleExpressions

protected static @Nullable 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