org.apache.calcite.sql2rel

Class RelStructuredTypeFlattener

java.lang.Object

org.apache.calcite.sql2rel.RelStructuredTypeFlattener

All Implemented Interfaces:

ReflectiveVisitor

public class RelStructuredTypeFlattener
extends Object
implements ReflectiveVisitor

RelStructuredTypeFlattener removes all structured types from a tree of relational expressions. Because it must operate globally on the tree, it is implemented as an explicit self-contained rewrite operation instead of via normal optimizer rules. This approach has the benefit that real optimizer and codegen rules never have to deal with structured types.

As an example, suppose we have a structured type ST(A1 smallint, A2 bigint), a table T(c1 ST, c2 double), and a query select t.c2, t.c1.a2 from t. After SqlToRelConverter executes, the unflattened tree looks like:

 LogicalProject(C2=[$1], A2=[$0.A2])
   LogicalTableScan(table=[T])
 

After flattening, the resulting tree looks like

 LogicalProject(C2=[$3], A2=[$2])
   FtrsIndexScanRel(table=[T], index=[clustered])
 

The index scan produces a flattened row type (boolean, smallint, bigint, double) (the boolean is a null indicator for c1), and the projection picks out the desired attributes (omitting $0 and $1 altogether). After optimization, the projection might be pushed down into the index scan, resulting in a final tree like

 FtrsIndexScanRel(table=[T], index=[clustered], projection=[3, 2])
 

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	RelStructuredTypeFlattener.RewriteRelVisitor Visitor that flattens each relational expression in a tree.
private class	RelStructuredTypeFlattener.RewriteRexShuttle Shuttle that rewrites scalar expressions.
static interface	RelStructuredTypeFlattener.SelfFlatteningRel Mix-in interface for relational expressions that know how to flatten themselves.

Field Summary

Fields

Modifier and Type	Field and Description
private RelNode	currentRel
private RelDataType	flattenedRootType
private int	iRestructureInput
private Map<RelNode,RelNode>	oldToNewRelMap
private boolean	restructure
(package private) boolean	restructured
private RexBuilder	rexBuilder
private RelOptTable.ToRelContext	toRelContext

Constructor Summary

Constructors

Constructor and Description
RelStructuredTypeFlattener(RexBuilder rexBuilder, RelOptTable.ToRelContext toRelContext, boolean restructure)

Method Summary

Modifier and Type	Method and Description
private int	calculateFlattenedOffset(RelDataType rowType, int ordinal)
private void	flattenInputs(List<RelDataTypeField> fieldList, RexNode prefix, List<Pair<RexNode,String>> flattenedExpList) Generates expressions that reference the flattened input fields from a given row type.
private void	flattenNullLiteral(RelDataType type, List<Pair<RexNode,String>> flattenedExps)
private void	flattenProjection(RelStructuredTypeFlattener.RewriteRexShuttle shuttle, RexNode exp, String fieldName, List<Pair<RexNode,String>> flattenedExps)
private void	flattenProjections(RelStructuredTypeFlattener.RewriteRexShuttle shuttle, List<? extends RexNode> exps, List<String> fieldNames, String prefix, List<Pair<RexNode,String>> flattenedExps)
protected int	getNewForOldInput(int oldOrdinal) Maps the ordinal of a field pre-flattening to the ordinal of the corresponding field post-flattening, and optionally returns its type.
private Mappings.TargetMapping	getNewForOldInputMapping(RelNode oldRel) Returns a mapping between old and new fields.
protected RelNode	getNewForOldRel(RelNode oldRel)
private boolean	isConstructor(RexNode rexNode)
private RexNode	restructure(RelDataType structuredType)
private List<RexNode>	restructureFields(RelDataType structuredType)
RelNode	rewrite(RelNode root)
void	rewriteGeneric(RelNode rel)
void	rewriteRel(Collect rel)
void	rewriteRel(LogicalAggregate rel)
void	rewriteRel(LogicalCalc rel)
void	rewriteRel(LogicalChi rel)
void	rewriteRel(LogicalCorrelate rel)
void	rewriteRel(LogicalDelta rel)
void	rewriteRel(LogicalFilter rel)
void	rewriteRel(LogicalIntersect rel)
void	rewriteRel(LogicalJoin rel)
void	rewriteRel(LogicalMatch rel)
void	rewriteRel(LogicalMinus rel)
void	rewriteRel(LogicalProject rel)
void	rewriteRel(LogicalTableFunctionScan rel)
void	rewriteRel(LogicalTableModify rel)
void	rewriteRel(LogicalUnion rel)
void	rewriteRel(LogicalValues rel)
void	rewriteRel(RelStructuredTypeFlattener.SelfFlatteningRel rel)
void	rewriteRel(Sample rel)
void	rewriteRel(Sort rel)
void	rewriteRel(TableScan rel)
void	rewriteRel(Uncollect rel)
protected void	setNewForOldRel(RelNode oldRel, RelNode newRel)
void	updateRelInMap(SortedMap<CorrelationId,LogicalCorrelate> mapCorVarToCorRel)
void	updateRelInMap(com.google.common.collect.SortedSetMultimap<RelNode,CorrelationId> mapRefRelToCorVar)

Methods inherited from class java.lang.Object

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

Field Detail

rexBuilder

private final RexBuilder rexBuilder

restructure

private final boolean restructure

oldToNewRelMap

private final Map<RelNode,RelNode> oldToNewRelMap

currentRel

private RelNode currentRel

iRestructureInput

private int iRestructureInput

flattenedRootType

private RelDataType flattenedRootType

restructured

boolean restructured

toRelContext

private final RelOptTable.ToRelContext toRelContext

Constructor Detail

RelStructuredTypeFlattener

public RelStructuredTypeFlattener(RexBuilder rexBuilder,
                                  RelOptTable.ToRelContext toRelContext,
                                  boolean restructure)

Method Detail

updateRelInMap

public void updateRelInMap(com.google.common.collect.SortedSetMultimap<RelNode,CorrelationId> mapRefRelToCorVar)

updateRelInMap

public void updateRelInMap(SortedMap<CorrelationId,LogicalCorrelate> mapCorVarToCorRel)

rewrite

public RelNode rewrite(RelNode root)

restructureFields

private List<RexNode> restructureFields(RelDataType structuredType)

restructure

private RexNode restructure(RelDataType structuredType)

setNewForOldRel

protected void setNewForOldRel(RelNode oldRel,
                               RelNode newRel)

getNewForOldRel

protected RelNode getNewForOldRel(RelNode oldRel)

getNewForOldInput

protected int getNewForOldInput(int oldOrdinal)

Maps the ordinal of a field pre-flattening to the ordinal of the corresponding field post-flattening, and optionally returns its type.

Parameters:

oldOrdinal - Pre-flattening ordinal

Returns:

Post-flattening ordinal

getNewForOldInputMapping

private Mappings.TargetMapping getNewForOldInputMapping(RelNode oldRel)

Returns a mapping between old and new fields.

Parameters:

oldRel - Old relational expression

Returns:

Mapping between fields of old and new

calculateFlattenedOffset

private int calculateFlattenedOffset(RelDataType rowType,
                                     int ordinal)

rewriteRel

public void rewriteRel(LogicalTableModify rel)

rewriteRel

public void rewriteRel(LogicalAggregate rel)

rewriteRel

public void rewriteRel(Sort rel)

rewriteRel

public void rewriteRel(LogicalFilter rel)

rewriteRel

public void rewriteRel(LogicalJoin rel)

rewriteRel

public void rewriteRel(LogicalCorrelate rel)

rewriteRel

public void rewriteRel(Collect rel)

rewriteRel

public void rewriteRel(Uncollect rel)

rewriteRel

public void rewriteRel(LogicalIntersect rel)

rewriteRel

public void rewriteRel(LogicalMinus rel)

rewriteRel

public void rewriteRel(LogicalUnion rel)

rewriteRel

public void rewriteRel(LogicalValues rel)

rewriteRel

public void rewriteRel(LogicalTableFunctionScan rel)

rewriteRel

public void rewriteRel(Sample rel)

rewriteRel

public void rewriteRel(LogicalProject rel)

rewriteRel

public void rewriteRel(LogicalCalc rel)

rewriteRel

public void rewriteRel(RelStructuredTypeFlattener.SelfFlatteningRel rel)

rewriteGeneric

public void rewriteGeneric(RelNode rel)

flattenProjections

private void flattenProjections(RelStructuredTypeFlattener.RewriteRexShuttle shuttle,
                                List<? extends RexNode> exps,
                                List<String> fieldNames,
                                String prefix,
                                List<Pair<RexNode,String>> flattenedExps)

flattenProjection

private void flattenProjection(RelStructuredTypeFlattener.RewriteRexShuttle shuttle,
                               RexNode exp,
                               String fieldName,
                               List<Pair<RexNode,String>> flattenedExps)

flattenNullLiteral

private void flattenNullLiteral(RelDataType type,
                                List<Pair<RexNode,String>> flattenedExps)

isConstructor

private boolean isConstructor(RexNode rexNode)

rewriteRel

public void rewriteRel(TableScan rel)

rewriteRel

public void rewriteRel(LogicalDelta rel)

rewriteRel

public void rewriteRel(LogicalChi rel)

rewriteRel

public void rewriteRel(LogicalMatch rel)

flattenInputs

private void flattenInputs(List<RelDataTypeField> fieldList,
                           RexNode prefix,
                           List<Pair<RexNode,String>> flattenedExpList)

Generates expressions that reference the flattened input fields from a given row type.