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
static interface	RelStructuredTypeFlattener.SelfFlatteningRel Mix-in interface for relational expressions that know how to flatten themselves.

Constructor Summary

Constructors

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

Method Summary

Methods

Modifier and Type	Method and Description
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.
protected RelNode	getNewForOldRel(RelNode oldRel)
RelNode	rewrite(RelNode root, boolean restructure)
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(LogicalMinus rel)
void	rewriteRel(LogicalProject rel)
void	rewriteRel(LogicalTableFunctionScan rel)
void	rewriteRel(LogicalTableModify rel)
void	rewriteRel(LogicalTableScan rel)
void	rewriteRel(LogicalUnion rel)
void	rewriteRel(LogicalValues rel)
void	rewriteRel(RelStructuredTypeFlattener.SelfFlatteningRel rel)
void	rewriteRel(Sample rel)
void	rewriteRel(Sort 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

Constructor Detail

RelStructuredTypeFlattener

public RelStructuredTypeFlattener(RexBuilder rexBuilder,
                          RelOptTable.ToRelContext toRelContext)

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,
              boolean restructure)

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

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)

rewriteRel

public void rewriteRel(LogicalTableScan rel)

rewriteRel

public void rewriteRel(LogicalDelta rel)

rewriteRel

public void rewriteRel(LogicalChi rel)