greenplumn CLogicalNAryJoin 源码

  • 2022-08-18
  • 浏览 (520)

greenplumn CLogicalNAryJoin 代码

文件路径:/src/backend/gporca/libgpopt/include/gpopt/operators/CLogicalNAryJoin.h

//---------------------------------------------------------------------------
//	Greenplum Database
//	Copyright (C) 2011 EMC Corp.
//
//	@filename:
//		CLogicalNAryJoin.h
//
//	@doc:
//		N-ary inner join operator
//---------------------------------------------------------------------------
#ifndef GPOS_CLogicalNAryJoin_H
#define GPOS_CLogicalNAryJoin_H

#include "gpos/base.h"

#include "gpopt/operators/CLogicalJoin.h"

namespace gpopt
{
//---------------------------------------------------------------------------
//	@class:
//		CLogicalNAryJoin
//
//	@doc:
//		N-ary inner join operator
//
//---------------------------------------------------------------------------
class CLogicalNAryJoin : public CLogicalJoin
{
private:
	// Indexes that help to find ON predicates for LOJs.
	// If all joins in this NAry join are inner joins, this pointer is NULL and
	// the scalar child of this NAry join contains all join predicates directly.
	// Otherwise, the scalar child is a CScalarNaryJoinPredList and this ULongPtr
	// array has as many entries as there are logical children of the NAry
	// join. For each logical child i, if that child i is part of an inner join
	// or the outer table of an LOJ, then the corresponding entry
	// (*m_lojChildPredIndexes)[i] in this array is 0
	// (GPOPT_ZERO_INNER_JOIN_PRED_INDEX). If the logical child is the right table
	// of an LOJ, the corresponding index indicates the child index of the
	// CScalarNAryJoinPredList expression that contains the ON predicate for the
	// LOJ.
	ULongPtrArray *m_lojChildPredIndexes;

public:
	CLogicalNAryJoin(const CLogicalNAryJoin &) = delete;

	// ctor
	explicit CLogicalNAryJoin(CMemoryPool *mp);

	CLogicalNAryJoin(CMemoryPool *mp, ULongPtrArray *lojChildIndexes);

	// dtor
	~CLogicalNAryJoin() override
	{
		CRefCount::SafeRelease(m_lojChildPredIndexes);
	}

	// ident accessors
	EOperatorId
	Eopid() const override
	{
		return EopLogicalNAryJoin;
	}

	// return a string for operator name
	const CHAR *
	SzId() const override
	{
		return "CLogicalNAryJoin";
	}

	//-------------------------------------------------------------------------------------
	// Derived Relational Properties
	//-------------------------------------------------------------------------------------

	// derive not nullable columns
	CColRefSet *DeriveNotNullColumns(CMemoryPool *mp,
									 CExpressionHandle &exprhdl) const override;

	// derive max card
	CMaxCard DeriveMaxCard(CMemoryPool *mp,
						   CExpressionHandle &exprhdl) const override;

	// derive constraint property
	CPropConstraint *DerivePropertyConstraint(
		CMemoryPool *mp, CExpressionHandle &exprhdl) const override;

	//-------------------------------------------------------------------------------------
	// Derived Stats
	//-------------------------------------------------------------------------------------

	// promise level for stat derivation
	EStatPromise
	Esp(CExpressionHandle &	 // exprhdl
	) const override
	{
		// we should use the expanded join order for stat derivation
		return EspLow;
	}

	//-------------------------------------------------------------------------------------
	// Transformations
	//-------------------------------------------------------------------------------------

	// candidate set of xforms
	CXformSet *PxfsCandidates(CMemoryPool *mp) const override;

	//-------------------------------------------------------------------------------------
	//-------------------------------------------------------------------------------------
	//-------------------------------------------------------------------------------------

	// conversion function
	static CLogicalNAryJoin *
	PopConvert(COperator *pop)
	{
		GPOS_ASSERT(nullptr != pop);

		return dynamic_cast<CLogicalNAryJoin *>(pop);
	}

	// conversion function, only if the NAryJoin has LOJ children
	static CLogicalNAryJoin *PopConvertNAryLOJ(COperator *pop);

	BOOL
	HasOuterJoinChildren() const
	{
		return (nullptr != m_lojChildPredIndexes);
	}

	BOOL
	IsInnerJoinChild(ULONG child_num) const
	{
		return (nullptr == m_lojChildPredIndexes ||
				*((*m_lojChildPredIndexes)[child_num]) == 0);
	}

	ULongPtrArray *
	GetLojChildPredIndexes() const
	{
		return m_lojChildPredIndexes;
	}

	CExpression *
	GetInnerJoinPreds(CExpression *nary_join_expr) const
	{
		GPOS_ASSERT(nary_join_expr->Pop() == this);
		if (HasOuterJoinChildren())
		{
			// return the first child of CScalarNAryJoinPredList
			return (*((*nary_join_expr)[nary_join_expr->Arity() - 1]))[0];
		}
		return (*nary_join_expr)[nary_join_expr->Arity() - 1];
	}

	CExpression *
	GetOnPredicateForLOJChild(CExpression *nary_join_expr,
							  ULONG child_num) const
	{
		GPOS_ASSERT(nary_join_expr->Pop() == this);
		GPOS_ASSERT(0 < *(*m_lojChildPredIndexes)[child_num]);

		// m_lojChildPredIndexes stores the index in the child of the scalar argument
		// (a CScalarNAryJoinPredList) that has our ON predicate
		//     |------ the scalar child of the NAry join ------|  |- grandchild corresponding to LOJ-|
		return (*((*nary_join_expr)[nary_join_expr->Arity() - 1]))[*(
			*m_lojChildPredIndexes)[child_num]];
	}

	// get the true inner join predicates, excluding predicates that use ColRefs
	// coming from non-inner joins
	CExpression *GetTrueInnerJoinPreds(CMemoryPool *mp,
									   CExpressionHandle &exprhdl) const;

	// given an existing scalar child of an NAry join, make a new copy, replacing
	// only the inner join predicates and leaving the LOJ ON predicates the same
	CExpression *ReplaceInnerJoinPredicates(
		CMemoryPool *mp, CExpression *old_nary_join_scalar_expr,
		CExpression *new_inner_join_preds);

	IOstream &OsPrint(IOstream &os) const override;

};	// class CLogicalNAryJoin

}  // namespace gpopt


#endif	// !GPOS_CLogicalNAryJoin_H

// EOF

相关信息

greenplumn 源码目录

相关文章

greenplumn CExpression 源码

greenplumn CExpressionFactorizer 源码

greenplumn CExpressionHandle 源码

greenplumn CExpressionPreprocessor 源码

greenplumn CExpressionUtils 源码

greenplumn CHashedDistributions 源码

greenplumn CLogical 源码

greenplumn CLogicalApply 源码

greenplumn CLogicalAssert 源码

greenplumn CLogicalBitmapTableGet 源码

0  赞