greenplumn CScalarMinMax 源码
greenplumn CScalarMinMax 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/operators/CScalarMinMax.h
//---------------------------------------------------------------------------
// Greenplum Database
// Copyright (C) 2015 VMware, Inc. or its affiliates.
//
// @filename:
// CScalarMinMax.h
//
// @doc:
// Scalar MinMax operator
//
// This returns the minimum (or maximum) value from a list of any number of
// scalar expressions. NULL values in the list are ignored. The result will
// be NULL only if all the expressions evaluate to NULL.
//---------------------------------------------------------------------------
#ifndef GPOPT_CScalarMinMax_H
#define GPOPT_CScalarMinMax_H
#include "gpos/base.h"
#include "gpopt/base/CDrvdProp.h"
#include "gpopt/operators/CScalar.h"
namespace gpopt
{
using namespace gpos;
//---------------------------------------------------------------------------
// @class:
// CScalarMinMax
//
// @doc:
// Scalar MinMax operator
//
//---------------------------------------------------------------------------
class CScalarMinMax : public CScalar
{
public:
// types of operations: either min or max
enum EScalarMinMaxType
{
EsmmtMin,
EsmmtMax,
EsmmtSentinel
};
private:
// return type
IMDId *m_mdid_type;
// min/max type
EScalarMinMaxType m_esmmt;
// is operator return type BOOL?
BOOL m_fBoolReturnType;
public:
CScalarMinMax(const CScalarMinMax &) = delete;
// ctor
CScalarMinMax(CMemoryPool *mp, IMDId *mdid_type, EScalarMinMaxType esmmt);
// dtor
~CScalarMinMax() override;
// ident accessors
EOperatorId
Eopid() const override
{
return EopScalarMinMax;
}
// operator name
const CHAR *
SzId() const override
{
return "CScalarMinMax";
}
// return type
IMDId *
MdidType() const override
{
return m_mdid_type;
}
// min/max type
EScalarMinMaxType
Esmmt() const
{
return m_esmmt;
}
// operator specific hash function
ULONG HashValue() const override;
// match function
BOOL Matches(COperator *pop) const override;
// sensitivity to order of inputs
BOOL
FInputOrderSensitive() const override
{
return false;
}
// return a copy of the operator with remapped columns
COperator *
PopCopyWithRemappedColumns(CMemoryPool *, //mp,
UlongToColRefMap *, //colref_mapping,
BOOL //must_exist
) override
{
return PopCopyDefault();
}
// boolean expression evaluation
EBoolEvalResult
Eber(ULongPtrArray *pdrgpulChildren) const override
{
// MinMax returns Null only if all children are Null
return EberNullOnAllNullChildren(pdrgpulChildren);
}
// print
IOstream &OsPrint(IOstream &os) const override;
// conversion function
static CScalarMinMax *
PopConvert(COperator *pop)
{
GPOS_ASSERT(nullptr != pop);
GPOS_ASSERT(EopScalarMinMax == pop->Eopid());
return dynamic_cast<CScalarMinMax *>(pop);
}
}; // class CScalarMinMax
} // namespace gpopt
#endif // !GPOPT_CScalarMinMax_H
// EOF
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