greenplumn CLogicalMaxOneRow 源码
greenplumn CLogicalMaxOneRow 代码
文件路径:/src/backend/gporca/libgpopt/include/gpopt/operators/CLogicalMaxOneRow.h
//---------------------------------------------------------------------------
// Greenplum Database
// Copyright (C) 2014 VMware, Inc. or its affiliates.
//
// @filename:
// CLogicalMaxOneRow.h
//
// @doc:
// MaxOneRow operator,
// an operator that can pass at most one row from its input
//---------------------------------------------------------------------------
#ifndef GPOPT_CLogicalMaxOneRow_H
#define GPOPT_CLogicalMaxOneRow_H
#include "gpos/base.h"
#include "gpopt/operators/CExpressionHandle.h"
namespace gpopt
{
//---------------------------------------------------------------------------
// @class:
// CLogicalMaxOneRow
//
// @doc:
// MaxOneRow operator
//
//---------------------------------------------------------------------------
class CLogicalMaxOneRow : public CLogical
{
private:
public:
CLogicalMaxOneRow(const CLogicalMaxOneRow &) = delete;
// ctors
explicit CLogicalMaxOneRow(CMemoryPool *mp) : CLogical(mp)
{
}
// dtor
~CLogicalMaxOneRow() override = default;
// ident accessors
EOperatorId
Eopid() const override
{
return EopLogicalMaxOneRow;
}
// name of operator
const CHAR *
SzId() const override
{
return "CLogicalMaxOneRow";
}
// match function;
BOOL
Matches(COperator *pop) const override
{
return (Eopid() == pop->Eopid());
}
// 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();
}
// return true if we can pull projections up past this operator from its given child
BOOL FCanPullProjectionsUp(ULONG //child_index
) const override
{
return false;
}
//-------------------------------------------------------------------------------------
// Derived Relational Properties
//-------------------------------------------------------------------------------------
// derive output columns
CColRefSet *
DeriveOutputColumns(CMemoryPool *, // mp
CExpressionHandle &exprhdl) override
{
return PcrsDeriveOutputPassThru(exprhdl);
}
// derive partition consumer info
CPartInfo *
DerivePartitionInfo(CMemoryPool *mp,
CExpressionHandle &exprhdl) const override
{
return PpartinfoDeriveCombine(mp, exprhdl);
}
// dervive keys
CKeyCollection *
DeriveKeyCollection(CMemoryPool *, // mp
CExpressionHandle &exprhdl) const override
{
return PkcDeriveKeysPassThru(exprhdl, 0 /* ulChild */);
}
// derive max card
CMaxCard
DeriveMaxCard(CMemoryPool *, // mp,
CExpressionHandle & // exprhdl
) const override
{
return CMaxCard(1 /*ull*/);
}
// derive constraint property
CPropConstraint *
DerivePropertyConstraint(CMemoryPool *mp,
CExpressionHandle &exprhdl) const override
{
return PpcDeriveConstraintFromPredicates(mp, exprhdl);
}
// promise level for stat derivation
EStatPromise Esp(CExpressionHandle &exprhdl) const override;
//-------------------------------------------------------------------------------------
// Required Relational Properties
//-------------------------------------------------------------------------------------
// compute required stat columns of the n-th child
CColRefSet *PcrsStat(CMemoryPool *mp, CExpressionHandle &exprhdl,
CColRefSet *pcrsInput,
ULONG child_index) const override;
//-------------------------------------------------------------------------------------
// Transformations
//-------------------------------------------------------------------------------------
// candidate set of xforms
CXformSet *PxfsCandidates(CMemoryPool *mp) const override;
//-------------------------------------------------------------------------------------
//-------------------------------------------------------------------------------------
//-------------------------------------------------------------------------------------
// conversion function
static CLogicalMaxOneRow *
PopConvert(COperator *pop)
{
GPOS_ASSERT(nullptr != pop);
GPOS_ASSERT(EopLogicalMaxOneRow == pop->Eopid());
return dynamic_cast<CLogicalMaxOneRow *>(pop);
}
// derive statistics
IStatistics *PstatsDerive(CMemoryPool *mp, CExpressionHandle &exprhdl,
IStatisticsArray * // stats_ctxt
) const override;
}; // class CLogicalMaxOneRow
} // namespace gpopt
#endif // !GPOPT_CLogicalMaxOneRow_H
// EOF
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