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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