greenplumn CDistributionSpecRandom 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/base/CDistributionSpecRandom.h
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2011 EMC Corp.
/
/ @filename:
/ CDistributionSpecRandom.h
/
/ @doc:
/ Description of a forced random distribution;
/ Can be used as required or derived property;
/---------------------------------------------------------------------------
#ifndef GPOPT_CDistributionSpecRandom_H
#define GPOPT_CDistributionSpecRandom_H
#include "gpos/base.h"
#include "gpopt/base/CDistributionSpec.h"
namespace gpopt
{
using namespace gpos;
/---------------------------------------------------------------------------
/ @class:
/ CDistributionSpecRandom
/
/ @doc:
/ Class for representing forced random distribution.
/
/---------------------------------------------------------------------------
class CDistributionSpecRandom : public CDistributionSpec
{
protected:
/ is the random distribution sensitive to duplicates
BOOL m_is_duplicate_sensitive{false};
/ does Singleton spec satisfy current distribution?
/ by default, Singleton satisfies hashed/random since all tuples with the same hash value
/ are moved to the same host/segment,
/ this flag adds the ability to mark a distribution request as non-satisfiable by Singleton
/ in case we need to enforce across segments distribution
BOOL m_fSatisfiedBySingleton{true};
/ private copy ctor
CDistributionSpecRandom(const CDistributionSpecRandom &);
CColRef *m_gp_segment_id = {nullptr};
public:
/ctor
CDistributionSpecRandom();
CDistributionSpecRandom(CColRef *gp_segment_id_);
/ accessor
EDistributionType
Edt() const override
{
return CDistributionSpec::EdtRandom;
}
virtual const CHAR *
SzId() const
{
return "RANDOM";
}
/ is distribution duplicate sensitive
BOOL
IsDuplicateSensitive() const
{
return m_is_duplicate_sensitive;
}
/ mark distribution as unsatisfiable by Singleton
void
MarkDuplicateSensitive()
{
GPOS_ASSERT(!m_is_duplicate_sensitive);
m_is_duplicate_sensitive = true;
}
/ does Singleton spec satisfy current distribution?
BOOL
FSatisfiedBySingleton() const
{
return m_fSatisfiedBySingleton;
}
/ mark distribution as unsatisfiable by Singleton
void
MarkUnsatisfiableBySingleton()
{
GPOS_ASSERT(m_fSatisfiedBySingleton);
m_fSatisfiedBySingleton = false;
}
/ does this distribution match the given one
BOOL Matches(const CDistributionSpec *pds) const override;
/ does current distribution satisfy the given one
BOOL FSatisfies(const CDistributionSpec *pds) const override;
/ append enforcers to dynamic array for the given plan properties
void AppendEnforcers(CMemoryPool *mp, CExpressionHandle &exprhdl,
CReqdPropPlan *prpp, CExpressionArray *pdrgpexpr,
CExpression *pexpr) override;
/ return distribution partitioning type
EDistributionPartitioningType
Edpt() const override
{
return EdptPartitioned;
}
/ print
IOstream &OsPrint(IOstream &os) const override;
/ conversion function
static CDistributionSpecRandom *
PdsConvert(CDistributionSpec *pds)
{
GPOS_ASSERT(nullptr != pds);
GPOS_ASSERT(EdtRandom == pds->Edt());
return dynamic_cast<CDistributionSpecRandom *>(pds);
}
/ conversion function: const argument
static const CDistributionSpecRandom *
PdsConvert(const CDistributionSpec *pds)
{
GPOS_ASSERT(nullptr != pds);
GPOS_ASSERT(EdtRandom == pds->Edt());
return dynamic_cast<const CDistributionSpecRandom *>(pds);
}
}; / class CDistributionSpecRandom
} / namespace gpopt
#endif / !GPOPT_CDistributionSpecRandom_H
/ EOF
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