greenplumn CColumnFactory 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/base/CColumnFactory.h
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2008, 2009 Greenplum, Inc.
/
/ @filename:
/ CColumnFactory.h
/
/ @doc:
/ Column reference management; one instance per optimization
/---------------------------------------------------------------------------
#ifndef GPOPT_CColumnFactory_H
#define GPOPT_CColumnFactory_H
#include "gpos/base.h"
#include "gpos/common/CList.h"
#include "gpos/common/CSyncHashtable.h"
#include "gpopt/base/CColRefSet.h"
#include "gpopt/metadata/CColumnDescriptor.h"
#include "naucrates/md/IMDId.h"
#include "naucrates/md/IMDType.h"
namespace gpopt
{
class CExpression;
using namespace gpos;
using namespace gpmd;
/---------------------------------------------------------------------------
/ @class:
/ CColumnFactory
/
/ @doc:
/ Singleton factory class used to generate and manage CColRefs in ORCA.
/ The created CColRef objects are maintained in a hash table keyed by
/ Column ID. CColumnFactory provides various overloaded PcrCreate()
/ methods to create CColRef and a LookupColRef() method to probe the hash
/ table.
/ NB: The class also owns the memory pool in which CColRefs are
/ allocated.
/
/---------------------------------------------------------------------------
class CColumnFactory
{
private:
/ MTS memory pool
CMemoryPool *m_mp{nullptr};
/ mapping between column id of computed column and a set of used column references
ColRefToColRefSetMap *m_phmcrcrs{nullptr};
/ id counter
ULONG m_aul{0};
/ hash table
CSyncHashtable<CColRef, ULONG> m_sht;
/ implementation of factory methods
CColRef *PcrCreate(const IMDType *pmdtype, INT type_modifier, ULONG id,
const CName &name);
CColRef *PcrCreate(const CColumnDescriptor *pcoldesc, ULONG id,
const CName &name, ULONG ulOpSource,
BOOL mark_as_used = true, IMDId *mdid_table = nullptr);
public:
CColumnFactory(const CColumnFactory &) = delete;
/ ctor
CColumnFactory();
/ dtor
~CColumnFactory();
/ initialize the hash map between computed column and used columns
void Initialize();
/ create a column reference given only its type and type modifier, used for computed columns
CColRef *PcrCreate(const IMDType *pmdtype, INT type_modifier);
/ create column reference given its type, type modifier, and name
CColRef *PcrCreate(const IMDType *pmdtype, INT type_modifier,
const CName &name);
/ create a column reference given its descriptor and name
CColRef *PcrCreate(const CColumnDescriptor *pcoldescr, const CName &name,
ULONG ulOpSource, BOOL mark_as_used, IMDId *mdid_table);
/ create a column reference given its type, attno, nullability and name
CColRef *PcrCreate(const IMDType *pmdtype, INT type_modifier,
IMDId *mdid_table, INT attno, BOOL is_nullable, ULONG id,
const CName &name, ULONG ulOpSource, BOOL isDistCol,
ULONG ulWidth = gpos::ulong_max);
/ create a column reference with the same type as passed column reference
CColRef *
PcrCreate(const CColRef *colref)
{
return PcrCreate(colref->RetrieveType(), colref->TypeModifier());
}
/ add mapping between computed column to its used columns
void AddComputedToUsedColsMap(CExpression *pexpr);
/ lookup the set of used column references (if any) based on id of computed column
const CColRefSet *PcrsUsedInComputedCol(const CColRef *pcrComputedCol);
/ create a copy of the given colref
CColRef *PcrCopy(const CColRef *colref);
/ lookup by id
CColRef *LookupColRef(ULONG id);
/ destructor
void Destroy(CColRef *);
}; / class CColumnFactory
} / namespace gpopt
#endif / !GPOPT_CColumnFactory_H
/ EOF
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