greenplumn CMDIdColStats 代码
文件路径：/src/backend/gporca/libnaucrates/include/naucrates/md/CMDIdColStats.h
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2012 EMC Corp.
/
/ @filename:
/ CMDIdColStats.h
/
/ @doc:
/ Class for representing mdids for column statistics
/---------------------------------------------------------------------------
#ifndef GPMD_CMDIdColStats_H
#define GPMD_CMDIdColStats_H
#include "gpos/base.h"
#include "gpos/common/CDynamicPtrArray.h"
#include "gpos/string/CWStringConst.h"
#include "naucrates/dxl/gpdb_types.h"
#include "naucrates/md/CMDIdGPDB.h"
#include "naucrates/md/CSystemId.h"
namespace gpmd
{
using namespace gpos;
/---------------------------------------------------------------------------
/ @class:
/ CMDIdColStats
/
/ @doc:
/ Class for representing ids of column stats objects
/
/---------------------------------------------------------------------------
class CMDIdColStats : public IMDId
{
private:
/ mdid of base relation
CMDIdGPDB *m_rel_mdid;
/ position of the attribute in the base relation
ULONG m_attr_pos;
/ buffer for the serialized mdid
WCHAR m_mdid_buffer[GPDXL_MDID_LENGTH];
/ string representation of the mdid
CWStringStatic m_str;
/ serialize mdid
void Serialize();
public:
CMDIdColStats(const CMDIdColStats &) = delete;
/ ctor
CMDIdColStats(CMDIdGPDB *rel_mdid, ULONG attno);
/ dtor
~CMDIdColStats() override;
EMDIdType
MdidType() const override
{
return EmdidColStats;
}
/ string representation of mdid
const WCHAR *GetBuffer() const override;
/ source system id
CSystemId
Sysid() const override
{
return m_rel_mdid->Sysid();
}
/ accessors
IMDId *GetRelMdId() const;
ULONG Position() const;
/ equality check
BOOL Equals(const IMDId *mdid) const override;
/ computes the hash value for the metadata id
ULONG
HashValue() const override
{
return gpos::CombineHashes(m_rel_mdid->HashValue(),
gpos::HashValue(&m_attr_pos));
}
/ is the mdid valid
BOOL
IsValid() const override
{
return IMDId::IsValid(m_rel_mdid);
}
/ serialize mdid in DXL as the value of the specified attribute
void Serialize(CXMLSerializer *xml_serializer,
const CWStringConst *attribute_str) const override;
/ debug print of the metadata id
IOstream &OsPrint(IOstream &os) const override;
/ const converter
static const CMDIdColStats *
CastMdid(const IMDId *mdid)
{
GPOS_ASSERT(nullptr != mdid && EmdidColStats == mdid->MdidType());
return dynamic_cast<const CMDIdColStats *>(mdid);
}
/ non-const converter
static CMDIdColStats *
CastMdid(IMDId *mdid)
{
GPOS_ASSERT(nullptr != mdid && EmdidColStats == mdid->MdidType());
return dynamic_cast<CMDIdColStats *>(mdid);
}
/ make a copy in the given memory pool
IMDId *
Copy(CMemoryPool *mp) const override
{
CMDIdGPDB *mdid_rel = CMDIdGPDB::CastMdid(m_rel_mdid->Copy(mp));
return GPOS_NEW(mp) CMDIdColStats(mdid_rel, m_attr_pos);
}
};
} / namespace gpmd
#endif / !GPMD_CMDIdColStats_H
/ EOF
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