greenplumn IMDRelationExternal 源码
greenplumn IMDRelationExternal 代码
文件路径：/src/backend/gporca/libnaucrates/include/naucrates/md/IMDRelationExternal.h
//---------------------------------------------------------------------------
// Greenplum Database
// Copyright (C) 2013 EMC Corp.
//
// @filename:
// IMDRelationExternal.h
//
// @doc:
// Interface for external relations in the metadata cache
//---------------------------------------------------------------------------
#ifndef GPMD_IMDRelationExternal_H
#define GPMD_IMDRelationExternal_H
#include "gpos/base.h"
#include "naucrates/md/IMDRelation.h"
namespace gpmd
{
using namespace gpos;
//---------------------------------------------------------------------------
// @class:
// IMDRelationExternal
//
// @doc:
// Interface for external relations in the metadata cache
//
//---------------------------------------------------------------------------
class IMDRelationExternal : public IMDRelation
{
public:
// storage type
Erelstoragetype
RetrieveRelStorageType() const override
{
return ErelstorageExternal;
}
// is this a temp relation
BOOL
IsTemporary() const override
{
return false;
}
// is this a partitioned table
BOOL
IsPartitioned() const override
{
return false;
}
// return true if a hash distributed table needs to be considered as random
BOOL ConvertHashToRandom() const override = 0;
// number of partition columns
ULONG
PartColumnCount() const override
{
return 0;
}
// number of partitions
ULONG
PartitionCount() const override
{
return 0;
}
// retrieve the partition column at the given position
const IMDColumn *PartColAt(ULONG /*pos*/) const override
{
GPOS_ASSERT(!"External tables have no partition columns");
return nullptr;
}
// retrieve list of partition types
CharPtrArray *
GetPartitionTypes() const override
{
GPOS_ASSERT(!"External tables have no partition types");
return nullptr;
}
// retrieve the partition type at the given position
CHAR PartTypeAtLevel(ULONG /*pos*/) const override
{
GPOS_ASSERT(!"External tables have no partition types");
return (CHAR) 0;
}
// part constraint
CDXLNode *
MDPartConstraint() const override
{
return nullptr;
}
// reject limit
virtual INT RejectLimit() const = 0;
// reject limit in rows?
virtual BOOL IsRejectLimitInRows() const = 0;
// format error table mdid
virtual IMDId *GetFormatErrTableMdid() const = 0;
};
} // namespace gpmd
#endif // !GPMD_IMDRelationExternal_H
// EOF
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