greenplumn IMDAggregate 源码
greenplumn IMDAggregate 代码
文件路径：/src/backend/gporca/libnaucrates/include/naucrates/md/IMDAggregate.h
//---------------------------------------------------------------------------
// Greenplum Database
// Copyright (C) 2011 EMC Corp.
//
// @filename:
// IMDAggregate.h
//
// @doc:
// Interface for aggregates in the metadata cache
//---------------------------------------------------------------------------
#ifndef GPMD_IMDAggregate_H
#define GPMD_IMDAggregate_H
#include "gpos/base.h"
#include "naucrates/md/IMDCacheObject.h"
namespace gpmd
{
using namespace gpos;
//---------------------------------------------------------------------------
// @class:
// IMDAggregate
//
// @doc:
// Interface for aggregates in the metadata cache
//
//---------------------------------------------------------------------------
class IMDAggregate : public IMDCacheObject
{
public:
// object type
Emdtype
MDType() const override
{
return EmdtAgg;
}
// type of intermediate results computed by the aggregate's
// transformation function
virtual IMDId *GetIntermediateResultTypeMdid() const = 0;
// result type
virtual IMDId *GetResultTypeMdid() const = 0;
// is aggregate ordered
virtual BOOL IsOrdered() const = 0;
// is aggregate splittable
virtual BOOL IsSplittable() const = 0;
virtual
// is aggregate hash capable
BOOL
IsHashAggCapable() const = 0;
};
} // namespace gpmd
#endif // !GPMD_IMDAggregate_H
// EOF
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