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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