//---------------------------------------------------------------------------
//	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;

	// is aggregate replicate slice execution safe
	virtual BOOL IsAggRepSafe() const = 0;

	// mdid of the transition function (pg_aggregate.aggtransfn).  Returned
	// pointer is owned by the cache object — do not release.  May be
	// nullptr for cache entries created from DXL (since DXL does not
	// serialize this field); cost-model code must tolerate that.
	virtual IMDId *
	GetTransfnMdid() const
	{
		return nullptr;
	}
};
}  // namespace gpmd

#endif	// !GPMD_IMDAggregate_H

// EOF