greenplumn IMDFunction 源码
greenplumn IMDFunction 代码
文件路径：/src/backend/gporca/libnaucrates/include/naucrates/md/IMDFunction.h
//---------------------------------------------------------------------------
// Greenplum Database
// Copyright (C) 2011 EMC Corp.
//
// @filename:
// IMDFunction.h
//
// @doc:
// Interface for functions in the metadata cache
//---------------------------------------------------------------------------
#ifndef GPMD_IMDFunction_H
#define GPMD_IMDFunction_H
#include "gpos/base.h"
#include "naucrates/md/IMDCacheObject.h"
namespace gpmd
{
using namespace gpos;
//---------------------------------------------------------------------------
// @class:
// IMDFunction
//
// @doc:
// Interface for functions in the metadata cache
//
//---------------------------------------------------------------------------
class IMDFunction : public IMDCacheObject
{
public:
// function stability property
enum EFuncStbl
{
EfsImmutable, /* never changes for given input */
EfsStable, /* does not change within a scan */
EfsVolatile, /* can change even within a scan */
EfsSentinel
};
// function data access property
enum EFuncDataAcc
{
EfdaNoSQL,
EfdaContainsSQL,
EfdaReadsSQLData,
EfdaModifiesSQLData,
EfdaSentinel
};
// object type
Emdtype
MDType() const override
{
return EmdtFunc;
}
// does function return NULL on NULL input
virtual BOOL IsStrict() const = 0;
// does function preserve NDVs of input (for cardinality estimation)
virtual BOOL IsNDVPreserving() const = 0;
// does function return a set of values
virtual BOOL ReturnsSet() const = 0;
// is this function allowed for Partition selection
virtual BOOL IsAllowedForPS() const = 0;
// function stability
virtual EFuncStbl GetFuncStability() const = 0;
// function data access
virtual EFuncDataAcc GetFuncDataAccess() const = 0;
// result type
virtual IMDId *GetResultTypeMdid() const = 0;
// output argument types
virtual IMdIdArray *OutputArgTypesMdidArray() const = 0;
};
} // namespace gpmd
#endif // !GPMD_IMDFunction_H
// EOF
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