greenplumn IMDColStats 代码
文件路径：/src/backend/gporca/libnaucrates/include/naucrates/md/IMDColStats.h
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2012 EMC Corp.
/
/ @filename:
/ IMDColStats.h
/
/ @doc:
/ Interface for column stats
/---------------------------------------------------------------------------
#ifndef GPMD_IMDColStats_H
#define GPMD_IMDColStats_H
#include "gpos/base.h"
#include "naucrates/md/CDXLBucket.h"
#include "naucrates/md/IMDCacheObject.h"
namespace gpmd
{
using namespace gpos;
using namespace gpdxl;
/---------------------------------------------------------------------------
/ @class:
/ IMDColStats
/
/ @doc:
/ Interface for column stats
/
/---------------------------------------------------------------------------
class IMDColStats : public IMDCacheObject
{
public:
/ object type
Emdtype
MDType() const override
{
return EmdtColStats;
}
/ number of buckets
virtual ULONG Buckets() const = 0;
/ width
virtual CDouble Width() const = 0;
/ null fraction
virtual CDouble GetNullFreq() const = 0;
/ ndistinct of remaining tuples
virtual CDouble GetDistinctRemain() const = 0;
/ frequency of remaining tuples
virtual CDouble GetFreqRemain() const = 0;
/ is the columns statistics missing in the database
virtual BOOL IsColStatsMissing() const = 0;
/ get the bucket at the given position
virtual const CDXLBucket *GetDXLBucketAt(ULONG ul) const = 0;
};
} / namespace gpmd
#endif / !GPMD_IMDColStats_H
/ EOF
相关信息
相关文章
greenplumn CDXLStatsDerivedColumn 源码
greenplumn CDXLStatsDerivedRelation 源码
greenplumn CMDAggregateGPDB 源码