文章出處

SQL Server表分區的NULL值問題

SQL Server表分區只支持range分區這一種類型，但是本人覺得已經夠用了

雖然MySQL支持四種分區類型：RANGE分區、LIST分區、HASH分區、KEY分區，還支持子分區，但是功能有些欠缺

共同點是MySQL跟SQL Server也有分區對齊的問題，都是水平切分，大家都允許分區列存在NULL值

這次我們測試SQL Server表分區的分區列的NULL值，究竟NULL值是被存放在哪個區間，以前一直沒有注意

測試腳本

--1.創建文件組
ALTER DATABASE [sss]
ADD FILEGROUP [FG_TinyBlog_Id_01]

ALTER DATABASE [sss]
ADD FILEGROUP [FG_TinyBlog_Id_02]

ALTER DATABASE [sss]
ADD FILEGROUP [FG_TinyBlog_Id_03]

ALTER DATABASE [sss]
ADD FILEGROUP [FG_TinyBlog_Id_04]

ALTER DATABASE [sss]
ADD FILEGROUP [FG_TinyBlog_Id_05]


--2.創建文件
ALTER DATABASE [sss]
ADD FILE
(NAME = N'FG_TinyBlog_Id_01_data',FILENAME = N'E:\DataBase\sss\FG_TinyBlog_Id_01_data.ndf',SIZE = 96MB, FILEGROWTH = 24MB )
TO FILEGROUP [FG_TinyBlog_Id_01];

ALTER DATABASE [sss]
ADD FILE
(NAME = N'FG_TinyBlog_Id_02_data',FILENAME = N'E:\DataBase\sss\FG_TinyBlog_Id_02_data.ndf',SIZE = 96MB, FILEGROWTH = 24MB )
TO FILEGROUP [FG_TinyBlog_Id_02];

ALTER DATABASE [sss]
ADD FILE
(NAME = N'FG_TinyBlog_Id_03_data',FILENAME = N'E:\DataBase\sss\FG_TinyBlog_Id_03_data.ndf',SIZE = 96MB, FILEGROWTH = 24MB )
TO FILEGROUP [FG_TinyBlog_Id_03];

ALTER DATABASE [sss]
ADD FILE
(NAME = N'FG_TinyBlog_Id_04_data',FILENAME = N'E:\DataBase\sss\FG_TinyBlog_Id_04_data.ndf',SIZE = 96MB, FILEGROWTH = 24MB )
TO FILEGROUP [FG_TinyBlog_Id_04];

ALTER DATABASE [sss]
ADD FILE
(NAME = N'FG_TinyBlog_Id_05_data',FILENAME = N'E:\DataBase\sss\FG_TinyBlog_Id_05_data.ndf',SIZE = 96MB, FILEGROWTH = 24MB )
TO FILEGROUP [FG_TinyBlog_Id_05];


--3.創建分區函數
CREATE PARTITION FUNCTION
Fun_TinyBlog_Id(INT) AS
RANGE LEFT
FOR VALUES(-10,0,1,6)


--4.創建分區方案
CREATE PARTITION SCHEME
[Sch_TinyBlog_Id] AS
PARTITION [Fun_TinyBlog_Id]
TO([FG_TinyBlog_Id_01],[FG_TinyBlog_Id_02],[FG_TinyBlog_Id_03],[FG_TinyBlog_Id_04],[FG_TinyBlog_Id_05])

View Code

插入測試數據

USE [sss]



CREATE TABLE TinyBlog(id INT  NULL,NAME VARCHAR(100)) 
 ON [Sch_TinyBlog_Id](id)




SELECT * FROM TinyBlog ORDER BY id 


INSERT INTO [dbo].[TinyBlog]
        ( [id], [NAME] )
VALUES  ( NULL, -- id - int
          '3232'  -- NAME - varchar(100)
          )

INSERT INTO [dbo].[TinyBlog]
        ( [id], [NAME] )
VALUES  ( -2, -- id - int
          '-2'  -- NAME - varchar(100)
          )


INSERT INTO [dbo].[TinyBlog]
        ( [id], [NAME] )
VALUES  ( 66, -- id - int
          '66'  -- NAME - varchar(100)
          )

INSERT INTO [dbo].[TinyBlog]
        ( [id], [NAME] )
VALUES  ( 0, -- id - int
          '0'  -- NAME - varchar(100)
          )

INSERT INTO [dbo].[TinyBlog]
        ( [id], [NAME] )
VALUES  ( -30, -- id - int
          '-30'  -- NAME - varchar(100)
          )

表數據如下

SELECT * FROM TinyBlog ORDER BY id

分區分布

--查看分區架構文件組分布
SELECT  CONVERT(VARCHAR(MAX), ps.name) AS partition_scheme ,
        p.partition_number ,
        CONVERT(VARCHAR(MAX), ds2.name) AS filegroup ,
        CONVERT(VARCHAR(MAX), ISNULL(v.value, ''), 120) AS range_boundary ,
        STR(p.rows, 9) AS rows
FROM    sys.indexes i
        JOIN sys.partition_schemes ps ON i.data_space_id = ps.data_space_id
        JOIN sys.destination_data_spaces dds ON ps.data_space_id = dds.partition_scheme_id
        JOIN sys.data_spaces ds2 ON dds.data_space_id = ds2.data_space_id
        JOIN sys.partitions p ON dds.destination_id = p.partition_number
                                 AND p.object_id = i.object_id
                                 AND p.index_id = i.index_id
        JOIN sys.partition_functions pf ON ps.function_id = pf.function_id
        LEFT JOIN sys.Partition_Range_values v ON pf.function_id = v.function_id
                                                  AND v.boundary_id = p.partition_number
                                                  - pf.boundary_value_on_right
WHERE   i.object_id = OBJECT_ID('TinyBlog')
        AND i.index_id IN ( 0, 1 )
ORDER BY p.partition_number


--分區區間
--SELECT  *  FROM    sys.partition_range_values

View Code

分區情況

--分區情況
SELECT  c.* ,
        b.[groupname] AS '分區方案對應的文件組名稱' ,
        d.name '當前分區函數對應的分區方案'
FROM    sys.destination_data_spaces AS a
        INNER JOIN sysfilegroups AS b ON a.[data_space_id] = b.[groupid]
        INNER JOIN ( SELECT $PARTITION.Fun_TinyBlog_Id(id) AS 分區編號 ,
                            MIN(id) AS Min_value ,
                            MAX(id) AS Max_value ,
                            COUNT(id) AS 記錄數
                     FROM   [dbo].[TinyBlog]
                     GROUP BY $PARTITION.Fun_TinyBlog_Id(id)
                   ) AS c ON c.[分區編號] = a.[destination_id]
        INNER JOIN sys.partition_schemes AS d ON a.[partition_scheme_id] = d.data_space_id
ORDER BY c.[分區編號]