sql-server - 在 Sql Server 维护计划中重组索引与重建索引

Question

在更好的 SQL Server 数据库的 SSW 规则中有一个完整的数据库维护计划的示例：SSW。在示例中，他们同时运行 Reorganize Index、Rebuild Index 和 Update Statistics。这有什么意义吗？我认为 Reorganize Index 是 Rebuild Index 的一个快速但效率较低的版本？并且索引重建也会自动更新统计信息（至少在聚集索引上）。

Answer 1

重组和重建是不同的事情。

重组：它是索引的碎片整理。获取现有索引并对现有页面进行碎片整理。但是，如果页面不是连续的，它们会像以前一样保持不变。只有页面的内容在变化。

重建：实际上它删除索引并从头开始重建它。这意味着您将获得一个全新的索引，其中包含碎片整理和连续页面。

此外，通过rebuild，您可以更改分区或文件组，但通过reorganize，您不仅可以对整个索引进行碎片整理，还可以对索引的一个分区进行碎片整理。

更新统计信息在聚集索引上是自动的，但不是在非聚集索引上。

Answer 2

在考虑维护索引之前，重要的是要回答两个主要问题：

1. 碎片化程度如何？
2. 什么是适当的行动？重组还是重建？

如本文所述http://solutioncenter.apexsql.com/why-when-and-how-to-rebuild-and-reorganize-sql-server-indexes/，并帮助您确定是否应该执行索引重建或指数重组，请理解以下内容：

• 索引重组是 SQL Server 遍历现有索引并清理它的过程。索引重建是一个繁重的过程，其中索引被删除，然后以全新的结构从头开始重新创建，没有所有堆积的碎片和空白页面。

• 虽然索引重组是一种纯粹的清理操作，它使系统状态保持原样，而不会锁定受影响的表和视图，但重建过程会在整个重建期间锁定受影响的表，这可能会导致长时间停机，这在一些环境。考虑到这一点，很明显，索引重建是一个具有“更强”解决方案的过程，但它带来了代价——可能会在受影响的索引表上长时间锁定。

另一方面，索引重组是一个“轻量级”的过程，它将以一种不太有效的方式解决碎片——因为清理过的索引总是仅次于完全从头开始制作的新索引。但是从效率的角度来看，重组索引要好得多，因为它在操作过程中不会锁定受影响的索引表。

上述文章还解释了如何使用 SSMS、T-SQL（在表中重组/重建索引）和名为 ApexSQL Backup 的第 3 方工具来重组和重建索引。

Answer 3

在相同的索引上执行 aREORGANIZE然后 a是没有意义的，因为执行.REBUILDREORGANIZEREBUILD

更糟糕的是，在 SSW 的维护计划图中，它执行了SHRINK第一个操作，将索引碎片化，这是它释放空间方式的副作用。然后在操作REBUILD期间再次为数据库文件分配更多空间作为工作空间REBUILD。

• REORGANIZE是一种联机操作，它使用很少的额外工作空间逐页对聚集或非聚集索引中的叶页进行碎片整理。

• REBUILD在 Enterprise 版本中是联机操作，在其他版本中是脱机操作，并且再次使用与索引大小一样多的额外工作空间。它创建索引的新副本，然后删除旧的副本，从而消除碎片。默认情况下，作为此操作的一部分重新计算统计信息，但可以禁用。

有关详细信息，请参阅重组和重建索引。

不要将SHRINKexcept 与TRUNCATEONLY选项一起使用，即使文件会再次增长，那么您应该认真考虑是否有必要：

sqlservercentral_SHRINKFILE

Answer 4

在对索引进行重组时，如果索引分布在两个或多个物理文件中，则数据只会在数据文件中进行碎片整理。页面不会从一个数据文件移动到另一个数据文件。

当索引在单个文件中时，reorg 和 reindex 将具有相同的最终结果。

有时重组会更快，有时重建索引会更快，具体取决于索引的碎片程度。索引的碎片越少，重组就会越快，碎片越多，重组的速度就越慢，但重组的速度就越快。

Answer 5

正是比里所说的。以下是我将如何重新索引整个数据库：

EXEC [sp_MSforeachtable] @command1="RAISERROR('DBCC DBREINDEX(''?'') ...',10,1) WITH NOWAIT DBCC DBREINDEX('?')"

Answer 6

我用这个SP

CREATE PROCEDURE dbo.[IndexRebuild]
AS 
DECLARE @TableName NVARCHAR(500);
DECLARE @SQLIndex NVARCHAR(MAX);
DECLARE @RowCount INT;
DECLARE @Counter INT;

DECLARE @IndexAnalysis TABLE
    (
      AnalysisID INT IDENTITY(1, 1)
                     NOT NULL
                     PRIMARY KEY ,
      TableName NVARCHAR(500) ,
      SQLText NVARCHAR(MAX) ,
      IndexDepth INT ,
      AvgFragmentationInPercent FLOAT ,
      FragmentCount BIGINT ,
      AvgFragmentSizeInPages FLOAT ,
      PageCount BIGINT
    )

BEGIN
    INSERT  INTO @IndexAnalysis
            SELECT  [objects].name ,
                    'ALTER INDEX [' + [indexes].name + '] ON ['
                    + [schemas].name + '].[' + [objects].name + '] '
                    + ( CASE WHEN (   [dm_db_index_physical_stats].avg_fragmentation_in_percent >= 20
                                    AND [dm_db_index_physical_stats].avg_fragmentation_in_percent < 40
                                  ) THEN 'REORGANIZE'
                             WHEN [dm_db_index_physical_stats].avg_fragmentation_in_percent > = 40
                             THEN 'REBUILD'
                        END ) AS zSQL ,
                    [dm_db_index_physical_stats].index_depth ,
                    [dm_db_index_physical_stats].avg_fragmentation_in_percent ,
                    [dm_db_index_physical_stats].fragment_count ,
                    [dm_db_index_physical_stats].avg_fragment_size_in_pages ,
                    [dm_db_index_physical_stats].page_count
            FROM    [sys].[dm_db_index_physical_stats](DB_ID(), NULL, NULL,
                                                       NULL, 'LIMITED') AS   [dm_db_index_physical_stats]
                    INNER JOIN [sys].[objects] AS [objects] ON (   [dm_db_index_physical_stats].[object_id] = [objects].[object_id] )
                    INNER JOIN [sys].[schemas] AS [schemas] ON ( [objects].[schema_id]  = [schemas].[schema_id] )
                    INNER JOIN [sys].[indexes] AS [indexes] ON (  [dm_db_index_physical_stats].[object_id] = [indexes].[object_id]
                                                          AND  [dm_db_index_physical_stats].index_id = [indexes].index_id
                                                          )
            WHERE   index_type_desc <> 'HEAP'
                    AND [dm_db_index_physical_stats].avg_fragmentation_in_percent > 20
END

SELECT  @RowCount = COUNT(AnalysisID)
FROM    @IndexAnalysis

SET @Counter = 1
WHILE @Counter <= @RowCount 
    BEGIN

        SELECT  @SQLIndex = SQLText
        FROM    @IndexAnalysis
        WHERE   AnalysisID = @Counter

        EXECUTE sp_executesql @SQLIndex

        SET @Counter = @Counter + 1

    END
 GO

并创建一个每周执行此 SP 的作业。

Answer 7

更好的是：

EXEC sp_MSforeachtable 'ALTER INDEX ALL ON ? REINDEX'

或者

EXEC sp_MSforeachtable 'ALTER INDEX ALL ON ? REORGANIZE'

Answer 8

我在网络上进行了研究，发现了一些不错的文章。我在下面编写了函数和脚本，用于重组、重新创建或重建数据库中的所有索引。

首先，您可能需要阅读这篇文章以了解为什么我们不只是重新创建所有索引。

其次，我们需要一个函数来为索引构建创建脚本。所以这篇文章可能会有所帮助。我也在下面分享工作功能。

最后一步制作一个while循环来查找和组织数据库中的所有索引。该视频是制作此视频的绝佳示例。

功能：

create function GetIndexCreateScript(
    @index_name nvarchar(100)
) 
returns nvarchar(max)
as
begin

declare @Return   varchar(max)

SELECT @Return = ' CREATE ' + 
    CASE WHEN I.is_unique = 1 THEN ' UNIQUE ' ELSE '' END  +  
    I.type_desc COLLATE DATABASE_DEFAULT +' INDEX ' +   
    I.name  + ' ON '  +  
    Schema_name(T.Schema_id)+'.'+T.name + ' ( ' + 
    KeyColumns + ' )  ' + 
    ISNULL(' INCLUDE ('+IncludedColumns+' ) ','') + 
    ISNULL(' WHERE  '+I.Filter_definition,'') + ' WITH ( ' + 
    CASE WHEN I.is_padded = 1 THEN ' PAD_INDEX = ON ' ELSE ' PAD_INDEX = OFF ' END + ','  + 
    'FILLFACTOR = '+CONVERT(CHAR(5),CASE WHEN I.Fill_factor = 0 THEN 100 ELSE I.Fill_factor END) + ','  + 
    -- default value 
    'SORT_IN_TEMPDB = OFF '  + ','  + 
    CASE WHEN I.ignore_dup_key = 1 THEN ' IGNORE_DUP_KEY = ON ' ELSE ' IGNORE_DUP_KEY = OFF ' END + ','  + 
    CASE WHEN ST.no_recompute = 0 THEN ' STATISTICS_NORECOMPUTE = OFF ' ELSE ' STATISTICS_NORECOMPUTE = ON ' END + ','  + 
    -- default value  
    ' DROP_EXISTING = ON '  + ','  + 
    -- default value  
    ' ONLINE = OFF '  + ','  + 
   CASE WHEN I.allow_row_locks = 1 THEN ' ALLOW_ROW_LOCKS = ON ' ELSE ' ALLOW_ROW_LOCKS = OFF ' END + ','  + 
   CASE WHEN I.allow_page_locks = 1 THEN ' ALLOW_PAGE_LOCKS = ON ' ELSE ' ALLOW_PAGE_LOCKS = OFF ' END  + ' ) ON [' + 
   DS.name + ' ] '  
FROM sys.indexes I   
 JOIN sys.tables T ON T.Object_id = I.Object_id    
 JOIN sys.sysindexes SI ON I.Object_id = SI.id AND I.index_id = SI.indid   
 JOIN (SELECT * FROM (  
    SELECT IC2.object_id , IC2.index_id ,  
        STUFF((SELECT ' , ' + C.name + CASE WHEN MAX(CONVERT(INT,IC1.is_descending_key)) = 1 THEN ' DESC ' ELSE ' ASC ' END 
    FROM sys.index_columns IC1  
    JOIN Sys.columns C   
       ON C.object_id = IC1.object_id   
       AND C.column_id = IC1.column_id   
       AND IC1.is_included_column = 0  
    WHERE IC1.object_id = IC2.object_id   
       AND IC1.index_id = IC2.index_id   
    GROUP BY IC1.object_id,C.name,index_id  
    ORDER BY MAX(IC1.key_ordinal)  
       FOR XML PATH('')), 1, 2, '') KeyColumns   
    FROM sys.index_columns IC2   
    --WHERE IC2.Object_id = object_id('Person.Address') --Comment for all tables  
    GROUP BY IC2.object_id ,IC2.index_id) tmp3 )tmp4   
  ON I.object_id = tmp4.object_id AND I.Index_id = tmp4.index_id  
 JOIN sys.stats ST ON ST.object_id = I.object_id AND ST.stats_id = I.index_id   
 JOIN sys.data_spaces DS ON I.data_space_id=DS.data_space_id   
 JOIN sys.filegroups FG ON I.data_space_id=FG.data_space_id   
 LEFT JOIN (SELECT * FROM (   
    SELECT IC2.object_id , IC2.index_id ,   
        STUFF((SELECT ' , ' + C.name  
    FROM sys.index_columns IC1   
    JOIN Sys.columns C    
       ON C.object_id = IC1.object_id    
       AND C.column_id = IC1.column_id    
       AND IC1.is_included_column = 1   
    WHERE IC1.object_id = IC2.object_id    
       AND IC1.index_id = IC2.index_id    
    GROUP BY IC1.object_id,C.name,index_id   
       FOR XML PATH('')), 1, 2, '') IncludedColumns    
   FROM sys.index_columns IC2    
   --WHERE IC2.Object_id = object_id('Person.Address') --Comment for all tables   
   GROUP BY IC2.object_id ,IC2.index_id) tmp1   
   WHERE IncludedColumns IS NOT NULL ) tmp2    
ON tmp2.object_id = I.object_id AND tmp2.index_id = I.index_id   
WHERE I.is_primary_key = 0 AND I.is_unique_constraint = 0 
AND I.[name] = @index_name

return @Return

end

Sql一会儿：

declare @RebuildIndex Table(
    IndexId int identity(1,1),
    IndexName varchar(100),
    TableSchema varchar(50),
    TableName varchar(100),
    Fragmentation decimal(18,2)
)


insert into @RebuildIndex (IndexName,TableSchema,TableName,Fragmentation)
SELECT 
    B.[name] as 'IndexName', 
    Schema_Name(O.[schema_id]) as 'TableSchema',
    OBJECT_NAME(A.[object_id]) as 'TableName',
    A.[avg_fragmentation_in_percent] Fragmentation
FROM sys.dm_db_index_physical_stats(db_id(),NULL,NULL,NULL,'LIMITED') A 
INNER JOIN sys.indexes B ON A.[object_id] = B.[object_id] and A.index_id = B.index_id  
INNER JOIN sys.objects O ON O.[object_id] = B.[object_id]  
 where B.[name] is not null and B.is_primary_key = 0 AND B.is_unique_constraint = 0 and A.[avg_fragmentation_in_percent] >= 5  

--select * from @RebuildIndex

 declare @begin int = 1
 declare @max int
 select @max = Max(IndexId) from @RebuildIndex
 declare @IndexName varchar(100), @TableSchema varchar(50), @TableName varchar(100) , @Fragmentation decimal(18,2)

 while @begin <= @max
 begin

    Select @IndexName = IndexName from @RebuildIndex where IndexId = @begin
    select @TableSchema = TableSchema  from @RebuildIndex where IndexId = @begin
    select @TableName = TableName  from @RebuildIndex where IndexId = @begin 
    select @Fragmentation = Fragmentation  from @RebuildIndex where IndexId = @begin 

    declare @sql nvarchar(max)
    if @Fragmentation < 31
    begin
        set @sql = 'ALTER INDEX ['+@IndexName+'] ON ['+@TableSchema+'].['+@TableName+'] REORGANIZE WITH ( LOB_COMPACTION = ON )'
        print 'Reorganized Index ' + @IndexName + ' for ' + @TableName + ' Fragmentation was ' + convert(nvarchar(18),@Fragmentation)
    end
    else
    begin
        set @sql = (select dbo.GetIndexCreateScript(@IndexName))
        if(@sql is not null)
        begin
            print 'Recreated Index ' + @IndexName + ' for ' + @TableName + ' Fragmentation was ' + convert(nvarchar(18),@Fragmentation)
        end 
        else
        begin
            set @sql = 'ALTER INDEX ['+@IndexName+'] ON ['+@TableSchema+'].['+@TableName+'] REBUILD PARTITION = ALL WITH (ONLINE = ON)'
            print 'Rebuilded Index ' + @IndexName + ' for ' + @TableName + ' Fragmentation was ' + convert(nvarchar(18),@Fragmentation)
        end
    end

    execute(@sql)


    set @begin = @begin+1

end

Answer 9

我的两分钱......此方法遵循技术网上概述的规范：http ://technet.microsoft.com/en-us/library/ms189858(v=sql.105).aspx

USE [MyDbName]
GO

SET ANSI_NULLS OFF
GO

SET QUOTED_IDENTIFIER OFF
GO

CREATE PROCEDURE [maintenance].[IndexFragmentationCleanup]
AS
DECLARE @reIndexRequest VARCHAR(1000)

DECLARE reIndexList CURSOR
FOR
SELECT INDEX_PROCESS
FROM (
    SELECT CASE 
            WHEN avg_fragmentation_in_percent BETWEEN 5
                    AND 30
                THEN 'ALTER INDEX [' + i.NAME + '] ON [' + t.NAME + '] REORGANIZE;'
            WHEN avg_fragmentation_in_percent > 30
                THEN 'ALTER INDEX [' + i.NAME + '] ON [' + t.NAME + '] REBUILD with(ONLINE=ON);'
            END AS INDEX_PROCESS
        ,avg_fragmentation_in_percent
        ,t.NAME
    FROM sys.dm_db_index_physical_stats(NULL, NULL, NULL, NULL, NULL) AS a
    INNER JOIN sys.indexes AS i ON a.object_id = i.object_id
        AND a.index_id = i.index_id
    INNER JOIN sys.tables t ON t.object_id = i.object_id
    WHERE i.NAME IS NOT NULL
    ) PROCESS
WHERE PROCESS.INDEX_PROCESS IS NOT NULL
ORDER BY avg_fragmentation_in_percent DESC

OPEN reIndexList

FETCH NEXT
FROM reIndexList
INTO @reIndexRequest

WHILE @@FETCH_STATUS = 0
BEGIN
    BEGIN TRY

        PRINT @reIndexRequest;

        EXEC (@reIndexRequest);

    END TRY

    BEGIN CATCH
        DECLARE @ErrorMessage NVARCHAR(4000);
        DECLARE @ErrorSeverity INT;
        DECLARE @ErrorState INT;

        SELECT @ErrorMessage = 'UNABLE TO CLEAN UP INDEX WITH: ' + @reIndexRequest + ': MESSAGE GIVEN: ' + ERROR_MESSAGE()
            ,@ErrorSeverity = 9 
            ,@ErrorState = ERROR_STATE();

    END CATCH;

    FETCH NEXT
    FROM reIndexList
    INTO @reIndexRequest
END

CLOSE reIndexList;

DEALLOCATE reIndexList;

RETURN 0

GO