Question

我正在寻找一个脚本来识别单个数据库中的高度分散的索引，并且可选择单个表，因为我认为sys.dm_db_index_physical_stats是非常耗费资源的。

还可以选择让桌子离线吗？我读到这可能在某个地方？

Answer 1

这是来自MSDN的一个：

--This example shows a simple way to defragment all indexes in a database that is fragmented above a declared threshold.

/*Perform a 'USE <database name>' to select the database in which to run the script.*/
-- Declare variables
SET NOCOUNT ON
DECLARE @tablename VARCHAR (128)
DECLARE @execstr   VARCHAR (255)
DECLARE @objectid  INT
DECLARE @indexid   INT
DECLARE @frag      DECIMAL
DECLARE @maxfrag   DECIMAL

-- Decide on the maximum fragmentation to allow
SELECT @maxfrag = 30.0

-- Declare cursor
DECLARE tables CURSOR FOR
   SELECT TABLE_NAME
   FROM INFORMATION_SCHEMA.TABLES
   WHERE TABLE_TYPE = 'BASE TABLE'

-- Create the table
CREATE TABLE #fraglist (
   ObjectName CHAR (255),
   ObjectId INT,
   IndexName CHAR (255),
   IndexId INT,
   Lvl INT,
   CountPages INT,
   CountRows INT,
   MinRecSize INT,
   MaxRecSize INT,
   AvgRecSize INT,
   ForRecCount INT,
   Extents INT,
   ExtentSwitches INT,
   AvgFreeBytes INT,
   AvgPageDensity INT,
   ScanDensity DECIMAL,
   BestCount INT,
   ActualCount INT,
   LogicalFrag DECIMAL,
   ExtentFrag DECIMAL)

-- Open the cursor
OPEN tables

-- Loop through all the tables in the database
FETCH NEXT
   FROM tables
   INTO @tablename

WHILE @@FETCH_STATUS = 0
BEGIN
-- Do the showcontig of all indexes of the table
   INSERT INTO #fraglist 
   EXEC ('DBCC SHOWCONTIG (''' + @tablename + ''') 
      WITH FAST, TABLERESULTS, ALL_INDEXES, NO_INFOMSGS')
   FETCH NEXT
      FROM tables
      INTO @tablename
END

-- Close and deallocate the cursor
CLOSE tables
DEALLOCATE tables

-- Declare cursor for list of indexes to be defragged
DECLARE indexes CURSOR FOR
   SELECT ObjectName, ObjectId, IndexId, LogicalFrag
   FROM #fraglist
   WHERE LogicalFrag >= @maxfrag
      AND INDEXPROPERTY (ObjectId, IndexName, 'IndexDepth') > 0

-- Open the cursor
OPEN indexes

-- loop through the indexes
FETCH NEXT
   FROM indexes
   INTO @tablename, @objectid, @indexid, @frag

WHILE @@FETCH_STATUS = 0
BEGIN
   PRINT 'Executing DBCC INDEXDEFRAG (0, ' + RTRIM(@tablename) + ',
      ' + RTRIM(@indexid) + ') - fragmentation currently '
       + RTRIM(CONVERT(varchar(15),@frag)) + '%'
   SELECT @execstr = 'DBCC INDEXDEFRAG (0, ' + RTRIM(@objectid) + ',
       ' + RTRIM(@indexid) + ')'
   EXEC (@execstr)

   FETCH NEXT
      FROM indexes
      INTO @tablename, @objectid, @indexid, @frag
END

-- Close and deallocate the cursor
CLOSE indexes
DEALLOCATE indexes

-- Delete the temporary table
DROP TABLE #fraglist
GO

Answer 2

运行此查询：

SELECT  OBJECT_NAME(DMV.object_id) AS TABLE_NAME ,
    SI.NAME AS INDEX_NAME ,
    avg_fragmentation_in_percent AS FRAGMENT_PERCENT ,
    DMV.record_count
FROM    sys.dm_db_index_physical_stats(DB_ID(), NULL, NULL, NULL, 'SAMPLED')
    AS DMV
    LEFT OUTER JOIN SYS.INDEXES AS SI ON DMV.OBJECT_ID = SI.OBJECT_ID
                                         AND DMV.INDEX_ID = SI.INDEX_ID
WHERE   avg_fragmentation_in_percent > 10
    AND index_type_desc IN ( 'CLUSTERED INDEX', 'NONCLUSTERED INDEX' )
    AND DMV.record_count >= 2000
ORDER BY TABLE_NAME DESC

所有索引FRAGMENT_PERCENT的重建次数超过30％。

Answer 3

此代码将在Frag > Target时生成重建代码。作为作业的第1步运行，以生成您在步骤2中运行的代码（我从你们所有人那里学到了很多东西。： - ）

执行master.sys.sp_MSforeachdb＆＃34; USE [？];选择＆＃39;使用＆＃39; + DB_NAME（db_id（））+＆＃39;;＆＃39; SELECT＆＃39; ALTER INDEX [＆＃39; + SI.NAME +＆＃39;] ON [＆＃39; + OBJECT_NAME（DMV.object_id）+＆＃39;] REBUILD WITH（ONLINE = ON）;＆＃39; +＆＃39; - 碎片：＆＃39; +转换（varchar（40），avg_fragmentation_in_percent） FROM sys.dm_db_index_physical_stats（DB_ID（），NULL，NULL，NULL，＆＃39; SAMPLED＆＃39;）DMV LEVE OUTER JOIN SYS.INDEXES为DMV.OBJECT_ID = SI.OBJECT_ID AND DMV.INDEX_ID = SI.INDEX_ID WHERE avg_fragmentation_in_percent＆gt; 29 AND index_type_desc IN（＆＃39; CLUSTERED INDEX＆＃39;，＆＃39; NONCLUSTERED INDEX＆＃39;） AND DMV.record_count＆gt; = 2000 ORDER BY OBJECT_NAME（DMV.object_id），SI.NAME＆＃34;

识别高度分散的索引并重建单个数据库/表SQL Server 2005/2008

3 个答案: