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数据库索引碎片的自动重建或重组
2014-11-24 00:43:56 来源: 作者: 【 】 浏览:5
Tags:数据库 索引 碎片 自动 重建 重组

数据库随着使用时间,若不进行相应管理就会越来越慢,优化数据库方法很多,在此不介绍,说一下,如何自动对其索引产生的碎片进行自动重建,索引碎片的增多,有什么影响,在此不阐述!

直接看代码~!节约时间。


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/*功能描述:自动重新组织或重新生成数据库中平均碎片超过 10% 的所有分区。

执行此查询需注意以下几点:
1)、需要 VIEW DATABASE STATE 权限。
2)、在不指定数据库名称的情况下,指定 DB_ID 作为第一个参数。
3)、确定当前数据库为80以上。
*/
USE MASTER
SET NOCOUNT ON;
DECLARE @objectid int;
DECLARE @indexid int;
DECLARE @partitioncount bigint;
DECLARE @schemaname nvarchar(130);
DECLARE @objectname nvarchar(130);
DECLARE @indexname nvarchar(130);
DECLARE @partitionnum bigint;
DECLARE @partitions bigint;
DECLARE @frag float;
DECLARE @command nvarchar(4000);
-- Conditionally select tables and indexes from the sys.dm_db_index_physical_stats function
-- and convert object and index IDs to names.
SELECT
object_id AS objectid,
index_id AS indexid,
partition_number AS partitionnum,
avg_fragmentation_in_percent AS frag
INTO #work_to_do
FROM sys.dm_db_index_physical_stats (db_id('TABLE_NAME'), NULL, NULL , NULL, 'LIMITED')
WHERE avg_fragmentation_in_percent > 10.0 AND index_id > 0;

-- Declare the cursor for the list of partitions to be processed.
DECLARE partitions CURSOR FOR SELECT * FROM #work_to_do;

-- Open the cursor.
OPEN partitions;

-- Loop through the partitions.
WHILE (1=1)
BEGIN;
FETCH NEXT
FROM partitions
INTO @objectid, @indexid, @partitionnum, @frag;
IF @@FETCH_STATUS < 0 BREAK;
SELECT @objectname = QUOTENAME(o.name), @schemaname = QUOTENAME(s.name)
FROM sys.objects AS o
JOIN sys.schemas as s ON s.schema_id = o.schema_id
WHERE o.object_id = @objectid;
SELECT @indexname = QUOTENAME(name)
FROM sys.indexes
WHERE object_id = @objectid AND index_id = @indexid;
SELECT @partitioncount = count (*)
FROM sys.partitions
WHERE object_id = @objectid AND index_id = @indexid;

-- 30 is an arbitrary decision point at which to switch between reorganizing and rebuilding.
IF @frag < 30.0
SET @command = N'ALTER INDEX ' + @indexname + N' ON ' + @schemaname + N'.' + @objectname + N' REORGANIZE';
IF @frag >= 30.0
SET @command = N'ALTER INDEX ' + @indexname + N' ON ' + @schemaname + N'.' + @objectname + N' REBUILD';
IF @partitioncount > 1
SET @command = @command + N' PARTITION=' + CAST(@partitionnum AS nvarchar(10));
EXEC (@command);
PRINT N'Executed: ' + @command;
END;

-- Close and deallocate the cursor.
CLOSE partitions;
DEALLOCATE partitions;

-- Drop the temporary table.
DROP TABLE #work_to_do;
GO

2011 EricHu

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