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SQL SERVER 2008 R2如何重建索引
SQL SERVER 2008 R2如何重建索引
项目升级数据库由SQL2000升级到2008R2,今天对数据库表进行碎片扫描,发现有些表碎片较大,于是决定重建索引,MSDN联机帮助是最好的老师,将相关脚本摘录备后查。
参考sys.dm_db_index_physical_stats
检查索引碎片情况
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- SELECT
- OBJECT_NAME(object_id) as objectname,
- object_id AS objectid,
- index_id AS indexid,
- partition_number AS partitionnum,
- avg_fragmentation_in_percent AS fra
- FROM sys.dm_db_index_physical_stats (DB_ID(), NULL, NULL , NULL, 'LIMITED')
- WHERE avg_fragmentation_in_percent > 10.0 AND index_id > 0;
- 使用脚本中的 sys.dm_db_index_physical_stats 重新生成或重新组织索引 (来源于联机帮助)
- 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(), 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