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,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)
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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 |