Donnerstag, 18. September 2008

SQL Server – Defragmentieren von Indizies

Ein weiteres nettes Script zum Defragmentieren aller Indizies einer Datenbank (gefunden in der MSDN):

-- Ensure a USE <databasename> statement has 
-- been executed first.
SET NOCOUNT ON; DBCC UPDATEUSAGE(0) 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); -- EXEC (N'ALTER INDEX ALL ON ' + @schemaname +
-- N'.' + @objectname + N' REBUILD')
-- IF @indexid <> 255 DBCC INDEXDEFRAG (MyDataBase,
-- @objectname, @indexid)
END; -- Close and deallocate the cursor. CLOSE partitions; DEALLOCATE partitions; -- Drop the temporary table. DROP TABLE #work_to_do; GO

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