SQL Server索引维护指导

sp_msforeachtable @command1="dbcc dbreindex('?','',85)"

针对SQL Server 2005的通用维护过程

(碎片小于30%的联机组织，碎片>=30%的脱机重建)：

-- ensure a USE <databasename> statement has been executed first.
SET NOCOUNT ON;
DECLARE @objectid int;
DECLARE @indexid int;
DECLARE @partitioncount bigint;
DECLARE @schemaname sysname;
DECLARE @objectname sysname;
DECLARE @indexname sysname;
DECLARE @partitionnum bigint;
DECLARE @partitions bigint;
DECLARE @frag float;
DECLARE @command varchar(8000);
-- ensure the temporary table does not exist
IF EXISTS (SELECT name FROM sys.objects WHERE name = 'work_to_do')
　　DROP TABLE work_to_do;
-- conditionally select from the function, converting 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.
FETCH NEXT
　 FROM partitions
　 INTO @objectid, @indexid, @partitionnum, @frag;
　　WHILE @@FETCH_STATUS = 0
　　BEGIN;
　　　　SELECT @objectname = o.name, @schemaname = 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 = 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 and @frag>5
　　BEGIN;
　　SELECT @command = 'ALTER INDEX ' + @indexname + ' ON ' + @schemaname + '.' + @objectname + ' REORGANIZE';
　　IF @partitioncount > 1
　　　　SELECT @command = @command + ' PARTITION=' + CONVERT (CHAR, @partitionnum);
　　EXEC (@command);
　　END;
　　IF @frag >= 30.0
　　BEGIN;
　　SELECT @command = 'ALTER INDEX ' + @indexname +' ON ' + @schemaname + '.' + @objectname + ' REBUILD';
　　IF @partitioncount > 1
　　　　SELECT @command = @command + ' PARTITION=' + CONVERT (CHAR, @partitionnum);
　　EXEC (@command);
　　END;
PRINT 'Executed ' + @command;
　　FETCH NEXT FROM partitions INTO @objectid, @indexid, @partitionnum, @frag;
END;
-- Close and deallocate the cursor.
CLOSE partitions;
DEALLOCATE partitions;
　　-- drop the temporary table
IF EXISTS (SELECT name FROM sys.objects WHERE name = 'work_to_do')
　　DROP TABLE work_to_do;
GO

总结

索引的维护是有参考依据的，应该根据具体的碎片情况以及是否需要联机操作等需求，采用合理的维护方法。自动化的索引维护策略是可行的。