SQL索引碎片整理脚本

原文发布时间为：2011-02-23 —— 来源于本人的百度文章 [由搬家工具导入]

reindex是比较好的选择，速度快，但是他不能在线操作
INDEXDEFRAG 比较慢，但是可以在线操作
rebuild建议在碎片较少时采用。

附上微软的重建索引脚本，从里面也可以看出微软根据碎片大小推荐的方式，不过这个要随每个不同的数据库而定。
-- 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>5 AND @frag <= 30.0
    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