目錄

• 1.查看索引的碎片率
• 2.reorganize索引
• 3.rebuild索引
• 4.rebuild表上所有的索引
• 5.rebuild數據庫中所有的索引　　

1.查看索引的碎片率

SELECT object_name(ips.object_id) AS TableName, ips.index_id, name AS IndexName, 
avg_fragmentation_in_percent,db_name(ips.database_id) AS DatabaseName
FROM sys.dm_db_index_physical_stats
    (Db_id(DB_NAME())
, NULL
, NULL
, NULL
, NULL) AS ips
INNER JOIN sys.indexes AS SI ON ips.object_id = SI.object_id AND ips.index_id = SI.index_id
WHERE ips.avg_fragmentation_in_percent > 5 AND SI.index_id <> 0

索引的碎片率低于5%或者，索引的頁數少于1000，可以忽略；
索引碎片率在5%-30%之間的，建議reorganize；
索引碎片率大于30%的，建議rebuild。

2.reorganize索引

alter index [索引名] on [dbo].[表名] reorganize;

3.rebuild索引

alter index [索引名] on [dbo].[表名] rebuild;

4.rebuild表上所有的索引

alter index all on [dbo].[表名] rebuild;

5.rebuild數據庫中所有的索引　　

USE [數據庫名]
GO
DECLARE @NoOfPartitions BIGINT;
DECLARE @objectid INT;
DECLARE @indexid INT;
DECLARE @idxname NVARCHAR(255);
DECLARE @objname NVARCHAR(255);
DECLARE @partitionnum BIGINT;
DECLARE @schemaname NVARCHAR(255);
DECLARE @partitions BIGINT;
DECLARE @frag FLOAT;
DECLARE @statement VARCHAR(8000);
-- checking existance of the table that we create for temporary purpose
IF OBJECT_ID("defrag_work", "U") IS NOT NULL
  DROP TABLE defrag_work;
-- Copy the fragmented indexes data into defrag_work table
-- All the indexes that has fragmentation < 5 are getting stored into our work table
SELECT  [object_id] AS objectid ,
index_id AS indexid ,
partition_number AS partition_no ,
avg_fragmentation_in_percent AS frag
INTO    defrag_work
FROM    sys.dm_db_index_physical_stats(DB_ID(), NULL, NULL, NULL, "LIMITED")
WHERE   avg_fragmentation_in_percent >5.0 and index_id > 0;
-- cursor to process the list of partitions
DECLARE partitions CURSOR
FOR
    SELECT  *
    FROM    defrag_work;
-- Open the cursor.
OPEN partitions;
-- Looping through the partitions
FETCH NEXT
   FROM partitions
   INTO @objectid, @indexid, @partitionnum, @frag;
WHILE @@FETCH_STATUS = 0
    BEGIN;
SELECT  @objname= QUOTENAME(so.name) ,
@schemaname = QUOTENAME(ss.name)
FROM    sys.objects AS so
JOIN sys.schemas AS ss ON ss.schema_id = so.schema_id
WHERE   so.object_id = @objectid;
SELECT  @idxname = QUOTENAME(name)
FROM    sys.indexes
WHERE   object_id = @objectid
AND index_id = @indexid;
SELECT  @NoOfPartitions = COUNT(*)
FROM    sys.partitions
WHERE   object_id = @objectid
AND index_id = @indexid;
/*
Let"s say N = fragmentation percentage
N <= 5 = IGNORE
5 < N < 30 = REORGANIZE
N > 30 = REBUILD
*/
IF (@frag < 30.0) -- @frag > 5 is already filtered in our first query, so we need that condition here
    BEGIN;
SELECT  @statement = "ALTER INDEX " + @idxname + " ON "
+ @schemaname + "." + @objname + " REORGANIZE";
IF @NoOfPartitions > 1
    SELECT  @statement = @statement + " PARTITION="
    + CONVERT (CHAR, @partitionnum);
EXEC (@statement);
    END;
IF @frag >= 30.0
    BEGIN;
SELECT  @statement = "ALTER INDEX " + @idxname + " ON "
+ @schemaname + "." + @objname + " REBUILD";
IF @NoOfPartitions > 1
    SELECT  @statement = @statement + " PARTITION="
    + CONVERT (CHAR, @partitionnum);
EXEC (@statement);
    END;
PRINT "Executed " + @statement;
FETCH NEXT FROM partitions INTO @objectid, @indexid, @partitionnum,
    @frag;
    END;
-- Close and deallocate the cursor.
CLOSE partitions;
DEALLOCATE partitions;
-- drop the table
IF OBJECT_ID("defrag_work", "U") IS NOT NULL
  DROP TABLE defrag_work;

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