SQLServer 表的索引碎片查询和处理

目录

• 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数据库中所有的索引　　

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，索引的页数少于1000，可以忽略；
索引碎片率在5%-30%之间的，建议reorganize；
索引碎片率大于30%的，建议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数据库中所有的索引　　

USE [数据库名]
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;

到此这篇关于SQLServer 表的索引碎片查询和处理的文章就介绍到这了,更多相关SQLServer 表索引碎片内容请搜索以前的文章或继续浏览下面的相关文章希望大家以后多多支持！