SQLServer 表的索引碎片查询和处理
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本文主要介绍了SQLServer 表的索引碎片查询和处理,文中通过示例代码介绍的非常详细,对大家的学习或者工作具有一定的参考学习价值,需要的朋友们下面随着小编来一起学习学习吧
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;
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