SQL脚本:

-- 未被使用的索引
SELECT OBJECT_NAME(i.[object_id]) AS [Table Name],i.name FROM sys.indexes AS i INNER JOIN sys.objects AS o ON i.[object_id] = o.[object_id] WHERE i.index_id NOT IN ( SELECT ddius.index_id FROM sys.dm_db_index_usage_stats AS ddius WHERE ddius.[object_id] = i.[object_id] AND i.index_id = ddius.index_id AND database_id = DB_ID() ) AND o.[type] = 'U' ORDER BY OBJECT_NAME(i.[object_id]) ASC;

--需要维护但是未被用过的索引
SELECT '[' + DB_NAME() + '].[' + su.[name] + '].[' + o.[name] + ']' AS [statement],i.[name] AS [index_name],ddius.[user_seeks] + ddius.[user_scans] + ddius.[user_lookups] AS [user_reads],ddius.[user_updates] AS [user_writes],SUM(SP.rows) AS [total_rows] FROM sys.dm_db_index_usage_stats ddius INNER JOIN sys.indexes i ON ddius.[object_id] = i.[object_id] AND i.[index_id] = ddius.[index_id] INNER JOIN sys.partitions SP ON ddius.[object_id] = SP.[object_id] AND SP.[index_id] = ddius.[index_id] INNER JOIN sys.objects o ON ddius.[object_id] = o.[object_id] INNER JOIN sys.sysusers su ON o.[schema_id] = su.[UID] WHERE ddius.[database_id] = DB_ID() -- current database only AND OBJECTPROPERTY(ddius.[object_id],'IsUserTable') = 1 AND ddius.[index_id] > 0 GROUP BY su.[name],o.[name],i.[name],ddius.[user_seeks] + ddius.[user_scans] + ddius.[user_lookups],ddius.[user_updates] HAVING ddius.[user_seeks] + ddius.[user_scans] + ddius.[user_lookups] = 0 ORDER BY ddius.[user_updates] DESC,su.[name],i.[name] -- 可能不高效的非聚集索引 (writes > reads) SELECT OBJECT_NAME(ddius.[object_id]) AS [Table Name],i.name AS [Index Name],i.index_id,user_updates AS [Total Writes],user_seeks + user_scans + user_lookups AS [Total Reads],user_updates - ( user_seeks + user_scans + user_lookups ) AS [Difference] FROM sys.dm_db_index_usage_stats AS ddius WITH ( NOLOCK ) INNER JOIN sys.indexes AS i WITH ( NOLOCK ) ON ddius.[object_id] = i.[object_id] AND i.index_id = ddius.index_id WHERE OBJECTPROPERTY(ddius.[object_id],'IsUserTable') = 1 AND ddius.database_id = DB_ID() AND user_updates > ( user_seeks + user_scans + user_lookups ) AND i.index_id > 1 ORDER BY [Difference] DESC,[Total Writes] DESC,[Total Reads] ASC;

--没有用于用户查询的索引
SELECT '[' + DB_NAME() + '].[' + su.[name] + '].[' + o.[name] + ']' AS [statement],ddios.[leaf_insert_count],ddios.[leaf_delete_count],ddios.[leaf_update_count],ddios.[nonleaf_insert_count],ddios.[nonleaf_delete_count],ddios.[nonleaf_update_count] FROM sys.dm_db_index_usage_stats ddius INNER JOIN sys.indexes i ON ddius.[object_id] = i.[object_id] AND i.[index_id] = ddius.[index_id] INNER JOIN sys.partitions SP ON ddius.[object_id] = SP.[object_id] AND SP.[index_id] = ddius.[index_id] INNER JOIN sys.objects o ON ddius.[object_id] = o.[object_id] INNER JOIN sys.sysusers su ON o.[schema_id] = su.[UID] INNER JOIN sys.[dm_db_index_operational_stats](DB_ID(),NULL,NULL) AS ddios ON ddius.[index_id] = ddios.[index_id] AND ddius.[object_id] = ddios.[object_id] AND SP.[partition_number] = ddios.[partition_number] AND ddius.[database_id] = ddios.[database_id] WHERE OBJECTPROPERTY(ddius.[object_id],'IsUserTable') = 1 AND ddius.[index_id] > 0 AND ddius.[user_seeks] + ddius.[user_scans] + ddius.[user_lookups] = 0 ORDER BY ddius.[user_updates] DESC,i.[name] --查找丢失索引 SELECT user_seeks * avg_total_user_cost * ( avg_user_impact * 0.01 ) AS [index_advantage],dbmigs.last_user_seek,dbmid.[statement] AS [Database.Schema.Table],dbmid.equality_columns,dbmid.inequality_columns,dbmid.included_columns,dbmigs.unique_compiles,dbmigs.user_seeks,dbmigs.avg_total_user_cost,dbmigs.avg_user_impact FROM sys.dm_db_missing_index_group_stats AS dbmigs WITH ( NOLOCK ) INNER JOIN sys.dm_db_missing_index_groups AS dbmig WITH ( NOLOCK ) ON dbmigs.group_handle = dbmig.index_group_handle INNER JOIN sys.dm_db_missing_index_details AS dbmid WITH ( NOLOCK ) ON dbmig.index_handle = dbmid.index_handle WHERE dbmid.[database_id] = DB_ID() ORDER BY index_advantage DESC;

--索引上的碎片超过15%并且索引体积较大（超过500页）的索引。
SELECT '[' + DB_NAME() + '].[' + OBJECT_SCHEMA_NAME(ddips.[object_id],DB_ID()) + '].[' + OBJECT_NAME(ddips.[object_id],DB_ID()) + ']' AS [statement],ddips.[index_type_desc],ddips.[partition_number],ddips.[alloc_unit_type_desc],ddips.[index_depth],ddips.[index_level],CAST(ddips.[avg_fragmentation_in_percent] AS SMALLINT) AS [avg_frag_%],CAST(ddips.[avg_fragment_size_in_pages] AS SMALLINT) AS [avg_frag_size_in_pages],ddips.[fragment_count],ddips.[page_count] FROM sys.dm_db_index_physical_stats(DB_ID(),'limited') ddips INNER JOIN sys.[indexes] i ON ddips.[object_id] = i.[object_id] AND ddips.[index_id] = i.[index_id] WHERE ddips.[avg_fragmentation_in_percent] > 15 AND ddips.[page_count] > 500 ORDER BY ddips.[avg_fragmentation_in_percent],OBJECT_NAME(ddips.[object_id],DB_ID()),i.[name] --缺失索引 SELECT migs.group_handle,mid.* FROM sys.dm_db_missing_index_group_stats AS migs INNER JOIN sys.dm_db_missing_index_groups AS mig ON (migs.group_handle = mig.index_group_handle) INNER JOIN sys.dm_db_missing_index_details AS mid ON (mig.index_handle = mid.index_handle) WHERE migs.group_handle = 2 --无用索引 SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED SELECT DB_NAME() AS DatbaseName,SCHEMA_NAME(O.Schema_ID) AS SchemaName,OBJECT_NAME(I.object_id) AS TableName,I.name AS IndexName INTO #TempNeverUsedIndexes FROM sys.indexes I INNER JOIN sys.objects O ON I.object_id = O.object_id WHERE 1=2 EXEC sp_MSForEachDB 'USE [?]; INSERT INTO #TempNeverUsedIndexes SELECT DB_NAME() AS DatbaseName,SCHEMA_NAME(O.Schema_ID) AS SchemaName,OBJECT_NAME(I.object_id) AS TableName,I.NAME AS IndexName FROM sys.indexes I INNER JOIN sys.objects O ON I.object_id = O.object_id LEFT OUTER JOIN sys.dm_db_index_usage_stats S ON S.object_id = I.object_id AND I.index_id = S.index_id AND DATABASE_ID = DB_ID() WHERE OBJECTPROPERTY(O.object_id,''IsMsShipped'') = 0 AND I.name IS NOT NULL AND S.object_id IS NULL' SELECT * FROM #TempNeverUsedIndexes ORDER BY DatbaseName,SchemaName,TableName,IndexName DROP TABLE #TempNeverUsedIndexes --经常被大量更新，但是却基本不适用的索引项- SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED SELECT DB_NAME() AS DatabaseName,SCHEMA_NAME(o.Schema_ID) AS SchemaName,OBJECT_NAME(s.[object_id]) AS TableName,i.name AS IndexName,s.user_updates,s.system_seeks + s.system_scans + s.system_lookups AS [System usage] INTO #TempUnusedIndexes FROM sys.dm_db_index_usage_stats s INNER JOIN sys.indexes i ON s.[object_id] = i.[object_id] AND s.index_id = i.index_id INNER JOIN sys.objects o ON i.object_id = O.object_id WHERE 1=2 EXEC sp_MSForEachDB 'USE [?]; INSERT INTO #TempUnusedIndexes SELECT TOP 20 DB_NAME() AS DatabaseName,SCHEMA_NAME(o.Schema_ID) AS SchemaName,OBJECT_NAME(s.[object_id]) AS TableName,i.name AS IndexName,s.system_seeks + s.system_scans + s.system_lookups AS [System usage] FROM sys.dm_db_index_usage_stats s INNER JOIN sys.indexes i ON s.[object_id] = i.[object_id] AND s.index_id = i.index_id INNER JOIN sys.objects o ON i.object_id = O.object_id WHERE s.database_id = DB_ID() AND OBJECTPROPERTY(s.[object_id],''IsMsShipped'') = 0 AND s.user_seeks = 0 AND s.user_scans = 0 AND s.user_lookups = 0 AND i.name IS NOT NULL ORDER BY s.user_updates DESC' SELECT TOP 20 * FROM #TempUnusedIndexes ORDER BY [user_updates] DESC DROP TABLE #TempUnusedIndexes 

（编辑：李大同）

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