原文:SQL SERVER性能优化SQL
sql server 性能优化方法
目录
六、修改索引填充因子（FILLFACTOR：填充因子,ONLINE:ON 重建索引时表仍然可以正常使用）
一、查看是否有死锁
dECLARE @tab TABLE(NAME varchar(100),value varchar(200)); INSERT INTO @tab EXEC('DBCC OPENTRAN WITH TABLERESULTS'); SELECT name,CAST(value AS DATETIME) startDate,getdate() currentDate ,DATEDIFF(s,CAST(value AS DATETIME),getdate()) diffsecond FROM @tab WHERE name in ('OLDACT_STARTTIME') SELECT spid, blocked, DB_NAME(sp.dbid) AS DBName, program_name, waitresource, lastwaittype, sp.loginame, sp.hostname, a.[Text] AS [TextData], SUBSTRING(A.text, sp.stmt_start / 2, (CASE WHEN sp.stmt_end = -1 THEN DATALENGTH(A.text) ELSE sp.stmt_end END - sp.stmt_start) / 2) AS [current_cmd] FROM sys.sysprocesses AS sp OUTER APPLY sys.dm_exec_sql_text (sp.sql_handle) AS A WHERE spid =(SELECT CASE WHEN ISNUMERIC(value)=0 THEN -1 ELSE value end FROM @tab WHERE name in ('OLDACT_SPID') )
二、查看当前正在执行的sql语句
SELECT [Spid] = session_id , ecid , [Database] = DB_NAME(sp.dbid) ,[User] = nt_username , [Status] = er.status , [Wait] = wait_type , [Individual Query] = SUBSTRING(qt.text, er.statement_start_offset / 2, ( CASE WHEN er.statement_end_offset = -1 THEN LEN(CONVERT(NVARCHAR(MAX), qt.text)) * 2 ELSE er.statement_end_offset END - er.statement_start_offset ) / 2) , [Parent Query] = qt.text , Program = program_name ,hostname , nt_domain , start_time FROM sys.dm_exec_requests er INNER JOIN sys.sysprocesses sp ON er.session_id = sp.spid CROSS APPLY sys.dm_exec_sql_text(er.sql_handle) AS qt WHERE session_id > 50 -- Ignore system spids. AND session_id NOT IN ( @@SPID ) -- Ignore this current statement. ORDER BY 1 , 2 --删除解锁 KILL 1000 --spid
三、查询前 10 个可能是性能最差的 SQL 语句
SELECT TOP 10 TEXT AS 'SQL Statement' ,last_execution_time AS 'Last Execution Time' ,(total_logical_reads + total_physical_reads + total_logical_writes) / execution_count AS [Average IO] ,(total_worker_time / execution_count) / 1000000.0 AS [Average CPU Time (sec)] ,(total_elapsed_time / execution_count) / 1000000.0 AS [Average Elapsed Time (sec)] ,execution_count AS "Execution Count" ,qp.query_plan AS "Query Plan" FROM sys.dm_exec_query_stats qs CROSS APPLY sys.dm_exec_sql_text(qs.plan_handle) st CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) qp ORDER BY total_elapsed_time / execution_count DESC
四、查询逻辑读取最高的sql
SELECT TOP ( 25 ) P.name AS [SP Name] , Deps.total_logical_reads AS [TotalLogicalReads] , deps.total_logical_reads / deps.execution_count AS [AvgLogicalReads] , deps.execution_count , ISNULL(deps.execution_count / DATEDIFF(SECOND, deps.cached_time, GETDATE()), 0) AS [Calls/Second] , deps.total_elapsed_time , deps.total_elapsed_time / deps.execution_count AS [avg_elapsed_time] , deps.cached_time FROM sys.procedures AS p INNER JOIN sys.dm_exec_procedure_stats AS deps ON p.[Object_id] = deps.[Object_id] WHERE deps.Database_id = DB_ID() ORDER BY deps.total_logical_reads DESC
五、 查询索引碎片
--创建变量 指定要查看的表 declare @table_id int set @table_id=object_id('TableName') --执行 dbcc showcontig(@table_id)
Logical Scan Fragmentation-逻辑扫描碎片：该百分比应该在0％到10％之间，高了则说明有外部碎片。
Extent Scan Fragmentation-扩展盘区扫描碎片：该百分比应该是0％，高了则说明有外部碎片。
扫描密度［最佳值:实际值］：该百分比应该尽可能靠近100％。低了则说明有外部碎片。
六、修改索引填充因子（FILLFACTOR：填充因子,ONLINE:ON 重建索引时表仍然可以正常使用）
--修改表下所有索引填充因子 ALTER INDEX ALL ON TableName REBUILD WITH (FILLFACTOR=90,ONLINE=ON) --修改表下指定索引填充因子 ALTER INDEX indexName ON TableName REBUILD WITH (FILLFACTOR = 80);
七、查询未使用过的索引
SELECT DB_NAME(diu.database_id) AS DatabaseName , s.name +'.' +QUOTENAME(o.name) AS TableName , i.index_id AS IndexID , i.name AS IndexName , CASE WHEN i.is_unique =1 THEN 'UNIQUE INDEX' ELSE 'NOT UNIQUE INDEX' END AS IS_UNIQUE, CASE WHEN i.is_disabled=1 THEN 'DISABLE' ELSE 'ENABLE' END AS IndexStatus, o.create_date AS IndexCreated, STATS_DATE(o.object_id,i.index_id) AS StatisticsUpdateDate, diu.user_seeks AS UserSeek , diu.user_scans AS UserScans , diu.user_lookups AS UserLookups , diu.user_updates AS UserUpdates , p.TableRows , 'DROP INDEX ' + QUOTENAME(i.name) + ' ON ' + QUOTENAME(s.name) + '.' + QUOTENAME(OBJECT_NAME(diu.object_id)) +';' AS 'Drop Index Statement' FROM sys.dm_db_index_usage_stats diu INNER JOIN sys.indexes i ON i.index_id = diu.index_id AND diu.object_id = i.object_id INNER JOIN sys.objects o ON diu.object_id = o.object_id INNER JOIN sys.schemas s ON o.schema_id = s.schema_id INNER JOIN ( SELECT SUM(p.rows) TableRows , p.index_id , p.object_id FROM sys.partitions p GROUP BY p.index_id , p.object_id ) p ON p.index_id = diu.index_id AND diu.object_id = p.object_id WHERE OBJECTPROPERTY(diu.object_id, 'IsUserTable') = 1 AND diu.database_id = DB_ID() AND i.is_primary_key = 0 --排除主键索引 AND i.is_unique_constraint = 0 --排除唯一索引 AND diu.user_updates <> 0 --排除没有数据变化的索引 AND diu.user_lookups = 0 AND diu.user_seeks = 0 AND diu.user_scans = 0 AND i.name IS NOT NULL --排除那些没有任何索引的堆表 ORDER BY ( diu.user_seeks + diu.user_scans + diu.user_lookups ) ASC,diu.user_updates DESC; GO
八、查询表下索引使用情况
select db_name(database_id) as N'数据库名称', object_name(a.object_id) as N'表名', b.name N'索引名称', user_seeks N'用户索引查找次数', user_scans N'用户索引扫描次数', max(last_user_seek) N'最后查找时间', max(last_user_scan) N'最后扫描时间', max(rows) as N'表中的行数' from sys.dm_db_index_usage_stats a join sys.indexes b on a.index_id = b.index_id and a.object_id = b.object_id join sysindexes c on c.id = b.object_id where database_id=db_id('数据库名称') --指定数据库 and object_name(a.object_id) not like 'sys%' and object_name(a.object_id) like '表名' --指定索引表 and b.name is not null --and b.name like '索引名' --指定索引名称 可以先使用 sp_help '你的表名' 查看表的结构和所有的索引信息 group by db_name(database_id) , object_name(a.object_id), b.name, user_seeks , user_scans order by user_seeks,user_scans,object_name(a.object_id)
九、查询表结构信息
SELECT 表名 = CASE WHEN a.colorder = 1 THEN d.name ELSE '' END , 表说明 = CASE WHEN a.colorder = 1 THEN ISNULL(f.value, '') ELSE '' END , 字段序号 = a.colorder , 字段名 = a.name , 标识 = CASE WHEN COLUMNPROPERTY(a.id, a.name, 'IsIdentity') = 1 THEN '√' ELSE '' END , 主键 = CASE WHEN EXISTS ( SELECT 1 FROM sysobjects WHERE xtype = 'PK' AND parent_obj = a.id AND name IN ( SELECT name FROM sysindexes WHERE indid IN ( SELECT indid FROM sysindexkeys WHERE id = a.id AND colid = a.colid ) ) ) THEN '√' ELSE '' END , 类型 = b.name , 占用字节数 = a.length , 长度 = COLUMNPROPERTY(a.id, a.name, 'PRECISION') , 小数位数 = ISNULL(COLUMNPROPERTY(a.id, a.name, 'Scale'), 0) , 允许空 = CASE WHEN a.isnullable = 1 THEN '√' ELSE '' END , 默认值 = ISNULL(e.text, '') , 字段说明 = ISNULL(g.[value], '') FROM syscolumns a LEFT JOIN systypes b ON a.xusertype = b.xusertype INNER JOIN sysobjects d ON a.id = d.id AND d.xtype = 'U' AND d.name <> 'dtproperties' LEFT JOIN syscomments e ON a.cdefault = e.id LEFT JOIN sys.extended_properties g ON a.id = G.major_id AND a.colid = g.minor_id LEFT JOIN sys.extended_properties f ON d.id = f.major_id AND f.minor_id = 0 WHERE d.name = 'TableName' --如果只查询指定表,加上此红色where条件，tablename是要查询的表名；去除红色where条件查询说有的表信息ORDER BY a.id , a.colorder
来源：https://www.cnblogs.com/lonelyxmas/p/12382606.html