数据库优化

数据库优化 1. 查看活动监视器。 2. 查看慢Sql. 3. 查看Resources Waits里面等等类型Lock的多不多。 4. 逻辑读太多，cpu就会高。 select * from syserrorlog where friendlymsg like '%列“%”不属于表 Table%' select errorpage a,createdate aa,friendlymsg c1,* from syserrorlog where friendlymsg like '%was deadlocked on lock | communication buffer resources with another process and has been chosen as the deadlock victim. Rerun the transaction%' order by createdate desc 获取慢sql语句 A.获取有关按平均 CPU 时间排在最前面的五百个查询的信息 SELECT TOP 500 DB_NAME([st].dbid) AS DB_NAME ,OBJECT_NAME([st].objectid) as OBJECTNAME, SUBSTRING(st.text, (qs.statement_start_offset/2)+1, ((CASE qs.statement_end_offset WHEN -1 THEN DATALENGTH(st.text) ELSE qs.statement_end_offset END - qs.statement_start_offset)/2) + 1) AS statement_text,total_worker_time/execution_count AS [Avg CPU Time],execution_count, plan_generation_num, last_execution_time, total_worker_time, last_worker_time, min_worker_time, max_worker_time, max_logical_writes, total_logical_reads, min_logical_reads, max_logical_reads, total_physical_reads, last_physical_reads, min_physical_reads, max_physical_reads, total_logical_writes, last_logical_writes, min_logical_writes FROM sys.dm_exec_query_stats AS qs CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) AS st where st.dbid = DB_ID('fx361_new') ORDER BY total_worker_time/execution_count DESC; B. 查看系统等待的sql： SELECT ss.host_name, req.session_id ,req.status ,req.blocking_session_id ,req.wait_type ,req.wait_time ,req.wait_resource ,req.transaction_id ,st.text FROM sys.dm_exec_requests req CROSS APPLY sys.dm_exec_sql_text(req.sql_handle) as ST cross apply sys.dm_exec_sessions ss where req.status = N'suspended' and ss.session_id=req.session_id C.返回按批执行的 SQL 查询的文本，并提供有关它们的统计信息 SELECT DB_NAME([s2].dbid) as DBNAME,s2.dbid, OBJECT_NAME([s2].objectid) as OBJECTNAME, s1.sql_handle, (SELECT TOP 1 SUBSTRING(s2.text,statement_start_offset / 2+1 , ( (CASE WHEN statement_end_offset = -1 THEN (LEN(CONVERT(nvarchar(max),s2.text)) * 2) ELSE statement_end_offset END) - statement_start_offset) / 2+1)) AS sql_statement, plan_generation_num, last_execution_time, total_worker_time, last_worker_time, min_worker_time, max_worker_time, max_logical_writes, total_logical_reads, min_logical_reads, max_logical_reads, total_physical_reads, last_physical_reads, min_physical_reads, max_physical_reads, total_logical_writes, last_logical_writes, min_logical_writes FROM sys.dm_exec_query_stats AS s1 CROSS APPLY sys.dm_exec_sql_text(sql_handle) AS s2 WHERE s2.objectid is null ORDER BY s1.sql_handle, s1.statement_start_offset, s1.statement_end_offset;