Oracle Enterprise Manager 12c 新特性:实时Real-Time Addm

在Oracle Enterprise Manager 12c中引入了Real-Time addm的新特性。 DBA可以直接从EM界面上启动实时ADDM(Automatic Database Diagnostic Monitor )信息收集， 也叫做Emergency ADDM。

"Emergency ADDM adds performance diagnostics for databases suffering from severe performance problems. Real-time ADDM. You can connect to the database and investigate what is going on when you cannot connect to the database because it is hanging on"

登录EM 12c后Target -> Database -> 选择指定的数据库 -> Performance -> Real-Time Addm:





进入"Real-Time ADDM"后点选start按钮，第一次使用会出现"Required PL/SQL package not installed. Use the link below to deploy the package. The error message from the server is:Package dbsnmp.prvt_eaddm is not found" 的错误:





使用Real-Time Addm要求预安装dbsnmp.prvt_eaddm包，点选下方的PL/SQL Package Deployment链接，进入Package Deployment页面，选择合适的身份认证，并install。





进入Job Run: DATABASE MANAGEMENT PL/SQL DEPLOYMENT JOB页面等待作业完成。

以测试为目的登录数据库并运行以下消耗CPU的SQL语句(不要用在生产库！):

 select count(1) from obj$,obj$,obj$;

回到"Real-Time ADDM"页面再次点击start , 等待一段时间后会自动stop，如下图:





Real-Time Addm有所发现，这里的Number of finding =1 ,点击Findings 可以看到Prority、Performance Impact、Finding Details等信息:





当出现服务进程hang的情况，例如进程因"enq: TM contention" 本文出自 “Ask Maclean Liu Oracle” 博客，请务必保留此出处http://maclean.blog.51cto.com/2923249/1278113