I'm using a medical records system built on an Oracle database. Our vendor just told us that we need to shut down Oracle's Enterprise Manager service when we're not using it, because it uses too much of the system's resources. I know I can get actual numbers by checking Sysinternals Process Explorer, but I was hoping that someone can give me info from their personal experience.
Do I need to shut down EM when I'm done with it, or is he being overly concerned? Thanks.
We do the same thing on our testing and production servers too. I don't have any metrics to hand, but it did make a noticeable improvement in overall database response
The only thing that immediately springs to mind to me is that the Enterprise Manager (for Oracle 9 and pre) was Java based.
I guess that would give it the potential for a bit of runaway resource usage, but I have never seen any evidence of that on any of the machines that I have used it on here.
Oracle's EM lets you configure out much of its overhead. This overhead consists of polling many of the services to report alerts if a threshold is met or to provide graphs of performance. That being said, if you configure these features out, then why run it at all.
EM should not be that intrusive. I find that it takes about 10% cpu for less then 2 seconds every 30 seconds with the default install (YMMV) and when the system is under load, it doesn't even seem to do that.
When I talk about EM here, I am NOT talking about the load on the oracle.exe process, but instead from the nmesrvc and the perl, cmd and emagent processes it spawns. To see its impact on the database itself requires a bit of an oracle expert.
I find process explorer a nice tool to help review this real time because it shows the process hierarchy from the service parent nmesrvc.
Frankly, if you're actually seeing an end user difference when stopping the dbconsole service, then your box is over capacity and you likely need to grow up or out.
If you use a different tool to manage and monitor oracle and other application processes, there's not much need for the dbconsole process to run all the time.
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I have found that just running Oracle EM can take a lot of resources depending on what you are asking it to do. I have found that I have rarely used the out of the box configuration and by removing services I don't need I can reduce the amount of resources EM needs considerably.
In general, I run EM on a separate application server, not on my DB server. The real power and value of EM is when running / maintaining / monitoring multiple databases and having EM on its own server means I don't have to worry about it affecting any of the DBs.
Everything that EM does, you can do manually and I usually go down this route if just managing one DB. However, this route does require a reasonable level of DBA knowledge.
It's a hog, I like to run Oracle on Linux, and turn off the GUI after the initial install (Oracle's installer requires it).