Hi Vikash,
This all depends on your environment - is it Conventional (Primary/Secondary) or Advanced Availability (Background, Standby App servers)? In conventional, only the primary talks to the db, but in advanced availability, all the servers talk to the db independently. If you are in a conventional setup, during a time when you feel the system is a bit slow, you can run the command pdm_vdbinfo on your primary server and pipe it out to a file (pdm_vdbinfo > vdbinfo.txt). The output will include the following:
C:\Users\Administrator>pdm_vdbinfo
========================================
VDBINFO invoked at 09/16/2016 13:28:14
========================================
Min Config Agents = 6
Max Config Agents = 6
Max DB Agents = 6
Tgt num idle = 2
Num Agents running = 20
Num Agents starting = 0
Num Requests pending = 0
Actual num idle = 2
What you want to look for is the "Actual number idle" - which if you ever see that its "0" then there are no dbagents available. The vdbinfo will also show you queued requests that are in a wait state as well, so if there are a lot of those, that is also a telltale sign.
Now, with all that in mind, performance issues can be casued by a large number of different factors, not just dbagents. So if you are having a noticeable slowdown in the product performance, you should open a support case and one of our engineers will look into the problem with you to pinpoint the cause. We have also created a tec document that is published which gives you some things to look at as well - you can find that document here: CA Service Desk Manager Performance Problems - Quick Checklist
Hope this helps,
Thanks,
Jon I.