ORA-00020 when OEM is started

[former_member201910]

The other day, I tried to login, I get ORA-00020 and my connections were denied.

ERROR:
ORA-00020: maximum number of processes (500) exceeded

This happened before when dbconsole is open. So I stopped OEM then I started to be able to login to sql.I figured out that too many sessions was established that cause it to block new connections. However, this is a newly created db so I dont think it would create a lot of sessions. my session limit is 500 by the way. Since I stopped the OEM, the oracle error never occurred again. This happened for 2x already. I want to start OEM for future monitoring but I'm afraid this might occur again.

My question is, what is wrong with enterprise manager? What could have potentially caused that? And how to fix that issue? I have oracle 11g.

Thank you.

Maria

[janos_mucsi-besze]

Hi Maria,

Oracle Enterprise Manager (OEM) is a DB management tool and so uses connections and sessions to the database instance. Naturally, this requires resources too. Since for the SAP databases we have the DBACOCKPIT transaction we do not use OEM. However just as you all, of our customer can use this tool, although SAP can not support you in case of problems. But this is not what I want to concentrate on here, just wanted to let you know.

SAP has good recommendations to parameters 'processes' and 'sessions'. Both company SAP and Oracle calculates the value of 'sessions' based on parameter 'processes'. The thing is that in SAP database instances we (SAP) does not plan with the additional load made by the OEM. In the light of this, having ORA-00020 while OEM is started is expected.

As you can see here, the equation to set up the good value for 'processes' in SAP System is:

(#ABAP work processes * 2) + (#J2EE server processes * <max-connections> ) + PARALLEL_MAX_SERVERS + 40

OEM is not calulated with.

Simply increase the value of 'processes' and 'sessions' (2*processes) until you won't see ORA-00020 at the end.