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Oracle SESSIONS Parameter value needs to be increased (Cause : ORA-00018 )


Noticed the following error in SM21 and also found out that that many background jobs got canceled.

Database error 18 at COM
> ORA-00018: maximum number of sessions exceeded.
Function COMMIT on connection R/3 failed.
Error at DB Commit, return code 001024.
Database error 18 at COM
Perform rollback

While looking for a solution for the issue, understood that we need to change the SESSIONS parameter to a

higher value.

(Solution Note : 398927 - ORA errors because dimensions of parameters are too small)

(As per the above note, we are trying to sort out the issue, which also says a lot of things in which one could be the reason for the error. But we finally got to know that SESSIONS parameter is the problem and should be made to a higher value.)

Currently our BW Production Server, the settings are as follows:


■ SESSIONS = 251

(For your information:

PROCESSES Formula u21D2 ABAP work processes * 2 + #J2EE server processes *<max-connections> +



As per the above thing, SESSIONS should be 224 * 2 which should be 448.

Hence we are planning to change the same to 448.



1. What other things(OS Side, DB side, + Oracle Parameters etc) should be considered

in order to change the SESSIONS to 448.

2. Is there any problems anticipated by changing the SESSIONS parameter.

Thanks & Best Regards

Raghunahth L


Hello Raghunahth,

1. the Oracle documentation speaks about two dependencies for the SESSIONS parameter: ENQUEUE_RESOURCES and TRANSACTIONS:

However I never changed these other parameters, I don't think they are relevant for SAP systems.

2. no problems anticipated, you simply have to raise the sessions parameter if you encounter ORA-00018 on SAP systems



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