MaxDB "No SQL connection possible despite ONLINE" but vanishes after a while without any action

[DM-TakeASP]

Hello,

currently while monitoring some MaxDB-Instances with Solution Manager 7.2, we see the warning (state: yellow) "No SQL connection possible despite ONLINE". There is nothing we have to do, since the warning disappears without any action ans switches back to state "green" after a little while. I've tried to do some searching why this happens, but I can't find any clue. What is causing this warning?

It happens to a couple different MaxDB-instances in one network segment. The DBs also have different versions and configurations, so I don't believe it is a specific configuration error in the database.

I checked the pararmeter MaxUserTasks on the different instances and it ranges from 100 to 500 and while the warning appears the sessions on the instances are never nearly exhausted. I also applied the SAP MaxDB parameter recommendations to all of the databases.

Any ideas from your side would be greatly appreciated! 🙂

[JamesZ]

MaxUserTasks is correct parameter which is related.
Next time, when this error occurs, please check the active tasks:

x_cons SID show active
=> this will show what maxdb db task are doing.

Another assumption, like log area full? And the system is doing auto log backup, once finished, the hung tasks will continue, and release session, this is why the issue gone itself?😀

[DM-TakeASP]

Hello JamesZ,

thanks for your response! I will see if this helps me in further analysis. Log area full was never the cause.

Anyway, we made some progress in this topic since I posted my issue here. Looks like issuing "dbmcli -U c" in the command line for a couple of times will lead to an "Error! Connection failed to node ... Connection broken to PID ..." every once in a while. I've also had the dbmcli crashing with a "Emergency stack trace". While seeing this behaviour it came to my attention that the installed anti virus (Eset) was scanning everything, especially files like "<SID>.dbm.shm".

Due to that we found the following SAP notes and asked the customer to exclude SAP concerning directories from scanning:
3356389 - Antivirus or other security software affecting SAP operations
3410068 - Exclusion of SAP related file\folders from virus scanning

At the moment we are waiting for feedback. Also changed the monitoring metric in Solution Manager to "best of 3", which means that Solution Manager will check three times within 30 minutes and if there was one positive (green) result, no alert will be raised.

Best
Daniel