SIMCA-online stops responding and the server has to be restarted (Q917)

The information in this article applies to: 
SIMCA-online 15.1
SIMCA-online 15

SIMCA-online clients become unresponsive and doesn't show updates and hang. You cannot log in to the server. The SIMCA-online web client shows no updates, and returns errors. Server log shows very little activity compared to normal.

This can happen on SIMCA-online 15.0 and 15.1 servers with many executing project configurations, relatively high load (many users), in combination with usage of Batch Context Generator and the use of Notifications.


The server experiences a deadlock when multiple threads need access to the same database. The server cannot recover from this.


Stopping the server service, or if that doesn't work ending the server process SIMCAonlineserver.exe in Task Manager, and then restarting the service fixes the problem. Previously reset alarms and any notes created for active batches are lost if you end the server process, but active batches will be caught up and predicted again when the server is restarted. SIMCA-online 15.1 will preserve alarms and batch history if you were able to stop the service without exiting the process in Task Manager.

This problem can be mitigated in the affected products by stopping execution for project configurations that are not needed, using Batch Context Generator less, and not using Notifications.


This issue is fixed in SIMCA-online 16.0.

Date modified: Nov 15, 2019
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