Piwik Log Analytics - Visit Detection

Hello everybody,

I am currently working with Piwik Log Analytics.

The logs available to me have a unique session ID in each logline, which would make it possible to creat a session context over the loglines. However, I found neither in the documentation, nor in the code itself, the possibility to set such an ID (session ID, visit ID). The only thing I saw was the UserID, but this is for the Cross-Device / Unique Visitor Tracking, if I understood it right

Have I overlooked something? Is there any way to set a session id? If there is none, how is the session build while importing the logs?

Thank you for your answers.

Best wishes,