I see that when my user tasks are completed they are removed from the db. I need to keep them for auditing/history purposes. Is there any setting to not remove them from the db but just update their status to 'completed' or something?

As a side not, I noticed that nothing is being stored in any of my log tables (Processinstancelog, nodeinstancelog and variableinstancelog). I am not sure if I need to do anything explicit to start storing this info.

Thanks for your help