I dunno about Germany but in the UK it would work like this....assuming its just Katatonia along with Porcupine Tree on the lineup...and assuming the doors open at 7:00 PM (maybe 7:30), then Katatonia would come on stage at around 8:00 PM, and play for around an hour, then the headliner would come on sometime after 9 PM and play for however long they play for. In the UK most gigs usually finish at 11 PM or so.