Unexpected CPU load

Hi, I’m new to influx. I’m running influx as persistence layer in openhab and visualizing the data using grafana. It runs fine, the only thing that is bothering me is the CPU load. I noticed my Raspberry getting a little warmer than usual, ran ‘top’ and noticed that influxdb’s CPU % temporarilty rises to ~35% every 2-3 seconds. Rest of the time it’s close to 0%. During these high CPU periods, influx, as far as I can tell (set logging to info level) is not doing anything; no sensor data being stored, no grafana access.

Is this normal? What’s it doing, and can I prevent that?