Metabase running on one CPU core only?


It seems to me that metabase on Linux (built with docker image) is running on one CPU core only. This makes
even simple queries quite slow and prone to crashing the front-end. Is there some build flag or something that I’m missing, that would allow it to run on several cores?
I am checking with top/htop what’s the load on the cores. When I submit a metabase query, only one core goes to 100%, then drops after the query is completed. I can guarantee that this is not a database issue (mongoDB) since native queries do not have this problem.

Any help is appreciated!