Jupyter garbage collection failing and "julia" process not shutting down

[benoitseron]

Using relatively large data sets with a Jupyter notebook, I have problems with garbage collection: I used as a test x = fill(NaN, (5000000,8)) as in a similar post and tried the proposed solution of empty!(Out) and GC.gc(), both of which fail to free up memory.

More annoyingly, even if I shutdown the notebook (browser and terminal), a process 'julia' still takes a lot of memory, even though everything should be closed.

I use Julia 1.0.4, Ubuntu 18.04.3 LTS, IJulia 1.21.1.