JupyterLab is laggy in some cases

I’m just here to share my experience on JupyterLab.

Recently I was experiencing very slow interface response (especially in the terminal opened via jupyterLab) and in the jupyterLab interface.

After doing so many tests (reinstalling different versions of anaconda, different virtual environments, different versions of python and other applications) for days, I finally found the different cases that lead to slowdown and of course the case where JupyterLab works well !
In the attached image at the end of the post, I’ve written “KO” for the slowdown situation and “OK” if there is no slowdown.

To reproduce the problem, just create a new environment via anaconda (or manually) and launch jupyterLab, then create an empty notebook, run the first empty cell, then open a terminal tab (in case KO you should already see that opening the terminal is lonnnnnng) then try typing a few words into termin, it will feel awfully slow!

See attached photo for cases, thanks.

I’m bringing today another FIX detail.
When creating new virtual env with python >= 3.7 till python < 3.10 and installing jupiter lab >= 3.0.11 we enter then the KO case which can be fixed by installing Spyder (5.1.5)
In that case, installing spyder is no longer needed ! : if your current (in you virtual env) package “jupyter_client” version == 7.1.0 then just downgrade it to 7.06 via the Anaconda navigator Environments Tab !

Conclusion : something goes wrong with 7.1.0 version of “jupyter_client” package when using jupyterlab !

Enjoy ! :wink:

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