Fix extremely long kernel restart times

[jbweston]

(original issue on GitLab)

opened by Bas Nijholt (@basnijholt) at 2017-09-07T13:20:38.839Z

Not sure why this happens, but kernel restarts can take >30 seconds sometimes.

Probably running the notebook local and looking at the terminal will tell you more.

[jbweston]

originally posted by Bas Nijholt (@basnijholt) at 2017-09-15T13:07:49.356Z on GitLab

Potentially fixed by cd089d9 and 2d931fe.

[jbweston]

originally posted by Joseph Weston (@jbweston) at 2017-10-27T13:02:19.396Z on GitLab

The problem is indeed to do with the fact that asyncio notebook integration does not play nicely with concurrent.futures.Executor.

I have opened an upstream issue here,

but the maintainers do not seem very active

[jbweston]

originally posted by Bas Nijholt (@basnijholt) at 2018-01-02T13:04:29.324Z on GitLab

There is an issue that addresses this problem here ipykernel/issues/291.

[jbweston]

originally posted by Joseph Weston (@jbweston) at 2018-02-14T09:09:32.566Z on GitLab

@basnijholt did we check that the master version of ipykernel fixes everything?

[jbweston]

originally posted by Bas Nijholt (@basnijholt) at 2018-02-14T09:55:33.437Z on GitLab

The fix is even in the latest released version :)

[jbweston]

originally posted by Joseph Weston (@jbweston) at 2018-02-19T14:33:51.512Z on GitLab

Seems fixed with the versions of ipykernel and jupyter_client that we require

[jbweston]

originally posted by Bas Nijholt (@basnijholt) at 2018-02-19T14:36:04.195Z on GitLab

Actually, there is still this issue that is open.

The notebook processes get cleaned up correctly, but the restarting is still slow.

I'll reopen and add a 'Blocked' label.

[jbweston]

originally posted by Bas Nijholt (@basnijholt) at 2018-12-07T19:13:24.210Z on GitLab

This seems to be fixed for quite a while now.