Executor: the discovery REST entrypoint takes 7 seconds in vivian

In vivian, when pressing the "DISCOVER" button, it takes 7 seconds on my machine before the rest call returns:

Additionally, this blocks MaRS DB for this entire time:

[WARNING] __exit__: MaRS DB lock held for an unusually long time: 7013.9 ms

I would suggest to:

• Figure out why it takes that long (likely the PDU port call)
• Make sure we free MaRS DB before doing anything that could take time