UI appears to not be functioning

[James McMahon <js...@gmail.com>]

I hope someone has experienced the following problem and can point me to a
resolution. I have a NiFi flow in the 1.7.1.g environment. It appears that
my flow - contained in a Process Group - is no longer responding at the UI
level. In fact, none of my process group flows are responding in the UI.

Here is an example. I have a RouteOnAttribute processor that has populated
the following queue with 40 flowfiles. Those 40 now just sit in queue,
never being processed by the ControlRate processor fed by this queue. I've
tried stopping both processors and deleting the flowiles in this queue. I
get this notification, but then it sits in this state, never changing or
returning with the standard response that the flowfiles have been deleted:

"Waiting for destination component to complete its action."
I've even tried connecting this queue to a MonitorActivity processor, then
issuing the delete. The same behavior results.

It almost seems like my UI actions are not being processed.

Can anyone recommend actions to get my UI restored to proper working order?

This is the sequence of steps I plan to try, barring any other insights:
1. blow away the flowfile_repository, stop and restart my nifi service, try
again
2. blow away my content and provenance repositories, stop and restart, try
again
3. blow away my conf/flow.xml.gz file and replace it with a week old backup
from my Git repo, stop and restart, try again
4. yum uninstall my JDK, yum (re)install my JDK, stop and restart, try
again (I currently employ Java 1.8.0_171)
5. uninstall NiFi, reinstall it, restore my flow.xml.gz, start the service,
try again
I hope that I can avoid 4 and 5.

Any guidance?