problem

In general: if activating the maintenance mode this may lead to hanging workers.

In our hosting: Imports during the night are stopped by the backup. Each night we set maintenance mode to make backups. Also we restart all termtaggers for memory cleanup. This could lead to stucking imports.

solution

1. set workers only to running if no maintenance is scheduled! If maintenance is scheduled we leave them waiting
2. After releasing maintenance a /editor/worker/queue should be triggered to start waiting workers