Root zone performance dropped significantly
!2655 (merged) caused a double-digit performance drop in the root zone scenario:
- https://perflab.isc.org/#/config/run/5bf195f683ba91a870b29770/ (master)
- https://perflab.isc.org/#/config/run/5c920c9a5e4b7c3476986130/ (v9_14)
!2655 (merged) addresses a thread safety issue, so it cannot just be reverted.
We should evaluate if there is any way for us to get the performance back up again for the root zone scenario.