Hyperoptimizing for the fast path today and ignoring that hardware and usage patterns change is the reason modern software is so slooow :)

A more robust strategy would be at least be to check if the rule was the same as the previous one (or a small hash table) so that the system is self-healing.

Ken’s solution is at least robust and by that property I would prefer it since it’s just as fast but doesn’t have any weird tail latencies where the requests out of your cache distribution are as fast as the ones in.