[lightswitch05]

It is resource inefficient, which is why PiHole supports it, but does not allow you to subscribe to list containing regex, as that would quickly make it unusable. I'm not sure how Dnsmasqs would be accomplishing this feature without some sort of pattern matching logic - which would have the same inefficiencies. Basically O(N) where N is the number of domains/patterns that should be blocked. There could certainly be a cache to keep track of matched/unmatched queries, but I would imagine with the modern web the average case would still be very close to O(N). Just speculation.