So in the worst case (new feed) it takes 70 seconds ONCE to run a regular expression on every single post ever made, but all queries after that only need to check the new groups and latest posts (so very fast!). Cache is also stored with rkyv, with key being the blake3 hash of the filter params :)

There is a trick if you ever need to make the historical match very fast based on a reverse index of trigrams. swtch.com/~rsc/regexp/...