Updated. Sorry about that - been pretty distracted with work, which kept me from paying more attention here. Should not overload the memory in a production environment anymore. Default batch size is now 500, the strings (from my small-sample testing) appear to be 128-130 bytes each, so this should be pretty safe. Might be worth increasing for bulkier systems.

Also - as a small bonus - it now uses Redis' native binary / O(log(n)) search if it is provided a timestamp; using this method on a reasonably well distributed schedule should be very fast now.