I want to use Scylla to write simple rate limiter (because I already use Scylla and don’t want to add another DB just for that).
Counters look like a good tool for that, however they don’t have any kind of expiration. I already solved similar problem, where I need a limit per day. I basically create table every day and use it for writes, then create new one and use that (the old is deleted via cronjob).
Now I want to rate limit requests per minute, so it’s not a good solution. I can use something like that:
create table rate_limiter ( id ascii, slot int, cu_used counter, PRIMARY KEY (id, slot) );
Where slot is basically a time slot (say floor(unixtime/60)). It would be enough, but of course I need some expiration. I could probably do the same, create new table every day, delete the old one. However, this looks messy and I don’t like that at all.
- I could probably use something other than counters, but only the have increments.
- Inserting a row per request looks like too much overhead for rate limiting
Are there any better solutions?