Actually, the query is a really nice idea but `LIMIT 1` will not make sense since we need oldest event in each bucket. This query will give oldest event in bucket 3 only. Limit 3 may also not work since it can give 3 events from bucket 3 and skip bucket 6 and 9. I think no limit is the only option which defeats the purpose. IMHO,  individual queries should be good because each query will goto different CASS node and each queries a different bucket which will come from different physical node. So, I feel its a good use of a distributed architecture.