Big fan of ClickHouse, but in the case of S3 there doesn't seem to be much point fighting city hall. I was the author of the original clickhouse-local-in-Lambda ticket FWIW. Even if that approach worked well, it'd still only be <50% cheaper than Athena's fractions-of-a-cent for queries on efficiently partitioned data, and still there is setup work involved. I think CH-local-in-Lambda might still easily compete on cost with Athena for raw CSV queries though