[druid-user] Druid query parallelization

Druid will use up to one core per shard per query. So if you have two shards for a day, and you query just that day, that query could use at most two cores at once. But, two queries can process the same shard at the same time. Your shards seem like they’re a reasonable size, so I wouldn’t worry too much about making them smaller to get more parallelism per query. If you’re getting a good amount of concurrent queries that should be enough to fully utilize your hardware.