Keen isn't a columnstore, it's a custom database built on top of Cassandra where they take JSON records and split them into compressed batches with each unique property stored in the CQL data model, and it's processed by Storm workers. It's an outdated architecture compared to modern columnstores that can now handle unstructured/nested data really well.

BigQuery is designed for throughput instead of latency. There is a minimum 3-5 seconds to schedule your query across the server pool before it even starts processing. It's also a single shared cluster for all customers so performance is variable, but the trade-off is that 100TB also takes seconds to scan.