For our metrics and autoscaling engine at Cloud 66, we went through 5 iterations before settling on Clickhouse: 1. Redis 2. Cassandra 3. Handrolled: Ruby + RabbitMQ 4. Handrolled: Go + RabbitMQ 5. Clickhouse

Every time we reached some limit or huge optimization burdens that were unfeasible. Clickhouse has been rock solid for the past 4 years.