ClickHouse's intial release was circa 2016 IIRC. The work I was doing at NGINX predates ClickHouse's initial release by 1-2 years. ClickHouse was certainly so

ClickHouse's intial release was circa 2016 IIRC. The work I was doing at NGINX predates ClickHouse's initial release by 1-2 years. ClickHouse was certainly something we evaluated later on when we were looking at moving to a true columnar storage approach, but like most columnar systems there are trade-offs. * Partial SQL support. * No transactions (not ACID). * Certain workloads are less efficient like updates and deletes, or single key look ups. None of these are unique to ClickHouse, they are fairly well known trade-offs most columnar stores make to improve write throughput and prioritize high scaling sequential read performance. As I mentioned before, the amount of data we were ingesting never really reached the limits of even Postgres 9.4, so we didn't feel like we had to make those trade-offs...yet. I would imagine that servicing ad events is several factors larger scale than we were dealing with.