ClickHouse announced today they closed a $400M Series D financing round led by Dragoneer. The company says their ARR has grown over 250% year over year and they now have about 3,000 customers. They also announced the acquisition of Langfuse to expand into LLM observability and introduced a native Postgres service. The goal is to unify transactional and analytical workloads for AI applications. Dragoneer said they invested because infrastructure companies sitting close to production tend to do well during platform shifts.