ClickHouse recently got the support of TimeSeries table Engine [1]. It is marked as experimental, so yes - early stage. This engine is quite interesting, the data can be ingested via Prometheus remote write protocol. And read back via Prometheus remote read protocol. But reading back is the weakest part here, because Prometheus remote read requires sending blocks of data back to Prometheus, where Prometheus will unpack those blocks and do the filtering&transformations on its own. As you see, this doesn't allow leveraging the true power of ClickHouse - query performance.

Yes, you can use SQL to read metrics directly from ClickHouse tables. However, many people prefer the simplicity of PromQL compared to the flexibility of SQL. So until ClickHouse gets native PromQL support, it is in the early stages.

[1] https://clickhouse.com/docs/en/engines/table-engines/special...

Not a fan of bad mouthing other offerings. As @iampims is saying, alerts is a big missing piece. Clickhouse is also a general purpose database for many use cases including analytics, financial servers, ML& Gen AI, fraud, and observability.