This is exactly how TiDB works like a charm. Internally, thanks to the Raft consensus algorithm (http://raft.github.io/), we could schedule and process the workloads separately: OLTP workloads to the leader replicas, OLAP to the follower replicas for the random or heavy analytics.

The past solution of the separate operational database and data warehouse poses great challenges for real-time analytics because it needs either data pipeline or the ETL process which could be the bottleneck of being "real-time", not to mention the waste of time, efforts and human resources maintaining multiple data warehouses. It was impossible for real-time analysis because, in the past, you would need a data pipeline, or message queue with the equivalent throughputs with your OLTP database, which I believe does not exist.

However, whether to adopt this hybrid solution depends on your specific usage scenario. For cases where users want to do real-time analysis in their data warehouse upon the same data table as in their OLTP database, TiDB is your choice.