1. The Problem We Hit The frontend requests are heavy, concurrency is high, and access is slow. The bottlenecks show up mainly as: Large single tables Large single databases Slow network IO Slow disk IO Optimizing network and disk IO mainly relies on hardware upgrades. In theory, a database imposes no limit on the size of a single database or a single table, but an oversized single database or table means more requests land on a single machine, putting pressure on IO.