.NET 后端面试 26 问：并发、缓存、数据库与工业通信实战解析

What if a single misconfigured timeout could bring down an entire industrial production line? This exploration delves into the intricate mechanics of .NET backend engineering, moving far beyond basic syntax to dissect the high-stakes realities of concurrency, data persistence, and industrial communication. It examines how a seemingly simple Modbus coil write can hide a fatal byte-order trap, and why forcing an async method to wait for a result in a desktop app guarantees a deadlock that no amount of debugging can easily fix. The narrative weaves through the fragile ecosystem of caching, distinguishing between the silent killer of cache penetration and the thunderous collapse of a cache avalanche, revealing why a logical expiration strategy might be the only way to keep a hot key from crushing a database. As the scale expands to tens of terabytes of IoT time-series data, the text challenges the conventional reliance on general-purpose databases, questioning whether MongoDB’s sharding is...--AI Generated