Hash table is easy to understand in concept. But the key value store, a distributed hash table with high availability requires sophisticated design.
Dependency injection is one of my favorite design pattern. The application is kind of transparent, which is one-off configuration in the app startup, and then use it naturally like it doesn’t exist.
My recent project uses Azure SQL Data Warehouse. The performance surprised me. I have the question is SQL Data Warehouse based on the technology of traditional SQL Server, and scale up?