Database migrations to arrive at a target state are an interesting beast. It’s not just the destination that matters, it’s how you get there. The naive approac

Database migrations to arrive at a target state are an interesting beast. It’s not just the destination that matters, it’s how you get there. The naive approach of applying whatever DDL you need to turn database schema A into B is not necessarily the one anybody would actually want to run, and in larger deployments it’s most definitely not the one you’d want to run. Intermediate availability and data migration go well beyond simply adding tables or columns. They’re highly application specific. The main improvements in this space are making existing operations CONCURRENT (e.g., like index creation) and minimizing overall lock times for operations that cannot (e.g., adding columns with default values).