Things I Wished More Developers Knew About Databases

- You are lucky if 99.999% of the time network is not a problem.

- ACID has many meanings.

- Each database has different consistency and isolation capabilities.

- Optimistic locking is an option when you can’t hold a lock.

- There are anomalies other than dirty reads and data loss.

- My database and I don’t always agree on ordering.

- Application-level sharding can live outside the application.

- AUTOINCREMENT’ing can be harmful.

- Stale data can be useful and lock-free.

- Clock skews happen between any clock sources.

- Latency has many meanings.

- Evaluate performance requirements per transaction.

- Nested transactions can be harmful.

- Transactions shouldn’t maintain application state.

- Query planners can tell a lot about databases.

- Online migrations are complex but possible.

- Significant database growth introduces unpredictability.