I wrote the first article, and I thought documentation is clear, but then I saw comment by Hipp which got confused me:

> If you switch to WAL mode, the default behavior is that transactions are durable across application crashes (or SIGKILL or similar) but are not necessarily durable across OS crashes or power failures. Transactions are atomic across OS crashes and power failures. But if you commit a transaction in WAL mode and take a power loss shortly thereafter, the transaction might be rolled back after power is restored.

https://news.ycombinator.com/item?id=45014296

the documentation is in contradiction with this.