Comment by ori_b

> Thanks for the link, but only when the OS or your computer crashes, not even the application itself.

Ah, right there are also the journalling knobs that you'd tweak to get to max performance -- either in-memory or no journalling at all make a big impact. There are a bunch of them scattered throughout the docs.

> Could you introduce any application file format that is safe in that case? Obviously your JSON file format is much more unsafe than that, not to mention the huge overhead of JSON with binary data.

Yes, any format is safe if you write to a temporary file, and then rename(2) it to replace it. This is guaranteed to be atomic, so it works with anything (including sqlite, though at that point all sqlite does is cost you performance and complexity).