Comment by IshKebab
4 years ago
> The fact that `F_FULLSYNC` isn't safe means that you cannot write a transactional database on Mac, it is also a surprise to me.
Yeah you can definitely write a transactional database without having to rely on knowing you've flushed data to disk. Not only can you, but you surely have to otherwise you risk data corruption e.g. when there's a power-cut mid-write.
The whole point of transactional flush to disk is that you get confirmation that data is now safe from power loss. You don't get any guarantee because you _called_ flush. The guarantee comes from flush returning.