[kentonv]

> This is not true. This depends on how the file was opened. You may request DIRECT | SYNC

Well sure, but 99.9% of people don't do that (and shouldn't, unless they really know what they are doing).

> In the world of today, you are very rarely writing to something that's not network attached, and depending on your appliance, the meaning of acknowledgement from write() differs.

What network-attached storage actually uses O_SYNC behavior without being asked? I'd be quite surprised if any did this as it would make typical workloads incredibly slow in order to provide a guarantee they didn't ask for.

[pclmulqdq]

100% of people writing a database know about filesystem options like DIRECT and SYNC, and that is the subject of this paper.

Also, most of the network-attached storage we people use is in the form of things like EBS, which is very careful to imitate the behavior of a real disk, but with different performance and some different (albeit very rare) failure modes.

[kentonv]

100% of people writing databases also know how fsync() and msync() work. I interpreted this thread as being targeted at a wider audience.

[crabbone]

It's literally for people writing their own database. Why would you interpret it differently?