Re: [pgsql-hackers-win32] Sync vs. fsync during checkpoint

Shridhar Daithankar <shridhar(at)frodo(dot)hserus(dot)net> writes:
> There are other benefits of writing pages earlier even though they might not
> get synced immediately.

Such as?

> It would tell kernel that this is latest copy of updated buffer. Kernel VFS
> should make that copy visible to every other backend as well. The buffer
> manager will fetch the updated copy from VFS cache next time. All without
> going to disk actually..(Within the 30 seconds window of course..)

This seems quite irrelevant given the way we handle shared buffers.

> frequent fsyncs or frequent fsyncs per file descriptor written? I thought it
> was later.

You can only fsync one FD at a time (too bad ... if there were a
multi-file-fsync API it'd solve the overspecified-write-ordering issue).

regards, tom lane