Re: fallocate / posix_fallocate for new WAL file creation (etc...)

* Andres Freund (andres@2ndquadrant.com) wrote:
> After a bit of standard perusing writing a single byte to the end of the
> file after the fallocate ought to make at least the reading guaranteed
> to be defined. If we did seek(last_byte); write(); posix_fallocate() we
> should even always have defined content. Yuck.

Alright, but would that actually be any better than just doing what
glibc's posix_fallocate() does in the generic case?  And, to be honest,
it makes me a bit nervous to seek/write like that because it looks like
the typical "create a hole" setup, which we certainly aren't intending,
yet if the posix_fallocate() call disappeared, or did nothing, or this
code was copied w/o it, or someone didn't understand what it did, we
could end up with that.

Not a fan. :(
Thanks,
    Stephen