Re: making relfilenodes 56 bits

On Wed, Sep 28, 2022 at 9:40 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> Thanks, Thomas, these all look fine to me. So far we have committed
> the patch to make relfilenode 56 bits wide. The Tombstone file
> removal patch is still pending to be committed, so when I will rebase
> that patch I will accommodate all these comments in that patch.

I noticed that your new unlinking algorithm goes like this:

stat("x")
stat("x.1")
stat("x.2")
stat("x.3") -> ENOENT /* now we know how many segments there are */
truncate("x.2")
unlink("x.2")
truncate("x.1")
unlink("x.1")
truncate("x")
unlink("x")

Could you say what problem this solves, and, guessing that it's just
that you want the 0 file to be "in the way" until the other files are
gone (at least while we're running; who knows what'll be left if you
power-cycle), could you do it like this instead?

truncate("x")
truncate("x.1")
truncate("x.2")
truncate("x.3") -> ENOENT /* now we know how many segments there are */
unlink("x.2")
unlink("x.1")
unlink("x")