Re: Why does PostgreSQL ftruncate before unlink?

On Fri, Feb 21, 2014 at 4:14 PM, Jon Nelson <jnelson+pgsql@jamponi.net> wrote:
> When dropping lots of tables, I noticed postgresql taking longer than
> I would have expected.
>
> strace seems to report that the largest contributor is the ftruncate
> and not the unlink. I'm curious what the logic is behind using
> ftruncate before unlink.
>
> I'm using an ext4 filesystem.

I'm guessing that this is so that it can be rolled back. Unlink is
likely issued at commit;