On Thu, 2006-01-19 at 12:30, [EMAIL PROTECTED] wrote: > [EMAIL PROTECTED] wrote on 01/19/2006 12:30:47 > PM: > > > 3) Atomically rename database.db.new to database.db > > Can you enlightne me on what "Atomically rename" means? How is that > different than just a mv command. I can understand that a process that > opened the file under the old name is still going to point to the file > based on its location on disk, not by name. I'm just picturing mushroom > clouds and guys in lead hazmat suits trying to do an atomic rename. :)
The non-atomic version boils down to unlink(newname) - if newname filename already exists link(oldname, newname) - now both exist unlink(oldname) Other processes may get timeslices that see the filesystem in any of those states, including the one where the newname doesn't exist at all. I think mv will attempt a rename and only do it the hard way if the rename fails, which should only happen if the old/new files are on different filesystems in which case the hard way involves a copy. -- Les Mikesell [EMAIL PROTECTED] _______________________________________________ NOTE: If there is a disclaimer or other legal boilerplate in the above message, it is NULL AND VOID. You may ignore it. Visit http://www.mimedefang.org and http://www.roaringpenguin.com MIMEDefang mailing list [email protected] http://lists.roaringpenguin.com/mailman/listinfo/mimedefang
