On Thu, Dec 19, 2013 at a4:01 PM, Chris Murphy <lists@xxxxxxxxxxxxxxxxx> wrote: > Does anyone know exactly what's happening during the rebuild? I understand from light documentation how deltarpm works, what I'm not sure is if most of the time is spent reconstructing a virtual oldrpm from an installed rpm, or applying the delta, or writing out the new install? It reconstructs a real honest-to-God RPM file that must match the shasum/GPG sig of the old one exactly, lest it be thrown out. (Those of us who've been around awhile might remember that in the past it couldn't handle changed config files properly, so deltas used to fail on various daemons all the time, greatly reducing their utility.) Said RPM is then passed on to rpm to update normally. rpm itself has no knowledge of this wizardry, it all happens in yum. See `man applydeltarpm` and /usr/share/doc/deltarpm/README for more detailed information about the underpinnings. Yum just shells out to it. > If it's not the former reconstruction aspect, it seems like a Btrfs aware deltarpm could simply write out the delta blocks to disk, which would be rather small, and then obsolete the old ones if the operation is successful. Fully rewriting the files isn't necessary by design with Btrfs. That would be awesome, but yeah, rpm would have to get a lot smarter than it is currently. ;-) -T.C. -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines Have a question? Ask away: http://ask.fedoraproject.org
