On Wed, Jan 13, 2016 at 02:01:23PM +0100, Florian Festi wrote: > On 01/11/2016 09:06 PM, Richard W.M. Jones wrote: > > On Mon, Jan 11, 2016 at 03:46:27PM +0100, Jan Kurik wrote: > >> = Proposed System Wide Change: Change Proposal Name NewRpmDBFormat = > >> https://fedoraproject.org/wiki/Changes/NewRpmDBFormat > > > > Details of the format? > > > > What forward and backward compatibility guarantees are there? > > RPM will keep support for BDB for now. But to get rid of the dependency > it will be dropped at some point in the future. So it will stay backward > compatible.
What I meant here is what about forward and backward compatibility of the new format. Obviously I understand why BDB is being dropped and that the new format cannot possibly be compatible with BDB. It's accepted that there will be a break in Fedora 24 for reasons that are outside our control. Say, for example, that Fedora 24 moves to the new format. Will Fedora 34 be able to read Fedora 24 RPM databases? How about Fedora 24 being able to read Fedora 34 RPM databases? > > Currently we use the (BDB-specific obviously) db_dump tool for this > > purpose. Other distros such as Debian as much simpler in this regard > > since they expose the package data as plain text files. > > > > https://github.com/libguestfs/libguestfs/blob/master/src/inspect-apps.c > > I would advice to change these over to using librpm or one of the rpm > cli tools. If there are any tools missing, please let me know and we > will try to come up with them. > > If possible the rpm installation of the system examined should be used. This isn't possible - it's insecure to rely on running guest code (and not even possible in some situations). Carrying around old versions of librpm on the host isn't ideal either. > If this cannot be done you might need a new version of rpm on the host > system. Are you implying that all Fedora librpm will be backwards compatible? (not caring about Fedora < 24 obviously) Another thing to think about is endianness and word size, since with BDB we can examine, say, an i686 guest from an ppc64 host (and people even do this). Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://people.redhat.com/~rjones/virt-df/ -- devel mailing list devel@lists.fedoraproject.org http://lists.fedoraproject.org/admin/lists/devel@lists.fedoraproject.org
