[packagekit] Caching of repository metadata (esp. Yum)

[Duncan Mac-Vicar Prett]

Tim Lauridsen wrote:
> There is mayor issues here.
> It is by design that yum has a lock, so the yum metadata don't change 
> while it is doing some action or strange things will happen.
> rpm also has some locking, so multi processes can't do some actions cant 
> be done in parallel.
> This is safety matters, it is more important to keep your system 
> consistent, than being able to do multiple actions  at once.
> Another matter is the size of the metadata, my current yum metadata is 
> 296 M, it is a lot of data to cache and reload, it will add
> another level of complexity.
>   
I would say, don't make PackageKit more complex because some yum
specific problem.

We (ZYpp developers) had the performance issues in the past and it is
possible to fix them. We still suffer from the locking problem, for
example if you open YaST or run zypper, it may happen that we get the
ZYpp locked by packagekitd exception. We workaround it by setting the
daemon timeout to a really short time, but we plan to fix it with a more
granular lock in the future.

Duncan