Created attachment 957302 [details]
55MB of package updates for 313kb of actual updates.

Description of problem:

While this is not technically a bug, I don't know where else to report it.

The single most annoying thing with yum/dnf is the size of the package update downloads. For example today I downloaded close to 55MB of package lists for a 313k update.

Surely these lists don't chance dramatically from day to day, so is it possible to have delta's of the package lists so your only downloading the differences.  

Delta files have made a huge improvement to the actually rpm download sizes, and having the same happen for update lists might really speed up the whole process.  Often, the time taken to download package updates is the single longest part to running yum or dnf from the command line (and I guess for software too).

A side benefit would be for users with limited data (either small connections, or paying for data like on a mobile phone).


Version-Release number of selected component (if applicable):

$ rpm -q yum dnf
yum-3.4.3-153.fc21.noarch
dnf-0.6.2-1.fc21.noarch