DNF: why does it refresh metadata all the time

[drago01]

On Fri, Jun 20, 2014 at 12:19 PM, Reindl Harald <h.reindl at thelounge.net> wrote:
>
>
> Am 20.06.2014 11:57, schrieb Mat Booth:
>> On 20 June 2014 10:19, Reindl Harald <h.reindl at thelounge.net <mailto:h.reindl at thelounge.net>> wrote:
>>
>>     Am 20.06.2014 08:55, schrieb drago01:
>>     > On Thu, Jun 19, 2014 at 8:59 PM, Jared K. Smith
>>     > <jsmith at fedoraproject.org <mailto:jsmith at fedoraproject.org>> wrote:
>>     >> On Thu, Jun 19, 2014 at 2:01 PM, Reindl Harald <h.reindl at thelounge.net <mailto:h.reindl at thelounge.net>>
>>     >> wrote:
>>     >> Whether you like it or not, one of the most common complaints about yum
>>     >> (especially from people coming from another package management system) is
>>     >> that it seems slow because of the necessity to download the metadata.  The
>>     >> DNF developers -- in trying to address this common complaint -- had solved
>>     >> it by handling metadata in a different way.  They've also added settings so
>>     >> that power users like you and I can tune it to better fit our particular
>>     >> needs.
>>     >>
>>     >>> and *no* traffic is not cheap everywhere, by far not
>>     >>
>>     >> I probably understand this better than a lot of people on this list, as I've
>>     >> been on a bandwidth-limited connection for the past nine years.  Only in the
>>     >> past month have I been able to get high speed internet in my home that
>>     >> wasn't limited to a few gigabytes per month.  So yes, I completely
>>     >> understand that traffic isn't cheap (or fast) everywhere.
>>     >
>>     > It should be at least smart enough to not do it on mobile broadband
>>     > (like packagekit does)
>>
>>     how should it do that?
>>
>>     it's imagination that any software knows anything about the internet connection
>>     even 11 years ago with a 56k modem that access was shared for my LAN and so
>>     the only thing the notebook knew about the inernet was "appears to be slow"
>>
>>
>> IIRC, NetworkManager's DBus API should be able to give you that information
>
> from where should it get that information if your network connection is
> a Gigabit-Ethernet LAN to the router with a slow DSL upstream?
>
> your whole machine has no idea about your WAN connection

As he said there is a NM API but it is indeed somehow limited as the
example you mentioned shows also it (currently) won't work for a
simpler case ... tethered Android Phone over USB (because it looks
like USB Ethernet).

But that does not mean that we should not try to limit the impact if
we want to do the background download stuff (perfect is not the enemy
of good).