Finishing rebuild of rpms, from deltarpms

[JD]

On 04/15/2011 04:44 PM, Joe Zeff wrote:
> On 04/15/2011 03:42 PM, JD wrote:
>> Doing yum update cause yum to issue
>> this message
>> Finishing rebuild of rpms, from deltarpms
>>
>> What is the significance of this, and why is
>> it being done?
> Presumably, you have the presto plugin installed and active.  This means
> that instead of downloading the complete rpm for each update, yum just
> downloads the deltarpm, which only contains the changes from the last
> version, then applies the changes to the cached copies of the rpms,
> changing them to the latest version before updating.  As most of the
> updated rpm is the same as the older version, this drops the amount of
> data downloaded by anywhere from 70-90%, sometimes more.  Of course,
> people on unlimited data plans may not worry about the extra bandwidth,
> but very often the time taken to rebuild the rpms is less than the time
> needed to download the complete new version.
>
> If the above doesn't quite make sense, don't worry; yum is just telling
> you that it's just finished saving you some (possibly valuable) bandwidth.
Sure it makes sense! So, only the items (files)
of the rpm that changed get downloaded (my guess)??
That's not too bad. What would be better is
getting a program to do a binary diff between
old rpm and new rpm, producing a binary
patch file, and applying the binary patch
file on the user's old cache of the rpm and installing
that.  See http://www.daemonology.net/bsdiff/
and of course, bsdiff and bspatch are in the fedora repo
as bsdiff-4.3-7.fc12.i686

Cheers,

JD