delta rpms - can we turn them off

[Jonathan Dieter]

On 06/28/2014 10:56 AM, drago01 wrote:
> On Sat, Jun 28, 2014 at 6:54 PM, Orcan Ogetbil <oget.fedora at gmail.com> wrote:
>> On Sat, Jun 28, 2014 at 11:49 AM, Kevin Fenzi wrote:
>>>
>>> So, sure, we could sign drpms and yum/dnf could check that, but they
>>> still need to assemble the final rpm in order to pass it to rpm.
>>>
>>
>> The question, to my understanding, which may be wrong, is whether the
>> contents of the assembled rpm need to be compressed or not.
>
> Yeah its about the rpm payload compression.

Sorry for jumping into this so late; we've just flown back to the States 
for a vacation, so I've been off the net while we were traveling.

A few years back I looked at what it would take to skip the 
recompression step of deltarpm while still verifying signatures.  IIRC, 
the following would need to be done:

1. Yum/DNF repodata would need to include uncompressed checksums as well 
as compressed checksums.

2. RPM would also need to support signatures across the uncompressed 
payload as well as the compressed payload.

3. Deltarpm would need to be patched to build non-compressed rpms when 
rebuilding the deltarpms.

As the maintainer of deltarpm, I can easily do (3), but there didn't 
seem to be much buy-in for (1) and (2) the last time I suggested it (no 
references; I can't seem to find the previous thread in the archives).

Please note that this would severely reduce the need for CPU during the 
deltarpm rebuild process, but at the expense of increasing IO as we're 
writing an uncompressed RPM.

Jonathan