delta rpms - can we turn them off

Jonathan Dieter jdieter at
Sun Jun 29 21:20:44 UTC 2014

On 06/29/2014 04:36 AM, Florian Weimer wrote:
> On 06/29/2014 12:32 PM, drago01 wrote:
>> On Sun, Jun 29, 2014 at 1:55 AM, Jonathan Dieter <jdieter at>
>> wrote:
>>> 2. RPM would also need to support signatures across the uncompressed
>>> payload
>>> as well as the compressed payload.
>> Well Florian said that only the header is actually signed not the
>> payload. So this shouldn't be necessary.
> I missed that the information that the payload is XZ-compressed is
> likely signed (hard to tell because the current RPM format isn't
> documented).  So we'd need a fake XZ implementation that produces an
> essentially uncompressed data stream (xz -0 still compresses).
> In the meantime, we could try to reduce the compression level to 0
> unconditionally in applydeltarpm.

We can do this, but createrepo would need to store the checksum of 0 
level compressed xz rpms in primary, which involve making createrepo 
decompress each rpm and then recompress at level 0.  Not sure what the 
infra folks think about this.

I may run some tests over the next few weeks to see what implementing 
this would actually take.  I am on a two-month vacation, so no promises 
on how quick I'll be.


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