No more deltarpms by default

Florian Festi ffesti at redhat.com
Mon Oct 6 17:45:45 UTC 2014


On 10/06/2014 06:53 PM, Jonathan Dieter wrote:
>> Get to coding. ;)
> 
> As mentioned elsewhere, the problem *is* signatures.  yum (quite
> rightly) refuses to install an rpm whose signature doesn't match the one
> in the primary repodata.  And I believe that the signature in the RPM is
> also over the whole compressed rpm.  To make this work, we'd need to add
> an "uncompressed" signature for every package to the primary repodata as
> well as probably the rpms themselves.
>
> We have already written the code to have yum run applydeltarpm in
> parallel according to the number of processors on a system, but it
> remains a single-threaded application that spends most of its time
> recompressing the data.

The way of getting around all this unnecessary computation is
establishing trust via the deltarpm itself and giving up the idea of
reconstructing the originally rpm as a prove of everything worked out
just fine.

To save even more time the delta would need to be applied directly on
disk without creating an package at all. This would require a deeper
integration with rpm and requires some tricky algorithms to make sure
everything is ok in advance and won't blow up during the rpm
transaction. So if anyone needs a hobby...

Florian

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