[Mageia-dev] [ANN] [RFC] support for deltarpms in urpmi

[Thierry Vignaud]

Hi

urpmi now have basic support for delta rpms, aka it can install them
(never worked before).
We could think about providing updates as delta rpms for mga3.
Example for libreoffice:
both
core/release/libreoffice-writer-3.5.3.2-1.mga2.x86_64.rpm and
libreoffice-writer-3.5.5.3-0.3.mga2.x86_64.rpm
are 4,2M big but:
makedeltarpm core/release/libreoffice-writer-3.5.3.2-1.mga2.x86_64.rpm
core/updates/libreoffice-writer-3.5.5.3-0.3.mga2.x86_64.rpm
/tmp/libreoffice-writer-3.5.5.3-0.3.mga2.x86_64.drpm2
results in a 405k delta rpm.
Aka a 10 fold reduction in download needs.

We should think about what's needed:
- new deltarpm update media to hold deltarpms ?
- recording source version in synthesis
- keeping:
  o all deltarpm (not as big as full classic rpms)
  o or only keeping both:
    * core/release > latest core/updates
    * previous core/updates > latest core/updates
- option do disable deltarpm support in /etc/urpmi.cfg?
- having a fallback in urpmi if applydeltarpm fails
- having urpmi select the right package
  o either deltarpm if there's one for installed_version -> update_version path
  o or regular update package else

WDYT?