changelogs in packages and space use

[seth vidal]

Colin Walters mentioned on irc reducing the changelogs kept in pkgs a
bit to help us fit on the livecd a bit better. I didn't really believe
it would make enough of an impact to be noticeable but I did a little
mucking about and found I was wrong. So I wrote this:

http://skvidal.fedorapeople.org/changelog/changelog-sizes.py

It'll dump out 4 files:

- old-repo.txt : changelogs from the pkgs in the repos where the
changelog entry is > 1yr old
- new-repo.txt : changelogs from the pkgs in the repos where the
changelog entry is < 1yr old


- old-db.txt : changelogs from the pkgs in the rpmdb where the changelog
entry is > 1yr old
- new-db.txt : changelogs from the pkgs in the rpmdb where the changelog
entry is < 1yr old

On a mostly-rawhide system with rawhide repos I found:

8157 pkgs in rawhide repos:
  new changelogs: 12M
  old changelogs: 31M

on my system 1128 packages installed:
  new changelogs: 2.2M
  old changelogs: 8.6M


That may not seem like much but when we're squinched for space in 700M
on a livecd that 8.6M might be all that's needed. Moreover it may be a
bit silly to be carting all of this history around in all the pkgs and
repodata and in the rpmdb. Esp if we're trying to trim download sizes
for various items. So things we can do:

1. trim the changelogs at createrepo-runtime - fine - but that only gets
it for the repodata

2. trim repos at rpmbuild time - great - I've suggested it as an option
to rpmbuild on rpm-maint list. 

3. trim them out of the pkgs the next time we change a package. Just
prune them down to the last years worth of changelogs - maybe saving the
old changelogs in a file in the cvs repository - or even into an unused
source file in the srpm?

What're people's thoughts on this?

-sv