Yum-presto 0.3.9 - FC6 *and* Rawhide
Thomas M Steenholdt
tmus at tmus.dk
Mon Apr 16 06:43:38 UTC 2007
Tony Nelson wrote:
>
> I think the powers that be would want to be shown exactly how much storage
> and how many files would be required for all the pairs of package updates.
> The number of updates for all pairs for a fast-moving frequently updated
> package, e.g. the kernel and its ilk, might be large. Well, I only notice
> 5, but I may have missed some. I don't know how to find out all the
> released updates.
>
> n! n*(n-1)
> d = C(n,2) = -------- = -------
> 2*(n-2)! 2
>
> n is number of versions (original + updates)
> d is number of deltas
> recurrance: d(n+1) = d(n)+n
>
> 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
> 0 1 3 6 10 15 21 28 36 45 55 66 78 91 105
The way I see it, the function is more like
d = n - 1
Slightly simpler. For every version of a package, we would need to be
able to update from any previous version, to the current version. I
don't think it makes sense to be able to have deltas for updating to a
non-current version, so i guess my suggestion to "keep all possible
deltas" is inaccurate in this way. What I meant was "keep all possible
deltas, allowing a user to update from any previous version to the current".
Michael Wiktowy had a perhaps even better suggestion elsewhere in this
thread, that would further reduce the number of deltas kept, by dropping
previous deltas (other that current minus one -> current and original ->
current) after a period of time.
/Thomas
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