[Yum] yum dep resolution-offer of help

David Relson relson at osagesoftware.com
Sun Jan 18 16:09:04 UTC 2004


On Sun, 18 Jan 2004 09:26:53 -0500
seth vidal <skvidal at phy.duke.edu> wrote:

> On Sun, 2004-01-18 at 06:45, Raphael Clifford wrote:
> > Hi,
> > 
> > I have noticed that the dependency resolution stage of yum can be 
> > painfully slow.  To give an example, I am running yum 2.0.4 on
> > redhat 9 and "yum install xine" has been at that stage for several
> > minutes now with the CPU at near 100 percent utilisation.  It seems
> > to me, perhaps naively, that using the correct data structure and
> > caching this should take no more than a second or two.  As a result
> > I would like to offer to help redesign the algorithm used.  So what
> > I really need is some technical information about what is required
> > and who I should be in touch with.
> 
> Hi,
>  you're right it can take up time and ram to resolve deps. A lot of
>  that
> has to do with the mechanism of rpm that yum uses. If you're familiar
> with the dep resolution mechanisms of rpm then I'll just explain that
> yum uses ts.addInstall(hdr, 'a') modes to let rpm decide what's 'best'
> for it.
> 
> The work that is being done is to ditch this direction.
> If you'd like to help look at:
> http://linux.duke.edu/metadata/
> and http://linux.duke.edu/metadata/import - specifically test.py -
> it's just testing code but it's what I will break out to make the dep
> resolution code.
> 
> Get your head wrapped around the packageSack search methods in that
> code and that will be the direction I want to follow.
> 
> thanks.
> -sv

Seth, 

Early last week, I reported that a simple "yum install ethereal" on my
Mandrake 9.2 system (500Mhz PIII, 384MB ram) was taking 30mins plus and
using 200MB+ ram.  With those figures, yum is not too useful.  (For
reference, "urpmi" only takes a few seconds).

Hopefully Raphael's project will make a BIG difference.

David

P.S.  I have lots of programming experince, but don't know python beyond
the simplest basics.  If a profile of the slow command would help, let
me know how to do it, and I'll be glad to run it.



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