Yum-presto (deltarpms) ready for testing.

seth vidal skvidal at linux.duke.edu
Tue Mar 27 12:26:43 UTC 2007


On Tue, 2007-03-27 at 13:29 +0300, Jonathan Dieter wrote:
> On Tue, 2007-03-27 at 12:05 +0200, Michael Schroeder wrote:
> > On Mon, Mar 26, 2007 at 04:34:21PM -0400, seth vidal wrote:
> > > 1. why are you using md5sum and not sha1sums?
> > 
> > It checks if the md5sum of the file matches the sum from the rpm
> > header.
> > 
> > It works basically like this: The "sequence" tells applydeltarpm
> > which of the files from the rpm header were used to create the
> > deltarpm and the order of those files (thus the name "sequence"
> > in case you wondered). makedeltarpm doesn't use all files to
> > create the delta, config files and files that have the "verify"
> > bit off get excluded. If you ask applydeltarpm to check if a
> > deltarpm can be applied it uses this sequence to verify that all
> > used files are unchanged, either by just checking the size (the
> > fast method) or by checking the md5sum (like rpm does).
> > The fast method makes sense if the updater has a fallback to
> > fetch the complete rpm if applydeltarpm failes, as in most cases
> > files are unchanged if the size is the same.
> > 
> > Cheers,
> >   Michael.
> > 
> And I changed Presto last night to use the full method, rather than the
> fast method.  Our fallback method is pretty lousy (exiting with an
> error, working the second time yum is called), at least for the moment.
> 

Why is that? I need to take a look at the code but there doesn't seem to
be any reason why it shouldn't be able to fall back to downloading the
whole package. It knows where it is.

-sv





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