Re: Question about your git habits

Alexey Dobriyan
2008-02-23T08:45:51Z

On Sat, Feb 23, 2008 at 03:23:49AM +0100, J.C. Pizarro wrote:
> On 2008/2/23, Al Viro <viro@zeniv.linux.org.uk> wrote:
> > On Fri, Feb 22, 2008 at 05:51:04PM -0800, Junio C Hamano wrote:
> > > Al Viro <viro@ZenIV.linux.org.uk> writes:
> > >
> > > > On Sat, Feb 23, 2008 at 02:37:00AM +0100, Jan Engelhardt wrote:
> > > >
> > > >> >do you tend to clone the entire repository repeatedly into a series
> > > >> >of separate working directories
> > > >>
> > > >> Too time consuming on consumer drives with projects the size of Linux.
> > > >
> > > > git clone -l -s
> > > >
> > > > is not particulary slow...
> > >
> > > How big is a checkout of a single revision of kernel these days,
> > > compared to a well-packed history since v2.6.12-rc2?
> > >
> > > The cost of writing out the work tree files isn't ignorable and
> > > probably more than writing out the repository data (which -s
> > > saves for you).
> >
> >
> > Depends... I'm using ext2 for that and noatime everywhere, so that might
> > change the picture, but IME it's fast enough... As for the size, it gets
> > to ~320Mb on disk, which is comparable to the pack size (~240-odd Mb).
>
> Yesterday, i had git cloned git://foo.com/bar.git ( 777 MiB )
> Today, i've git cloned git://foo.com/bar.git ( 779 MiB )
>
> Both repos are different binaries , and i used 777 MiB + 779 MiB = 1556 MiB
> of bandwidth in two days. It's much!
>
> Why don't we implement "binary delta between old git repo and recent git repo"
> with "SHA1 built git repo verifier"?
>
> Suppose the size cost of this binary delta is e.g. around 52 MiB instead of
> 2 MiB due to numerous mismatching of binary parts, then the bandwidth
> in two days will be 777 MiB + 52 MiB = 829 MiB instead of 1556 MiB.
>
> Unfortunately, this "binary delta of repos" is not implemented yet :|

See git-pull .