Re: [WISH] Store also tag dereferences in packed-refs

["Marco Costalba" <mcostalba@gmail.com>]

On 11/18/06, Petr Baudis <pasky@suse.cz> wrote:
> On Sat, Nov 18, 2006 at 07:38:11PM CET, Junio C Hamano wrote:
> > "Marco Costalba" <mcostalba@gmail.com> writes:
> >
> > > Time needed to execute git-peek-remote in my box with cold cache currently is:
> > >
> > > - git tree 2.347 ms
> > > - linux tree 2.144 ms
> > >
> > > And refs are *already* packed in both repos.
> > >
> > > Looking at packed-refs file, it contains something like:
> > >
> > > d9b0f913ce0508fcc83e642e0241f373428368e5 refs/tags/v1.4.3
> > > 4314f5982d2aac08001a977fc0b1b611e858e025 refs/tags/v1.4.3-rc1
> > >
> > > while I would need something like git-peek-remote output,
> > >
> > > d9b0f913ce0508fcc83e642e0241f373428368e5        refs/tags/v1.4.3
> > > e0b0830726286287744cc9e1a629a534bbe75452        refs/tags/v1.4.3^{}
> > > 4314f5982d2aac08001a977fc0b1b611e858e025        refs/tags/v1.4.3-rc1
> > > 1965efb1599f59b8e3380335d1fa395e2008a30b        refs/tags/v1.4.3-rc1^{}
> > >
> > > Because the sha value a tag points to is needed to match against
> > > git-rev-list output so to identify tagged revisions.
> > >
> > > Would be possible to store in packed-refs also the dereferenced tag
> > > info, so that cold opening of a repository would be much faster?
> > >
> > > Just to give an idea, with warmed up cache, refs reading times are:
> > >
> > > - git tree 43 ms
> > > - linux tree 28 ms
> > >
> > > Thanks
> > > Marco
> > >
> > > P.S: In case it's not clear I don't suggest to read directly the
> > > packed-refs file with the added info, but always to use
> > > git-peek-remote that _would_ became much faster.
> >
> > I think the question is why you would want to run peek-remote.
> > Do you use the ^{} peeled-onion information and if so how and
> > why?
>
> My wild guess would be to attach tags to the right commits in qgit?
>
Yes. It is. From a list like

> > > d9b0f913ce0508fcc83e642e0241f373428368e5        refs/tags/v1.4.3
> > > e0b0830726286287744cc9e1a629a534bbe75452        refs/tags/v1.4.3^{}
> > > 4314f5982d2aac08001a977fc0b1b611e858e025        refs/tags/v1.4.3-rc1
> > > 1965efb1599f59b8e3380335d1fa395e2008a30b        refs/tags/v1.4.3-rc1^{}
>
qgit (but also gitk FWIK) extracts

e0b0830726286287744cc9e1a629a534bbe75452
1965efb1599f59b8e3380335d1fa395e2008a30b

Stores in a quick look-up container and then checks against loaded
commits to, as Pasky says, attach the nice green markers to tags.