Re: [PATCH 08/13] prevent try_delta from using objects not in pack

From: Dana How <danahow@gmail.com>
Date: Apr 6, 2007, 03:47 UTC
Message-ID: <56b7f5510704052047r30166e53kffbdd8bf71885264@mail.gmail.com>
In-Reply-To: <alpine.LFD.0.98.0704052320560.28181@xanadu.home>

On 4/5/07, Nicolas Pitre <nico@cam.org> wrote:

Show 25 quoted lines

> On Thu, 5 Apr 2007, Dana How wrote:
> > On 4/5/07, Nicolas Pitre <nico@cam.org> wrote:
> > > What is the purpose of this patch?
> > >
> > > The try_delta() function is called with all objects before any object is
> > > written to a pack to find out how to deltify objects upfront.
> >
> > I set no_write for 2 different reasons in the patchset.
> > (1) When the blob is too big (--blob-limit) and will never be written.
> > (2) When the blob has been written to a previous, finished pack.
> >
> > You're correct that this patch will never see condition (2).
>
> Given that I proposed another way for big blobs in my previous email,
> then (1) should not be needed either.
>
> > I think my repository statistics are a little unusual.
> > Perhaps I'm getting ahead of myself here,
> > but I also wanted to experiment with writing all blobs to one set
> > of packs,  and all trees, commits, and tags to another set
> > (but probably just one small pack).
> > I would use no_write for that and it would matter here.
>
> Again you should simply _not_ add objects you don't want to the list
> instead of adding them and marking them as unwanted.

Agreed, the marking just required less code change at the time. I would like not to have to add nr_skipped and nr_actual.

Currently we have get_object_list -> traverse_commit_list -> show_{commit,object} -> add_object_entry , which is all called way before get_object_details -> check_object -> sha1_object_info . Can I safely move the sha1_object_info calll earlier into add_object_entry so I will know the size for pruning?

In your other email you mention memory consumption due to object_entry. This structure could benefit somewhat from some attention beyond removing my no_write.(e.g. int->short for .depth and .delta_limit; int->enum for .preferred_base). Perhaps for later.

Thanks,

-- 
Dana L. How  danahow@gmail.com  +1 650 804 5991 cell