Re: [jgit-dev] GIT 2.0 and BITMAP_OPT_HASH_CACHE

[Shawn Pearce <spearce@xxxxxxxxxxx>]

On Wed, Mar 12, 2014 at 8:48 AM, Alexander Riss <ariss@xxxxxxxxx> wrote:
> Hi all,
>
> Since git 2.0 introduces the support for the JGIT bitmap accelerator
> files, i was wondering if there are any plans to also support the
> additions made to the index files in JGIT: BITMAP_OPT_HASH_CACHE
>
> Citing from the documentation:
>
> pack.writeBitmapHashCache:
>         When true, git will include a "hash cache" section in the bitmap
>         index (if one is written). This cache can be used to feed git's
>         delta heuristics, potentially leading to better deltas between
>         bitmapped and non-bitmapped objects (e.g., when serving a fetch
>         between an older, bitmapped pack and objects that have been
>         pushed since the last gc). The downside is that it consumes 4
>         bytes per object of disk space, and that JGit's bitmap
>         implementation does not understand it, causing it to complain if
>         Git and JGit are used on the same repository. Defaults to false.
>
>
> Full implementation details here:
> https://git.kernel.org/cgit/git/git.git/commit/?id=0f9e62e0847c075678a7a5a7
> 48567d1e881d16f8

Yes, we should implement this. Unfortunately it slipped my mind and I
haven't had time to do it. Colby (author of the JGit bitmap work) has
moved onto another project, and sadly does not have time to do this
either.