Re: [PATCH 00/30] [RFC] Path-walk API and applications

From: Junio C Hamano <gitster@pobox.com>
Date: Sep 22, 2024, 18:37 UTC
Message-ID: <xmqqplov7cw8.fsf@gitster.g>
In-Reply-To: <53dc17f8-82e5-40fa-81b7-af89f987928b@gmail.com>

Derrick Stolee <stolee@gmail.com> writes:

Show 19 quoted lines

> Combining the two features actually ends up with very similar performance
> to what `--full-name-hash` already does. It's actually important that the
> `--path-walk` option does a full pass of the objects via the standard
> name-hash after its first pass in groups based on the path.
> ...
> I was not clear about this, but the RFC is 30 patches so it's possible to see
> the big picture, but I will be breaking it into at least four series in
> sequence for actual review. They match the four sections described above, but
> will be in the opposite order:
>
>  A. `git repack --full-name-hash`
>  B. `git pack-objects --path-walk`
>  C. `git survey`
>  D. `git backfill`
>
> (It's possible that `git survey` and `git backfill` may be orthogonal enough
> that they could be under review at the same time. Alternatively, `git backfill`
> may jump the line because it's so simple to implement once the path-walk API
> is established.)

I actually was hoping to hear something like "since it turns out that --path-walk gives a better performance and it does not regress small incremental transfer like --full-name-hash does, the real series drops --full-name hash", i.e. without part (A). That reduces things we need to worry about (like having to either keep track of two "hashes" per object, or making small incremental transfer more costly) greatly.

Thanks.