From: Derrick Stolee <stolee@gmail.com>
Date: Thu, 09 May 2019 12:25:01 GMT
Subject: Re: [PATCH 12/17] Documentation: describe split commit-graphs
Message-ID: <8195f9a4-1808-e23e-f633-7e6809cc3656@gmail.com>
In-Reply-To: <xmqq8svgfczw.fsf@gitster-ct.c.googlers.com>

On 5/9/2019 12:49 AM, Junio C Hamano wrote:
> Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
> 
>> With commit-graph-<HASH> all these unlink() race conditions go away,
>> partial reads due to concurrent graph writing becomes a non-issue (we'd
>> just leave the old files, "gc" deals with them later..), no need to
>> carefully fsync() files/dirs etc as we need to carefully juggle N and
>> N+1 files.
> 
> The above would give a nice course correction to be in line with the
> rest of the system, like how split index knows about and chains to
> its base.  Thanks for a dose of sanity.

I'm working on a detailed response to Ævar's ideas, to be sure we are
talking about the same thing, because the original motivation for the
commit-graph format v2 was to allow the 'commit-graph' file to point
to a chain of base files by a list of hashes (like the split index
does). The current proposal was created in response to an unwillingness
to break the file format for the 'commit-graph' file.

-Stolee