Re: [RFC PATCH 00/18] Multi-pack index (MIDX)

From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date: Jan 8, 2018, 11:43 UTC
Message-ID: <87fu7gbmoy.fsf@evledraar.gmail.com>
In-Reply-To: <c08416f1-bbec-2037-34a6-f454d85de439@gmail.com>

On Mon, Jan 08 2018, Derrick Stolee jotted:

Show 11 quoted lines

> On 1/7/2018 5:42 PM, Ævar Arnfjörð Bjarmason wrote:
>> If something cares about both throughput and e.g. is saving the
>> abbreviated SHA-1s isn't it better off picking some arbitrary size
>> (e.g. --abbrev=20), after all the default abbreviation is going to show
>> something as small as possible, which may soon become ambigous after the
>> next commit.
>
> Unfortunately, with the way the abbreviation algorithms work, using
> --abbrev=20 will have similar performance problems because you still
> need to inspect all packfiles to ensure there isn't a collision in the
> first 20 hex characters.

I meant (but forgot to write) that this would be some new mode, e.g. --abbrev=20 --no-abbrev-check which would just perform a substr() of the 40 character SHA-1. It might be interesting to add that for reasons completely unrelated to your series.

Thanks for answering the rest.