Re: [PATCH 4/4] core.abbrev: raise the default abbreviation to 12 hexdigits

> On Thu, Sep 29, 2016 at 11:55 AM, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
>>
>> For the kernel, just the *math* right now actually gives 12
>> characters. For current git it actually seems to say that 8 is the
>> correct number. For small projects, you'll still see 7.
>
> Sorry, the git number is 9, not 8. The reason is that git has roughly
> 212k objects, and 9 hex digits gets expected collisions at about 256k
> objects.
>
> So the logic means that we'll see 7 hex digits for projects with less
> than 16k objects, 8 hex digits if there are less than 64k objects, and
> 9 hex digits for projects like git that currently have fewer than 256k
> objects.