[QUESTION] How does Git ref backend work

ZheNing Hu· Apr 12, 2023, 06:25 UTC · lore

1. I noticed that normally refs transactions use the refs files-backend,
looking at the reference transaction of refs files-backend alone:
First, it opens a transaction in memory, then multiple update items
are added in memory, and finally, when the reference transaction
is committed, it creates a ref.lock for each update item, renames it
to the real address of the ref.

but there seems to be some packed-backend logic coupled inside of files-backend. This makes me wonder why these ref backends are not independent?

2. Is the reftable backend in a usable state? How can I enable it?
I couldn't find any clues on https://www.git-scm.com/docs/reftable.
3. Will future git refs backend possibly support external storage media
e.g. Redis?

Thanks, -- ZheNing Hu

ZheNing Hu· Apr 12, 2023, 06:48 UTC · re: ZheNing Hu · lore

Re: [QUESTION] How does Git ref backend work

ZheNing Hu <adlternative@gmail.com> 于2023年4月12日周三 14:25写道：

Show 17 quoted lines

>
> 1. I noticed that normally refs transactions use the refs files-backend,
> looking at the reference transaction of refs files-backend alone:
> First, it opens a transaction in memory, then multiple update items
> are added in memory, and finally, when the reference transaction
> is committed, it creates a ref.lock for each update item, renames it
> to the real address of the ref.
>
> but there seems to be some packed-backend logic coupled inside of
> files-backend. This makes me wonder why these ref backends are not
> independent?
>
> 2. Is the reftable backend in a usable state? How can I enable it?
> I couldn't find any clues on https://www.git-scm.com/docs/reftable.
> 3. Will future git refs backend possibly support external storage media
> e.g. Redis?
>

I just found a similar discussion on the mailing list: https://lore.kernel.org/git/CAJoAoZn7Nt37Eh17dpLDK+YX2BaEaAaii2rJPXO3L0BmQQkcgQ@mail.gmail.com/

> Thanks,
> --
> ZheNing Hu