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Re: [git-users] How hard would it be to implement sparse fetching/pulling?






On 11/30/2017 3:12 AM, Konstantin Khomoutov wrote:
On Wed, Nov 29, 2017 at 06:42:54PM -0800, vit via Git for human beings wrote:

I'm looking for ways to improve fetch/pull/clone time for large git
(mono)repositories with unrelated source trees (that span across multiple
services).
I've found sparse checkout approach appealing and helpful for most of
client-side operations (e.g. status, reset, commit, add etc)
The problem is that there is no feature like sparse fetch/pull in git, this
means that ALL objects in unrelated trees are always fetched.
It takes a lot of time for large repositories and results in some practical
scalability limits for git.
This forced some large companies like Facebook and Google to move to
Mercurial as they were unable to improve client-side experience with git
and Microsoft has developed GVFS which seems to be a step back to CVCS
world.
[...]

(To anyone interested, there's a cross-post to the main Git list which
Vitaly failed to mention: [1]. I think it could spark some interesting
discussion.)

As to the essence of the question, I think you blame GVFS for no real
reason. While Microsoft is being Microsoft — their implementation of
GVFS is written in .NET and *requires* Windows 10 (this one is beyond
me), it's based on an open protocol [2] which basically assumes the
presence of a RESTful HTTP endpoint at the "Git server side" and
apparently designed to work well with the repository format the current
stock Git uses which makes it implementable on both sides by anyone
interested.

The second hint I have is that the idea of fetching data lazily
is being circulated among the Git developers for some time already, and
something is really being done in this venue so you could check and see
what's there [3, 4] and maybe trial it and help out those who works on this
stuff.

1. https://public-inbox.org/git/CANxXvsMbpBOSRKaAi8iVUikfxtQp=kofZ60N0pHXs+R+q1k3_Q@xxxxxxxxxxxxxx/
2. https://github.com/Microsoft/GVFS/blob/master/Protocol.md
3. https://public-inbox.org/git/?q=lazy+fetch
4. https://public-inbox.org/git/?q=partial+clone


For completeness with the git-users mailing list.
Here is info on the work-in-progress for this feature.

https://public-inbox.org/git/e2d5470b-9252-07b4-f3cf-57076d103a17@xxxxxxxxxxxxxxxxx/

Jeff