On Mon, 12 Jan 2009, Tim 'mithro' Ansell wrote: > > I just had an idea: we can use this mechanism to better manage large > > binary files in Git, by using replacements for _blobs_. > > > > We want to be able to have two flavours of repository: one with large > > blobs (media files usually), and one without. We can use stubs in the > > place of large binary files in 'no-megablobs' flavor, and add contents > > of those files via refs/replace/* for _blobs_ in 'with-megablobs' > > flavour. We can control which objects we want to have, and which > > objects to transfer. > > > > What do you think about this (abuse of) an idea? > > I'm not sure I understand. I don't really care much about the > implementation details if it's transparent to the user :) > > I have not really had much time to pursue my idea of getting sha1_file > to read download blob on an as-needed basis (work has been hectic). Actually this idea is a bit different from lazy / on demand downloading of large blobs. In "on demand loading" solution you have sha-1 of _full_ blob in a tree, but git knows that not having it is not a fatal error (somehow), and you can ask git to download it. This is as far as I understand the solution you proposed and partially implemented. In "replacement blobs" solution, the (ab)use of object replacement mechanism meant originally for easier bisect, you have sha-1 of _stub_ object in a tree. If you want full (large) blob, you add replacement in refs/replace/*, replacing stub blob object (must be unique; it can for example contain some header + sha-1 of full object) with full object. If you want to have large object, you need to transfer refs/replace/*. This solution means that user needs to be aware of this mechanism, or have some wrapper (script) around it. Different solution, and a bit different behavior wrt getting large object for the user. -- Jakub Narebski Poland -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
