On Fri, 22 Sep 2017 17:02:11 -0400 Jeff Hostetler <git@xxxxxxxxxxxxxxxxx> wrote: > > I was struggling a bit with the terminology, true. > > > > Right now I'm thinking of: > > - promisor remote (as you defined) > > - promisor packfile (as you defined) > > - promisor object is an object known to belong to the promisor (whether > > because we have it in a promisor packfile or because it is referenced > > by an object in a promisor packfile) > > > > This might eliminate "promise(d)", and thus eliminate the confusion > > between "promised" and "promisor", but I haven't done an exhaustive > > search. > > > > maybe just call the "promised" ones "missing". They are not the same, though - "missing" usually just means that the local repo does not have it, without regard to whether another repo has it. > >> I guess it depends on how many missing-objects you expect the client > >> to have. My concern here is that we're limiting the design to the > >> "occasional" big file problem, rather than the more general scale > >> problem. > > > > Do you have a specific situation in mind? > > > > I have would like to be able do sparse-enlistments in the Windows > source tree. (3.5M files at HEAD.) Most developers only need a small > feature area (a device driver or file system or whatever) and not the > whole tree. A typical Windows developer may have only 30-50K files > populated. If we can synchronize on a sparse-checkout spec and use > that for both the checkout and the clone/fetch, then we can bulk fetch > the blobs that they'll actually need. GVFS can hydrate the files as > they touch them, but I can use this to pre-fetch the needed blobs in > bulk, rather than faulting and fetching them one-by-one. > > So, my usage may have >95% of the ODB be missing blobs. Contrast that > with the occasional large blob / LFS usage where you may have <5% of > the ODB as large objects (by count of OIDs not disk usage). I don't think the current design precludes a more intelligent bulk fetching (e.g. being allowed to specify a "want" tree and several "have" trees, although we will have to figure out a design for that, including how to select the "have" trees to inform the server about). In the meantime, yes, this will be more useful for occasional large blob repos, and (if/when the hook support is added) a GVFS situation where the missing objects are available network-topologically close by.
