Jeff Hostetler wrote: > On 11/30/2017 6:43 PM, Philip Oakley wrote: >> The 'companies' problem is that it tends to force a client-server, always-on >> on-line mentality. I'm also wanting the original DVCS off-line capability to >> still be available, with _user_ control, in a generic sense, of what they >> have locally available (including files/directories they have not yet looked >> at, but expect to have. IIUC Jeff's work is that on-line view, without the >> off-line capability. >> >> I'd commented early in the series at [1,2,3]. > > Yes, this does tend to lead towards an always-online mentality. > However, there are 2 parts: > [a] dynamic object fetching for missing objects, such as during a > random command like diff or blame or merge. We need this > regardless of usage -- because we can't always predict (or > dry-run) every command the user might run in advance. > [b] batch fetch mode, such as using partial-fetch to match your > sparse-checkout so that you always have the blobs of interest > to you. And assuming you don't wander outside of this subset > of the tree, you should be able to work offline as usual. > If you can work within the confines of [b], you wouldn't need to > always be online. Just to amplify this: for our internal use we care a lot about disconnected usage working. So it is not like we have forgotten about this use case. > We might also add a part [c] with explicit commands to back-fill or > alter your incomplete view of the ODB Agreed, this will be a nice thing to add. [...] >> At its core, my idea was to use the object store to hold markers for the >> 'not yet fetched' objects (mainly trees and blobs). These would be in a >> known fixed format, and have the same effect (conceptually) as the >> sub-module markers - they _confirm_ the oid, yet say 'not here, try >> elsewhere'. > > We do have something like this. Jonathan can explain better than I, but > basically, we denote possibly incomplete packfiles from partial clones > and fetches as "promisor" and have special rules in the code to assert > that a missing blob referenced from a "promisor" packfile is OK and can > be fetched later if necessary from the "promising" remote. > > The main problem with markers or other lists of missing objects is > that it has scale problems for large repos. Any chance that we can get a design doc in Documentation/technical/ giving an overview of the design, with a brief "alternatives considered" section describing this kind of thing? E.g. some of the earlier descriptions like https://public-inbox.org/git/20170915134343.3814dc38@xxxxxxxxxxxxxxxxxxxxxxxxxxx/ https://public-inbox.org/git/cover.1506714999.git.jonathantanmy@xxxxxxxxxx/ https://public-inbox.org/git/20170113155253.1644-1-benpeart@xxxxxxxxxxxxx/ may help as a starting point. Thanks, Jonathan
