Re: warning: no common commits - slow pull

[Daniel Barkalow <barkalow@iabervon.org>]

On Thu, 6 Mar 2008, David Brownell wrote:

> Any progress on fixing this?
> 
> I'll report that with git version 1.5.4.3.447.gc95b3.dirty
> (just a couple days old) I've observed this when updating
> a clone by pulling from
> 
>  (a) a parent on the same disk partition
>  (b) a parent on a non-mirrored network server
> 
> So that would seem to trash the assumptions that this is
> related to version mismatch between mirrors, and that the
> fix can (or should!) wait till 1.6.0 ...
> 
> I was glad to see the "^C" workaround, that seems to work.
> 
> When I "git pull" it first fetches a bunch of files, then
> concludes (wrongly) "no common commits", then starts a
> second fetch of a *HUGE* number of files ... 400 MB is too
> much to pay when updating from rc3-last-week to rc4.  But
> if I interrupt that second one with ^C, it seems that the
> first one fetched enough to make the next "git pull" go
> pretty quickly.
> 
> 
> This does seem appear to show up more often lately because
> of RC4 having been tagged ... but I don't know for sure.
> 
> I've got a couple kernel workspaces still on last Friday's
> version, which -- if this holds true to form! -- will show
> this bug when I "git pull".  So if there are experiments
> that would help nail down what's going on here, please
> spell them out to me ("this command, then this ... send
> this output...").

Actually, if you can make a tarball of the .git directory of one of those 
workspaces, and see if the bug is reproducable with that .git directory 
every time (particularly when pulling a local repository), it would be 
really helpful to have a reliable test case.

There's a debugging thing that would help, but it's not in your version. 
It's in next as

49aaddd102aff Teach upload-pack to log the received need lines to an fd

With that commit, you should be able to do:

GIT_DEBUG_SEND_PACK=3 git pull 3>UPLOAD_LOG

and get a file UPLOAD_LOG that will show what it's doing, although there's 
a reasonable chance that it'll only demonstrate that it's doing nothing 
helpful, which we already pretty much know.

	-Daniel
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