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Re: Simultaneous gc and repack




On Thursday, April 13, 2017 11:03:14 AM Jacob Keller wrote:
> On Thu, Apr 13, 2017 at 10:31 AM, David Turner 
<novalis@xxxxxxxxxxx> wrote:
> > Git gc locks the repository (using a gc.pid file) so
> > that other gcs don't run concurrently. But git repack
> > doesn't respect this lock, so it's possible to have a
> > repack running at the same time as a gc.  This makes
> > the gc sad when its packs are deleted out from under it
> > with: "fatal: ./objects/pack/pack-$sha.pack cannot be
> > accessed".  Then it dies, leaving a large temp file
> > hanging around.
> > 
> > Does the following seem reasonable?
> > 
> > 1. Make git repack, by default, check for a gc.pid file
> > (using the same logic as git gc itself does).
> > 2. Provide a --force option to git repack to ignore said
> > check. 3. Make git gc provide that --force option when
> > it calls repack under its own lock.
> 
> What about just making the code that calls repack today
> just call gc instead? I guess it's more work if you don't
> strictly need it but..?

There are many scanerios where this does not achieve the 
same thing.  On the obvious side, gc does more than 
repacking, but on the other side, repacking has many 
switches that are not available via gc.

Would it make more sense to move the lock to repack instead 
of to gc?

-Martin

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