[PATCH] treemanifest: store submanifest revlog per directory

[Matt Mackall]

On Fri, 2015-05-15 at 20:28 +0200, Adrian Buehlmann wrote:
> On 2015-05-15 14:20, Martin von Zweigbergk wrote:
> > I think it will be optional forever, because it will probably generally
> > be faster with flat manifests for small and medium-sized projects. Also
> > note that the format is hidden behind an experimental config option, so
> > we can still modify the format after this commit until we move the
> > format out of experimental.
> > 
> > I'm still curious to hear what you had in mind regarding changes to the
> > format.
> 
> Given that it will be optional forever and intended for very big repos
> only, it's probably not that relevant for me anyway. Most people will
> thus ignore it.
> 
> Matt queued it, so it's already in.
> 
> What I was wondering is: Why yet another directory tree inside meta/,
> which only contains exactly one file per directory, is really needed /
> really makes sense. Creating lots of directories is also not that fast,
> especially not on Windows.

Just so we're all on the same page: the target repo size here is 1
billion files (not a typo). So there are indeed lots of Other Problems,
which collectively are going to effectively rule out full clones to
normal workstations anyway. Some form of partial clone and sparse
checkout will be needed. The crossover point for tree manifests being
worthwhile in terms of headaches caused/solved is probably north of 1M
files.

-- 
Mathematics is the supreme nostalgia of our time.