RE: reftable [v5]: new ref storage format

-----Original Message-----
From: Shawn Pearce [mailto:spearce@spearce.org]
In git-core, I'm worried about the caveats related to locking. Git tries to work
nicely on NFS, and it seems LMDB wouldn't. Git also runs fine on a read-only
filesystem, and LMDB gets a little weird about that. Finally, Git doesn't have
nearly the risks LMDB has about a crashed reader or writer locking out future
operations until the locks have been resolved. This is especially true with shared
user repositories, where another user might setup and own the semaphore.

FWIW, git has problems with stale lock file in the event of a crash (refs/foo.lock 
might still exist, and git does nothing to clean it up).

In my testing (which involved a *lot* of crashing), I never once had to clean up a
stale LMDB lock.  That said, I didn't test on a RO filesystem.