Re: another packed-refs race
- From
Jeff King <peff@peff.net>
- Date
- May 3, 2013, 18:26 UTC
- Message-ID
- <20130503182649.GA25379@sigill.intra.peff.net>
- In-Reply-To
- <20130503172853.GB21715@sigill.intra.peff.net>
On Fri, May 03, 2013 at 01:28:53PM -0400, Jeff King wrote:
Show 18 quoted lines
> > The following solution might work in both the resolve-a-single-ref and > > enumerating-refs case: > > > > 0. Look for ref already cached in memory. If found, OK. > > > > 1. Look for loose ref. If found, OK. > > > > 2. If not found, load all loose refs and packed-refs from disk (in > > that order), and store in memory for remainder of this process. Never > > reload packed-refs from disk (unless you also reload all loose refs > > first). > > I think that would be correct (modulo that step 1 cannot happen for > enumeration). But we would like to avoid loading all loose refs if we > can. Especially on a cold cache, it can be quite slow, and you may not > even care about those refs for the current operation (I do not recall > the exact original motivation for the lazy loading, but it was something > along those lines).
Actually, forgetting about enumeration for a minute, that would make single-ref lookup quite painful. Running "git rev-parse foo" shouldn't have to even look at most loose refs in the first place. It should be a couple of open() calls looking for the right spot, and then fall back to loading packed-refs.
-Peff