Re: [PATCH 1/2] pack-revindex: drop hash table

> On Mon, Dec 21, 2015 at 1:19 AM, Jeff King <peff@peff.net> wrote:
> > The main entry point to the pack-revindex code is
> > find_pack_revindex(). This calls revindex_for_pack(), which
> > lazily computes and caches the revindex for the pack.
> >
> > We store the cache in a very simple hash table. It's created
> > by init_pack_revindex(), which inserts an entry for every
> > packfile we know about, and we never grow or shrink the
> > hash. If we ever need the revindex for a pack that isn't in
> > the hash, we die() with an internal error.
> >
> > This can lead to a race, because we may load more packs
> > after having called init_pack_revindex(). For example,
> > imagine we have one process which needs to look at the
> > revindex for a variety of objects (e.g., cat-file's
> > "%(objectsize:disk)" format).  Simultaneously, git-gc is
> > running, which is doing a `git repack -ad` is running. We
> > might hit a sequence like:
> 
> Probably want to drop one of the "is running"s...