From: Jeff King <peff@peff.net>
Date: Sun, 05 Sep 2021 12:49:14 GMT
Subject: Re: [hacky PATCH 0/2] speeding up trivial for-each-ref invocations
Message-ID: <YTS8yiYwR+eeZf4+@coredump.intra.peff.net>
In-Reply-To: <CAOLTT8RzHb5zWUm1psZRTP=iST-jP4DBmG2Zh1UPdo6z+QyHcg@mail.gmail.com>

On Sun, Sep 05, 2021 at 04:19:53PM +0800, ZheNing Hu wrote:

> > In this version there are 2 patches, tested against 'git for-each-ref
> > --format="%(objectname) %(refname)"' on a fully packed repo with 500k
> > refs:
> >
> 
> Regarding this 500k refs, is there any way I can reproduce it?

Try this in a clone of linux.git (or any other repo):

  git rev-list HEAD |
  head -500000 |
  perl -lne 'print "create refs/foo/$. $_"' |
  git update-ref --stdin

  git pack-refs --all --prune

Though I actually think for these tests that it is not important that
each ref point to a unique commit (we are not opening up the objects at
all, and just treating the oids as strings).

-Peff