From: Jeff King <peff@peff.net>
To: Jakub Narebski <jnareb@gmail.com>
Cc: Junio C Hamano <gitster@pobox.com>,
Michael Haggerty <mhagger@alum.mit.edu>,
git discussion list <git@vger.kernel.org>
Subject: Re: RFC: New reference iteration paradigm
Date: Tue, 29 May 2018 12:52:22 -0400 [thread overview]
Message-ID: <20180529165221.GB13385@sigill.intra.peff.net> (raw)
In-Reply-To: <86h8mu1g8j.fsf@gmail.com>
On Sat, May 26, 2018 at 07:25:32PM +0200, Jakub Narebski wrote:
> > At one point I wrote a patch to binary search the packed-refs file, find
> > the first "refs/tags/" entry, and then walk linearly through there. What
> > stopped me is that the current refs.c code (I guess file-backend.c these
> > days) was not happy with me partially filling in the ref_dir structs in
> > this "inside out" way.
> [...]
>
> Isn't this what reftable - an alternative way of storing refs in Git,
> tested by being used by JGit - would solve? See Christian Couder post
> "Implementing reftable in Git"
>
> https://public-inbox.org/git/CAP8UFD0PPZSjBnxCA7ez91vBuatcHKQ+JUWvTD1iHcXzPBjPBg@mail.gmail.com/t/#u
>
> 'Efficient lookup of an entire namespace, such as refs/tags/' is
> allegedly one of the objectives of this format.
The thread you are responding to is over 2 years old. ;)
Since then, Michael rewrote the packed-refs code to handle this case,
and we mmap and binary-search the file since v2.15.
Reftables would also have (amortized) log-n lookup, and also fix some
other problems (like lack of atomic transactions). So yes, I hope we do
eventually move to reftable, too.
-Peff
next prev parent reply other threads:[~2018-05-29 16:52 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-31 16:13 RFC: New reference iteration paradigm Michael Haggerty
2016-03-31 18:01 ` Junio C Hamano
2016-03-31 19:31 ` Jeff King
2016-03-31 20:08 ` Junio C Hamano
2018-05-26 17:25 ` Jakub Narebski
2018-05-29 16:52 ` Jeff King [this message]
2016-03-31 20:15 ` David Turner
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