5cf7a17dfb
When pushing, we feed pack-objects a list of both positive and negative
objects. The positive objects are what we want to send, and the negative
objects are what the other side told us they have, which we can use to
limit the size of the push.
Before passing along a negative object, send_pack() will make sure we
actually have it (since we only know about it because the remote
mentioned it, not because it's one of our refs). So it's expected that
some of these objects will be missing on the local side. But looking for
a missing object is more expensive than one that we have: it triggers
reprepare_packed_git() to handle a racy repack, plus it has to explore
every alternate's loose object tree (which can be slow if you have a lot
of them, or have a high-latency filesystem).
This isn't usually a big problem, since repositories you're pushing to
don't generally have a large number of refs that are unrelated to what
the client has. But there's no reason such a setup is wrong, and it
currently performs poorly.
We can fix this by using OBJECT_INFO_QUICK, which tells the lookup
code that we expect objects to be missing. Notably, it will not re-scan
the packs, and it will use the loose cache from 61c7711cfe (sha1-file:
use loose object cache for quick existence check, 2018-11-12).
The downside is that in the rare case that we race with a local repack,
we might fail to feed some objects to pack-objects, making the resulting
push larger. But we'd never produce an invalid or incorrect push, just a
less optimal one. That seems like a reasonable tradeoff, and we already
do similar things on the fetch side (e.g., when marking COMPLETE
commits).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git - fast, scalable, distributed revision control system
Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.
Git is an Open Source project covered by the GNU General Public License version 2 (some parts of it are under different licenses, compatible with the GPLv2). It was originally written by Linus Torvalds with help of a group of hackers around the net.
Please read the file INSTALL for installation instructions.
Many Git online resources are accessible from https://git-scm.com/ including full documentation and Git related tools.
See Documentation/gittutorial.txt to get started, then see
Documentation/giteveryday.txt for a useful minimum set of commands, and
Documentation/git-<commandname>.txt for documentation of each command.
If git has been correctly installed, then the tutorial can also be
read with man gittutorial or git help tutorial, and the
documentation of each command with man git-<commandname> or git help <commandname>.
CVS users may also want to read Documentation/gitcvs-migration.txt
(man gitcvs-migration or git help cvs-migration if git is
installed).
The user discussion and development of Git take place on the Git mailing list -- everyone is welcome to post bug reports, feature requests, comments and patches to git@vger.kernel.org (read Documentation/SubmittingPatches for instructions on patch submission). To subscribe to the list, send an email with just "subscribe git" in the body to majordomo@vger.kernel.org. The mailing list archives are available at https://public-inbox.org/git/, http://marc.info/?l=git and other archival sites.
Issues which are security relevant should be disclosed privately to the Git Security mailing list git-security@googlegroups.com.
The maintainer frequently sends the "What's cooking" reports that list the current status of various development topics to the mailing list. The discussion following them give a good reference for project status, development direction and remaining tasks.
The name "git" was given by Linus Torvalds when he wrote the very first version. He described the tool as "the stupid content tracker" and the name as (depending on your mood):
- random three-letter combination that is pronounceable, and not actually used by any common UNIX command. The fact that it is a mispronunciation of "get" may or may not be relevant.
- stupid. contemptible and despicable. simple. Take your pick from the dictionary of slang.
- "global information tracker": you're in a good mood, and it actually works for you. Angels sing, and a light suddenly fills the room.
- "goddamn idiotic truckload of sh*t": when it breaks