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The `--auto` flag for git-pack-refs(1) allows the ref backend to decide whether or not a repack is in order. This switch has been introduced mostly with the "reftable" backend in mind, which already knows to auto-compact its tables during normal operations. When the flag is set, then it will use the same auto-compaction mechanism and thus end up doing nothing in most cases. The "files" backend does not have any such heuristic yet and instead packs any loose references unconditionally. So we rewrite the complete "packed-refs" file even if there's only a single loose reference to be packed. Even worse, starting with 9f6714ab3e (builtin/gc: pack refs when using `git maintenance run --auto`, 2024-03-25), `git pack-refs --auto` is unconditionally executed via our auto maintenance, so we end up repacking references every single time auto maintenance kicks in. And while that commit already mentioned that the "files" backend unconditionally packs refs now, the author obviously didn't quite think about the consequences thereof. So while the idea was sound, we really should have added a heuristic to the "files" backend before implementing it. Introduce a heuristic that decides whether or not it is worth to pack loose references. The important factors to decide here are the number of loose references in comparison to the overall size of the "packed-refs" file. The bigger the "packed-refs" file, the longer it takes to rewrite it and thus we scale up the limit of allowed loose references before we repack. As is the nature of heuristics, this mechansim isn't obviously "correct", but should rather be seen as a tradeoff between how much resources we spend packing refs and how inefficient the ref store becomes. For all I can say, we have successfully been using the exact same heuristic in Gitaly for several years by now. Signed-off-by: Patrick Steinhardt <ps@pks.im> 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 and Documentation/CodingGuidelines).
Those wishing to help with error message, usage and informational message
string translations (localization l10) should see po/README.md
(a po file is a Portable Object file that holds the translations).
To subscribe to the list, send an email to git+subscribe@vger.kernel.org (see https://subspace.kernel.org/subscribing.html for details). The mailing list archives are available at https://lore.kernel.org/git/, https://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