NAME | SYNOPSIS | DESCRIPTION | OPTIONS | CONFIGURATION | NOTES | HOOKS | SEE ALSO | GIT | COLOPHON

GIT-GC(1)                        Git Manual                        GIT-GC(1)

NAME         top

       git-gc - Cleanup unnecessary files and optimize the local repository

SYNOPSIS         top

       git gc [--aggressive] [--auto] [--quiet] [--prune=<date> | --no-prune] [--force]

DESCRIPTION         top

       Runs a number of housekeeping tasks within the current repository,
       such as compressing file revisions (to reduce disk space and increase
       performance) and removing unreachable objects which may have been
       created from prior invocations of git add.

       Users are encouraged to run this task on a regular basis within each
       repository to maintain good disk space utilization and good operating
       performance.

       Some git commands may automatically run git gc; see the --auto flag
       below for details. If you know what you’re doing and all you want is
       to disable this behavior permanently without further considerations,
       just do:

           $ git config --global gc.auto 0

OPTIONS         top

       --aggressive
           Usually git gc runs very quickly while providing good disk space
           utilization and performance. This option will cause git gc to
           more aggressively optimize the repository at the expense of
           taking much more time. The effects of this optimization are
           persistent, so this option only needs to be used occasionally;
           every few hundred changesets or so.

       --auto
           With this option, git gc checks whether any housekeeping is
           required; if not, it exits without performing any work. Some git
           commands run git gc --auto after performing operations that could
           create many loose objects.

           Housekeeping is required if there are too many loose objects or
           too many packs in the repository. If the number of loose objects
           exceeds the value of the gc.auto configuration variable, then all
           loose objects are combined into a single pack using git repack -d
           -l. Setting the value of gc.auto to 0 disables automatic packing
           of loose objects.

           If the number of packs exceeds the value of gc.autoPackLimit,
           then existing packs (except those marked with a .keep file) are
           consolidated into a single pack by using the -A option of git
           repack. Setting gc.autoPackLimit to 0 disables automatic
           consolidation of packs.

       --prune=<date>
           Prune loose objects older than date (default is 2 weeks ago,
           overridable by the config variable gc.pruneExpire). --prune=all
           prunes loose objects regardless of their age and increases the
           risk of corruption if another process is writing to the
           repository concurrently; see "NOTES" below. --prune is on by
           default.

       --no-prune
           Do not prune any loose objects.

       --quiet
           Suppress all progress reports.

       --force
           Force git gc to run even if there may be another git gc instance
           running on this repository.

CONFIGURATION         top

       The optional configuration variable gc.reflogExpire can be set to
       indicate how long historical entries within each branch’s reflog
       should remain available in this repository. The setting is expressed
       as a length of time, for example 90 days or 3 months. It defaults to
       90 days.

       The optional configuration variable gc.reflogExpireUnreachable can be
       set to indicate how long historical reflog entries which are not part
       of the current branch should remain available in this repository.
       These types of entries are generally created as a result of using git
       commit --amend or git rebase and are the commits prior to the amend
       or rebase occurring. Since these changes are not part of the current
       project most users will want to expire them sooner. This option
       defaults to 30 days.

       The above two configuration variables can be given to a pattern. For
       example, this sets non-default expiry values only to remote-tracking
       branches:

           [gc "refs/remotes/*"]
                   reflogExpire = never
                   reflogExpireUnreachable = 3 days

       The optional configuration variable gc.rerereResolved indicates how
       long records of conflicted merge you resolved earlier are kept. This
       defaults to 60 days.

       The optional configuration variable gc.rerereUnresolved indicates how
       long records of conflicted merge you have not resolved are kept. This
       defaults to 15 days.

       The optional configuration variable gc.packRefs determines if git gc
       runs git pack-refs. This can be set to "notbare" to enable it within
       all non-bare repos or it can be set to a boolean value. This defaults
       to true.

       The optional configuration variable ‘gc.aggressiveWindow` controls
       how much time is spent optimizing the delta compression of the
       objects in the repository when the --aggressive option is specified.
       The larger the value, the more time is spent optimizing the delta
       compression. See the documentation for the --window’ option in
       git-repack(1) for more details. This defaults to 250.

       Similarly, the optional configuration variable gc.aggressiveDepth
       controls --depth option in git-repack(1). This defaults to 50.

       The optional configuration variable gc.pruneExpire controls how old
       the unreferenced loose objects have to be before they are pruned. The
       default is "2 weeks ago".

NOTES         top

       git gc tries very hard not to delete objects that are referenced
       anywhere in your repository. In particular, it will keep not only
       objects referenced by your current set of branches and tags, but also
       objects referenced by the index, remote-tracking branches, refs saved
       by git filter-branch in refs/original/, or reflogs (which may
       reference commits in branches that were later amended or rewound). If
       you are expecting some objects to be deleted and they aren’t, check
       all of those locations and decide whether it makes sense in your case
       to remove those references.

       On the other hand, when git gc runs concurrently with another
       process, there is a risk of it deleting an object that the other
       process is using but hasn’t created a reference to. This may just
       cause the other process to fail or may corrupt the repository if the
       other process later adds a reference to the deleted object. Git has
       two features that significantly mitigate this problem:

        1. Any object with modification time newer than the --prune date is
           kept, along with everything reachable from it.

        2. Most operations that add an object to the database update the
           modification time of the object if it is already present so that
           #1 applies.

       However, these features fall short of a complete solution, so users
       who run commands concurrently have to live with some risk of
       corruption (which seems to be low in practice) unless they turn off
       automatic garbage collection with git config gc.auto 0.

HOOKS         top

       The git gc --auto command will run the pre-auto-gc hook. See
       githooks(5) for more information.

SEE ALSO         top

       git-prune(1) git-reflog(1) git-repack(1) git-rerere(1)

GIT         top

       Part of the git(1) suite

COLOPHON         top

       This page is part of the git (Git distributed version control system)
       project.  Information about the project can be found at 
       ⟨http://git-scm.com/⟩.  If you have a bug report for this manual page,
       see ⟨http://git-scm.com/community⟩.  This page was obtained from the
       project's upstream Git repository ⟨https://github.com/git/git.git⟩ on
       2017-07-05.  If you discover any rendering problems in this HTML ver‐
       sion of the page, or you believe there is a better or more up-to-date
       source for the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original man‐
       ual page), send a mail to man-pages@man7.org

Git 2.12.0.244.g625568           03/12/2017                        GIT-GC(1)

Pages that refer to this page: git(1)git-clone(1)git-config(1)git-fetch(1)git-p4(1)git-pack-objects(1)git-prune(1)git-reflog(1)git-repack(1)gitrepository-layout(5)gitnamespaces(7)