git-gc - Cleanup unnecessary files and optimize the local repository
git gc [--aggressive] [--auto] [--quiet] [--prune=<date> | --no-prune] [--force] [--keep-largest-pack]
Runs a number of housekeeping tasks within the current repository, such as
compressing file revisions (to reduce disk space and increase performance),
removing unreachable objects which may have been created from prior
invocations of git add
, packing refs, pruning reflog, rerere metadata
or stale working trees.
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
$ git config --global gc.auto 0
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
With this option, git gc
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
disables automatic packing of loose objects.
If the number of packs exceeds the value of gc.autoPackLimit
existing packs (except those marked with a .keep
file or over
limit) are consolidated into a single pack by using
option of git repack
. If the amount of memory is
estimated not enough for git repack
to run smoothly and
is not set, the largest pack will also be excluded
(this is the equivalent of running git gc
). Setting gc.autoPackLimit
to 0 disables
automatic consolidation of packs.
If houskeeping is required due to many loose objects or packs, all other
housekeeping tasks (e.g. rerere, working trees, reflog...) will be performed
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.
Do not prune any loose objects.
Suppress all progress reports.
Force git gc to run even if there may
be another git gc instance running on this repository.
All packs except the largest pack and those
marked with a .keep files are consolidated into a single pack. When
this option is used, gc.bigPackThreshold is ignored.
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
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:
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
The optional configuration variable gc.rerereUnresolved
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
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".
Optional configuration variable gc.worktreePruneExpire
controls how old a
stale working tree should be before git worktree prune
Default is "3 months ago".
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
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
1.Any object with modification time newer
than the --prune date is kept, along with everything reachable from
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
The git gc --auto
command will run the pre-auto-gc
for more information.
git-prune(1) git-reflog(1) git-repack(1)
Part of the git(1)