gc: automatically write commit-graph files
[git/git.git] / Documentation / git-gc.txt
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1git-gc(1)
2=========
3
4NAME
5----
6git-gc - Cleanup unnecessary files and optimize the local repository
7
8
9SYNOPSIS
10--------
7791a1d9 11[verse]
ae4e89e5 12'git gc' [--aggressive] [--auto] [--quiet] [--prune=<date> | --no-prune] [--force] [--keep-largest-pack]
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13
14DESCRIPTION
15-----------
16Runs a number of housekeeping tasks within the current repository,
17such as compressing file revisions (to reduce disk space and increase
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18performance), removing unreachable objects which may have been
19created from prior invocations of 'git add', packing refs, pruning
20reflog, rerere metadata or stale working trees.
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21
22Users are encouraged to run this task on a regular basis within
23each repository to maintain good disk space utilization and good
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24operating performance.
25
0b444cdb 26Some git commands may automatically run 'git gc'; see the `--auto` flag
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27below for details. If you know what you're doing and all you want is to
28disable this behavior permanently without further considerations, just do:
29
30----------------------
31$ git config --global gc.auto 0
32----------------------
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34OPTIONS
35-------
36
0d7566a5 37--aggressive::
0b444cdb 38 Usually 'git gc' runs very quickly while providing good disk
5049012f 39 space utilization and performance. This option will cause
0b444cdb 40 'git gc' to more aggressively optimize the repository at the expense
0d7566a5 41 of taking much more time. The effects of this optimization are
5049012f 42 persistent, so this option only needs to be used occasionally; every
0d7566a5 43 few hundred changesets or so.
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44
45--auto::
0b444cdb 46 With this option, 'git gc' checks whether any housekeeping is
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47 required; if not, it exits without performing any work.
48 Some git commands run `git gc --auto` after performing
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49 operations that could create many loose objects. Housekeeping
50 is required if there are too many loose objects or too many
51 packs in the repository.
d7e56dbc 52+
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53If the number of loose objects exceeds the value of the `gc.auto`
54configuration variable, then all loose objects are combined into a
55single pack using `git repack -d -l`. Setting the value of `gc.auto`
56to 0 disables automatic packing of loose objects.
d7e56dbc 57+
da0005b8 58If the number of packs exceeds the value of `gc.autoPackLimit`,
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59then existing packs (except those marked with a `.keep` file
60or over `gc.bigPackThreshold` limit)
d7e56dbc 61are consolidated into a single pack by using the `-A` option of
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62'git repack'.
63If the amount of memory is estimated not enough for `git repack` to
64run smoothly and `gc.bigPackThreshold` is not set, the largest
65pack will also be excluded (this is the equivalent of running `git gc`
66with `--keep-base-pack`).
67Setting `gc.autoPackLimit` to 0 disables automatic consolidation of
68packs.
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69+
70If houskeeping is required due to many loose objects or packs, all
71other housekeeping tasks (e.g. rerere, working trees, reflog...) will
72be performed as well.
73
e3ff4b24 74
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75--prune=<date>::
76 Prune loose objects older than date (default is 2 weeks ago,
61929404 77 overridable by the config variable `gc.pruneExpire`).
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78 --prune=all prunes loose objects regardless of their age and
79 increases the risk of corruption if another process is writing to
80 the repository concurrently; see "NOTES" below. --prune is on by
81 default.
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82
83--no-prune::
84 Do not prune any loose objects.
85
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86--quiet::
87 Suppress all progress reports.
88
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89--force::
90 Force `git gc` to run even if there may be another `git gc`
91 instance running on this repository.
92
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93--keep-largest-pack::
94 All packs except the largest pack and those marked with a
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95 `.keep` files are consolidated into a single pack. When this
96 option is used, `gc.bigPackThreshold` is ignored.
ae4e89e5 97
76a8788c 98CONFIGURATION
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99-------------
100
ae9f6311 101The optional configuration variable `gc.reflogExpire` can be
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102set to indicate how long historical entries within each branch's
103reflog should remain available in this repository. The setting is
104expressed as a length of time, for example '90 days' or '3 months'.
105It defaults to '90 days'.
106
ae9f6311 107The optional configuration variable `gc.reflogExpireUnreachable`
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108can be set to indicate how long historical reflog entries which
109are not part of the current branch should remain available in
110this repository. These types of entries are generally created as
6cf378f0 111a result of using `git commit --amend` or `git rebase` and are the
23bfbb81 112commits prior to the amend or rebase occurring. Since these changes
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113are not part of the current project most users will want to expire
114them sooner. This option defaults to '30 days'.
115
eb523a8d 116The above two configuration variables can be given to a pattern. For
60109d0e 117example, this sets non-default expiry values only to remote-tracking
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118branches:
119
120------------
121[gc "refs/remotes/*"]
122 reflogExpire = never
da0005b8 123 reflogExpireUnreachable = 3 days
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124------------
125
ae9f6311 126The optional configuration variable `gc.rerereResolved` indicates
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127how long records of conflicted merge you resolved earlier are
128kept. This defaults to 60 days.
129
ae9f6311 130The optional configuration variable `gc.rerereUnresolved` indicates
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131how long records of conflicted merge you have not resolved are
132kept. This defaults to 15 days.
133
ae9f6311 134The optional configuration variable `gc.packRefs` determines if
4be0c352 135'git gc' runs 'git pack-refs'. This can be set to "notbare" to enable
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136it within all non-bare repos or it can be set to a boolean value.
137This defaults to true.
30f610b7 138
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139The optional configuration variable `gc.commitGraph` determines if
140'git gc' should run 'git commit-graph write'. This can be set to a
141boolean value. This defaults to false.
142
ae9f6311 143The optional configuration variable `gc.aggressiveWindow` controls how
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144much time is spent optimizing the delta compression of the objects in
145the repository when the --aggressive option is specified. The larger
146the value, the more time is spent optimizing the delta compression. See
bed21a8a 147the documentation for the --window option in linkgit:git-repack[1] for
c9486ae8 148more details. This defaults to 250.
125f8146 149
ae9f6311 150Similarly, the optional configuration variable `gc.aggressiveDepth`
7e823880 151controls --depth option in linkgit:git-repack[1]. This defaults to 50.
0d7566a5 152
ae9f6311 153The optional configuration variable `gc.pruneExpire` controls how old
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154the unreferenced loose objects have to be before they are pruned. The
155default is "2 weeks ago".
156
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157Optional configuration variable `gc.worktreePruneExpire` controls how
158old a stale working tree should be before `git worktree prune` deletes
159it. Default is "3 months ago".
160
3ffb58be 161
76a8788c 162NOTES
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163-----
164
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165'git gc' tries very hard not to delete objects that are referenced
166anywhere in your repository. In
3ffb58be 167particular, it will keep not only objects referenced by your current set
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168of branches and tags, but also objects referenced by the index,
169remote-tracking branches, refs saved by 'git filter-branch' in
3ed0b11e 170refs/original/, or reflogs (which may reference commits in branches
3ffb58be 171that were later amended or rewound).
f1350d0c 172If you are expecting some objects to be deleted and they aren't, check
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173all of those locations and decide whether it makes sense in your case to
174remove those references.
175
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176On the other hand, when 'git gc' runs concurrently with another process,
177there is a risk of it deleting an object that the other process is using
178but hasn't created a reference to. This may just cause the other process
179to fail or may corrupt the repository if the other process later adds a
180reference to the deleted object. Git has two features that significantly
181mitigate this problem:
182
183. Any object with modification time newer than the `--prune` date is kept,
184 along with everything reachable from it.
185
186. Most operations that add an object to the database update the
187 modification time of the object if it is already present so that #1
188 applies.
189
190However, these features fall short of a complete solution, so users who
191run commands concurrently have to live with some risk of corruption (which
192seems to be low in practice) unless they turn off automatic garbage
193collection with 'git config gc.auto 0'.
194
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195HOOKS
196-----
197
198The 'git gc --auto' command will run the 'pre-auto-gc' hook. See
199linkgit:githooks[5] for more information.
200
201
56ae8df5 202SEE ALSO
30f610b7 203--------
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204linkgit:git-prune[1]
205linkgit:git-reflog[1]
206linkgit:git-repack[1]
207linkgit:git-rerere[1]
30f610b7 208
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209GIT
210---
9e1f0a85 211Part of the linkgit:git[1] suite