Documentation/git-gc.txt - jrn/git - Git at Google

 git-gc(1)
 =========

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


 SYNOPSIS
 --------
 [verse]
 'git gc' [--aggressive] [--auto] [--quiet] [--prune=<date> | --no-prune] [--force] [--keep-largest-pack]

 DESCRIPTION
 -----------
 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. May also update ancillary
 indexes such as the commit-graph.

 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
 -------

 --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
 or over `gc.bigPackThreshold` limit)
 are consolidated into a single pack by using the `-A` option of
 'git repack'.
 If the amount of memory is estimated not enough for `git repack` to
 run smoothly and `gc.bigPackThreshold` is not set, the largest
 pack will also be excluded (this is the equivalent of running `git gc`
 with `--keep-base-pack`).
 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 as well.


 --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.

 --keep-largest-pack::
 	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.

 CONFIGURATION
 -------------

 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.writeCommitGraph` determines if
 'git gc' should run 'git commit-graph write'. This can be set to a
 boolean value. This defaults to false.

 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 linkgit:git-repack[1] for
 more details.  This defaults to 250.

 Similarly, the optional configuration variable `gc.aggressiveDepth`
 controls --depth option in linkgit: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` deletes
 it. Default is "3 months ago".


 NOTES
 -----

 '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:

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

 . 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
 -----

 The 'git gc --auto' command will run the 'pre-auto-gc' hook.  See
 linkgit:githooks[5] for more information.


 SEE ALSO
 --------
 linkgit:git-prune[1]
 linkgit:git-reflog[1]
 linkgit:git-repack[1]
 linkgit:git-rerere[1]

 GIT
 ---
 Part of the linkgit:git[1] suite
	git-gc(1)
	=========

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


	SYNOPSIS
	--------
	[verse]
	'git gc' [--aggressive] [--auto] [--quiet] [--prune=<date> \| --no-prune] [--force] [--keep-largest-pack]

	DESCRIPTION
	-----------
	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. May also update ancillary
	indexes such as the commit-graph.

	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
	-------

	--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
	or over `gc.bigPackThreshold` limit)
	are consolidated into a single pack by using the `-A` option of
	'git repack'.
	If the amount of memory is estimated not enough for `git repack` to
	run smoothly and `gc.bigPackThreshold` is not set, the largest
	pack will also be excluded (this is the equivalent of running `git gc`
	with `--keep-base-pack`).
	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 as well.


	--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.

	--keep-largest-pack::
	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.

	CONFIGURATION
	-------------

	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.writeCommitGraph` determines if
	'git gc' should run 'git commit-graph write'. This can be set to a
	boolean value. This defaults to false.

	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 linkgit:git-repack[1] for
	more details. This defaults to 250.

	Similarly, the optional configuration variable `gc.aggressiveDepth`
	controls --depth option in linkgit: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` deletes
	it. Default is "3 months ago".


	NOTES
	-----

	'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:

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

	. 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
	-----

	The 'git gc --auto' command will run the 'pre-auto-gc' hook. See
	linkgit:githooks[5] for more information.


	SEE ALSO
	--------
	linkgit:git-prune[1]
	linkgit:git-reflog[1]
	linkgit:git-repack[1]
	linkgit:git-rerere[1]

	GIT
	---
	Part of the linkgit:git[1] suite