Documentation/git-repack.adoc

git-repack(1)
=============

NAME
----
git-repack - Pack unpacked objects in a repository


SYNOPSIS
--------
[verse]
'git repack' [-a] [-A] [-d] [-f] [-F] [-l] [-n] [-q] [-b] [-m]
	[--window=<n>] [--depth=<n>] [--threads=<n>] [--keep-pack=<pack-name>]
	[--write-midx[=<mode>]] [--name-hash-version=<n>] [--path-walk]
	[--filter=<filter-spec>] [--drop-filtered [--dry-run]]

DESCRIPTION
-----------

This command is used to combine all objects that do not currently
reside in a "pack", into a pack.  It can also be used to re-organize
existing packs into a single, more efficient pack.

A pack is a collection of objects, individually compressed, with
delta compression applied, stored in a single file, with an
associated index file.

Packs are used to reduce the load on mirror systems, backup
engines, disk storage, etc.

OPTIONS
-------

-a::
	Instead of incrementally packing the unpacked objects,
	pack everything referenced into a single pack.
	Especially useful when packing a repository that is used
	for private development. Use
	with `-d`.  This will clean up the objects that `git prune`
	leaves behind, but `git fsck --full --dangling` shows as
	dangling.
+
Note that users fetching over dumb protocols will have to fetch the
whole new pack in order to get any contained object, no matter how many
other objects in that pack they already have locally.
+
Promisor packfiles are repacked separately: if there are packfiles that
have an associated ".promisor" file, these packfiles will be repacked
into another separate pack, and an empty ".promisor" file corresponding
to the new separate pack will be written.

-A::
	Same as `-a`, unless `-d` is used.  Then any unreachable
	objects in a previous pack become loose, unpacked objects,
	instead of being left in the old pack.  Unreachable objects
	are never intentionally added to a pack, even when repacking.
	This option prevents unreachable objects from being immediately
	deleted by way of being left in the old pack and then
	removed.  Instead, the loose unreachable objects
	will be pruned according to normal expiry rules
	with the next 'git gc' invocation. See linkgit:git-gc[1].

-d::
	After packing, if the newly created packs make some
	existing packs redundant, remove the redundant packs.
	Also run  'git prune-packed' to remove redundant
	loose object files.

--cruft::
	Same as `-a`, unless `-d` is used. Then any unreachable objects
	are packed into a separate cruft pack. Unreachable objects can
	be pruned using the normal expiry rules with the next `git gc`
	invocation (see linkgit:git-gc[1]). Incompatible with `-k`.

--cruft-expiration=<approxidate>::
	Expire unreachable objects older than `<approxidate>`
	immediately instead of waiting for the next `git gc` invocation.
	Only useful with `--cruft -d`.

--max-cruft-size=<n>::
	Override `--max-pack-size` for cruft packs. Inherits the value of
	`--max-pack-size` (if any) by default. See the documentation for
	`--max-pack-size` for more details.

--combine-cruft-below-size=<n>::
	When generating cruft packs without pruning, only repack
	existing cruft packs whose size is strictly less than `<n>`
	bytes, which can optionally
	be suffixed with "k", "m", or "g". Cruft packs whose size is
	greater than or equal to `<n>` are left as-is and not repacked.
	Useful when you want to avoid repacking large cruft pack(s) in
	repositories that have many and/or large unreachable objects.

--expire-to=<dir>::
	Write a cruft pack containing pruned objects (if any) to the
	directory `<dir>`. This option is useful for keeping a copy of
	any pruned objects in a separate directory as a backup. Only
	useful with `--cruft -d`.

-l::
	Pass the `--local` option to 'git pack-objects'. See
	linkgit:git-pack-objects[1].

-f::
	Pass the `--no-reuse-delta` option to `git-pack-objects`, see
	linkgit:git-pack-objects[1].

-F::
	Pass the `--no-reuse-object` option to `git-pack-objects`, see
	linkgit:git-pack-objects[1].

-q::
--quiet::
	Show no progress over the standard error stream and pass the `-q`
	option to 'git pack-objects'. See linkgit:git-pack-objects[1].

-n::
	Do not update the server information with
	'git update-server-info'.  This option skips
	updating local catalog files needed to publish
	this repository (or a direct copy of it)
	over HTTP or FTP.  See linkgit:git-update-server-info[1].

--window=<n>::
--depth=<n>::
	These two options affect how the objects contained in the pack are
	stored using delta compression. The objects are first internally
	sorted by type, size and optionally names and compared against the
	other objects within `--window` to see if using delta compression saves
	space. `--depth` limits the maximum delta depth; making it too deep
	affects the performance on the unpacker side, because delta data needs
	to be applied that many times to get to the necessary object.
+
The default value for --window is 10 and --depth is 50. The maximum
depth is 4095.

--threads=<n>::
	This option is passed through to `git pack-objects`.

--window-memory=<n>::
	This option provides an additional limit on top of `--window`;
	the window size will dynamically scale down so as to not take
	up more than '<n>' bytes in memory.  This is useful in
	repositories with a mix of large and small objects to not run
	out of memory with a large window, but still be able to take
	advantage of the large window for the smaller objects.  The
	size can be suffixed with "k", "m", or "g".
	`--window-memory=0` makes memory usage unlimited.  The default
	is taken from the `pack.windowMemory` configuration variable.
	Note that the actual memory usage will be the limit multiplied
	by the number of threads used by linkgit:git-pack-objects[1].

--max-pack-size=<n>::
	Maximum size of each output pack file. The size can be suffixed with
	"k", "m", or "g". The minimum size allowed is limited to 1 MiB.
	If specified, multiple packfiles may be created, which also
	prevents the creation of a bitmap index.
	The default is unlimited, unless the config variable
	`pack.packSizeLimit` is set. Note that this option may result in
	a larger and slower repository; see the discussion in
	`pack.packSizeLimit`.

--filter=<filter-spec>::
	Remove objects matching the filter specification from the
	resulting packfile and put them into a separate packfile. Note
	that objects used in the working directory are not filtered
	out. So for the split to fully work, it's best to perform it
	in a bare repo and to use the `-a` and `-d` options along with
	this option.  Also `--no-write-bitmap-index` (or the
	`repack.writebitmaps` config option set to `false`) should be
	used otherwise writing bitmap index will fail, as it supposes
	a single packfile containing all the objects. See
	linkgit:git-rev-list[1] for valid `<filter-spec>` forms.

--filter-to=<dir>::
	Write the pack containing filtered out objects to the
	directory `<dir>`. Only useful with `--filter`. This can be
	used for putting the pack on a separate object directory that
	is accessed through the Git alternates mechanism. **WARNING:**
	If the packfile containing the filtered out objects is not
	accessible, the repo can become corrupt as it might not be
	possible to access the objects in that packfile. See the
	`objects` and `objects/info/alternates` sections of
	linkgit:gitrepository-layout[5].

--drop-filtered::
	Delete the local objects that match the `--filter` specification
	instead of keeping them in a separate packfile, reclaiming the
	disk space they occupy. This is intended for partial clones,
	where the filtered objects are promisor objects that remain
	recoverable from the promisor remote and are lazily re-fetched
	on demand when they are next needed.
+
Only large blobs are supported for now, so `--filter=blob:limit=<n>`
is currently the only accepted filter. Because dropped objects must be
recoverable, this option requires a promisor remote to be configured
and refuses to run otherwise.
+
This option requires `-a`, and implies `-d`: the objects are dropped by
rebuilding the promisor pack without them and then removing the now
redundant old packs, so the redundant packs must be deleted for the
space to actually be reclaimed. It is incompatible with `--filter-to`
and with bitmap writing (`-b`/`--write-bitmap-index`), since filtering
breaks the single-pack closure that bitmaps require. A bitmap setting
coming from configuration is silently disabled for the duration of the
command.
+
As a convenience, since dropped objects remain recoverable by lazy fetch,
`--drop-filtered` refuses to run while another operation
(merge, rebase, am, cherry-pick, revert, or bisect) is in progress, to
avoid a surprising network fetch mid-operation, and refuses to drop any
blob that the current index references, since such a blob would only be
lazily re-fetched by the next command that inspects the working tree.
These checks are skipped in bare repositories, which have neither a
working tree nor an index.

--dry-run::
	Only meaningful with `--drop-filtered`. List the objects that
	would be dropped, one object ID per line, without rebuilding any
	pack or deleting anything.

-b::
--write-bitmap-index::
	Write a reachability bitmap index as part of the repack. This
	only makes sense when used with `-a`, `-A` or `-m`, as the bitmaps
	must be able to refer to all reachable objects. This option
	overrides the setting of `repack.writeBitmaps`. This option
	has no effect if multiple packfiles are created, unless writing a
	MIDX (in which case a multi-pack bitmap is created).

--pack-kept-objects::
	Include objects in `.keep` files when repacking.  Note that we
	still do not delete `.keep` packs after `pack-objects` finishes.
	This means that we may duplicate objects, but this makes the
	option safe to use when there are concurrent pushes or fetches.
	This option is generally only useful if you are writing bitmaps
	with `-b` or `repack.writeBitmaps`, as it ensures that the
	bitmapped packfile has the necessary objects.

--keep-pack=<pack-name>::
	Exclude the given pack from repacking. This is the equivalent
	of having `.keep` file on the pack. `<pack-name>` is the
	pack file name without leading directory (e.g. `pack-123.pack`).
	The option can be specified multiple times to keep multiple
	packs.

--unpack-unreachable=<when>::
	When loosening unreachable objects, do not bother loosening any
	objects older than `<when>`. This can be used to optimize out
	the write of any objects that would be immediately pruned by
	a follow-up `git prune`.

-k::
--keep-unreachable::
	When used with `-ad`, any unreachable objects from existing
	packs will be appended to the end of the packfile instead of
	being removed. In addition, any unreachable loose objects will
	be packed (and their loose counterparts removed).

-i::
--delta-islands::
	Pass the `--delta-islands` option to `git-pack-objects`, see
	linkgit:git-pack-objects[1].

-g<factor>::
--geometric=<factor>::
	Arrange resulting pack structure so that each successive pack
	contains at least `<factor>` times the number of objects as the
	next-largest pack.
+
`git repack` ensures this by determining a "cut" of packfiles that need
to be repacked into one in order to ensure a geometric progression. It
picks the smallest set of packfiles such that as many of the larger
packfiles (by count of objects contained in that pack) may be left
intact.
+
Unlike other repack modes, the set of objects to pack is determined
uniquely by the set of packs being "rolled-up"; in other words, the
packs determined to need to be combined in order to restore a geometric
progression.
+
Loose objects are implicitly included in this "roll-up", without respect to
their reachability. This is subject to change in the future.
+
When writing a multi-pack bitmap, `git repack` selects the largest resulting
pack as the preferred pack for object selection by the MIDX (see
linkgit:git-multi-pack-index[1]).

-m::
--write-midx[=<mode>]::
	Write a multi-pack index (see linkgit:git-multi-pack-index[1])
	containing the non-redundant packs. The following modes are
	available:
+
--
	`default`;;
		Write a single MIDX covering all packs. This is the
		default when `--write-midx` is given without an
		explicit mode.

	`incremental`;;
		Write an incremental MIDX chain instead of a single
		flat MIDX.
+
Without `--geometric`, a new MIDX layer is appended to the existing
chain (or a new chain is started) containing whatever packs were written
by the repack. Existing layers are preserved as-is.
+
When combined with `--geometric`, the incremental mode maintains a chain
of MIDX layers that is compacted over time using a geometric merging
strategy. Each repack creates a new tip layer containing the newly
written pack(s). Adjacent layers are then merged whenever the newer
layer's object count exceeds `1/repack.midxSplitFactor` of the next
deeper layer's count. Layers that do not meet this condition are
retained as-is.
+
The result is that newer (tip) layers tend to contain many small packs
with relatively few objects, while older (deeper) layers contain fewer,
larger packs covering more objects. Because compaction is driven by the
tip of the chain, newer layers are also rewritten more frequently than
older ones, which are only touched when enough objects have accumulated
to justify merging into them. This keeps the total number of layers
logarithmic relative to the total number of objects.
+
Only packs in the tip MIDX layer are considered as candidates for the
geometric repack; packs in deeper layers are left untouched. If the tip
layer contains fewer packs than `repack.midxNewLayerThreshold`, those
packs are excluded from the geometry entirely, and a new layer is
created for any new pack(s) without disturbing the existing chain.
--

--name-hash-version=<n>::
	Provide this argument to the underlying `git pack-objects` process.
	See linkgit:git-pack-objects[1] for full details.

--path-walk::
	Pass the `--path-walk` option to the underlying `git pack-objects`
	process. See linkgit:git-pack-objects[1] for full details.

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

Various configuration variables affect packing, see
linkgit:git-config[1] (search for "pack" and "delta").

By default, the command passes `--delta-base-offset` option to
'git pack-objects'; this typically results in slightly smaller packs,
but the generated packs are incompatible with versions of Git older than
version 1.4.4. If you need to share your repository with such ancient Git
versions, either directly or via the dumb http protocol, then you
need to set the configuration variable `repack.UseDeltaBaseOffset` to
"false" and repack. Access from old Git versions over the native protocol
is unaffected by this option as the conversion is performed on the fly
as needed in that case.

Delta compression is not used on objects larger than the
`core.bigFileThreshold` configuration variable and on files with the
attribute `delta` set to false.

SEE ALSO
--------
linkgit:git-pack-objects[1]
linkgit:git-prune-packed[1]

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