git-commit-vandalism/Documentation/git-repack.txt
Michael Stahl 954176c128 document git-repack interaction of pack.threads and pack.windowMemory
Signed-off-by: Michael Stahl <mstahl@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-08-10 10:55:13 -07:00

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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] [--window=<n>] [--depth=<n>]
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.
-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.
-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::
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.
--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.
-b::
--write-bitmap-index::
Write a reachability bitmap index as part of the repack. This
only makes sense when used with `-a` or `-A`, 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.
--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.
Configuration
-------------
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.
SEE ALSO
--------
linkgit:git-pack-objects[1]
linkgit:git-prune-packed[1]
GIT
---
Part of the linkgit:git[1] suite