git/Documentation/git-repack.txt
Michael J Gruber 9a8531eeba git-repack.txt: Clarify implications of -a for dumb protocols
The current text makes some users feel uneasy, worrying whether
'-a' could lead to corrupt repositories. Clarify that '-a'
may lead to performance issues only for dumb protocols.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Helped-by: Stephen Boyd <bebarino@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-06-09 23:47:49 -07:00

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git-repack(1)
=============
NAME
----
git-repack - Pack unpacked objects in a repository
SYNOPSIS
--------
'git repack' [-a] [-A] [-d] [-f] [-l] [-n] [-q] [--window=N] [--depth=N]
DESCRIPTION
-----------
This script 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` 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-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, which is the
default.
--max-pack-size=<n>::
Maximum size of each output packfile, expressed in MiB.
If specified, multiple packfiles may be created.
The default is unlimited.
Configuration
-------------
When configuration variable `repack.UseDeltaBaseOffset` is set
for the repository, 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 (and including) v1.4.3; do not set
the variable in a repository that older version of git needs to
be able to read (this includes repositories from which packs can
be copied out over http or rsync, and people who obtained packs
that way can try to use older git with it).
Author
------
Written by Linus Torvalds <torvalds@osdl.org>
Documentation
--------------
Documentation by Ryan Anderson <ryan@michonline.com>
SEE ALSO
--------
linkgit:git-pack-objects[1]
linkgit:git-prune-packed[1]
GIT
---
Part of the linkgit:git[1] suite