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git/Documentation/git-index-pack.txt

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git-index-pack(1)
=================
NAME
----
git-index-pack - Build pack index file for an existing packed archive
SYNOPSIS
--------
[verse]
'git index-pack' [-v] [-o <index-file>] <pack-file>
'git index-pack' --stdin [--fix-thin] [--keep] [-v] [-o <index-file>]
[<pack-file>]
DESCRIPTION
-----------
Reads a packed archive (.pack) from the specified file, and
builds a pack index file (.idx) for it. The packed archive
together with the pack index can then be placed in the
objects/pack/ directory of a Git repository.
OPTIONS
-------
-v::
Be verbose about what is going on, including progress status.
-o <index-file>::
Write the generated pack index into the specified
file. Without this option the name of pack index
file is constructed from the name of packed archive
file by replacing .pack with .idx (and the program
fails if the name of packed archive does not end
with .pack).
--stdin::
When this flag is provided, the pack is read from stdin
instead and a copy is then written to <pack-file>. If
<pack-file> is not specified, the pack is written to
objects/pack/ directory of the current Git repository with
a default name determined from the pack content. If
<pack-file> is not specified consider using --keep to
prevent a race condition between this process and
'git repack'.
--fix-thin::
Fix a "thin" pack produced by `git pack-objects --thin` (see
linkgit:git-pack-objects[1] for details) by adding the
excluded objects the deltified objects are based on to the
pack. This option only makes sense in conjunction with --stdin.
--keep::
Before moving the index into its final destination
create an empty .keep file for the associated pack file.
This option is usually necessary with --stdin to prevent a
simultaneous 'git repack' process from deleting
the newly constructed pack and index before refs can be
updated to use objects contained in the pack.
--keep=<msg>::
Like --keep create a .keep file before moving the index into
its final destination, but rather than creating an empty file
place '<msg>' followed by an LF into the .keep file. The '<msg>'
message can later be searched for within all .keep files to
locate any which have outlived their usefulness.
--index-version=<version>[,<offset>]::
This is intended to be used by the test suite only. It allows
to force the version for the generated pack index, and to force
64-bit index entries on objects located above the given offset.
--strict::
Die, if the pack contains broken objects or links.
clone: open a shortcut for connectivity check In order to make sure the cloned repository is good, we run "rev-list --objects --not --all $new_refs" on the repository. This is expensive on large repositories. This patch attempts to mitigate the impact in this special case. In the "good" clone case, we only have one pack. If all of the following are met, we can be sure that all objects reachable from the new refs exist, which is the intention of running "rev-list ...": - all refs point to an object in the pack - there are no dangling pointers in any object in the pack - no objects in the pack point to objects outside the pack The second and third checks can be done with the help of index-pack as a slight variation of --strict check (which introduces a new condition for the shortcut: pack transfer must be used and the number of objects large enough to call index-pack). The first is checked in check_everything_connected after we get an "ok" from index-pack. "index-pack + new checks" is still faster than the current "index-pack + rev-list", which is the whole point of this patch. If any of the conditions fail, we fall back to the good old but expensive "rev-list ..". In that case it's even more expensive because we have to pay for the new checks in index-pack. But that should only happen when the other side is either buggy or malicious. Cloning linux-2.6 over file:// before after real 3m25.693s 2m53.050s user 5m2.037s 4m42.396s sys 0m13.750s 0m16.574s A more realistic test with ssh:// over wireless before after real 11m26.629s 10m4.213s user 5m43.196s 5m19.444s sys 0m35.812s 0m37.630s This shortcut is not applied to shallow clones, partly because shallow clones should have no more objects than a usual fetch and the cost of rev-list is acceptable, partly to avoid dealing with corner cases when grafting is involved. This shortcut does not apply to unpack-objects code path either because the number of objects must be small in order to trigger that code path. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-26 03:16:17 +02:00
--check-self-contained-and-connected::
Die if the pack contains broken links. For internal use only.
--threads=<n>::
Specifies the number of threads to spawn when resolving
deltas. This requires that index-pack be compiled with
pthreads otherwise this option is ignored with a warning.
This is meant to reduce packing time on multiprocessor
machines. The required amount of memory for the delta search
window is however multiplied by the number of threads.
Specifying 0 will cause Git to auto-detect the number of CPU's
and use maximum 3 threads.
Note
----
Once the index has been created, the list of object names is sorted
and the SHA-1 hash of that list is printed to stdout. If --stdin was
also used then this is prefixed by either "pack\t", or "keep\t" if a
new .keep file was successfully created. This is useful to remove a
.keep file used as a lock to prevent the race with 'git repack'
mentioned above.
GIT
---
Part of the linkgit:git[1] suite