'git pack-objects' [-q | --progress | --all-progress] [--all-progress-implied]
[--no-reuse-delta] [--delta-base-offset] [--non-empty]
[--local] [--incremental] [--window=<n>] [--depth=<n>]
- [--revs [--unpacked | --all]] [--stdout | base-name]
- [--shallow] [--keep-true-parents] < object-list
+ [--revs [--unpacked | --all]] [--keep-pack=<pack-name>]
+ [--stdout [--filter=<filter-spec>] | base-name]
+ [--shallow] [--keep-true-parents] [--[no-]sparse] < object-list
DESCRIPTION
-----------
-Reads list of objects from the standard input, and writes a packed
-archive with specified base-name, or to the standard output.
+Reads list of objects from the standard input, and writes either one or
+more packed archives with the specified base-name to disk, or a packed
+archive to the standard output.
A packed archive is an efficient way to transfer a set of objects
between two repositories as well as an access efficient archival
OPTIONS
-------
base-name::
- Write into a pair of files (.pack and .idx), using
+ Write into pairs of files (.pack and .idx), using
<base-name> to determine the name of the created file.
- When this option is used, the two files are written in
+ When this option is used, the two files in a pair are written in
<base-name>-<SHA-1>.{pack,idx} files. <SHA-1> is a hash
based on the pack content and is written to the standard
output of the command.
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 default value for --window is 10 and --depth is 50. The maximum
+depth is 4095.
--window-memory=<n>::
This option provides an additional limit on top of `--window`;
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.
+ `--window-memory=0` makes memory usage unlimited. The default
+ is taken from the `pack.windowMemory` configuration variable.
--max-pack-size=<n>::
- Maximum size of each output pack file. The size can be suffixed with
+ In unusual scenarios, you may not be able to create files
+ larger than a certain size on your filesystem, and this option
+ can be used to tell the command to split the output packfile
+ into multiple independent packfiles, each not larger than the
+ given size. 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.
+ This option
+ prevents the creation of a bitmap index.
The default is unlimited, unless the config variable
`pack.packSizeLimit` is set.
has a .keep file to be ignored, even if it would have
otherwise been packed.
+--keep-pack=<pack-name>::
+ This flag causes an object already in the given pack to be
+ ignored, even if it would have otherwise been
+ packed. `<pack-name>` is the pack file name without
+ leading directory (e.g. `pack-123.pack`). The option could be
+ specified multiple times to keep multiple packs.
+
--incremental::
This flag causes an object already in a pack to be ignored
even if it would have otherwise been packed.
Add --no-reuse-object if you want to force a uniform compression
level on all data no matter the source.
+--[no-]sparse::
+ Toggle the "sparse" algorithm to determine which objects to include in
+ the pack, when combined with the "--revs" option. This algorithm
+ only walks trees that appear in paths that introduce new objects.
+ This can have significant performance benefits when computing
+ a pack to send a small change. However, it is possible that extra
+ objects are added to the pack-file if the included commits contain
+ certain types of direct renames. If this option is not included,
+ it defaults to the value of `pack.useSparse`, which is true unless
+ otherwise specified.
+
--thin::
Create a "thin" pack by omitting the common objects between a
sender and a receiver in order to reduce network transfer. This
--shallow::
Optimize a pack that will be provided to a client with a shallow
- repository. This option, combined with \--thin, can result in a
+ repository. This option, combined with --thin, can result in a
smaller pack at the cost of speed.
--delta-base-offset::
With this option, parents that are hidden by grafts are packed
nevertheless.
+--filter=<filter-spec>::
+ Requires `--stdout`. Omits certain objects (usually blobs) from
+ the resulting packfile. See linkgit:git-rev-list[1] for valid
+ `<filter-spec>` forms.
+
+--no-filter::
+ Turns off any previous `--filter=` argument.
+
+--missing=<missing-action>::
+ A debug option to help with future "partial clone" development.
+ This option specifies how missing objects are handled.
++
+The form '--missing=error' requests that pack-objects stop with an error if
+a missing object is encountered. This is the default action.
++
+The form '--missing=allow-any' will allow object traversal to continue
+if a missing object is encountered. Missing objects will silently be
+omitted from the results.
++
+The form '--missing=allow-promisor' is like 'allow-any', but will only
+allow object traversal to continue for EXPECTED promisor missing objects.
+Unexpected missing object will raise an error.
+
+--exclude-promisor-objects::
+ Omit objects that are known to be in the promisor remote. (This
+ option has the purpose of operating only on locally created objects,
+ so that when we repack, we still maintain a distinction between
+ locally created objects [without .promisor] and objects from the
+ promisor remote [with .promisor].) This is used with partial clone.
+
+--keep-unreachable::
+ Objects unreachable from the refs in packs named with
+ --unpacked= option are added to the resulting pack, in
+ addition to the reachable objects that are not in packs marked
+ with *.keep files. This implies `--revs`.
+
+--pack-loose-unreachable::
+ Pack unreachable loose objects (and their loose counterparts
+ removed). This implies `--revs`.
+
+--unpack-unreachable::
+ Keep unreachable objects in loose form. This implies `--revs`.
+
+--delta-islands::
+ Restrict delta matches based on "islands". See DELTA ISLANDS
+ below.
+
+
+DELTA ISLANDS
+-------------
+
+When possible, `pack-objects` tries to reuse existing on-disk deltas to
+avoid having to search for new ones on the fly. This is an important
+optimization for serving fetches, because it means the server can avoid
+inflating most objects at all and just send the bytes directly from
+disk. This optimization can't work when an object is stored as a delta
+against a base which the receiver does not have (and which we are not
+already sending). In that case the server "breaks" the delta and has to
+find a new one, which has a high CPU cost. Therefore it's important for
+performance that the set of objects in on-disk delta relationships match
+what a client would fetch.
+
+In a normal repository, this tends to work automatically. The objects
+are mostly reachable from the branches and tags, and that's what clients
+fetch. Any deltas we find on the server are likely to be between objects
+the client has or will have.
+
+But in some repository setups, you may have several related but separate
+groups of ref tips, with clients tending to fetch those groups
+independently. For example, imagine that you are hosting several "forks"
+of a repository in a single shared object store, and letting clients
+view them as separate repositories through `GIT_NAMESPACE` or separate
+repos using the alternates mechanism. A naive repack may find that the
+optimal delta for an object is against a base that is only found in
+another fork. But when a client fetches, they will not have the base
+object, and we'll have to find a new delta on the fly.
+
+A similar situation may exist if you have many refs outside of
+`refs/heads/` and `refs/tags/` that point to related objects (e.g.,
+`refs/pull` or `refs/changes` used by some hosting providers). By
+default, clients fetch only heads and tags, and deltas against objects
+found only in those other groups cannot be sent as-is.
+
+Delta islands solve this problem by allowing you to group your refs into
+distinct "islands". Pack-objects computes which objects are reachable
+from which islands, and refuses to make a delta from an object `A`
+against a base which is not present in all of `A`'s islands. This
+results in slightly larger packs (because we miss some delta
+opportunities), but guarantees that a fetch of one island will not have
+to recompute deltas on the fly due to crossing island boundaries.
+
+When repacking with delta islands the delta window tends to get
+clogged with candidates that are forbidden by the config. Repacking
+with a big --window helps (and doesn't take as long as it otherwise
+might because we can reject some object pairs based on islands before
+doing any computation on the content).
+
+Islands are configured via the `pack.island` option, which can be
+specified multiple times. Each value is a left-anchored regular
+expressions matching refnames. For example:
+
+-------------------------------------------
+[pack]
+island = refs/heads/
+island = refs/tags/
+-------------------------------------------
+
+puts heads and tags into an island (whose name is the empty string; see
+below for more on naming). Any refs which do not match those regular
+expressions (e.g., `refs/pull/123`) is not in any island. Any object
+which is reachable only from `refs/pull/` (but not heads or tags) is
+therefore not a candidate to be used as a base for `refs/heads/`.
+
+Refs are grouped into islands based on their "names", and two regexes
+that produce the same name are considered to be in the same
+island. The names are computed from the regexes by concatenating any
+capture groups from the regex, with a '-' dash in between. (And if
+there are no capture groups, then the name is the empty string, as in
+the above example.) This allows you to create arbitrary numbers of
+islands. Only up to 14 such capture groups are supported though.
+
+For example, imagine you store the refs for each fork in
+`refs/virtual/ID`, where `ID` is a numeric identifier. You might then
+configure:
+
+-------------------------------------------
+[pack]
+island = refs/virtual/([0-9]+)/heads/
+island = refs/virtual/([0-9]+)/tags/
+island = refs/virtual/([0-9]+)/(pull)/
+-------------------------------------------
+
+That puts the heads and tags for each fork in their own island (named
+"1234" or similar), and the pull refs for each go into their own
+"1234-pull".
+
+Note that we pick a single island for each regex to go into, using "last
+one wins" ordering (which allows repo-specific config to take precedence
+over user-wide config, and so forth).
+
SEE ALSO
--------
linkgit:git-rev-list[1]
projects / platform / upstream / git.git / blobdiff