Traditionally, tips of branches and tags (collectively known as
refs
) were stored one file per ref in a (sub)directory
under
$GIT_DIR/refs
directory. While many branch tips tend to be updated often,
most tags and some branch tips are never updated. When a
repository has hundreds or thousands of tags, this
one-file-per-ref format both wastes storage and hurts
performance.
This command is used to solve the storage and performance
problem by storing the refs in a single file,
$GIT_DIR/packed-refs
. When a ref is missing from the
traditional
$GIT_DIR/refs
directory hierarchy, it is looked
up in this
file and used if found.
Subsequent updates to branches always create new files under
$GIT_DIR/refs
directory hierarchy.
A recommended practice to deal with a repository with too many
refs is to pack its refs with
--all
once, and
occasionally run
git pack-refs
. Tags are by
definition stationary and are not expected to change. Branch
heads will be packed with the initial
pack-refs --all
, but
only the currently active branch heads will become unpacked,
and the next
pack-refs
(without
--all
) will leave them
unpacked.
The command by default packs all tags and refs that are already
packed, and leaves other refs
alone. This is because branches are expected to be actively
developed and packing their tips does not help performance.
This option causes all refs to be packed as well, with the exception
of hidden refs, broken refs, and symbolic refs. Useful for a repository
with many branches of historical interests.
--no-prune
The command usually removes loose refs under
$GIT_DIR/refs
hierarchy after packing them. This option tells it not to.
--auto
Pack refs as needed depending on the current state of the ref database. The
behavior depends on the ref format used by the repository and may change in the
future.
"files": No special handling for
--auto
has been implemented.
"reftable": Tables are compacted such that they form a geometric
sequence. For two tables N and N+1, where N+1 is newer, this
maintains the property that N is at least twice as big as N+1. Only
tables that violate this property are compacted.
Pack refs based on a
glob(7)
pattern. Repetitions of this option
accumulate inclusion patterns. If a ref is both included in
--include
and
--exclude
,
--exclude
takes precedence. Using
--include
will preclude all
tags from being included by default. Symbolic refs and broken refs will never
be packed. When used with
--all
, it will be a noop. Use
--no-include
to clear
and reset the list of patterns.
--exclude <pattern>
Do not pack refs matching the given
glob(7)
pattern. Repetitions of this option
accumulate exclusion patterns. Use
--no-exclude
to clear and reset the list of
patterns. If a ref is already packed, including it with
--exclude
will not
unpack it.
When used with
--all
, pack only loose refs which do not match any of
the provided
--exclude
patterns.
When used with
--include
, refs provided to
--include
, minus refs that are
provided to
--exclude
will be packed.
Older documentation written before the packed-refs mechanism was
introduced may still say things like ".git/refs/heads/<branch> file
exists" when it means "branch <branch> exists".
