space utilization and performance. This option will cause
'git gc' to more aggressively optimize the repository at the expense
of taking much more time. The effects of this optimization are
- persistent, so this option only needs to be used occasionally; every
- few hundred changesets or so.
+ mostly persistent. See the "AGGRESSIVE" section below for details.
--auto::
With this option, 'git gc' checks whether any housekeeping is
`.keep` files are consolidated into a single pack. When this
option is used, `gc.bigPackThreshold` is ignored.
+AGGRESSIVE
+----------
+
+When the `--aggressive` option is supplied, linkgit:git-repack[1] will
+be invoked with the `-f` flag, which in turn will pass
+`--no-reuse-delta` to linkgit:git-pack-objects[1]. This will throw
+away any existing deltas and re-compute them, at the expense of
+spending much more time on the repacking.
+
+The effects of this are mostly persistent, e.g. when packs and loose
+objects are coalesced into one another pack the existing deltas in
+that pack might get re-used, but there are also various cases where we
+might pick a sub-optimal delta from a newer pack instead.
+
+Furthermore, supplying `--aggressive` will tweak the `--depth` and
+`--window` options passed to linkgit:git-repack[1]. See the
+`gc.aggressiveDepth` and `gc.aggressiveWindow` settings below. By
+using a larger window size we're more likely to find more optimal
+deltas.
+
+It's probably not worth it to use this option on a given repository
+without running tailored performance benchmarks on it. It takes a lot
+more time, and the resulting space/delta optimization may or may not
+be worth it. Not using this at all is the right trade-off for most
+users and their repositories.
+
CONFIGURATION
-------------
particular, it will keep not only objects referenced by your current set
of branches and tags, but also objects referenced by the index,
remote-tracking branches, refs saved by 'git filter-branch' in
-refs/original/, or reflogs (which may reference commits in branches
-that were later amended or rewound).
+refs/original/, reflogs (which may reference commits in branches
+that were later amended or rewound), and anything else in the refs/* namespace.
If you are expecting some objects to be deleted and they aren't, check
all of those locations and decide whether it makes sense in your case to
remove those references.