--split-index::
--no-split-index::
- Enable or disable split index mode. If enabled, the index is
- split into two files, $GIT_DIR/index and $GIT_DIR/sharedindex.<SHA-1>.
- Changes are accumulated in $GIT_DIR/index while the shared
- index file contains all index entries stays unchanged. If
- split-index mode is already enabled and `--split-index` is
- given again, all changes in $GIT_DIR/index are pushed back to
- the shared index file. This mode is designed for very large
- indexes that take a significant amount of time to read or write.
+ Enable or disable split index mode. If split-index mode is
+ already enabled and `--split-index` is given again, all
+ changes in $GIT_DIR/index are pushed back to the shared index
+ file.
++
+These options take effect whatever the value of the `core.splitIndex`
+configuration variable (see linkgit:git-config[1]). But a warning is
+emitted when the change goes against the configured value, as the
+configured value will take effect next time the index is read and this
+will remove the intended effect of the option.
--untracked-cache::
--no-untracked-cache::
Using --refresh
---------------
`--refresh` does not calculate a new sha1 file or bring the index
-up-to-date for mode/content changes. But what it *does* do is to
+up to date for mode/content changes. But what it *does* do is to
"re-match" the stat information of a file with the index, so that you
can refresh the index for a file that hasn't been changed but where
the stat entry is out of date.
different from assume-unchanged bit's. Skip-worktree also takes
precedence over assume-unchanged bit when both are set.
+Split index
+-----------
+
+This mode is designed for repositories with very large indexes, and
+aims at reducing the time it takes to repeatedly write these indexes.
+
+In this mode, the index is split into two files, $GIT_DIR/index and
+$GIT_DIR/sharedindex.<SHA-1>. Changes are accumulated in
+$GIT_DIR/index, the split index, while the shared index file contains
+all index entries and stays unchanged.
+
+All changes in the split index are pushed back to the shared index
+file when the number of entries in the split index reaches a level
+specified by the splitIndex.maxPercentChange config variable (see
+linkgit:git-config[1]).
+
+Each time a new shared index file is created, the old shared index
+files are deleted if their modification time is older than what is
+specified by the splitIndex.sharedIndexExpire config variable (see
+linkgit:git-config[1]).
+
+To avoid deleting a shared index file that is still used, its
+modification time is updated to the current time everytime a new split
+index based on the shared index file is either created or read from.
+
Untracked cache
---------------