Merge branch 'ks/doc-fixes' into maint

diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt
index 7386c931627f1c2bd1303407075db9831ec4045c..1579abf3c3b45f4e63f8f17746dde31a06a3a564 100644 (file)
--- a/Documentation/git-update-index.txt
+++ b/Documentation/git-update-index.txt
@@ -163,14 +163,16 @@ may not support it yet.
 
 --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::
@@ -388,6 +390,31 @@ Although this bit looks similar to assume-unchanged bit, its goal is
 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
 ---------------