SERVER-2023 touch command documentation

Author: Sam Kleinman

source/reference/commands.txt

@@ -1295,6 +1295,40 @@ Collections
 Administration
 ~~~~~~~~~~~~~~
 
+.. dbcommand:: touch
+
+   .. versionadded:: 2.2
+
+   The :dbcommand:`touch` command loads data from the data storage
+   layer into memory. :dbcommand:`touch` can load the data
+   (i.e. documents,) indexes or both documents and indexes. Use this
+   command to ensure that a collection, and/or its indexes, are in
+   memory before another operation. :dbcommand:`touch` command has the
+   following prototypical form:
+
+   .. code-block:: javascript
+
+      { touch: [collection], data: [boolean], index: [boolean] }
+
+   By default, ``data`` and ``index`` are false, and
+   :dbcommand:`touch` will provide no operation. For example to load
+   both the data and the index for a collection named ``records``, you
+   would use the following command in the :program:`mongo` shell:
+
+   .. code-block:: javascript
+
+      db.runCommand({ touch: "records", data: true, index: true })
+
+   :dbcommand:`touch` will not block operations on a program:`mongod`,
+   :and can run on :term:`secondary` members of replica sets.
+
+   .. note::
+
+      Using :dbcommand:`touch` to control or tweak what a
+      :program:`mongod` stores in memory may displace other records
+      data in memory and hinder performance. Use with caution in
+      production systems.
+
 .. dbcommand:: fsync
 
    :dbcommand:`fsync` is an *administrative command* that forces the

source/release-notes/2.2.txt

@@ -372,6 +372,14 @@ Additional Improvements
 
 :issue:`SERVER-4212`
 
+``touch`` Command
+`````````````````
+
+Added the :dbcommand:`touch` command to read the data and/or indexes
+from a collection into memory.
+
+See: :issue:`SERVER-2023` and :dbcommand:`touch` for more information.
+
 Tracking i/o Time and Lock Time in Profiler
 ```````````````````````````````````````````