DOCS-91 organization and additional facts

Author: Sam Kleinman

source/reference/limits.txt

@@ -13,22 +13,24 @@ the MongoDB system.
 Limits
 ------
 
+BSON Documents
+~~~~~~~~~~~~~~
+
 .. _limit-bson-document-size:
-.. limit:: BSON Object Size
+.. limit:: BSON Document Size
 
-   The maximum BSON object size is 16 megabytes.
+   The maximum BSON document size is 16 megabytes.
 
-.. _limit-index-size:
-.. limit:: Index Size
+.. _limit-nested-depth:
+.. limit:: Nested Depth for BSON Documents
 
-   Indexed items, including their namespace/database, can be *no
-   larger* than 1024 bytes. This value is the indexed content
-   (i.e. the field value.)
+   .. versionchanged:: 2.2
 
-.. _limit-number-of-indexes-per-collection:
-.. limit:: Number of Indexes per Collection
+   MongoDB supports no more than 100 levels of nesting for :term:`BSON
+   documents <document>`.
 
-   A single collection can have *no more* than 64 indexes.
+Namespaces
+~~~~~~~~~~
 
 .. _limit-namespace-length:
 .. limit:: Namespace Length
@@ -38,17 +40,6 @@ Limits
 
    .. fix when we know what the actual limit is.
 
-.. _limit-index-name-length:
-.. limit:: Index Name Length
-
-   The names of indexes, including their namespace (i.e database and
-   collection name) cannot be longer than 128 characters.
-
-   .. note: the default name is the concantiation of the fields and
-      directions.
-
-   .. ensureIndex/createIndex: supports giving an explicit name.
-
 .. _limit-number-of-namespaces:
 .. limit:: Number of Namespaces
 
@@ -66,28 +57,72 @@ Limits
    A 16 megabyte namespace file can support 24,000 namespaces.
 
 .. _limit-size-of-namespace-file:
-
 .. limit:: Size of Namespace File
 
    Namespace files can be no larger than 2 gigabytes.
 
    By default namespace files are 16 megabytes. You can configure the
    size using the :setting:`nssize`.
 
+Indexes
+~~~~~~~
+
+.. _limit-index-size:
+.. limit:: Index Size
+
+   Indexed items, including their namespace/database, can be *no
+   larger* than 1024 bytes. This value is the indexed content
+   (i.e. the field value.)
+
+.. _limit-number-of-indexes-per-collection:
+.. limit:: Number of Indexes per Collection
+
+   A single collection can have *no more* than 64 indexes.
+
+.. _limit-index-name-length:
+.. limit:: Index Name Length
+
+   The names of indexes, including their namespace (i.e database and
+   collection name) cannot be longer than 128 characters. The default
+   index name is the concatenation of the field names and index
+   directions.
+
+   You can explicitly specify an name to :dbcommand:`createIndex` or
+   the :method:`db.collection.ensureIndex()` helper if the default
+   index name is too long.
+
+.. _limit-sharding-unique-indexes:
+.. limit:: Unique Indexes in Sharded Collections
+
+   MongoDB does not support unique indexes across shards, except when
+   the unique index contains the full shard key as a prefix of the
+   index. In these situations MongoDB will enforce uniqueness across
+   the full key, not a single field.
+
+   .. see:: :doc:`/tutorial/enforce-unique-keys-for-sharded-collections`
+      for an alternate approach.
+
+Replica Sets
+~~~~~~~~~~~~
+
+.. limit:: Number of Members of a Replica Set
+
+   Replica sets can ho more than 12 members.
+
+.. limit:: Number of Voting Members of a Replica Set
+
+   Only 7 members of a replica set can have votes at any given
+   time. See can vote :ref:`replica-set-non-voting-members` for more information
+
+Operations
+~~~~~~~~~~
+
 .. _limit-sort:
 .. limit:: Sorted Documents
 
    MongoDB will only return sorted results on fields without an index
    *if* the sort operation uses less than 32 megabytes of memory.
 
-.. _limit-nested-depth:
-.. limit:: Nested Depth for BSON Objects
-
-   .. versionchanged:: 2.2
-
-   MongoDB only supports 100 levels of nesting for :term:`BSON
-   documents <document>`.
-
 .. _limit-sharding-limitations:
 .. limit:: Operations Unavailable in Sharded Environments
 
@@ -102,13 +137,49 @@ Limits
    from the :operator:`$where` function. This is uncommon in
    un-sharded collections.
 
-.. _limit-sharding-unique-indexes:
-.. limit:: Unique Indexes in Sharded Collections
+Naming Restrictions
+~~~~~~~~~~~~~~~~~~~
 
-   MongoDB does not support unique indexes across shards, except when
-   the unique index contains the full shard key as a prefix of the
-   index. In these situations MongoDB will enforce uniqueness across
-   the full key, not a single field.
+.. limit:: Restrictions on Database Names
 
-   .. see:: :doc:`/tutorial/enforce-unique-keys-for-sharded-collections`
-      for an alternate approach.
+   The dot (i.e. ``.``) character is not permissible in database
+   names.
+
+   Database names are only case sensitive if the underlying file
+   system has case sensitive file names.
+
+   .. versionchanged:: 2.2
+      For MongoDB instances running on Windows.
+
+      In 2.2 the following characters permissible in database names:
+
+      .. code-block:: none
+
+         /\. "*<>:|?
+
+      See :ref:`rn-2.2-database-name-restriction-windows` for more
+      information.
+
+.. limit:: Restriction on Collection Names
+
+   .. versionadded:: 2.2
+
+   Collection names should begin with an underscore or a letter
+   character, and *cannot*:
+
+   - contain the ``$``.
+
+   - be an empty string (e.g. ``""``).
+
+   - contain the null character.
+
+   - begin with the ``system.`` prefix. (Reserved for internal use.)
+
+   See :ref:`faq-restrictions-on-collection-names` and
+   :ref:`rn-2.2-collection-name-restriction` for more information.
+
+.. limit:: Restrictions on Field Names
+
+   Field names cannot contain dots (i.e. ``.``) or dollar signs
+   (i.e. ``$``.) See :ref:`faq-dollar-sign-escaping` for an
+   alternate approach.

source/release-notes/2.2.txt

@@ -304,6 +304,8 @@ See: :issue:`SERVER-6961` for more information.
 Behavioral Changes
 ~~~~~~~~~~~~~~~~~~
 
+.. _rn-2.2-collection-name-restriction:
+
 Restrictions on Collection Names
 ````````````````````````````````
 
@@ -337,6 +339,8 @@ Collections names may have any other valid UTF-8 string.
 See the :issue:`SERVER-4442` and the
 :ref:`faq-restrictions-on-collection-names` FAQ item.
 
+.. _rn-2.2-database-name-restriction-windows:
+
 Restrictions on Database Names for Windows
 ``````````````````````````````````````````