DOCS-14455 Add references for numHosts targeted in shardingStatistics

Author: ianf-mongodb

source/includes/fact-server-status-num-hosts-targeted.rst

@@ -0,0 +1,18 @@
+.. list-table::
+   :header-rows: 1
+   :widths: 20 40
+
+   * - Name
+     - Description
+
+   * - ``allShards``
+     - A command targeted all shards
+
+   * - ``manyShards``
+     - A command targeted more than one shard
+
+   * - ``oneShard``
+     - A command targeted one shard
+
+   * - ``unsharded``
+     - A command was run on an unsharded collection

source/reference/command/serverStatus.txt

@@ -2774,6 +2774,39 @@ shardingStatistics
          .. code-block:: javascript
 
             "shardingStatistics" : {
+               "numHostsTargeted": {
+                  "find" : {
+                     "allShards": NumberLong(<num>),
+                     "manyShards": NumberLong(<num>),
+                     "oneShard": NumberLong(<num>),
+                     "unsharded": NumberLong(<num>) 
+                           },
+                  "insert": { 
+                     "allShards": NumberLong(<num>),
+                     "manyShards": NumberLong(<num>),
+                     "oneShard": NumberLong(<num>),
+                     "unsharded": NumberLong(<num>) 
+                           },
+                  "update": { 
+                     "allShards": NumberLong(<num>),
+                     "manyShards": NumberLong(<num>),
+                     "oneShard": NumberLong(<num>),
+                     "unsharded": NumberLong(<num>) 
+                           },
+                  "delete": { 
+                     "allShards": NumberLong(<num>),
+                     "manyShards": NumberLong(<num>),
+                     "oneShard": NumberLong(<num>),
+                     "unsharded": NumberLong(<num>) 
+                           },
+                  "aggregate": { 
+                     "allShards": NumberLong(<num>),
+                     "manyShards": NumberLong(<num>),
+                     "oneShard": NumberLong(<num>),
+                     "unsharded": NumberLong(<num>) 
+                           }
+                  }
+               },
                "catalogCache" : {
                   "numDatabaseEntries" : NumberLong(<num>),
                   "numCollectionEntries" : NumberLong(<num>),
@@ -3364,6 +3397,29 @@ shardingStatistics
 
    .. versionadded:: 5.0
 
+.. serverstatus:: shardingStatistics.numHostsTargeted
+
+   Indicates the number of shards targeted for ``CRUD`` operations and 
+   aggregation commands. When a ``CRUD`` operation or aggregation
+   command is run, the following metrics will be incremented.
+
+   .. include:: /includes/fact-server-status-num-hosts-targeted.rst
+
+   .. note:: 
+
+      Running the :dbcommand:`serverStatus` command on :binary:`mongos` 
+      will provide insight into the CRUD and aggregation operations that
+      run on a sharded cluster.
+
+      Multi-shard operations can either be 
+      :ref:`scatter-gather<sharding-query-patterns>`
+      or shard specific. Multi-shard scatter-gather operations can
+      :ref:`consume more resources<sharding-troubleshooting-scatter-gather>`.
+      By using the 
+      :serverstatus:`shardingStatistics.numHostsTargeted`
+      metrics you can tune the aggregation queries that run on a 
+      sharded cluster.
+
 .. serverstatus:: shardingStatistics.resharding.coordinatorState
 
    State of the resharding coordinator for the current :ref:`resharding

source/release-notes/4.4.txt

@@ -1915,6 +1915,16 @@ output:
   - :serverstatus:`shardedIndexConsistency`
   - :serverstatus:`shardingStatistics.rangeDeleterTasks`
   - :serverstatus:`shardingStatistics.unfinishedMigrationFromPreviousPrimary`
+  - :serverstatus:`shardingStatistics.numHostsTargeted`
+
+``serverStatus`` Sharding Statistics Output Change
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+:serverstatus:`shardingStatistics.numHostsTargeted`
+which reports the number of shards targeted by CRUD operations and
+aggregation commands. The relevant find, insert, update, delete or
+aggregate metric will be incremented with each operation on a
+cluster.
 
 ``replSetGetStatus`` Output Change
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~