DOCS-8263: latencyStats part 2

source/includes/fact-latencystats-reference.rst

@@ -0,0 +1,84 @@
+
+.. list-table::
+    :header-rows: 1
+    :widths: 30 70
+
+    * - Field Name
+      - Description
+
+    * - ``reads``
+      - Latency statistics for read requests.
+
+    * - ``writes``
+      - Latency statistics for write requests.
+
+    * - ``commands``
+      - Latency statistics for database commands.
+
+Each of these fields contains an embedded document bearing the
+following fields:
+
+.. list-table::
+    :header-rows: 1
+    :widths: 30 70
+
+    * - Field Name
+      - Description
+
+    * - ``latency``
+      - A :bsontype:`long <data_numberlong>` giving the total combined
+        latency in microseconds.
+
+    * - ``ops``
+      - A :bsontype:`long <data_numberlong>` giving the total number of
+        operations performed on the collection since startup.
+
+    * - ``histogram``
+      - An array of embedded documents, each representing a latency range.
+        Each document covers twice the previous document's range. For
+        upper values between 2048 microseconds and roughly 1 second,
+        the histogram includes half-steps.
+
+        This field only exists given the
+        ``latencyStats: { histograms: true }`` option. Empty ranges with
+        a zero ``count`` are omitted from the output.
+
+        Each document bears the following fields:
+
+        .. list-table::
+
+           * - Field Name
+             - Description
+
+           * - ``micros``
+             - A :bsontype:`long <data_numberlong>` giving the inclusive
+               upper time bound of the current latency range in
+               microseconds.
+
+               The document's range spans between the previous document's
+               ``micros`` value, exclusive, and this document's
+               ``micros`` value, inclusive.
+
+           * - ``count``
+             - A :bsontype:`long <data_numberlong>` giving the number of
+               operations with latency less than or equal to ``micros``.
+
+        For example, if ``collStats`` returns the following histogram:
+
+        .. code-block:: javascript
+
+           histogram: [
+             { micros: NumberLong(1), count: NumberLong(10) },
+             { micros: NumberLong(2), count: NumberLong(1) },
+             { micros: NumberLong(4096), count: NumberLong(1)}
+             { micros: NumberLong(137438953472), count: NumberLong(1000) },
+             { micros: NumberLong(274877906944), count: NumberLong(100) }
+           ]
+
+        This indicates that there were:
+
+        - 10 operations taking 1 microsecond or less,
+        - 1 operation in the range (1, 2] microseconds,
+        - 1 operation in the range (3072, 4096] microseconds,
+        - 1000 operations in the range (68719476736, 137438953472], and
+        - 100 operations in the range (137438953472, 274877906944].

source/includes/ref-toc-method-collection.yaml

@@ -110,6 +110,10 @@ name: ":method:`db.collection.isCapped()`"
 file: /reference/method/db.collection.isCapped
 description: "Reports if a collection is a :term:`capped collection`."
 ---
+name: ":method:`db.collection.latencyStats()`"
+file: /reference/method/db.collection.latencyStats
+description: "Returns latency statistics for a collection."
+---
 name: ":method:`db.collection.mapReduce()`"
 file: /reference/method/db.collection.mapReduce
 description: "Performs map-reduce style data aggregation."

source/reference/command/serverStatus.txt

@@ -108,7 +108,7 @@ Instance Information
 .. serverstatus:: pid
 
    The process id number.
-   
+
 .. serverstatus:: uptime
 
    The number of seconds that the current MongoDB process has been
@@ -671,6 +671,34 @@ network
    values to ensure that MongoDB's network utilization is consistent
    with expectations and application use.
 
+opLatencies
+~~~~~~~~~~~
+
+.. code-block:: javascript
+
+   "opLatencies" : {
+      "reads" : <document>,
+      "writes" : <document>,
+      "commands" : <document>
+   },
+
+.. serverstatus:: opLatencies
+
+   A document containing operation latencies for the database as a whole.
+   See :ref:`latency-stats-document` for an description of this document.
+
+.. serverstatus:: opLatencies.reads
+
+   Latency statistics for read requests.
+
+.. serverstatus:: opLatencies.writes
+
+   Latency statistics for write operations.
+
+.. serverstatus:: opLatencies.commands
+
+   Latency statistics for database commands.
+
 .. _server-status-opcounters:
 
 opcounters
@@ -1026,7 +1054,7 @@ security
 .. serverstatus:: security
 
    .. versionadded:: 3.0
-   
+
    A document that reports on security configuration and details. Only
    appears for :program:`mongod` instances compiled with support for TLS/SSL.
 
@@ -1360,7 +1388,7 @@ wiredTiger
       cache` can provide an overview of the I/O activity.
 
    .. serverstatus:: wiredTiger.cache.pages written from cache
-      
+
       Number of pages written from the cache.
       :serverstatus:`wiredTiger.cache.pages written from cache`
       with the :serverstatus:`wiredTiger.cache.pages read into
@@ -1426,7 +1454,7 @@ wiredTiger
       Amount of time, in milliseconds, to create the most recent
       checkpoint. An increase in this value under stead write load may
       indicate saturation on the I/O subsystem.
-   
+
 .. serverstatus:: wiredTiger.concurrentTransactions
 
    .. versionadded:: 3.0
@@ -1533,8 +1561,8 @@ mem
 .. serverstatus:: mem.note
 
    The field :serverstatus:`mem.note` appears if
-   :serverstatus:`mem.supported` is false. 
-   
+   :serverstatus:`mem.supported` is false.
+
    The :serverstatus:`mem.note` field contains the text: ``"not all mem
    info support on this platform"``.
 

source/reference/method/db.collection.latencyStats.txt

@@ -0,0 +1,95 @@
+============================
+db.collection.latencyStats()
+============================
+
+.. default-domain:: mongodb
+
+.. contents:: On this page
+   :local:
+   :backlinks: none
+   :depth: 1
+   :class: singlecol
+
+Definition
+----------
+
+.. method:: db.collection.latencyStats(options)
+
+   :method:`db.collection.latencyStats()` returns latency
+   statistics for a given collection. It is a wrapper around
+   :pipeline:`$collStats`.
+
+   This method has the form:
+
+   .. code-block:: javascript
+
+      db.collection.latencyStats( { histograms: <boolean> } )
+
+   The ``histograms`` argument is an optional boolean. If
+   ``histograms: true`` then :method:`~db.collection.latencyStats()` adds
+   latency histograms to the return document.
+
+.. seealso:: :pipeline:`$collStats`
+
+Output
+------
+
+:method:`~db.collection.latencyStats()` returns a document containing
+a field ``latencyStats``, containing the following fields:
+
+.. include:: /includes/fact-latencystats-reference.rst
+
+Examples
+--------
+
+You can run :method:`~db.collection.latencyStats()` in a :program:`mongo`
+shell as follows:
+
+.. code-block:: javascript
+
+   db.data.latencyStats( { histograms: true } ).pretty()
+
+:method:`~db.collection.latencyStats()` returns a document such as
+the following:
+
+.. code-block:: javascript
+
+   {
+     "ns" : "test.data",
+     "localTime" : ISODate("2016-11-01T21:56:28.962Z"),
+     "latencyStats" : {
+       "reads" : {
+         "histogram" : [
+           {
+             "micros" : NumberLong(16),
+             "count" : NumberLong(6)
+           },
+           {
+             "micros" : NumberLong(512),
+             "count" : NumberLong(1)
+           }
+         ],
+         "latency" : NumberLong(747),
+         "ops" : NumberLong(7)
+       },
+       "writes" : {
+         "histogram" : [
+           {
+             "micros" : NumberLong(64),
+             "count" : NumberLong(1)
+           },
+           {
+             "micros" : NumberLong(24576),
+             "count" : NumberLong(1)
+           }
+         ],
+         "latency" : NumberLong(26845),
+         "ops" : NumberLong(2)
+       },
+       "commands" : {
+         "histogram" : [ ],
+         "latency" : NumberLong(0),
+         "ops" : NumberLong(0)
+       }
+     }
+   }

source/reference/operator/aggregation/collStats.txt

@@ -86,91 +86,7 @@ else the pipeline returns an error.
 The ``latencyStats`` embedded document only exists in the output if
 ``$collStats`` receives the ``latencyStats`` option.
 
-
-.. list-table::
-    :header-rows: 1
-    :widths: 30 70
-
-    * - Field Name
-      - Description
-
-    * - ``reads``
-      - Latency statistics for read requests.
-
-    * - ``writes``
-      - Latency statistics for write requests.
-
-    * - ``commands``
-      - Latency statistics for database commands.
-
-Each of these fields contains an embedded document bearing the
-following fields:
-
-.. list-table::
-    :header-rows: 1
-    :widths: 30 70
-
-    * - Field Name
-      - Description
-
-    * - ``latency``
-      - A :bsontype:`long <data_numberlong>` giving the total combined
-        latency in microseconds.
-
-    * - ``ops``
-      - A :bsontype:`long <data_numberlong>` giving the total number of
-        operations performed on the collection since startup.
-
-    * - ``histogram``
-      - An array of embedded documents, each representing a latency range.
-        Each document covers twice the previous document's range. For
-        upper values between 2048 microseconds and roughly 1 second,
-        the histogram includes half-steps.
-
-        This field only exists given the
-        ``latencyStats: { histograms: true }`` option. Empty ranges with
-        a zero ``count`` are omitted from the output.
-
-        Each document bears the following fields:
-
-        .. list-table::
-
-           * - Field Name
-             - Description
-
-           * - ``micros``
-             - A :bsontype:`long <data_numberlong>` giving the inclusive
-               upper time bound of the current latency range in
-               microseconds.
-
-               The document's range spans between the previous document's
-               ``micros`` value, exclusive, and this document's
-               ``micros`` value, inclusive.
-
-           * - ``count``
-             - A :bsontype:`long <data_numberlong>` giving the number of
-               operations with latency less than or equal to ``micros``.
-
-        For example, if ``collStats`` returns the following histogram:
-
-        .. code-block:: javascript
-
-           histogram: [
-             { micros: 1, count: 10 },
-             { micros: 2, count: 1 },
-             { micros: 4096, count: 1}
-             { micros: 137438953472, count: 1000 },
-             { micros: 274877906944, count: 100 }
-           ]
-
-        This indicates that there were:
-
-        - 10 operations taking 1 microsecond or less,
-        - 1 operation in the range (1, 2] microseconds,
-        - 1 operation in the range (3072, 4096] microseconds,
-        - 1000 operations in the range (68719476736, 137438953472], and
-        - 100 operations in the range (137438953472, 274877906944].
-
+.. include:: /includes/fact-latencystats-reference.rst
 
 For example, if you run ``$collStats`` with the ``latencyStats: {}`` option
 on a ``matrices`` collection: