DOCS-15516 Time series range outside 1970-2038 behavior (#2119) (#7914)

* DOCS-15516 Time series range outside 1970-2038 behavior (#2119)

* Rebuild

* Syntax fix

Author: nvillahermosa-mdb

source/core/timeseries-collections.txt

@@ -115,30 +115,39 @@ When you query time series collections, you operate on one document per
 measurement. Queries on time series collections take advantage of the
 optimized internal storage format and return results faster.
 
+.. tip::
+
+   To improve query performance, you can manually :ref:`add secondary
+   indexes <timeseries-add-secondary-index>` on measurement fields or
+   any field in your time series collection.
+
 .. important:: Backward-Incompatible Feature
 
    .. include:: /includes/downgrade-for-timeseries-collections.rst
 
 .. include:: /includes/database-profiler-note.rst
 
+.. _manual-timeseries-internal-index:
+
 Internal Index
 ``````````````
 
 When you create a time series collection, MongoDB automatically creates
 an internal :ref:`clustered index <clustered-collections>` on the time
-field. The internal index provides several performance benefits
-including improved query efficiency and reduced disk usage. To learn
-more about the performance benefits of clustered indexes, see
-:ref:`Clustered Collections <clustered-collections>`.
-
-The internal index for a time series collection is not displayed by
-:dbcommand:`listIndexes`.
-
-.. tip::
-
-   To improve query performance, you can manually :ref:`add secondary
-   indexes <timeseries-add-secondary-index>` on measurement fields or
-   any field in your time series collection.
+field. This index improves query efficiency and reduces disk 
+usage. To learn more about the performance benefits of clustered 
+indexes, see :ref:`Clustered Collections <clustered-collections>`.
+
+The internal index is not listed when you run :dbcommand:`listIndexes`.
+
+.. note::
+   If you insert a document into a collection with a ``timeField`` 
+   value before ``1970-01-01T00:00:00.000Z`` or after 
+   ``2038-01-19T03:14:07.000Z``, 
+   MongoDB logs a warning and prevents some query optimizations from 
+   using the internal index. :ref:`Create a secondary index <timeseries-add-secondary-index>` 
+   on the ``timeField`` to regain query performance and resolve the log 
+   warning.
 
 Get Started
 -----------

source/core/timeseries/timeseries-best-practices.txt

@@ -209,52 +209,7 @@ ratio.
 Optimize Query Performance
 --------------------------
 
-Query metaFields on Sub-Fields
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-MongoDB reorders the metaFields of time-series collections, which may
-cause servers to store data in a different field order than
-applications. If metaFields are objects, queries on entire metaFields
-may produce inconsistent results because metaField order may vary
-between servers and applications. To optimize queries on time-series
-metaFields, query timeseries metaFields on scalar sub-fields rather than
-entire metaFields. 
-
-The following example creates a time series collection:
-
-.. code-block:: javascript
-
-   db.weather.insertMany( [
-      {
-         "metaField": { "sensorId": 5578, "type": "temperature" },
-         "timestamp": ISODate( "2021-05-18T00:00:00.000Z" ),
-         "temp": 12
-      },
-      {
-         "metaField": { "sensorId": 5578, "type": "temperature" },
-         "timestamp": ISODate( "2021-05-18T04:00:00.000Z" ),
-         "temp": 11
-      }
-   ] )
-
-The following query on the ``sensorId`` and ``type`` scalar sub-fields
-returns the first document that matches the query criteria: 
-
-.. code-block:: javascript
-
-   db.weather.findOne( {
-      "metaField.sensorId": 5578,
-      "metaField.type": "temperature"
-   } )
-
-Example output:
-
-.. code-block:: javascript
-   :copyable: false
-
-   {
-     _id: ObjectId("6572371964eb5ad43054d572"),
-     metaField: { sensorId: 5578, type: 'temperature' },
-     timestamp: ISODate( "2021-05-18T00:00:00.000Z" ),
-     temp: 12
-   }
+To improve query performance, 
+:ref:`create one or more secondary indexes <timeseries-add-secondary-index>` 
+on your ``timeField`` and ``metaField`` to support common query 
+patterns. 

source/core/timeseries/timeseries-migrate-data-into-timeseries-collection.txt

@@ -239,9 +239,23 @@ The command returns the following output:
    :binary:`~bin.mongorestore` cannot create indexes on time series
    collections.
 
-If your original collection had secondary indexes, manually recreate them
-now.
+If your original collection had secondary indexes, manually recreate 
+them now. If your collection includes ``timeField`` values before 
+``1970-01-01T00:00:00.000Z`` or after ``2038-01-19T03:14:07.000Z``, 
+MongoDB logs a warning and disables some query optimizations that make 
+use of the :ref:`internal clustered index <manual-timeseries-internal-index>`. :ref:`Create a secondary index 
+<timeseries-add-secondary-index>` on the ``timeField`` to regain query 
+performance and resolve the log warning.
 
 .. seealso::
 
    :ref:`timeseries-add-secondary-index`
+
+
+   If you insert a document into a collection with a ``timeField`` 
+   value before ``1970-01-01T00:00:00.000Z`` or after 
+   ``2038-01-19T03:14:07.000Z``, 
+   MongoDB logs a warning and prevents some query optimizations from 
+   using the internal index. :ref:`Create a secondary index <timeseries-add-secondary-index>` 
+   on the ``timeField`` to regain query performance and resolve the log 
+   warning.

source/core/timeseries/timeseries-secondary-index.txt

@@ -116,14 +116,20 @@ measurements from weather sensors:
      ] 
    )
 
-Time Series collections automatically create a clustered index. The 
-clustered index may automatically be used by the query planner to 
-improve sort performance in some situations. For more information on 
-clustered indexes, see :ref:`clustered index 
-<db.createCollection.clusteredIndex>`.
-
-The following sort operation on the timestamp field uses the clustered 
-index to improve performance:
+Time Series collections automatically create an internal :ref:`clustered index <db.createCollection.clusteredIndex>`. 
+The query planner uses this index to improve sort performance. 
+
+.. note::
+   If you insert a document into a collection with a ``timeField`` 
+   value before ``1970-01-01T00:00:00.000Z`` or after 
+   ``2038-01-19T03:14:07.000Z``, 
+   MongoDB logs a warning and prevents some query optimizations from 
+   using the internal index. :ref:`Create a secondary index <timeseries-add-secondary-index>` 
+   on the ``timeField`` to regain query performance and resolve the log 
+   warning.
+
+The following sort operation on the ``timestamp`` field uses the 
+clustered index to improve performance:
 
 .. code-block:: javascript