(DOCSP-18813): Note that change streams cannot leverage indexes

Author: jeff-allen-mongo

source/administration/change-streams-production-recommendations.txt

@@ -83,3 +83,19 @@ From the moment an unsharded collection is sharded until the time the change
 stream catches up to the first chunk migration, the ``documentKey`` in the
 change stream notification document only includes the ``_id`` of the document,
 not the full shard key.
+
+Indexes and Performance
+-----------------------
+
+Change streams cannot use indexes. MongoDB does not support creating
+indexes on the :term:`oplog` collection. Therefore, avoid opening a high
+number of :ref:`specifically-targeted <changeStreams-watch-deployment>`
+change streams as these can impact server performance.
+
+Change Stream Optimization
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. |change-streams| replace:: change streams
+
+.. include:: /includes/change-streams-optimization.rst
+

source/changeStreams.txt

@@ -53,8 +53,10 @@ Change streams are available for :doc:`replica sets <replication>` and
 
   .. include:: /includes/extracts/changestream-rc-majority-4.2.rst
 
-Watch Collection/Database/Deployment
-------------------------------------
+.. _changeStreams-watch-deployment:
+
+Watch a Collection, Database, or Deployment
+-------------------------------------------
 
 You can open change streams against: