add sbe to 6.0 release notes (#1218)

* add sbe to 6.0 release notes

* fix alphabetizatioN

Author: jeff-allen-mongo

source/release-notes/6.0.txt

@@ -116,6 +116,9 @@ MongoDB 6.0 introduces the following aggregation operators:
      - Returns the ``n`` smallest values in an array.
        Distinct from the :group:`$minN` accumulator.
 
+   * - :expression:`$sortArray`
+     - Sorts an array based on its elements.
+
    * - :group:`$top`
      - Returns the top element within a group according to the specified 
        sort order.
@@ -125,9 +128,6 @@ MongoDB 6.0 introduces the following aggregation operators:
      - Returns an aggregation of the top ``n`` elements within a group,
        according to the specified sort order.
 
-   * - :expression:`$sortArray`
-     - Sorts an array based on its elements. 
-
    * - :expression:`$tsIncrement`
      - .. include:: /includes/tsIncrement-introduction.rst
 
@@ -139,15 +139,6 @@ MongoDB 6.0 introduces the following aggregation operators:
 
 .. include:: /includes/5.1-fact-sharded-lookup-graphlookup.rst
 
-|sbe-title| Can Execute ``$group`` and ``$lookup`` Stages
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-Starting in version 6.0, MongoDB uses the |sbe| to execute eligible 
-:pipeline:`$group` and :pipeline:`$lookup` stages when certain 
-conditions are met.
-
-For more information, see :ref:`sbe-pipeline-optimizations`.
-
 .. _6.0-rel-notes-change-streams:
 
 Change Streams
@@ -246,6 +237,39 @@ earlier versions of MongoDB, the default chunk size is 64 megabytes.
 Starting in MongoDB 6.0, the :dbcommand:`enableSharding` command is
 no longer required to shard a collection.
 
+.. _6.0-rel-notes-sbe:
+
+Slot-Based Query Execution Engine
+---------------------------------
+
+Starting in MongoDB 5.1, MongoDB uses a new query execution engine for
+eligible queries, called the slot-based query execution engine. If the
+slot-based query execution engine is used, new fields are included in
+the query explain plan output.
+
+- The new query execution engine is used if possible.
+
+- If the new query execution engine is used, new fields are included in
+  the :ref:`query explain plan output <explain-results-5.1-later>`.
+
+|sbe-title| Can Execute ``$group`` and ``$lookup`` Stages
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Starting in version 6.0, MongoDB uses the |sbe| to execute eligible 
+:pipeline:`$group` and :pipeline:`$lookup` stages when certain 
+conditions are met.
+
+For more information, see :ref:`sbe-pipeline-optimizations`.
+
+Set |sbe-title| Plan Cache Size
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+You can set the size of the :ref:`plan cache
+<read-operations-query-optimization>` for the new query engine with the
+:parameter:`planCacheSize` parameter.
+
+.. include:: /includes/fact-sbe-plan-cache-motivation.rst
+
 Stable API
 ----------