(DOCS-14833): Add parameter to control SBE cache

source/includes/fact-sbe-plan-cache-motivation.rst

@@ -0,0 +1,3 @@
+Increasing the plan cache size adds more cached query shapes for the
+:ref:`query planner <read-operations-query-optimization>`. This can
+improve query performance, but increases memory usage.

source/reference/parameters.txt

@@ -907,47 +907,6 @@ General Parameters
 
       :parameter:`connPoolMaxShardedConnsPerHost`
 
-.. parameter:: internalQueryEnableSlotBasedExecutionEngine
-
-   .. versionadded:: 5.1
-
-   *Type*: boolean
-
-   *Default*: true
-
-   |mongod-only|
-
-   If :parameter:`internalQueryEnableSlotBasedExecutionEngine` is
-   ``true``:
-
-   - Enhanced query execution is used if possible. If used, the document
-     structure is separated from the document content, and only the
-     required fields are used in the engine computations. This improves
-     performance and ensures database resources are efficiently used.
-
-   - If enhanced query execution is used, the query plan :ref:`explain
-     results <explain-results-enhanced-execution>` have a different
-     structure and contain additional information about the execution
-     plan.
-
-   If :parameter:`internalQueryEnableSlotBasedExecutionEngine` is
-   ``false``, enhanced query execution is not used.
-
-   The following sets
-   :parameter:`internalQueryEnableSlotBasedExecutionEngine` to
-   ``false``:
-
-   .. code-block:: bash
-
-      mongod --setParameter internalQueryEnableSlotBasedExecutionEngine=false
-
-   You can also use the :dbcommand:`setParameter` command within the
-   :mongosh:`MongoDB Shell </>`:
-
-   .. code-block:: javascript
-
-      db.adminCommand( { setParameter: 1, internalQueryEnableSlotBasedExecutionEngine: false } )
-
 .. parameter:: shardedConnPoolIdleTimeoutMinutes
 
    .. versionadded:: 3.6.3
@@ -4230,3 +4189,86 @@ Transaction Parameters
    .. code-block:: javascript
 
       db.adminCommand( { setParameter: 1, shouldMultiDocTxnCreateCollectionAndIndexes: false } )
+
+Slot-Based Execution Parameters
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. parameter:: internalQueryEnableSlotBasedExecutionEngine
+
+   .. versionadded:: 5.1
+
+   *Type*: boolean
+
+   *Default*: true
+
+   |mongod-only|
+
+   If :parameter:`internalQueryEnableSlotBasedExecutionEngine` is
+   ``true``:
+
+   - Enhanced query execution is used if possible. If used, the document
+     structure is separated from the document content, and only the
+     required fields are used in the engine computations. This improves
+     performance and ensures database resources are efficiently used.
+
+   - If enhanced query execution is used, the query plan :ref:`explain
+     results <explain-results-enhanced-execution>` have a different
+     structure and contain additional information about the execution
+     plan.
+
+   If :parameter:`internalQueryEnableSlotBasedExecutionEngine` is
+   ``false``, enhanced query execution is not used.
+
+   The following sets
+   :parameter:`internalQueryEnableSlotBasedExecutionEngine` to
+   ``false``:
+
+   .. code-block:: bash
+
+      mongod --setParameter internalQueryEnableSlotBasedExecutionEngine=false
+
+   You can also use the :dbcommand:`setParameter` command within the
+   :mongosh:`MongoDB Shell </>`:
+
+   .. code-block:: javascript
+
+      db.adminCommand( { setParameter: 1, internalQueryEnableSlotBasedExecutionEngine: false } )
+
+.. parameter:: planCacheSize
+
+   .. versionadded:: 5.1
+
+   *Type*: string
+
+   *Default*: 5%
+
+   |mongod-only|
+
+   Sets the size of the :ref:`plan cache
+   <read-operations-query-optimization>` for the enhanced query
+   execution engine.
+
+   You can set the :parameter:`planCacheSize` value to either:
+
+   - A percentage of the system's total physical memory to allocate for
+     the plan cache. For example, ``"8.5%"``.
+
+   - The exact amount of data to allocate for the plan cache in either
+     ``MB`` or ``GB``. For example, ``"100MB"`` or ``"1GB"``.
+
+   .. include:: /includes/fact-sbe-plan-cache-motivation.rst
+
+   The following startup command sets :parameter:`planCacheSize` to 80
+   megabytes:
+
+   .. code-block:: bash
+
+      mongod --setParameter planCacheSize="80MB"
+
+   You can also use the :dbcommand:`setParameter` command within the
+   :mongosh:`MongoDB Shell </>`:
+
+   .. code-block:: javascript
+
+      db.adminCommand( { setParameter: 1, planCacheSize: "80MB" } )
+

source/release-notes/5.1.txt

@@ -54,6 +54,32 @@ Starting in MongoDB 5.1, :expression:`$dateSubtract` and
 :expression:`$dateAdd` report an error when an overflow is detected for
 ``amount`` values.
 
+.. _5.1-rel-notes-sbe:
+
+Slot-Based Query Execution Engine
+---------------------------------
+
+Starting in MongoDB 5.1, a new query execution engine is available,
+which improves query performance.
+
+If the new parameter
+:parameter:`internalQueryEnableSlotBasedExecutionEngine` is ``true``:
+
+- 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-enhanced-execution>`.
+
+Set Slot-Based Query Execution 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
+
 .. _5.1-rel-notes-change-streams:
 
 Change Streams
@@ -95,22 +121,6 @@ Aggregation Metrics
 Resharding Statistics
   - :serverstatus:`shardingStatistics.resharding.lastOpEndingChunkImbalance`
 
-
-New Slot-Based Query Execution Engine
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-Starting in MongoDB 5.1, a new query execution engine is available,
-which improves query performance.
-
-If the new parameter
-:parameter:`internalQueryEnableSlotBasedExecutionEngine` is ``true``:
-
-- 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-enhanced-execution>`.
-
 Geo Indexing for Time Series collections
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~