From f908a8a3e06a6494877ee5653428eefbcaa66016 Mon Sep 17 00:00:00 2001
From: Kay Kim <kay.kim@10gen.com>
Date: Sun, 30 Jun 2019 18:23:36 -0400
Subject: [PATCH] DOCS-13944 Backport DOCS-12740 to 4.0:
 logicalSessionRecordCache.sessionCatalogSize

---
 ...xtracts-server-status-projection-base.yaml |  4 ++
 source/reference/command/serverStatus.txt     | 46 +++++++++++++++----
 source/reference/config-database.txt          |  6 +--
 3 files changed, 43 insertions(+), 13 deletions(-)

diff --git a/source/includes/extracts-server-status-projection-base.yaml b/source/includes/extracts-server-status-projection-base.yaml
index f7736a56c26..5d0a67cee96 100644
--- a/source/includes/extracts-server-status-projection-base.yaml
+++ b/source/includes/extracts-server-status-projection-base.yaml
@@ -12,6 +12,10 @@ content: |
 ref: _serverStatus-output-changes
 content: |
 
+  - Starting in MongoDB 4.0.22, {{operationName}} includes:
+
+    - :serverstatus:`logicalSessionRecordCache.sessionCatalogSize`
+
   - Starting in MongoDB 4.0.19, {{operationName}} includes:
 
     - :serverstatus:`security.metrics.aggStageCounters`
diff --git a/source/reference/command/serverStatus.txt b/source/reference/command/serverStatus.txt
index 3f695211c38..bbc03a46ae4 100644
--- a/source/reference/command/serverStatus.txt
+++ b/source/reference/command/serverStatus.txt
@@ -20,19 +20,24 @@ Definition
    applications can run this command at a regular interval to
    collect statistics about the instance.
 
-   .. code-block:: javascript
+Syntax
+------
+
+The command has the following syntax:
 
-      db.runCommand( { serverStatus: 1 } )
+.. code-block:: javascript
+
+   db.runCommand( { serverStatus: 1 } )
 
-   The value (i.e. ``1`` above) does not affect the operation of the
-   command. The :binary:`~bin.mongo` shell provides the
-   :method:`db.serverStatus()` wrapper for the command.
+The value specified (``1`` above) does not affect the operation of the
+command. The :binary:`~bin.mongo` shell provides the
+:method:`db.serverStatus()` wrapper for the command.
 
-   .. seealso::
+.. seealso::
 
-      Much of the output of :dbcommand:`serverStatus` is also displayed
-      dynamically by :binary:`~bin.mongostat`. See the
-      :doc:`/reference/program/mongostat` command for more information.
+   Much of the output of :dbcommand:`serverStatus` is also displayed
+   dynamically by :binary:`~bin.mongostat`. See the
+   :doc:`/reference/program/mongostat` command for more information.
 
 Behavior
 --------
@@ -822,9 +827,15 @@ logicalSessionRecordCache
       "transactionReaperJobCount" : <num>,
       "lastTransactionReaperJobDurationMillis" : <num>,
       "lastTransactionReaperJobTimestamp" : <Date>,
-      "lastTransactionReaperJobEntriesCleanedUp" : <num>
+      "lastTransactionReaperJobEntriesCleanedUp" : <num>,
+      "sessionCatalogSize" : <num>   // Starting in MongoDB 4.0.22
    },
 
+.. serverstatus:: logicalSessionRecordCache
+
+   Provides metrics for caching of :doc:`server sessions
+   </reference/server-sessions/>`.
+
 .. serverstatus:: logicalSessionRecordCache.activeSessionsCount
 
    The number of all active local sessions cached in memory by the
@@ -884,6 +895,21 @@ logicalSessionRecordCache
    The number of entries in the :data:`config.transactions` collection
    that were deleted during the last transaction record cleanup.
 
+.. serverstatus:: logicalSessionRecordCache.sessionCatalogSize
+
+   - For a :binary:`~bin.mongod` instance:
+        The size of its in-memory cache of the `config.transactions`
+        entries. This corresponds to retryable writes
+        or transactions whose sessions have not expired within the
+        :parameter:`localLogicalSessionTimeoutMinutes`.
+
+   - For a :binary:`~bin.mongos` instance:
+        The number of the in-memory cache of its sessions that have had
+        transactions within the most recent
+        :parameter:`localLogicalSessionTimeoutMinutes` interval.
+
+   .. versionadded:: 4.0.22
+
 .. _locks:
 .. _server-status-locks:
 
diff --git a/source/reference/config-database.txt b/source/reference/config-database.txt
index d5f7fc87c08..9449a018b56 100644
--- a/source/reference/config-database.txt
+++ b/source/reference/config-database.txt
@@ -483,9 +483,9 @@ instance.
 
 .. data:: config.transactions
 
-   The ``transactions`` collection stores records used to support
-   :ref:`retryable writes <retryable-writes>` for
-   replica sets and sharded clusters.
+   The ``transactions`` collection stores documents used to support
+   :ref:`retryable writes <retryable-writes>` and :doc:`transactions
+   </core/transactions>` for replica sets and sharded clusters.
 
    .. warning::