DOCS-13635 add minSnapshotHistoryWindowInSeconds

Author: npentrel

source/core/wiredtiger.txt

@@ -56,6 +56,10 @@ metadata table is atomically updated to reference the new checkpoint.
 Once the new checkpoint is accessible, WiredTiger frees pages from the
 old checkpoints.
 
+Starting in MongoDB 5.0, you can use the
+:parameter:`minSnapshotHistoryWindowInSeconds` parameter to control how
+long WiredTiger keeps the snapshot history.
+
 Using WiredTiger, even without :ref:`journaling
 <storage-wiredtiger-journal>`, MongoDB can recover from the last
 checkpoint; however, to recover changes made after the last checkpoint,

source/reference/parameters.txt

@@ -3377,43 +3377,6 @@ Sharding Parameters
 Storage Parameters
 ~~~~~~~~~~~~~~~~~~
 
-.. parameter:: journalCommitInterval
-
-   |mongod-only|
-
-   Specify an integer between ``1`` and ``500`` signifying the number
-   of milliseconds (ms) between journal commits.
-
-   Consider the following example which sets the
-   :parameter:`journalCommitInterval` to ``200`` ms:
-
-   .. code-block:: javascript
-
-      db.adminCommand( { setParameter: 1, journalCommitInterval: 200 } )
-
-   .. seealso:: :setting:`storage.journal.commitIntervalMs`
-
-.. parameter:: syncdelay
-
-   |mongod-only|
-
-   Specify the interval in seconds between :term:`fsync` operations
-   where :binary:`~bin.mongod` flushes its working memory to disk. By
-   default, :binary:`~bin.mongod` flushes memory to disk every 60
-   seconds. In almost every situation you should not set this value
-   and use the default setting.
-
-   Consider the following example which sets the ``syncdelay`` to
-   ``60`` seconds:
-
-   .. code-block:: javascript
-
-      db.adminCommand( { setParameter: 1, syncdelay: 60 } )
-
-   .. seealso:: 
-      - :parameter:`journalCommitInterval`
-      - :setting:`storage.syncPeriodSecs`
-
 .. parameter:: honorSystemUmask
 
    .. versionadded:: 3.6
@@ -3424,14 +3387,14 @@ Storage Parameters
 
    If :parameter:`honorSystemUmask` is set to ``true``, new files
    created by MongoDB have permissions in accordance with the
-   user's ``umask`` settings. You cannot set :parameter:`processUmask` 
+   user's ``umask`` settings. You cannot set :parameter:`processUmask`
    if :parameter:`honorSystemUmask` is set to ``true``.
 
    If :parameter:`honorSystemUmask` is set to ``false``, new files
    created by MongoDB have permissions set to ``600``, which gives
    read and write permissions only to the owner. New directories have
-   permissions set to ``700``. You can use :parameter:`processUmask` 
-   to override the default permissions for groups and other users on 
+   permissions set to ``700``. You can use :parameter:`processUmask`
+   to override the default permissions for groups and other users on
    all new files created by MongoDB.
 
    You can only set this parameter during start-up and cannot change
@@ -3445,28 +3408,71 @@ Storage Parameters
 
       :parameter:`honorSystemUmask` is not available on Windows systems.
 
+.. parameter:: journalCommitInterval
+
+   |mongod-only|
+
+   Specify an integer between ``1`` and ``500`` signifying the number
+   of milliseconds (ms) between journal commits.
+
+   Consider the following example which sets the
+   :parameter:`journalCommitInterval` to ``200`` ms:
+
+   .. code-block:: javascript
+
+      db.adminCommand( { setParameter: 1, journalCommitInterval: 200 } )
+
+   .. seealso:: :setting:`storage.journal.commitIntervalMs`
+
+.. parameter:: minSnapshotHistoryWindowInSeconds
+
+   ..versionadded:: 5.0
+
+   |mongod-only|
+
+   The minimum time window in seconds for which the storage engine keeps
+   the snapshot history. If you query data using read concern
+   :readconcern: snapshot and specify an
+   :ref:`atClusterTime <atClusterTime>` value older than the specified
+   ``minSnapshotHistoryWindowInSeconds``, :binary:`~bin.mongod` returns
+   a ``SnapshotTooOld`` error.
+
+   Specify an integer greater than or equal to (``>=``) 1.
+
+   Consider the following example which sets the
+   ``minSnapshotHistoryWindowInSeconds`` to ``600`` seconds:
+
+   .. code-block:: javascript
+
+      db.adminCommand( { setParameter: 1, minSnapshotHistoryWindowInSeconds: 600 } )
+
+   .. seealso::
+      - Read concern :readconcern:`"snapshot"`
+      - :ref:`Snapshots and Checkpoints
+        <storage-wiredtiger-checkpoints>`
+
 .. parameter:: processUmask
 
    .. versionadded:: 4.4
 
    |mongod-only|
 
-   Overrides the default permissions used for groups and other users 
-   when :parameter:`honorSystemUmask` is set to ``false``. By default, 
-   when :parameter:`honorSystemUmask` is set to ``false``, new files 
-   created by MongoDB have permissions set to ``600``. Use the 
-   ``processUmask`` parameter to override this default with a custom 
-   ``umask`` value. The file owner inherits permissions from the system 
-   ``umask``. 
- 
-   You cannot set this parameter if :parameter:`honorSystemUmask` is set 
-   to ``true``. You can only set this parameter during start-up and cannot 
-   change this setting using the :dbcommand:`setParameter` database 
+   Overrides the default permissions used for groups and other users
+   when :parameter:`honorSystemUmask` is set to ``false``. By default,
+   when :parameter:`honorSystemUmask` is set to ``false``, new files
+   created by MongoDB have permissions set to ``600``. Use the
+   ``processUmask`` parameter to override this default with a custom
+   ``umask`` value. The file owner inherits permissions from the system
+   ``umask``.
+
+   You cannot set this parameter if :parameter:`honorSystemUmask` is set
+   to ``true``. You can only set this parameter during start-up and cannot
+   change this setting using the :dbcommand:`setParameter` database
    command.
 
-   Consider the following example, which sets the permissions for groups 
-   and other users to read/write only and retains the system ``umask`` 
-   settings for the owner: 
+   Consider the following example, which sets the permissions for groups
+   and other users to read/write only and retains the system ``umask``
+   settings for the owner:
 
    .. code-block:: sh
 
@@ -3476,6 +3482,27 @@ Storage Parameters
 
       :parameter:`processUmask` is not available on Windows systems.
 
+.. parameter:: syncdelay
+
+   |mongod-only|
+
+   Specify the interval in seconds between :term:`fsync` operations
+   where :binary:`~bin.mongod` flushes its working memory to disk. By
+   default, :binary:`~bin.mongod` flushes memory to disk every 60
+   seconds. In almost every situation you should not set this value
+   and use the default setting.
+
+   Consider the following example which sets the ``syncdelay`` to
+   ``60`` seconds:
+
+   .. code-block:: javascript
+
+      db.adminCommand( { setParameter: 1, syncdelay: 60 } )
+
+   .. seealso::
+      - :parameter:`journalCommitInterval`
+      - :setting:`storage.syncPeriodSecs`
+
 WiredTiger Parameters
 ~~~~~~~~~~~~~~~~~~~~~
 

source/release-notes/5.0.txt

@@ -139,6 +139,15 @@ restarts, index creation resumes from the saved position.
 Removed Commands
 ----------------
 
+.. _5.0-new-parameters:
+
+New Parameters
+--------------
+
+Starting in MongoDB 5.0, you can use the
+:parameter:`minSnapshotHistoryWindowInSeconds` parameter to control how
+long WiredTiger keeps the snapshot history.
+
 .. _5.0-rel-notes-networking:
 
 Networking