DOCS-16135 transactionTooLargeForCache v6.0 Docs (#6499) (#6533)

* DOCS-16135 transactionTooLargeForCache v6.0 Docs (#6499)

* DOCS-16135 transactionTooLargeForCache 6.0 Docs

* *

* build errors 1/2

Author: ajhuh-mdb

source/core/transactions-in-applications.txt

@@ -46,7 +46,10 @@ The callback API incorporates logic:
   :ref:`transient-transaction-error`.
 
 - To retry the commit operation if the commit encounters an
-  :ref:`unknown-transaction-commit-result`.
+  :ref:`unknown-transaction-commit-result` error.
+
+Starting in MongoDB 5.0.16, the server does not retry the transaction if
+it receives a :ref:`transactionTooLargeForCache-error` error.
 
 Example
 ~~~~~~~
@@ -412,6 +415,27 @@ If the commit operation encounters an error labeled
   ``"UnknownTransactionCommitResult"``, applications should explicitly
   incorporate retry logic for the error.
 
+.. _transactionTooLargeForCache-error:
+
+``TransactionTooLargeForCache``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. versionadded:: 5.0.16
+
+Starting in MongoDB 5.0.16, the server does not retry the transaction if
+it receives a ``TransactionTooLargeForCache`` error. This error means
+the cache is too small and a retry is likely to fail.
+
+The default value for the
+:parameter:`transactionTooLargeForCacheThreshold` threshold is ``0.75``.
+The server returns ``TransactionTooLargeForCache`` instead of retrying
+the transaction when the transaction uses more than 75% of the cache.
+
+In earlier versions of MongoDB, the server returns
+``TemporarilyUnavailable`` or ``WriteConflict`` instead of
+``TransactionTooLargeForCache``.
+
+Use the :dbcommand:`setParameter` command to modify the error threshold. 
 
 Driver Version Errors
 ~~~~~~~~~~~~~~~~~~~~~

source/reference/parameters.txt

@@ -4567,7 +4567,36 @@ Transaction Parameters
    modified for all shard replica set members.
 
    .. include:: /includes/transactionLifetimeLimitSeconds-parameter.rst
+
+.. parameter:: transactionTooLargeForCacheThreshold
+
+   .. versionadded:: 5.0.16
+
+   |mongod-only|
+
+   *Type*: decimal
+
+   *Default*: 0.75
+
+   The threshold value for retrying transactions that fail due to cache
+   pressure. The value is a percentage of the dirty cache size. The
+   default value, ``0.75``, means 75% of the dirty cache.
+   
+   The dirty cache is limited to 20% of the total cache size. When
+   ``transactionTooLargeForCacheThreshold`` is set to ``0.75``, the
+   server only retries transactions that use less than 15%
+   (``0.75 * 20%``) of the total storage engine cache.
 
+   The limit only applies to retries. Large transactions can use more
+   than ``transactionTooLargeForCacheThreshold`` percent of the dirty
+   cache. However, if a large transaction is rolled back due to cache
+   pressure, the server issues a
+   :ref:`transactionTooLargeForCache-error` error and does not retry the
+   transaction. 
+  
+   To disable this behavior, set
+   ``transactionTooLargeForCacheThreshold`` to ``1.0``.
+
 .. parameter:: maxTransactionLockRequestTimeoutMillis
 
    |mongod-only|