(DOCS-13395): slowOpSampleRate affects secondary logs

Author: jeff-allen-mongo

source/core/replica-set-oplog.txt

@@ -207,6 +207,8 @@ there is any unintended replication delay.
 See :ref:`Replication Lag <replica-set-replication-lag>` for more
 information.
 
+.. _slow-oplog-application:
+
 Slow Oplog Application
 ----------------------
 
@@ -223,9 +225,6 @@ longer than the slow operation threshold to apply. These messages are
 
 The slow oplog application logging on secondaries are:
 
-- Not affected by the :setting:`~operationProfiling.slowOpSampleRate`;
-  i.e. all slow oplog entries are logged by the secondary.
-
 - Not affected by the
   :parameter:`logLevel`/:setting:`systemLog.verbosity` level (or the
   :setting:`systemLog.component.replication.verbosity` level); i.e. for

source/includes/extracts-4.2-changes.yaml

@@ -97,16 +97,33 @@ content: |
 ref: 4.2-changes-slow-oplog-log-message-footnote
 content: |
 
-   Starting in version 4.2 (also available starting in 4.0.6), secondary members of a replica set now
-   :ref:`log oplog entries <slow-oplog>` that take longer than the slow
-   operation threshold to apply. These slow oplog messages are logged
-   for the secondaries in the :option:`diagnostic log <mongod
-   --logpath>` under the :data:`REPL` component with the text ``applied
-   op: <oplog entry> took <num>ms``. These slow oplog entries depend
-   only on the slow operation threshold. They do not depend on the log
-   levels (either at the system or component level), or the profiling
-   level, or the slow operation sample rate. The profiler does not
-   capture slow oplog entries.
+   Starting in version 4.2 (also available starting in 4.0.6), secondary
+   members of a replica set now :ref:`log oplog entries
+   <slow-oplog-application>` that take longer than the slow operation
+   threshold to apply. These slow oplog messages:
+      
+   - Are logged for the secondaries in the
+     :option:`diagnostic log <mongod --logpath>`.
+     
+   - Are logged under the :data:`REPL` component with the text
+     ``applied op: <oplog entry> took <num>ms``.
+   
+   - Do not depend on the log levels (either at the system or component
+     level)
+   
+   - Do not depend on the profiling level.
+
+   - May be affected by :setting:`~operationProfiling.slowOpSampleRate`,
+     depending on your MongoDB version:
+
+     - In MongoDB 4.2 and earlier, these slow oplog entries are not
+       affected by the :setting:`~operationProfiling.slowOpSampleRate`.
+       MongoDB logs all slow oplog entries regardless of the sample rate.
+
+     - In MongoDB 4.4 and later, these slow oplog entries are affected by
+       the :setting:`~operationProfiling.slowOpSampleRate`.
+
+   The profiler does not capture slow oplog entries.
 ---
 ref: 4.2-changes-type-0
 content: |

source/includes/fact-log-slow-queries.rst

@@ -2,10 +2,7 @@
 
 When :parameter:`logLevel` is set to ``0``, MongoDB records *slow*
 operations to the diagnostic log at a rate determined by
-:setting:`~operationProfiling.slowOpSampleRate`. Starting in MongoDB
-4.2, the secondaries of replica sets log :ref:`all oplog entry messages
-that take longer than the slow operation threshold to apply
-<slow-oplog>` regardless of the sample rate.
+:setting:`~operationProfiling.slowOpSampleRate`.
 
 At higher :parameter:`logLevel` settings, all operations appear in
 the diagnostic log regardless of their latency with the following

source/reference/configuration-options.txt

@@ -4045,13 +4045,8 @@ LDAP Parameters
    *Default*: 1.0
 
    The fraction of *slow* operations that should be profiled or logged.
-   :setting:`operationProfiling.slowOpSampleRate` accepts values between 0 and 1, inclusive.
-   
-   :setting:`operationProfiling.slowOpSampleRate` does not affect the :ref:`slow oplog entry logging
-   <slow-oplog>` by the secondary members of a replica set. Secondary
-   members log all oplog entries that take longer than the slow
-   operation threshold regardless of the :setting:`operationProfiling.slowOpSampleRate`.
-
+   :setting:`operationProfiling.slowOpSampleRate` accepts values between
+   0 and 1, inclusive.
 
    .. versionchanged:: 4.0
 

source/reference/method/db.setProfilingLevel.txt

@@ -116,7 +116,7 @@ Parameters
 
        .. list-table::
           :stub-columns: 1
-          :widths: 15 85
+          :widths: 25 75
 
           * - :ref:`slowms <set-profiling-level-options-slowms>`
 

source/release-notes/4.2.txt

@@ -1467,9 +1467,9 @@ Logging
   temporary files due to memory restrictions. For more information on
   aggregation memory restrictions, see :ref:`agg-memory-restrictions`.
 
-- .. _slow-oplog:
+.. _slow-oplog:
 
-  Starting in version 4.2 (also available starting in 4.0.6),
+- Starting in version 4.2 (also available starting in 4.0.6),
   secondary members of a replica set now log oplog entries that take
   longer than the slow operation threshold to apply. These messages are
   :option:`logged <mongod --logpath>` for the secondaries under the

source/release-notes/4.4.txt

@@ -556,6 +556,19 @@ restart.
 
    :doc:`/core/replica-set-oplog`
 
+
+``slowOpSampleRate`` Affects Secondary Logs
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Starting in MongoDB 4.4, :ref:`slow oplog application
+<slow-oplog-application>` logs on replica set secondaries are affected
+by the :setting:`~operationProfiling.slowOpSampleRate`. In previous
+versions, MongoDB logs all slow oplog entries regardless of the sample
+rate.
+
+:setting:`~operationProfiling.slowOpSampleRate` specifies the fraction
+of slow operations that should be profiled or logged.
+
 Indexes Build Simultaneously on Data-Bearing Replica Set Members
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~