[GitHub] [couchdb-documentation] bessbd commented on a change in pull request #629: 3.x fair share scheduler documetation

[GitBox <gi...@apache.org>]

bessbd commented on a change in pull request #629:
URL: https://github.com/apache/couchdb-documentation/pull/629#discussion_r596088543



##########
File path: src/replication/replicator.rst
##########
@@ -21,6 +21,11 @@ Replicator Database
    anymore. There are new replication job states and new API endpoints
    ``_scheduler/jobs`` and ``_scheduler/docs``.
 
+.. versionchanged:: 3.2.0 Fair share scheduling was
+   introduced. Multiple ``_replicator`` databases get an equal chance

Review comment:
       Is the line wrap important here? Should `introduced` go to the line above?

##########
File path: src/config/replicator.rst
##########
@@ -249,3 +249,52 @@ Replicator Database Configuration
 
         .. note::
              In version 2.2, the session plugin is considered experimental and is not enabled by default.
+
+    .. config:option:: usage_coeff
+
+        .. versionadded:: 3.2.0
+
+        Usage coefficient decays historic fair share usage every
+        scheduling cycle. The value must be between 0.0 and 1.0. Lower
+        values will ensure historic usage decays quicker and higher
+        values means it will be remembered longer::
+
+            [replicator]
+            usage_coeff = 0.5
+
+    .. config:option:: priority_coeff
+
+        .. versionadded:: 3.2.0
+
+       Priority coefficient decays all the job priorities such that they slowly
+       drift towards the front of the run queue. This coefficient defines a maximum
+       time window over which this algorithm would operate. For example, if this
+       value is too small (0.1), after a few cycles quite a few jobs would end up at
+       priority 0, and would render this algorithm useless. The default value of
+       0.98 is picked such that if a job ran for one scheduler cycle, then didn't
+       get to run for 7 hours, it would still have priority > 0. 7 hours was picked
+       as it was close enough to 8 hours which is the default maximum error backoff
+       interval::
+
+            [replicator]
+            priority_coeff = 0.98
+
+.. _config/replicator.shares:
+
+Fair Share Replicator Share Allocation
+======================================
+
+.. config:section:: replicator.shares :: Per-Database Fair Share Allocation
+
+    .. config:option:: $replicator_db
+
+        .. versionadded:: 3.2.0
+
+        Fair share configuration section. More shares result in a
+        higher chance that jobs from that db get to run. The default
+        value is 100, minimum is 1 and maximum is 1000. The
+        configuration may be set even if the database does not exit::

Review comment:
       Nit
   ```suggestion
           configuration may be set even if the database does not exist::
   ```




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