Add a note about messenger:stop-workers command

Author: phansys

messenger.rst

@@ -490,8 +490,19 @@ On production, there are a few important things to think about:
     that they see the newly deployed code. To do this, run ``messenger:stop-workers``
     on deploy. This will signal to each worker that it should finish the message
     it's currently handling and shut down gracefully. Then, Supervisor will create
-    new worker processes. The command uses the :ref:`app <cache-configuration-with-frameworkbundle>`
-    cache internally - so make sure this is configured to use an adapter you like.
+    new worker processes.
+
+.. note::
+
+    By default, the ``messenger:stop-workers`` command uses the :ref:`cache.app <cache-configuration-with-frameworkbundle>`
+    cache pool internally.
+    In order to ensure there is never a conflict between pools, this pool will always
+    have its own namespace.
+    If you are not setting the `cache.prefix.seed` parameter and your deploy strategy
+    involves the creation of new target directories, please note that the `cache.app`
+    pool will use by default the value of the `kernel.project_dir` parameter as base
+    for the namespace, which will lead to different namespaces between deploys,
+    making this command obsolete.
 
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