Update documentation.

Author: anthony-tuininga

doc/src/user_guide/initialization.rst

@@ -32,7 +32,8 @@ upgrading a cx_Oracle application to python-oracledb, then refer to
 
     All connections in an application use the same mode.
 
-    Once the Thick mode is enabled, you cannot go back to Thin mode.
+    Once the Thick mode is enabled, you cannot go back to Thin mode except by
+    restarting the application.
 
 Enabling the python-oracledb Thick mode loads Oracle Client libraries which
 handle communication to your database.  The Oracle Client libraries need to be
@@ -43,9 +44,9 @@ installed separately.  See :ref:`installation`.
 
    Architecture of the python-oracledb driver in Thick mode
 
-You can validate the python-oracledb mode by querying the ``CLIENT_DRIVER``
-column of ``V$SESSION_CONNECT_INFO`` and verifying the value of the column
-begins with ``python-oracledb thk``. See :ref:`vsessconinfo`.
+You can validate python-oracledb is running in Thick mode by querying the
+``CLIENT_DRIVER`` column of ``V$SESSION_CONNECT_INFO`` and verifying the value
+of the column begins with ``python-oracledb thk``. See :ref:`vsessconinfo`.
 
 
 .. _libinit:

doc/src/user_guide/tuning.rst

@@ -248,10 +248,10 @@ Python.
 Tuning Fetching from REF CURSORS
 --------------------------------
 
-In python-oracledb, REF CURSORS can also be tuned by setting the values of
-``arraysize`` and ``prefetchrows``. The ``prefetchrows`` value must be set
-before calling the PL/SQL procedure as the REF CURSOR is executed on the
-server.
+In python-oracledb, fetching data from REF CURSORS can be tuned by setting the
+values of ``arraysize`` and ``prefetchrows``. The ``prefetchrows`` value must
+be set before calling the PL/SQL procedure because the REF CURSOR is executed
+on the server.
 
 For example:
 
@@ -272,6 +272,8 @@ For example:
 
 .. _roundtrips:
 
+Also see `Avoiding Premature Prefetching`_.
+
 Database Round-trips
 ====================