diff --git a/reference/oci8/functions/oci-set-prefetch.xml b/reference/oci8/functions/oci-set-prefetch.xml
index c2a10d44d6..b2942566d5 100644
--- a/reference/oci8/functions/oci-set-prefetch.xml
+++ b/reference/oci8/functions/oci-set-prefetch.xml
@@ -34,17 +34,17 @@
    re-executed statements or by other connections.
   </para>
   <para>
-    Call <function>oci_set_prefetch</function> before
-    calling <function>oci_execute</function>.
+   Call <function>oci_set_prefetch</function> before
+   calling <function>oci_execute</function>.
   </para>
   <para>
-    A tuning goal is to set the prefetch value to a reasonable size
-    for the network and database to handle.  For queries returning a
-    very large number of rows, overall system efficiency might be
-    better if rows are retrieved from the database in several chunks
-    (i.e set the prefetch value smaller than the number of rows).
-    This allows the database to handle other users' statements while
-    your script is processing the current set of rows.
+   A tuning goal is to set the prefetch value to a reasonable size for
+   the network and database to handle.  For queries returning a very
+   large number of rows, overall system efficiency might be better if
+   rows are retrieved from the database in several chunks (i.e set the
+   prefetch value smaller than the number of rows).  This allows the
+   database to handle other users' statements while your script is
+   processing the current set of rows.
   </para>
   <para>
    Query prefetching was introduced in Oracle 8i.  REF CURSOR
@@ -52,9 +52,12 @@
    linked with Oracle 11gR2 Client libraries and connected to 11gR2 or
    previous versions of the database.  Nested cursor prefetching was
    introduced in Oracle 11gR2 and requires both the Oracle Client
-   libraries and the database to be version 11gR2.  The prefetch value
-   is ignored and single-row fetches will be used when prefetching is
-   not supported.
+   libraries and the database to be version 11gR2.  
+  </para>
+  <para>
+   Prefetching is not supported when queries contain LONG or LOB
+   columns.  The prefetch value is ignored and single-row fetches will
+   be used in all the situations when prefetching is not supported.
   </para>
  </refsect1>