*** /tmp/8hB0Ty_xfunc.sgml	2015-07-31 14:05:45.331691017 -0400
--- doc/src/sgml/xfunc.sgml	2015-07-31 14:05:29.710696535 -0400
***************
*** 3339,3344 ****
--- 3339,3351 ----
  </programlisting>
       from <function>_PG_init</>.
      </para>
+     <note>
+      <para>
+       By default a minimum of 4 LWLocks are requested in order to maintain
+       backwards-compatibility, which may lead to debugging issues if the extensions
+       doesn't request the correct number of LWLocks needed.
+      </para>
+    </note>
      <para>
       To avoid possible race-conditions, each backend should use the LWLock
       <function>AddinShmemInitLock</> when connecting to and initializing