Added description of failover behaviour and more information on the effect of the "retry_interval" parameter

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@206459 c90b9560-bf6c-de11-be94-00142212c4b1

reference/memcache/functions/memcache-addserver.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.4 $ -->
+<!-- $Revision: 1.5 $ -->
 <refentry id="function.Memcache-addServer">
  <refnamediv>
   <refname>Memcache::addServer</refname>
@@ -27,6 +27,14 @@
    <function>Memcache::close</function>.
    You can also use the <function>memcache_add_server</function> function.
   </para>
+  
+  <para>
+   Failover may occur at any stage in any of the methods, as long as other 
+   servers are available the request the user won't notice. Any kind of 
+   socket or Memcached server level errors (except out-of-memory) may trigger 
+   the failover. Normal client errors such as adding an existing key will not 
+   trigger a failover.
+  </para>
 
   <note>
    <para>
@@ -94,6 +102,14 @@
        parameter has any effect when this extension is loaded dynamically
        via <function>dl</function>.
       </para>
+      <para>
+       Each failed connection struct has its own timeout and before it has expired 
+       the struct will be skipped when selecting backends to serve a request. Once 
+       expired the connection will be successfully reconnected or marked as failed 
+       for another <parameter>retry_interval</parameter> seconds. The typical 
+       effect is that each webserver child will retry the connection about every
+       <parameter>retry_interval</parameter> seconds when serving a page.
+      </para>
      </listitem>
     </varlistentry>
    </variablelist>