Weblogic Clustering Replica Session not Recovering

Question

Dear All,
Have One domains with WLS 10.3.4 on two physical machines, each machine hosting one managed server, cluster of the two servers, node manager on both servers and admin server on one of the servers. Using unicast and in-memory replication with replicate if clustered set in the weblogic.xml.
Apache balancing between the two and selected options to allow proxy plugin in the domain.
Question is I bring both servers up,
Log the user into test application.
In the console I can see from Cluster Monitoring that a single user connects on Managed Server 1 and that the session is correctly replicated onto Managed Server 2.
I then fail Managed Server 1 which is hosting the primary session, on manual page refresh the users request goes to the Managed Server 2 with the user staying logged in (as expected).
However when I return the failed Managed Server 1 to service I expected the current session now on Managed Server 2 to be replicated back to the Managed Server 1 (in case Managed Server 2 that is now hosting the primary session fails).
No matter how long I wait this replication does not take place, HOWEVER if after the Managed Server 1 is returned to service I manually refresh the Web Page which connects to Managed Server 2 this kicks the replication into action and creates a session replica back on Managed Server 1.
I don't think this is exected behaviour so any idea what is going wrong?
In the oracle docs it says
"In a two-server cluster, the client would transparently fail over to the server hosting the secondary session state. However, replication of the client’s session state would not continue unless another WebLogic Server became available and joined the cluster. For example, if the original primary server was restarted or reconnected to the network, it would be used to host the secondary session state. "
but in this case the second bit does not seem to host the secondary state unless the web page is actually used again (at which point you see the replica state created, it's almost like it will replicate going forwards but ignores the current state and does not re-sync between the managed servers, leading to a user being logging out if a flip-flop server failure test is carried out.
Thanks
Edited by: user10645195 on 18-Feb-2011 08:46
Edited by: user10645195 on 18-Feb-2011 08:52

Answer 1

HI,
The HttpSession replication happens Only when WebLogic creates a New HttpSession or Container encounters "session.setAttribute(obj,obj)" method...It means the Data is replicated to the Secondary JVM HttpSession only when application calls the setAttribute method of HttpSession. And in this case only the modified part of data is replicated NOT the complete HttpSession data.
So i think u can try adding a Simple temporary attribute in the HttpSession like
session.setAttribute("dummyData",""+new java.util.Date());
Now make sure that the above code is placed in each and every page of your application...sothat whenever a client will request the because of setAttribute() the Session modified data (dummyData) will be replicated...and if there are more setAttribute() on that page then all the those also will be replicated...
Example:
Map map = new HashMap();
session.setAttribute("map", map); <font color=maroon><b> -------> Here Session data Will be replicated to Node-2 (bcoz of setAttribute()) </b></font>
map.put("one", "aaa"); <font color=red>No Replication (Means No Session data Refresh...bcoz setAttribute is not called...)</font>
then from page1.jsp I go to page2.jsp and I do this:
Map map = (Map)session.getAttribute("map");
map.put("two", "bbb"); <font color=red>No Replication (Means No Session data Refresh...bcoz setAttribute is not called...)</font>
and then from page2.jsp I go to page3.jsp and I do this:
Map map = (Map)session.getAttribute("map");
map.put("three", "ccc"); <font color=red>No Replication (Means No Session data Refresh...bcoz setAttribute is not called...)</font>
Now you will see On The node2 the sessioncontains an EMPTY map ! <font color=maroon><b> (That is Correct) because when you executed </b></font><br>
Map map = new HashMap();
session.setAttribute("map", map);
<font color=maroon><b>
At that time The Map was not containing any data in it.
</b></font>
You need to try this:
Map map = new HashMap();
session.setAttribute("map", map);
map.put("one", "aaa"); <font color=green>----><b> Now session.setAttribute("map", map);</b></font> here session data will be refreshed in Node-2
then from page1.jsp I go to page2.jsp and I do this:
Map map = (Map)session.getAttribute("map");
map.put("two", "bbb"); <font color=green>----><b> Now session.setAttribute("map", map);</b></font> here session data will be refreshed in Node-2
and then from page2.jsp I go to page3.jsp and I do this:
Map map = (Map)session.getAttribute("map");
map.put("three", "ccc"); <font color=green>----><b> Now session.setAttribute("map", map);</b></font> here session data will be refreshed in Node-2
It means until u don't call session.setAttribute(---, ---)...The Session Data is not replicated (refreshed) to the Second Node(Secondary JVM).
Thanks
Jay SenSharma
http://middlewaremagic.com/ (Middleware magic Is Here)