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From Peter Rossbach ...@objektpark.de>
Subject Re: Extending PersistentValve ?
Date Mon, 16 Jan 2006 20:13:48 GMT



Am 16.01.2006 um 20:12 schrieb Gary Blomquist:

> I would like to be able to use round robin loading balancing with a
> JDBCStore.  However, it appears that using the PersistentManager with
> JDBC store could cause the sessions to be stale when a session  
> migrates
> between workers due to the asyncronous behavior of the
> PersistentManager.  (I realize their is a SimpleTcpCluster  
> available as
> a clusterering solution but I can not use because it relies on
> multicast.)
>
Wrote you own Membership tcp based service and use the real cluster  
implementation :-)

At my feeling the old PersistentManager is only a deprecated prototyp  
and not a real cluster solution.

> Viewing the source it appears that the PersistentValve with the
> PersistentManager  and JDBCStore could be a solution.   It appears  
> that
> it would load a session from the store at the begging of each request
> and save it back to the store at the end of the request.  I would like
> to modify the behavior to only load/save when the session is dirty  
> based
> on the last_access timestamps.
>
> Any comments on the solution? ( I realize their is some performance
> penalty due to object serialization and writing blobs to the database;
> however, in our case I think this would not be prohibitive esp. if  
> there
> is a small amount of data in the session.)
>
> Also,  when I attempt to run Tomcat with the PersistentValve I get the
> following exception:
>
> SEVERE: An exception or error occurred in the container during the
> request processing
> java.lang.ClassCastException: org.apache.catalina.core.StandardEngine
>         at
> org.apache.catalina.valves.PersistentValve.invoke 
> (PersistentValve.java:9
> 9)
>         at
> org.apache.catalina.connector.CoyoteAdapter.service 
> (CoyoteAdapter.java:1
> 48)
>         at
> org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:199)
>         at
> org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:282)
>         at
> org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:744)
>         at
> org.apache.jk.common.ChannelSocket.processConnection 
> (ChannelSocket.java:
> 674)
>         at
> org.apache.jk.common.ChannelSocket$SocketConnection.runIt 
> (ChannelSocket.
> java:866)
>         at
> org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run 
> (ThreadPool
> .java:684)
>         at java.lang.Thread.run(Thread.java:595)
>
> Note:  (I have not yet made mods to the PersistentValue)
>
>
> Thanks for your assistance,
>
> Gary Blomquist


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