BC4J / JDBC Failover BUG ?

Question

I have developed an ADF / BC4J application which works.
In our environment we have a failover configuration
I coded this approach for my ADF applications.
My Custom connect string in the connection wizard for the BC4J is:
jdbc:oracle:thin:@
(DESCRIPTION =
     (ADDRESS = (PROTOCOL = TCP) (HOST =aaa.bbb.yyy.zzz)(PORT = 1521))
     (ADDRESS = (PROTOCOL = TCP) (HOST =bbb.bbb.yyy.zzz)(PORT = 1521))
     (LOAD_BALANCE = yes)
     (CONNECT_DATA =
          (SERVER = DEDICATED)
          (SERVICE_NAME = db.yyy.zzz)
          (FAILOVER_MODE = (TYPE = SESSION) (METHOD = BASIC) (RETRIES = 180) (DELAY = 5))
When I press test connection it works and says success. (The first host in the list is actually down and we are using the failover host.)
However when I deploy the app to the OC4J Standalone Middle Tier (10.1.3.0) and then attempt to run the app I get the following error in the browser:
JBO-30003: The application pool (zzz.yyy.bbb.CustSubDivsAppLocal) failed to checkout an application module due to the following exception:
oracle.jbo.JboException: JBO-29000: Unexpected exception caught: oracle.jbo.JboException, msg=JBO-29000: Unexpected exception caught: oracle.jbo.JboException, msg=JBO-29000: Unexpected exception caught: oracle.jbo.DMLException, msg=JBO-26061: Error while opening JDBC connection.
If I remove the unavailable host (the first one) from the ADDRESS list the application works properly. If I change the order of the hosts so the first one is the one thats up it also seems to work ok.
It seems that the OC4J middle tier cannot handle the fact that the first host in the list is down and throws an exception instead of trying the second one. In JDeveloper BC4J Connection Wizard it seems to handle the down host properly.
Is this correct or have I setup the URL incorrectly ?
This has caused a huge headache for me as we are currently running on our failover hosts due to SAN maintenance and all my J2EE apps stopped working !!
Thanx
Andrew

Answer 1

Hi Hans,
A JDev developer, John S., recently created a bug report that if I remember
correctly, said that creatRoot... was not thread safe.
My scenario that caused this discovery (functionally identical to your looping threads cases)
was multple concurrent requests created by rapid clicking a submit button. This creates multple threads in the web tier
dispatching against a BC4J component calling createRoot....
in our JSP/Servlets. Just like your code, Hans.
The end result was some ugly exceptions and failed use cases of the 2nd or so to Nth threads.
In short, I believe that your design won't work.
I could work if you gave each thread a separate identity, via a separate BC4J cookie, thus simulating separate BC4J sessions.
I'm not at all familiar with this area of the BC4J API, just know general buzz words to be dangerous and confusing
to you. ;-(
Hopefully John S. will jump in here and help you.
Good luck, Curt.
PS please post your solutions?