Hi Azhagappan Balasubramanian,
I was testing a possible database crash scenario with 2 controllers
each with one database backend each. But in the documents I read that
Sequoia tolerates database crashes. I expected the backends to get
disabled automatically but I get the following error in the
controllers. The client after restart, proceeds further. But my
question here is, why does the client hangs when one database goes down ?
You have a configuration problem, see below.
2008-05-13 12:25:37,237 INFO controller.loadbalancer.RAIDb1 write
request 1543 failed:
Backend tmdp1 - BackendWorkerThread for backend 'backend11' with RAIDb
level:1 failed (Communications link failure
Last packet sent to the server was 6 ms ago.)
This one is normal, this indicates that tmdp1 has failed. If the other
backend succeeds then this one will be disabled.
2008-05-13 12:25:37,251 ERROR continuent.hedera.adapters
PullPushAdapter: Error while reading from channel
org.continuent.appia.core.message.MessageException: Trying to read an
unknown object from message.
at
org.continuent.appia.core.message.Message.popObject(Message.java:1254)
at
org.continuent.hedera.channel.AppiaReliableGroupChannel.receive(AppiaReliableGroupChannel.java:292)
at
org.continuent.hedera.adapters.PullPushAdapter.run(PullPushAdapter.java:166)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.ClassNotFoundException:
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
When the other controller receives the SQL exception, it is not a
regular SQLException but a custom MySQL type which is why it fails. You
will have to force the MySQL Connector/J jar in the controller classpath
(you can use the XTRA_CLASSPATH environment variable for that) so that
exceptions can be properly deserialized.
Another option is to use another version of Connector/J that generates
proper SQLExceptions.
Thanks for your interest in Sequoia,
Emmanuel
--
Emmanuel Cecchet
FTO @ Frog Thinker
Open Source Development & Consulting
--
Web: http://www.frogthinker.org
email: [EMAIL PROTECTED]
Skype: emmanuel_cecchet
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