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From Carl Trieloff <cctriel...@redhat.com>
Subject Re: Java failover manager
Date Tue, 03 Mar 2009 16:30:03 GMT

yes, the defaults don't seem to be the best, I would JIRA it.
Carl.


Arnaud Simon wrote:
> Hello,
>
> I have been playing with our 0.10 cluster. When testing it I used a 
> java client and 2 brokers. I quickly ran into this issue:
>
> org.apache.qpid.transport.ConnectionException: connection closed
> at org.apache.qpid.transport.Connection.send(Connection.java:294)
> at org.apache.qpid.transport.Session.send(Session.java:455)
> at org.apache.qpid.transport.Session.invoke(Session.java:599)
>
>
> It appears that this is an expected behaviour of our default Java 
> failover manager. The default heuristic is to go roundrobin through 
> the list of brokers. This is fine really but our implementation does 
> not reset the  cursor position after a successful failover. This means 
> that if you failover from A to B you will never failover from B to A 
> anymore (assuming that our list of broker only contains two brokers A 
> and B).   So, there is an optional parameter "cyclecount" that can be 
> used to define the number of times to loop through the list of 
> available brokers before failure. If this parameter can be used to 
> solve the issue of failing over to A after a successful failover from 
> A to B, it does solve this issue only for "cyclecount" times :( 
> Moreover, I believe that we don't really want to cycle through all the 
> brokers more than once when all the nodes of the broker are down. We 
> rather want to define a kind of back-retry mechanism.
>
> I would suggest that default implementation of our roundrobin failover 
> manbager should be changed to reset the cursor position within the 
> broker list to the current broker. Moreover, I believe that some 
> people are currently implementing a failover manager that uses a 
> failover exchange. I am wondering whether this manager shouldn't the 
> default manager for our 0.10 client?
>
> Please let me know what you think. Should we open a JIRA?
>
> Thanks
>
> Arnaud
>
>
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