[infinispan-issues] [JBoss JIRA] Commented: (ISPN-691) ReplicationQueue has an out-of-order issue

[Galder Zamarreño (JIRA)]

    [ https://jira.jboss.org/browse/ISPN-691?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12558717#action_12558717 ] 

Galder Zamarreño commented on ISPN-691:
---------------------------------------

Craig, there's something I don't understand about the logs. The background timer thread should, by default, be named as: "Scheduled-replicationQueue-thread-*", but in your logs I see none of that. All I see is "pool-*" threads. So, what configuration changes or code changes are you applying in your system? And, if all threads are called "pool-*", how do u figure out which is the background thread and which the worker thread?

Another thing I don't get is the fact that you have configured replication queue like this:
jgroups-infinispan-MyInfispanLooperMaster.log:34:2010-09-03 11:48:45,610 3919  TRACE [org.infinispan.remoting.ReplicationQueue] (main:) Starting replication queue, with interval 100000 and maxElements 500

So, it means that replication queue should be flushed, every 100.000 ms which is 100s and max elements of queue is 500.

However, when I look at the logs, I see plenty of flushes happening when the queue is 100 elements:

2010-09-03 11:49:43,244 61553 TRACE [org.infinispan.remoting.ReplicationQueue] (pool-5-thread-2:) flush(): flushing repl queue (num elements=100)
2010-09-03 11:49:43,244 61553 TRACE [org.infinispan.remoting.ReplicationQueue] (pool-5-thread-2:) Flushing 100 elements
...
2010-09-03 11:49:43,255 61564 TRACE [org.infinispan.remoting.ReplicationQueue] (pool-5-thread-9:) flush(): flushing repl queue (num elements=100)
2010-09-03 11:49:43,256 61565 TRACE [org.infinispan.remoting.ReplicationQueue] (pool-5-thread-9:) Flushing 100 elements

It seems like these flushes are based on number of elements rather than time, but they do not match the configuration settings.

> ReplicationQueue has an out-of-order issue
> ------------------------------------------
>
>                 Key: ISPN-691
>                 URL: https://jira.jboss.org/browse/ISPN-691
>             Project: Infinispan
>          Issue Type: Bug
>          Components: Core API
>    Affects Versions: 4.0.0.Final, 4.1.0.Final, 4.2.0.ALPHA3
>            Reporter: craig bomba
>            Assignee: Galder Zamarreño
>             Fix For: 4.2.0.BETA1, 4.2.0.Final
>
>         Attachments: ReplicationQueueImpl.java
>
>
> The ReplicationQueue has an exposure to distributing items out of order.  The ReplicationQueue may flush items in either of 2 ways.  One way is the background thread provided by a ThreadPoolExecutor flushing on a timer.  The other is via the current thread that does a put (which calls ReplicationQueue.add).  In the case of the call to add if it hits the max size (set in the config by replQueueMaxElements) then items may get flushed to other nodes out of order.  This is not evident when a test case only includes puts (new items or updated items in a cache).  Your test must include removals to expose this concern.

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