[jira] [Commented] (AMQ-2721) Broker hangs reading KahaDB data store

["Dariusz Szablinski (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/AMQ-2721?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13016592#comment-13016592 ] 

Dariusz Szablinski commented on AMQ-2721:
-----------------------------------------

In the past I came accross similar issue in the other application. In short: not synchronized, concurrent put/get operations on HashMap can cause infinite loop.
See this blog: http://lightbody.net/blog/2005/07/hashmapget_can_cause_an_infini.html

I think this problem has been fixed already (at least in current trunk) by adding synchronization on inflightTransactions map in getInflightTx method. In 5.3.1 this map wasn't synchronized and I think that caused your broker hang. 


> Broker hangs reading KahaDB data store
> --------------------------------------
>
>                 Key: AMQ-2721
>                 URL: https://issues.apache.org/jira/browse/AMQ-2721
>             Project: ActiveMQ
>          Issue Type: Bug
>          Components: Broker
>    Affects Versions: 5.3.1
>         Environment: Red hat enterprise
>            Reporter: Dennis Klinkott
>             Fix For: 5.6.0
>
>         Attachments: brokerjstack.log
>
>
> Broker hangs on loading the data store. Happens after using the broker for 10 hours in productive environment.
> In broker log the last entries we see is a bunch of loading kahadb debug entries.
> 2010-05-05 16:06:19,462 | DEBUG | loading | org.apache.kahadb.index.BTreeIndex | main
> But the broker doesn't stall completely. It is doing something with high cpu load. But it doesn't get the data store loaded. Even after a few hours it doesn't get finished (usually only takes a few seconds).
> I took a few jstack-dumps where we can see the broker being busy putting something into a hashmap.
> We have 2 brokers connected as network of brokers.

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