[jboss-jira] [JBoss JIRA] Commented: (JBMESSAGING-1775) Unsynchronized access to java.util.Set causing high CPU utilization

[Howard Gao (JIRA)]

    [ https://jira.jboss.org/jira/browse/JBMESSAGING-1775?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12498531#action_12498531 ] 

Howard Gao commented on JBMESSAGING-1775:
-----------------------------------------

Hi Justin,

This probably is caused by improper use of JMS API. 

The JMS spec says (2.8) that Session doesn't support concurrent use. The problem shows only if Session are shared among threads. Connections have no such problem.

In ConnectionState you can see it uses SyncSet to guarantee the concurrency. But in SessionState it uses HashSet. 

So if a user uses multiple threads to create producers from one same session, it will result in concurrent access to the same HashSet. Correct usage would be using a different session for each thread.


Howard




> Unsynchronized access to java.util.Set causing high CPU utilization
> -------------------------------------------------------------------
>
>                 Key: JBMESSAGING-1775
>                 URL: https://jira.jboss.org/jira/browse/JBMESSAGING-1775
>             Project: JBoss Messaging
>          Issue Type: Bug
>          Components: Messaging Core
>    Affects Versions: 1.4.0.SP3.CP08
>            Reporter: Justin Bertram
>            Assignee: Howard Gao
>             Fix For: 1.4.0.SP3.CP10, 1.4.6.GA.SP1, 1.4.7.GA
>
>
> Unsynchronized access to java.util.Set in org.jboss.jms.client.state.HierarchicalStateSupport causes high CPU utilization.

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