[jira] [Updated] (AMQ-5340) QueueBrowser hangs until accidentally woken by expired messages background job

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

     [ https://issues.apache.org/jira/browse/AMQ-5340?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Vermeulen updated AMQ-5340:
---------------------------
    Attachment: AMQ5340BrowsingPerformanceBug.java

Attached JUnit test that shows the issue. On my machine it runs in 0.7ms when sending 50 messages using EXPIRE_MESSAGES_PERIOD = 200. With EXPIRE_MESSAGES_PERIOD = 10000 and otherwise the same settings it runs in 10.5s, with EXPIRE_MESSAGES_PERIOD = 30000 in 30.5s.

> QueueBrowser hangs until accidentally woken by expired messages background job
> ------------------------------------------------------------------------------
>
>                 Key: AMQ-5340
>                 URL: https://issues.apache.org/jira/browse/AMQ-5340
>             Project: ActiveMQ
>          Issue Type: Bug
>          Components: Broker
>    Affects Versions: 5.9.0, 5.10.0
>            Reporter: Vermeulen
>            Priority: Critical
>         Attachments: AMQ5340BrowsingPerformanceBug.java
>
>
> I would expected browsing a queue with only a few messages to not take take a long time. Indeed it normally takes only a few ms. in my application. But sometimes the ActiveMQQueueBrowser hangs for up to 30 seconds at method before returning!!
> When the issue occurs, the loop in hasMoreElements() calls waitForMessage() multiple times which times out after 2s at semaphore.wait(2000) without receiving any message from the broker. I found that when the broker's background job that checks for expired messages runs, the browser happens to be woken even if there are no expired messages. So setting the expireMessagesPeriod to a low value (e.g. 200ms) is a good workaround for this issue, but this is quite brittle because it uses internal broker implementation that may not even be related to the issue!
> To reproduce:
> - (this is what I do in my application) create a queue, send a few message with an expiration time of 10 seconds and repeatedly browse it until it is empty. If I browse the queue after these 10 seconds have passed, the issue occurs!
> - I can always reproduce the issue by running AMQ580BrowsingBug from the related bug report AMQ-4595: this browsing test seems to always hang. I slightly adjusted the test so you can easily change the expired messages period and see the runtime differ with that.



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