[jira] Closed: (QPID-601) messages may be stranded when selectors are used

["Aidan Skinner (JIRA)" <qp...@incubator.apache.org>]

     [ https://issues.apache.org/jira/browse/QPID-601?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Aidan Skinner closed QPID-601.
------------------------------

    Resolution: Fixed

This was fixed by robs rewrite

> messages may be stranded when selectors are used
> ------------------------------------------------
>
>                 Key: QPID-601
>                 URL: https://issues.apache.org/jira/browse/QPID-601
>             Project: Qpid
>          Issue Type: Bug
>          Components: Java Broker
>    Affects Versions: M2, M2.1, M3
>            Reporter: Rafael H. Schloming
>            Assignee: Rob Godfrey
>
> ConcurrentSelectorDeliveryManager = CSDM
> PDQ = PreDeliveryQueue
> pPDQ = populatePreDeliveryQueue
> Messages may be stranded as a result of the way selectors are implemented. When a consumer subscribes to a queue using a filter, CSDM.pPDQ is called to move messages from CSDM._messages into the PDQ for that subscription. The pPDQ method does this by calling _messages.iterator() and placing matching messages into the PDQ of the subscription. The result of _messages.iterator() is not guaranteed to reflect concurrent changes made to _messages, and so a publish may end up causing a message that matches the subscription to be placed onto _messages. This message is then stranded there despite the fact that the subscription could accept the message because nothing ever reexamines the _messages queue after the initial pPDQ when the consumer subscribes.
>  One potential fix for this issue would be to make the pPDQ method block messages from being pushed onto the _messages queue while it operates. This would work, however it would introduce undesirable synchronization for all publishers attempting to place messages on the queue.
> So far I can't think of a proper fix for this issue that doesn't involve some substantial changes in the data structures for queuing and delivering messages.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.