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https://issues.apache.org/jira/browse/CAY-1864?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13824415#comment-13824415
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Andrus Adamchik commented on CAY-1864:
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On the Cayenne end , I am simply using JNDI variety of the DataSource. So it
needs to be configured and exposed via JNDI in your container. Don't have a
handy Tomcat example, but it should be easy to find. After all this pool is
native to Tomcat. It just requires a <Resource> declaration in the XML.
For Jetty we wrote a small factory class that I can share offline if needed.
> Process threads waiting for an available DB connection in the order they came
> in
> --------------------------------------------------------------------------------
>
> Key: CAY-1864
> URL: https://issues.apache.org/jira/browse/CAY-1864
> Project: Cayenne
> Issue Type: Improvement
> Components: Core Library
> Affects Versions: 3.2M1
> Reporter: John Huss
> Assignee: John Huss
> Attachments:
> 0001-CAY-1864-Process-threads-waiting-for-an-available-DB.patch
>
>
> Currently when all the DB connections in the pool are used up threads will
> wait for available connection. As connections become available they are
> given to essentially random threads, not the thread that was waiting first.
> This causes somewhat erratic behavior since some requests will come in and
> get a connection right away even though others have been waiting for a long
> time, eventually causing more threads to throw exceptions than may have been
> necessary if requests were processed in order.
> Particularly in cases with large but brief spikes in activity - errors may be
> wholly avoided if requests are processed in order where otherwise they could
> produce many failures. I have observed this in my testing.
> I have a patch I am testing out. It creates a queue to keep track of the
> waiting threads and then grant them connections in order.
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