Sometimes fixing a problem causes or reveals a new one. And sometimes this sets off a chain reaction of problems and fixes, where each solution exposes a deeper issue. In technology, cascades like these are common, often painful, and occasionally welcome. Our battle against CPU contention last fall is a good example of such a cascade. What began as a buffer pool adjustment triggered a series of issues and fixes that generated plenty of stress,...

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This post describes our odyssey with ActiveMQ, an open-source version of the Java Messaging Service (JMS) API. We use ActiveMQ as the message broker among our app servers. First, a word of thanks. To overcome the challenges we faced with ActiveMQ, we are greatly indebted to a very thorough description of an OpenJDK bug, as well as some other online resources. If you’re having problems with ActiveMQ, read on. Maybe our story can help you....

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