I was looking at Cassandra, one of the major NoSQL solutions, and I was immediately impressed with its write speed even on my notebook. But I also noticed that it was very volatile in its response time, so I took a deeper look at it. First Cassandra Write Test I did the first write tests [...]
Most articles about Garbage Collection ignore the fact that the Sun Hotspot JVM is not the only game in town. In fact whenever you have to work with either IBM WebSphere or Oracle WebLogic you will run on a different runtime. While the concept of Garbage Collection is the same, the implementation is not and [...]
Memory and Garbage Collection problems are still the most prominent issues in any java application. One of the reasons is that the very nature of Garbage Collection is often misunderstood. This prompted me to write a summary of some of the most frequent and also most obscure memory related issues that I have encountered in [...]
In my last post I explained what a major Garbage Collection is. While a major Collection certainly has a negative impact on performance it is not the only thing that we need to watch out for. And in case of the CMS we might not always be able to distinguish between major and minor GC. [...]
In a recent post we have shown how the Java Garbage Collection MXBean Counters have changed for the Concurrent Mark-and-Sweep Collector. It now reports all GC runs instead of just major collections. That prompted me to think about what a major GC actually is or what it should be. It is actually quite hard to find [...]
After my recent presentation at TSSJS – Performance Anti-Patterns in AJAX Applications – I got interesting feedback from one of the attendees: “The presentation was good but I thought you are talking more about actual problems with XHR/AJAX Requests”. I have to admit that I focused on all common problems of Web 2.0 applications – [...]
Searching for memory leaks can easily become an adventure – fighting through a jungle of objects and references. When the leak occurs in production time is short and you have to act fast. Like in a treasure hunt, we have to interpret signs, unravel mysteries to finally find the “lost” memory. Memory leaks – together [...]
The .NET Runtime can run with different GC flavors. The following article does a good job in explaining the options: Low Latency GC in .NET 3.5 by Sasha Goldshtein. Comparing the two modi with a sample application I was curious about how the different modi affect the time spent by the Garbage Collector. I therefore created [...]
Garbage Collection can have a major impact on application performance. The more distributed an application becomes the trickier it is to identify the impact on the overall transaction response times. If you are dealing with heterogeneous systems it is even harder because the set of tools out there usually don’t cross runtime and technology boundaries. [...]
Whenever the Garbage Collector kicks in to free up memory - the runtime puts all currently executing threads on hold in order to do the cleanup. The GC runs when the application tries to allocate new objects and not enough free memory is available in the 1st Generation Heap. Putting the current execution on hold means [...]
