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Tag Archives: Performance

Arrays.sort versus Arrays.parallelSort

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We all have used Arrays.sort to sort objects and primitive arrays. This API used merge sort OR Tim Sort underneath to sort the contents as shown below:                   public static void sort(Object[] a) { if (LegacyMergeSort.userRequested) legacyMergeSort(a); else ComparableTimSort.sort(a); } This is all done sequentially, even though merge sort uses divide and ...

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Java StringBuilder myth debunked

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The myth Concatenating two Strings with the plus operator is the source of all evil — Anonymous Java dev NOTE: The source code for the tests discussed here can be found on Github It’s from university time that I learned to regard String concatenation in Java using the ‘+’ plus operator as a deadly performance sin. Recently there has been ...

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OpenJPA: Memory Leak Case Study

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This article will provide the complete root cause analysis details and resolution of a Java heap memory leak (Apache OpenJPA leak) affecting an Oracle Weblogic server 10.0 production environment. This post will also demonstrate the importance to follow the Java Persistence API best practices when managing the javax.persistence.EntityManagerFactory lifecycle.             Environment specifications Java EE server: ...

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Adding Turbochargers to JEE Apps

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One of the key roles, I play is evangelizing Akka within my local community. As part of the discussions, the question/doubt usually in people’s mind is how can Akka provide better scalability and concurrency against a well written Java/JEE application. Since the underlying hardware/JVM remains the same, how can the actor model ooze out more power than the traditional JEE ...

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Scaling Scala vs Java

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In my previous post I showed how it makes no sense to benchmark Scala against Java, and concluded by saying that when it comes to performance, the question you should be asking is ‘How will Scala help me when my servers are falling over from unanticipated load?’ In this post I will seek to answer that, and show that indeed ...

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Benchmarking Scala against Java

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A question recently came up at work about benchmarks between Java and Scala. Maybe you came across my blog post because you too are wanting to know which is faster, Java or Scala. Well I’m sorry to say this, but if that is you, you are asking the wrong question. In this post, I will show you that Scala is ...

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Performance Analysis of REST/HTTP Services with JMeter and Yourkit

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My last post described how to accomplish stress- or load-testing of asynchronous REST/HTTP services with JMeter. However, running such tests often reveals that the system under test does not deal well with increasing load. The question is now how to find the bottleneck? Having an in-depth look at the code to detect suspicious parts could be one alternative. But considering ...

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Opinion: Performance Testing

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Performance tuning an application is time consuming, and expensive. Useful tests often need dedicated hardware to run on. It’s specialised and time consuming to prepare the ground work and write the various fixtures needed to run, and whose only perceived benefit is preventing a production issue that you don’t even know will happen yet. Stereotypical Scenarios and Outcomes Here’s some ...

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NUMA architecture and Java

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Time to deploy your application, looking forward to procure hardware that suits best to the load requirements. Boxes with 40 cores or 80 cores are pretty common these days. General conception is more cores, more processing power, more throughput. But I have seen a little contrary results, showing a small cpu-intensive test run performs slower on 80 core box than ...

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Single Writer Principle

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When trying to build a highly scalable system the single biggest limitation on scalability is having multiple writers contend for any item of data or resource. Sure, algorithms can be bad, but let’s assume they have a reasonable Big O notation so we’ll focus on the scalability limitations of the systems design. I keep seeing people just accept having multiple ...

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