This document discusses the importance of metrics and performance monitoring, and introduces Javamelody as a tool for monitoring Java applications. It notes that while profiling during development is useful, continuous monitoring of production is most important. Javamelody makes monitoring easy by adding as a servlet filter. Metrics can be stored locally and visualized with graphics to show correlations and impacts. Going further, the document suggests using complex event processing to analyze multiple sources and apply monitoring proactively.

1. Significance of metrics Using Javamelody for perf. stats 23. May 2011

2. Who am I? David Karlsen Work at EDB Financial Services as a senior architect david.karlsen@edb.com http://www.linkedin.com/in/davidkarlsen 2

3. When to measurewhat Profiling during development is nice (but heavy) – you need something to monitor ”in the long run” Constant monitoring during development and testcycles can help you discover stuff before you go into production But since production is what we really care about is where your app run For a long time Processing most data THIS IS MOST IMPORTANT “If you can’t measure it, you can’t improve it” - Lord Kelvin 3

4. Add value to the measures Graphics are able to show the information better When combining several measures in the same dashboard it becomes even more interesting Can correlate events and see the impact as a whole Make the stats available for ops so that you share this information 4

5. Javamelody ” The goal of JavaMelody is to monitor Java or Java EE application servers in QA and production environments” http://code.google.com/p/javamelody/ Really easy to get started with Add as a servlet filter Or additionally add an interceptor/aspect to add additional measure points Proxies for datasource to monitor all RDBS execution Stores data in .rrd format locally on disk – robust Can also have a central collector server 5

6. Example pointcuts @Pointcut( "withinApplication() && anyPublicMethodExecution() && targetIsMainApplicationType()" )public void anyPublicMethodExecutionWithinApplication(){} @Pointcut( "withinServices() || withinDaos() || withinIntegrationLayer() " )public void withinCoreLayer(){} 6

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12. Going further Significance of metrics Now that we have all this nice measures – wouldn’t it be nice to go further and use it even more proactively? Check out http://code.google.com/p/rocksteady/ “Too often after collecting many metric and creating many pretty graphs, one realizes graph serves only as a good postmortem analytic aid. Staring at dozen of graph on a TV wall isn't monitoring, it's a waste of time!” By analyzing several sources and using Esper – a Complex Event Processing (CEP) engine it’s possible to apply statistics realtime, and use this proactively to take actions. 12

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14. Summary Avoid black boxes - monitoring is easy and cheap – do it! Measure production continuously Graphs show the information in such a way that they provide more value Javamelody is an excellent way to get you started Hopefully leads to performance awareness by the team As you get to know the application you can go even further and apply monitoring proactively. 14