Today I was speaking on Coherence SIG event in London.
My topic was "Filtering 100M objects. What can go wrong?". It was a story of solving particular problem and obstacles we have encountered. One noticeable thing about this project - out team was using Performance Test Driven Development approach.
Guardian was introduced in Oracle Coherence 3.5 as uniform and reliable mean to detect and report various stalls and hangs on data grid members. In addition to monitoring internal components of Coherence, Guardian has an API accessible for application developer.
While out-of-box Guardian does its job pretty well, there (more...)
Recently I decided give that work some refreshing and today I'm publishing first HostSpot JVM options ref card covering generic GC options and CMS tuning. (G1 have got a plenty of tuning options during last (more...)
Oracle Coherence data grid has a powerful tool for inplace data manipulation - EntryProcessor. Using entry processor you can get reasonable atomicity guarantees without locks or transactions (and without drastic performance fees associated).
One good example of entry processor would be built-in ConditionalPut processor, which will verify certain condition before (more...)
Compressed OOPs (OOP – ordinary object pointer) is a technique reducing size of Java object in 64 bit environments. HotSpot wiki has a good article explaining details. Downside of this technique is what address uncompressing is required before accessing memory referenced by compressed OOPs. Instruction set (e.g. x86) may (more...)
In this post, I would like to share some knowledge about optimizing indexes in Oracle Coherence.
Normally you should not abuse queering features of your data grid and, hence, you are unlikely to ever need to tune indexing/queering (besides choosing which indexes to create). But sometimes, you really need to (more...)
There are bunch of graphical tools helping you to look inside of running JVM (VisualVm and JConsole are extremely helpful). Unfortunately, some times (almost always in my case), you may find yourself in SSH console on headless server side by side with your JVM (more...)
Writing automated tests for Coherence based application is quite challenging. Definitely, you can start single node cluster in your test JVM without too much hassle. Unfortunately, single node cluster will not allow you to replicate some important aspects of cluster (a thus, test wont be able to catch a number (more...)