Java GC in Numbers – Compressed OOPs

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...)

Coherence SIG: Performance Test Driven Development

Today was speaking at Oracle Coherence SIG at London.

Below you can find slide deck from my presentation.

Coherence 101, Filters performance and indexing

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...)

Java GC in Numbers – Parallel Young Collection

This is a first articles in series, where I would like to study effect of various HotSpot JVM options on duration of STW pauses associated with garbage collection.

This article will study how number of parallel threads affects duration of young collection Stop-the-World pause. HotSpot JVM has several young GC (more...)

Ad-hock diagnostic tools for JVM

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...)