7. JavaVM Memory Tuning

To improve the processing performance of systems, you must properly tune JavaVM as Java VM is the platform for the infrastructure. Hitachi JavaVM (called JavaVM hereafter) manages two types of memory spaces.

This chapter describes memory management in garbage collection and JavaVM, and the tuning of the Java heap and Explicit heap.

Organization of this chapter
7.1 Overview of garbage collection and JavaVM memory management
7.2 Overview of tuning to prevent the occurrence of full garbage collection
7.3 Java heap tuning
7.4 Estimating the memory size of the Tenured area in Java heap
7.5 Estimating the memory size of the New area in Java heap
7.6 Determining the handling of objects that exist for a fixed time period in Java heap
7.7 Deciding the maximum size or the initial size of Java heap
7.8 Estimating the memory size of the Permanent area in Java heap
7.9 How to analyze the factors of a full garbage collection using the extended verbosegc information
7.10 Explicit heap tuning
7.11 Estimating the memory size when using the explicit management heap functionality in the application
7.12 Determining the usage of the Explicit heap using the automatic allocation functionality of the Explicit Memory Management functionality
7.13 Errors that occur during the application of the Explicit Memory Management functionality and the solutions