Heap size and memory in 32-bit and 64-bit applications

Production environments must use a 64-bit operating system and a 64-bit JVM. 64-bit JVMs inherently use more memory to host the same number of objects. 32-bit JVMs have an inherent memory scalability limit that differs significantly across platforms. This scalability limit makes those platforms unsuitable production platforms. 64-bit JVMs are a more scalable option.

Note: The terms 32-bit and 64-bit refer to the size of the pointer used to reference an address.

Typically, a 64-bit JVM has an approximately 80% heap size overhead. For example, a 1024 MB heap for a 32-bit JVM would host the same amount of objects as a 1843 MB heap for a 64-bit JVM. Generally, non-production systems work correctly with heap sizes of 1024MB for a 32-bit JVM and 2048 MB for a 64-bit JVM.

For more information on heap size and tuning your production application to optimal performance, contact Guidewire Support.