Chapter 9. Performance Tuning

Initialization of Smooks takes some time and therefore it is important it is reused.

This can result in a huge performance boost, as some readers are very expensive to create.

SAX processing is a lot faster than DOM processing and uses less memory. It is mandatory for processing large messages. Check that all of the Smooks cartridges are SAX-compatible.

Smooks performs some intensive debug logging in parts of the code. This can result in significant additional processing overhead and lower throughput.

When it has been enabled, the HTMLReportGenerator incurs a significant performance overhead and with large message, can even result in OutOfMemory exceptions.

Contextual selectors can obviously have a negative effect on performance. For example, evaluating a match for a selector like "a/b/c/d/e" will obviously require more processing than that of a selector like "d/e". Obviously there will be situations where your data model will require deep selectors, but where it does not, you should try to optimize your selectors for performance.

Where possible, avoid using the Virtual Bean Model and create beans instead of maps. Creating and adding data to Maps is a lot slower than creating "plain old Java objects" (POJOs) and calling the "setter" methods.