Chapter 11. Performance Tuning
11.1. Performance Tuning Tips
- Cache and reuse the Smooks object.
- Initialization of Smooks takes some time and therefore it is important it is reused.
- Pool reader instances where possible
- This can result in a huge performance boost, as some readers are very expensive to create.
- Use SAX filtering where possible
SAXprocessing is a lot faster thanDOMprocessing and uses less memory. It is mandatory for processing large messages. Check that all of the Smooks cartridges areSAX-compatible.- Turn off debug logging
- Smooks performs some intensive debug logging in parts of the code. This can result in significant additional processing overhead and lower throughput.
Important
Remember that not having your logging configured at all may result in debug log statements being executed. - Only use the HTMLReportGenerator in a development environment.
- When it has been enabled, the
HTMLReportGeneratorincurs a significant performance overhead and with large message, can even result inOutOfMemoryexceptions. - Contextual selectors
- 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.
