Hibernate collects various data points to help you measure the usage and performance of your application. This includes data collected about the session, entities, collections, query, and cache. Here, we discuss how to obtain this data and what each set of data points means.
To instruct Hibernate to collect metrics, you first need to enable the generation of statistical data. You have already seen how this is done in Chapter 5, Hibernate Cache but, just in case you skipped ahead, all you need to do is add the following property to the session factory configuration:
Hibernate will then start collecting data points, however, be aware that this could slightly impact the performance of your application, since it now has to do more work. Later, we can see how you can enable and disable statistics data generation using JMX. You can also clear the statistics data and start over. For now, let's...