Sun Java System Application Server Enterprise Edition 8.1 2005Q2 Performance Tuning Guide

Commit Option

The commit option controls the action taken by the EJB container when an EJB component completes a transaction. The commit option has a significant impact on performance.

There are two possible values for the commit option:

Option B avoids ejbAcivate() and ejbPassivate() calls. So, in most cases it performs better than option C since it avoids some overhead in acquiring and releasing objects back to pool.

However, there are some cases where option C can provide better performance. If the beans in the cache are rarely reused and if beans are constantly added to the cache, then it makes no sense to cache beans. With option C is used, the container puts beans back into the pool (instead of caching them) after method invocation or on transaction completion. This option reuses instances better and reduces the number of live objects in the JVM, speeding garbage collection.

Determining the best commit option

To determine whether to use commit option B or commit option C, first take a look at the cache-hits value using the monitoring command for the bean. If the cache hits are much higher than cache misses, then option B is an appropriate choice. You might still have to change the max-cache-size and cache-resize-quantity to get the best result.

If the cache hits are too low and cache misses are very high, then the application is not reusing the bean instances and hence increasing the cache size (using max-cache-size) will not help (assuming that the access pattern remains the same). In this case you might use commit option C. If there is no great difference between cache-hits and cache-misses then tune max-cache-size, and probably cache-idle-timeout-in-seconds.