The other problem with increasing the _spin_count value is that all latches will be affected. Key to removing latch contention is focusing on the specific problematic latch. Changing the _spin_count value will affect not only the latch that has problems, but all other latches as well. So, the result is less predictable.

The only time I will increase _spin_count is if the operating system vendor's performance engineer, who must also be an Oracle expert, makes the recommendation and can clearly explain why latch acquisition response time will decrease after changing this value. This is exceptionally rare. If the engineer can't clearly explain why increasing _spin_count will help performance, he is guessing! And guessing is no way to fight performance fires or advance your career.

Using Oracle's wait interface, detecting Oracle latch contention is very straightforward. As I have mentioned, nearly every production Oracle system will have latch contention, but that does not imply there is a problem worthy of our attention. Only when the contention rises to the top of our wait event and ORTA reports is it significant and worthy of our precious time to improve the situation.