In high throughput environments with a large number of concurrent users committing transactions, a certain amount of contention for the log semaphore is expected. In some tests, very high throughput is maintained, even though log semaphore contention is in the range of 20 to 30%.
High contention is not normal. If you see high contention in your server, perform all the regular tuning procedures, including making sure the storage is properly configured and performing adequately.
In high throughput environments that include a large number of concurrent users committing transactions, you can expect contention for the log semaphore.
For more information, see “Asynchronous log service,” in Performance and Tuning Series: Query Processing.
