There are times when the application truly demands an immediate commit, which can result in a tremendous commit rate. For example, I know of systems where financial transactions arrive from multiple sources. The transactions are small, but because they are independent transactions, the legal and business rules require that each individual incoming transaction must be immediately committed to the database. In this situation, you have little choice but to devise a solution that does not involve changing the application.

Regardless of what you find, when experiencing significant log file sync waits, assume there is a rapid commit issue and find out why it is occurring. Understanding this will help you devise a better application and nonapplication solution strategy.

A log file sync wait event is commonly attributed to either a lack of IO or CPU resources, or both. If the bottleneck is both CPU and IO, it tends to quickly shift between the two, which when averaged over an interval, does not clearly show either one to be a problem. This can easily cloud your understanding of the situation, so you must be very careful.