Log file sync WAITS

Log Writer works independently of user sessions so that theoretically it could have written out the redo before you issue a commit. The 'log file sync' wait occurs when you issue a commit and the redo hasn't been flushed yet so you post Log Writer and wait. One of the conditions under which the Log Writer kicks in is when the Log Buffer is 1/3 full which will happen less often if the Log Buffer is large. Therefore by making it smaller, Log Writer will work more proactively to flush it ideally before you issue a commit and thus you eliminate the wait entirely. See in my report where I say that the frequency of 'log file sync' is roughly equal to the statistic 'user commits' (i.e. every commit is waiting). So, making it smaller is designed to reduce the 'frequency' of waits on 'log file sync'.