In the web server log file you donot see which user is actually using phpMyAdmin. It would be nice when this info is added to the log file as users are authenticated by the application.
For apache web server I have added the following line in main.php (line 80):
This helps a bit, but this only helps for a fraction of the logging. Unfortunately I cannot find a better place to do this (suggestion?), but I think it would improve tracebility a lot when this would become available.