WP Logger

This plugin makes it easy to keep a log of activity on your WordPress site. You can also decide how detailed you want the log to be, whether this is including any minor event or focus on the more substantial updates. You can get started with the free version. You can also skip straight to using the premium edition if you need features like email notifications, WordPress reports, and activity log integration tools.

For every event that the plugin records it also reports the:

• Date & time (and milliseconds) of when it happened,
• User & role of the user who did the change,
• Source IP address from where the change happened,
• The object on which the change has taken place.