FAQ: Unique Visitors
Can Sawmill count unique visitors?
Yes, using unique hostname or using cookies.
Yes; Sawmill can tell you the number of unique visitors for any item in the database, including the number of visitors for a particular day, the number of visitors from a particular domain, the number of visitors who hit any particular page or directory, or any other type of data Sawmill can display.
By default, Sawmill uses the hostname field of your log data to compute visitors based on unique hosts. That works for all log files, but it's a somewhat inaccurate count due to the effect of proxies and caches. If your log data tracks visitors using cookies, you can easily configure Sawmill to use the cookie information instead, by changing the "visitors" database field so it is based on the cookie log field instead (in the Log Filters section of the profile Config). See also Counting Visitors With Cookies.