Data Retention

I’m wondering what the retention period is for the visit data. I am currently not interested in the “referrers” plugin and the aggregated data it provides, but some time down the road I might be interested in it. I don’t want the tab to show in the Dashboard menu or the widget menu, so the best way I’ve found achieve this is to simply disable the plugin.

I’m concerned that if I do turn it on sometime later that I won’t have access to any referrer data from the time period in which I did not have the plugin enabled. Is the log_visit table maintained indefinitely, or does it get compressed/archived?