Re-importing e-mails that have already been imported

When you say ‘wipe the database’ do you mean all topics and posts from Discourse and also all records of incoming e-mails that went through the importer (but leave the structure of the discourse and users etc intact)? Or do you mean the database of imported e-mails, which would leave existing posts in place but allow me to re-run the importer with old e-mails?