I have a Sitecore 8.1-3 instance using Solr 4.10. I just finished rebuilding the reporting database following the Sitecore instructions. I am noticing that there are contacts that I know are in mongo that are not showing up in the Experience Profile search and also not anywhere in the Sitecore analytics index in Solr. From doing a little investigating I am noticing that it seems like the contacts that do not show up in the index also have no interactions in the Interactions collection in mongo. Is there something during the rebuilding of the reporting database that requires that each contact has at least one interaction in the Interactions collection in mongo or they won't be added to the analytics index?