CiviCRM and Apache Solr - Drupal 7
The apache solr module by default does not index civicrm tables. There is an integration with this module that indexes civicrm attachments:

https://github.com/civicrm/apachesolr_civiAttachments

This was work done for the New York State Senate. The next steps would be to get other civicrm tables indexed via this or other similar modules.

You might want to check the Drupal Entity  integration. This might make integrating with solr a lot easier

If you do make progress on this, please do share your work