Traceback (most recent call last):
  File "/usr/share/software-center/softwarecenter/models/appstore.py", line 421, in on_get_value
    doc = self.db.get_xapian_document(app.appname, app.pkgname)
  File "/usr/share/software-center/softwarecenter/db/database.py", line 406, in get_xapian_document
    doc = self.xapiandb.get_document(m.docid)
DocNotFoundError: Document 6291 not found.