Comment 45 for bug 507836

Some additional data point, the traceback data from the recent duplicates: #902480, #911251, #837736 (5.x and 4.x) show:

Traceback (most recent call last):
  File "/usr/share/software-center/softwarecenter/ui/gtk3/views/appdetailsview.py", line 1605, in _on_cache_ready
    self.show_app(self.app)
  File "/usr/share/software-center/softwarecenter/ui/gtk3/views/appdetailsview.py", line 1506, in show_app
    self.app_details = app.get_details(self.db)
  File "/usr/share/software-center/softwarecenter/db/application.py", line 77, in get_details
    return AppDetails(db, application=self)
  File "/usr/share/software-center/softwarecenter/db/application.py", line 195, in __init__
    self._app.appname, self._app.pkgname)
  File "/usr/share/software-center/softwarecenter/db/database.py", line 439, in get_xapian_document
    for m in self.xapiandb.postlist("AA"+appname):
  File "/usr/lib/python2.7/dist-packages/xapian/__init__.py", line 7222, in _database_gen_postlist_iter
    return PostingIter(self.postlist_begin(tname), self.postlist_end(tname),
DatabaseModifiedError: The revision being read has been discarded - you should call Xapian::Database::reopen() and retry the operation

I wonder if its a race condition in cache-open and the software-center-agent finishing at the same time.