kovidgoyal/calibre — pull request #299 by cbhaley (2014-09-09 11:06:19+00:00)
Title: Performance improvements:

- Add an option to booklists to not check for duplicates if the device knows there aren't any. Eliminates N squared lookup times.
- Make the wireless device driver use the above option.
- Change a comprehension to use a generator instead of a returned list of keys.

FWIW: found these because a CC user has 18,000 books on his device!