Search results are duplicated after update_index (django haystack+whoosh)

I use django-haystack with whoosh as a backend. I call update_index command in a scheduled intervals and I've noticed that after each update my search results contains a lot o开发者_开发百科f duplicated entries (eg. after 3 update_index calls I have 3 duplicates of the same model instance).

HAve you faced this problem? Any ideas how to solve it?

This was related to some bugs in whoosh. According to Whoosh author it is fixed now: https://bitbucket.org/mchaput/whoosh/issue/97/search-index-contains-a-lot-of-duplicates