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?

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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