I'm using Django with Python3 and Postgresql
I've read that Haystack uses Elastic Search (and I dislike Java), but I see Xapian-Haystack doesn't work with Python3 (but I've heard about Xapian before and I think like it).
djorm-ext-pgfulltext is a database full text search module and I really don't know how is different from the previous option, in terms of efficiency.
(3. The option to build a simple search module would be the most inefficient, I believe.)
A list with the modules is displayed at: https://www.djangopackages.com/grids/g/search/