jQuery UI Autocompletion with Elasticsearch Backend by Gerhard Hipfinger.
From the post:
I recently discovered Elasticsearch is an incredible easy search engine solution for JSON documents. As we heavily use CouchDB in our product development Elasticsearch and CouchDB are a perfect match. Even more since Elasticsearch comes with a great out of the box connection for CouchDB! So the next step is to use Elasticsearch as backend for a jQuery UI autocompletion field.
Your users may like some form of autocompletion in their topic map interface. If nothing else, it is amusing how far they land from what the user is looking for.
BTW, read the comments on this post.