After the installing for the first time, you must use the "Optimize Index" option and then re-index all content. This add-on requires ElasticSearch v2.0 or newer, it does not support 1.x or older!
Search Bar Auto Complete
When your users type in the search bar on your forum they will see suggestions based on what they have typed so far. The terms come from phrases used in your index rather than just common words. This means that it should work well for niche boards, any language, etc... This can really help reduce missed searches.
On a new thread, provides potentially similar threads as the title is being created.
On viewing a thread, provides a list of potentially similar threads (based of title and any tags). Uses caching to reduce hits to the search system (but still requires at least 1 SQL query to ensure visibility checks).
Suggestions/"Did You Mean" Functionality
There are two different "Did You Mean" features. One type is for even when the user has results for their search but there is a more popular, similar, term in your board's index. This can lead to better results. It also helps reduce typos. The other type is for when there are no results for their query, they will be presented with a list of similar terms that appear in your index.
On a user's profile, shows forums by post count where the user posts the most.
Search Deleted Content
Provides opt-in/out for searching deleted items from the advanced search page, if a user has permission to see deleted content for some forums, they may search for deleted content.
Deleted search options:
- Exclude deleted
- Include deleted
- Only search deleted
- [ESE] Use similar threads (Thread create)
- [ESE] Use similar threads (View Thread)
- [ESE] Use auto-complete
- Note; requires this to be granted at the user-group level for this feature to be usable from the search page or the forum root page.
The auto complete functionality does require your index to be deleted (and thus recreated) from the admin panel. It will not happen automatically on installation because I understand this might not be ideal.