Fuzzy-matching via ElasticSearch

[wetneb]

The Wikidata search service supports fuzzy search by adding ~ to some words:

• Searching for "Norbert Rötgen" does not return anything
• Searching for "Norbert Röttgen~" returns Norbert Röttgen (Q61903) as first candidate
• Searching for "Norbert~ Rötgen" does not return anything (fuzzy matching is only enabled for the first word, not the second)

So, how should the reconciliation service use this? Add ~ to all the words in the query to enable fuzzy search everywhere? Only do it if the exact query did not return any candidate? Just let users add ~ to their own queries when they want to enable the feature? Any other strategy?

Cc @darecoder1999 who brought up the issue

[thadguidry]

There's quite a bit more exposed even beyond ~ from the ElasticSearch-backed CirrusSearch as documented here: https://www.mediawiki.org/wiki/Help:CirrusSearch

Extra Specific Wikibase features are mentioned:

Wikibase search
The Wikibase extension defines some search keywords in order to make it easier to search for certain Wikibase items. This is useful on Wikidata and other Wikibase sites, including to search for images with Structured data on Wikimedia Commons. See Help:WikibaseCirrusSearch for details.

And documented here:
https://www.mediawiki.org/wiki/Help:Extension:WikibaseCirrusSearch