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We're using ElasticSearch for searching through millions of tags. Our users should be able to include boolean operators (+, -, "xy", AND, OR, brackets). If no hits are returned, we fall back to a spelling suggestion provided by ES and search again. That's our query:

$ curl -XGET 'http://127.0.0.1:9200/my_index/my_type/_search' -d '
{
    "query" : {
        "query_string" : {
            "query" : "some test query +bools -included",
            "default_operator" : "AND"
        }
    },
    "suggest" : {
        "text" : "some test query +bools -included",
        "simple_phrase" : {
            "phrase" : {
                "field" : "my_tags_field",
                "size" : 1
            }
        }
    }
}

Instead of only providing a fallback to spelling suggestions, we'd like to enable fuzzy matching. If, for example, a user searches for "stackoverfolw", ES should return matches for "stackoverflow".

Additional question: What's the better performing method for "correcting" spelling errors? As it is now, we have to perform two subsequent requests, first with the original search term, then with the by ES suggested term.

Simon Steinberger
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1 Answers1

4

The query_string does support some fuzziness but only when using the ~ operator, which I think doesn't your usecase. I would add a fuzzy query then and put it in or with the existing query_string. For instance you can use a bool query and add the fuzzy query as a should clause, keeping the original query_string as a must clause.

As for your additional question about how to correct spelling mistakes: I would use fuzzy queries to automatically correct them and two subsequent requests if you want the user to select the right correction from a list (e.g. Did you mean), but your approach sounds good too.

javanna
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  • Thanks - that confirms my thoughts. Anyhow, we stick to what we already have. It seems to be a much faster approach. Concerning "fuzzy query", the ElasticSearch docs even mention a warning about not being well scalable. – Simon Steinberger Sep 10 '13 at 07:59