The final topic that we should touch on before leaving multifield queries is that of exact-value not_analyzed fields. It is not useful to mix not_analyzed fields with analyzed fields in multi_match queries.

The reason for this can be demonstrated easily by looking at a query explanation. Imagine that we have set the title field to be not_analyzed:

GET /_validate/query?explain
{
    "query": {
        "multi_match": {
            "query":       "peter smith",
            "type":        "cross_fields",
            "fields":      [ "title", "first_name", "last_name" ]
        }
    }
}

Because the title field is not analyzed, it searches that field for a single term consisting of the whole query string!

title:peter smith
(
    blended("peter", fields: [first_name, last_name])
    blended("smith", fields: [first_name, last_name])
)

That term clearly does not exist in the inverted index of the title field, and can never be found. Avoid using not_analyzed fields in multi_match queries.