ElasticSearch - Partial Matches across Multiple Fields

Question

I'm relatively new to ElasticSearch, and working on getting some partial matches across multiple fields to work. Assume, for example, I have the following three documents indexed:

{
    "document-id": "Patient1",
    "document-type": "patients",
    "firstName": "Benjamin",
    "lastName": "Carlton",
    "medicalRecordNumber": "111-222-3333"
}
{
    "document-id": "Patient2",
    "document-type": "patients",
    "firstName": "Carly",
    "lastName": "Benson",
    "medicalRecordNumber": "111-222-3334"
}
{
    "document-id": "Patient3",
    "document-type": "patients",
    "firstName": "Jason",
    "lastName": "Benson",
    "medicalRecordNumber": "111-222-3335"
}

I would like to design an analyzer and search query such that searching for:

"ben" matches all three (that's easy)
"ben carl" matches #1 and #2
"carl ben" also matches #1 and #2
"benj carl" matches only #1 (does not follow as naturally from the previous ones as I thought, given the way ngram tokenizers seem to work)
"carlt ben" matches only #2 (same)
"benj carlt" will have no matches
"111-222-3334" matches only #2

I feel like I'm close, using the following analyzer:

{
    "settings": {
        "analysis": {
            "tokenizer": {
                "partialMatchTokenizer": {
                    "type": "edge_ngram",
                    "min_gram": 2,
                    "max_gram": 10
                }
            },
            "analyzer": {
                "partialMatchAnalyzer": {
                    "type": "custom",
                    "tokenizer": "partialMatchTokenizer",
                    "char_filter": [],
                    "filter": [
                        "lowercase"
                    ]
                }
            }
        }
    },
    "mappings": {
        "_doc": {
            "properties": {
                "lastName": {
                    "type": "text",
                    "analyzer": "partialMatchAnalyzer"
                },
                "firstName": {
                    "type": "text",
                    "analyzer": "partialMatchAnalyzer"
                }
            }
        }
    }
}

And the following query:

{
    "query": {
        "multi_match": {
            "query": "carlt ben",
            "type": "cross_fields",
            "fields": [
                "firstName",
                "lastName",
                "medicalRecordNumber"
            ],
            "operator": "or"
        }
    }
}

But it's not quite there. The "or" seems too permissive; an "and" seems too restrictive. And sometimes the n-gram matching seems to provide unexpected results. For example, the above query ("carlt ben") matches both #1 and #2 (i.e., "carlt" matches "Carly", presumably because the "carl" n-gram matches). Also, oddly, "carlt ben" and "ben carlt" provide two different result sets (#1 & #2 vs. #1 & #2 & #3).

Any ideas on how I need to change my analyzer and/or my query to get the results I described above?

ElasticSearch - Partial Matches across Multiple Fields

0 Answers