How to fix ElasticSearch 'Root mapping definition has unsupported parameters'

Problem:

You want to create an ElasticSearch index with a custom mapping or update the mapping of an existing ElasticSearch index but you see an error message like

elasticsearch.exceptions.RequestError: RequestError(400, 'mapper_parsing_exception', 'Root mapping definition has unsupported parameters:  [mappings : {properties={num_total={type=integer}, approved={type=integer}, num_translated={type=integer}, pattern_length={type=integer}, num_unapproved={type=integer}, pattern={type=keyword}, num_approved={type=integer}, translated={type=integer}, untranslated={type=integer}, num_untranslated={type=integer}, group={type=keyword}}}]')

Solution

This can point to multiple issues. Essentially, ElasticSearch is trying to tell you that the structure of your JSON is not correct.

Often this error is misinterpreted as *individual field definitions being wrong,*but this is rarely the issue (and only if an individual field definition is completely malformed).

If your message is structured like

... unsupported parameters:  [mappings : ...

then the most likely root cause is that you have mappings nested inside mappings in your JSON. This also applies if you update a mapping (put_mapping) - in this case the outer mapping is implicit!

Example: Your code looks like this:

es.indices.put_mapping(index='my_index, doc_type='_doc', body={
    "mappings": {
        "properties": {
            "pattern": {
                "type":  "keyword"
            }
        }
    }
})

ElasticSearch will internally create a JSON like this internally:

{
    "mappings": {
        "mappings": {
            "properties": {
                "pattern": {
                    "type":  "keyword"
                }
            }
        }
    }
}

See that there are two mappings inside each other? ElasticSearch does not view this as a correctly structured JSON, therefore you need to remove the "mapping": {...} from your code, resulting in

es.indices.put_mapping(index='my_index, doc_type='_doc', body={
    "properties": {
        "pattern": {
            "type":  "keyword"
        }
    }
})