Unknown parameter [data_type] on mapper of type [knn_vector]

Question

Based on the documentation, I am trying to create an index with the nested vector field using byte as the underlying data type:

PUT docs_byte
{
    "settings" : {
        "index" : {
            "number_of_shards" : 1, 
            "number_of_replicas" : 1
        }
    },
    "mappings": {
        "properties": {
            "title": {
                "type": "text"
            },
            "ideas": {
                "type": "nested",
                "properties": {
                    "vector": {
                        "type": "knn_vector",
                        "dimension": 384,
                        "data_type": "byte"
                    }
                }
            }
        }
    }
}

I get the error unknown parameter [data_type] on mapper [vector] of type [knn_vector]. What am I missing?

score 0 · Answer 1 · answered Aug 01 '23 at 15:23

The byte data_type is only supported by the the lucene engine, so you need to declare your field like this:

PUT docs_byte
{
    "settings" : {
        "index" : {
            "number_of_shards" : 1, 
            "number_of_replicas" : 1
        }
    },
    "mappings": {
        "properties": {
            "title": {
                "type": "text"
            },
            "ideas": {
                "type": "nested",
                "properties": {
                    "vector": {
                        "type": "knn_vector",
                        "dimension": 384,
                        "data_type": "byte",
                        "method": {
                            "name": "hnsw",
                            "space_type": "l2",
                            "engine": "lucene",        <------ add this
                            "parameters": {
                                "ef_construction": 128,
                                "m": 24
                            }
                        }
                    }
                }
            }
        }
    }
}

I tried this (and tried again now with the copy of your code to make sure). Same error. The error seems to be during parsing, so it seems to have nothing to do with what follows the problematic line... — AlwaysLearning, Aug 01 '23 at 16:54
I execute the queries in the dashboard. I assume it is running the latest stable version. — AlwaysLearning, Aug 03 '23 at 06:51
That doesn't tell me what version you're using. What does `GET /` return? — Val, Aug 03 '23 at 06:54

Unknown parameter [data_type] on mapper of type [knn_vector]

1 Answers1