Elasticsearch - Wrong field type - elasticsearch

Question

I'm running on ElasticSearch 6.8.
I tried to add a keyword type field to my index mapping.
What I want is a mapping with my_field seeming like that:
"my_field": {
"type": "keyword"
}
So in order to do that, I added a field to my mapping:
"properties": {
...
"my_field": {
"type": "keyword",
"norms": false
},
...
}
But currently, it gives me something like:
"my_field": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
}
I need this keyword type because I need to aggregate on it, and with a text type, it gave me:
Fielddata is disabled on text fields by default. Set fielddata=true on [my_field] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead.
But I'm not able to set fielddata to true.
I tried many things like creating a new index instead of updating one but none of these tries worked.
Anyone knows how to have the correct field type ? (the solution I prefer)
Or how to set fielddata to true in the mapping?
Best regards,
Jules

Answer 1

I just created set field-data to true on text field by using below curl command on Elasticsearch 6.X version:
curl -X POST "localhost:9200/my_index/type?pretty" -H 'Content-Type: application/json' -d'
> {
> "mappings" :{
> "properties": {
> "my_field": {
> "type": "text",
> "fielddata": true
> }
> }
> }
> }'
And it created index with proper mapping.
{
"_index" : "my_index",
"_type" : "type",
"_id" : "3Jl0F3EBg44VI1hJVGnz",
"_version" : 1,
"result" : "created",
"_shards" : {
"total" : 2,
"successful" : 1,
"failed" : 0
},
"_seq_no" : 0,
"_primary_term" : 1
}
Mapping API gives below JSON response.
{
"my_index": {
"mappings": {
"type": {
"properties": {
"mappings": {
"properties": {
"properties": {
"properties": {
"my_field": {
"properties": {
"fielddata": {
"type": "boolean"
},
"type": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
}
}
}
}
}
}
}
}
}
}
}
}