How can we get counts of each group when grouped by a certain field in elasticsearch?

Question

Here is how my doc looks like.

{
    "Summary": "The One Way You're Putting Pressure on Your Partner Without Realizing It=20",
    "Industry" : "Lifestyle and Fitness",
    "Name": "Kali Coleman",
    "Email" : "query-bixh@helpareporter.net",
    "Media Outlet": "Best Life Online"
},
{
    "Summary": "The One Way You're Putting Pressure on",
    "Industry" : "High Tech",
    "Name": "John Smith",
    "Email" : "query-tech@helpareporter.net",
    "Media Outlet": "Anonymous"
}

I want to count the documents for each type of "Industry" field. Here is what I want as an output.

{
    "key": "Lifestyle and Fitness",
    "count": 1200
},
{
    "key": "High Tech",
    "count": 590
}

I found a similar post here ElasticSearch count multiple fields grouped by, except that I do not have to filter. And I tried it on my Kibana console, got the following error.

"root_cause" : [
      {
          "type" : "illegal_argument_exception",
          "reason" : "Text fields are not optimised for operations that require per-document field data like aggregations and sorting, so these operations are disabled by default. Please use a keyword field instead. Alternatively, set fielddata=true on [Industry] in order to load field data by uninverting the inverted index. Note that this can use significant memory."
      }
]

Please let me know if anyone knows the solution for this.

Thanks

Answer 1

You can use a terms aggregation just like in the example and you can do so w/o a filter. Once you've configured your Industry field's mapping to be of type keyword, you can then run

GET index_name/_search
{
  "size": 0,
  "aggs": {
    "by_industry": {
      "terms": {
        "field": "Industry.keyword"
      }
    }
  }
}