ElasticSearch 5.1 Fielddata is disabled in text field by default [ERROR: trying to use aggregation on field]
You need to aggregate on the keyword sub-field, like this:
"aggs": {"answer": { "terms": { "field": "answer.keyword" }},That will work.
In Aggregation, just add keyword to answer.It worked for me. For text fields we need to add keyword. "field": "answer.keyword"
Adding to @Val's answer, you can also set the fielddata to true during your mapping itself:
"answer": { "type": "text", "fielddata": true, <-- add this line "fields": { "keyword": { "type": "keyword", "ignore_above": 256 } } },