Highlighting matched results on _all fields

Question

I want the matched results to be highlighted. This works for me if I mention the field name and it returns the highlighted text, however if I give the field as "_all", it is not returning any value. This works for me:

        curl -XGET "http://localhost:9200/my_index/my_type/_search?q=stackoverflow&size=999" -d '{
        "highlight":{
                    "fields":{
                             "my_field":{}
                    }
        }
}'

This returns the expected value as follows: [highlight] => stdClass Object ( [my_field] => Array ( [0] => stackoverflow is the best website for techies ) )

But when I give this:

        curl -XGET "http://localhost:9200/my_index/my_type/_search?q=stackoverflow&size=999" -d '{
        "highlight":{
                    "fields":{
                             "_all":{}
                    }
        }
}'

I get null value/no result.

[highlight] => stdClass Object ( [_all] => Array () )

How do I get it to work on any field so that I don't have to mention the field name?

Answer 1

To avoid the need to add _all as a stored field in your index

An alternative quick fix: use * instead of _all:

curl -XGET "http://localhost:9200/my_index/my_type/_search?q=stackoverflow&size=999" -d '{
  "highlight":{
    "fields":{
      "*":{}
    }
  }
}'