Use Completion Suggester for all the fields of across the Elasticsearch type

Question

I am implementing Completion Suggester in my application, and here goes my requirement:

I am using Elasticsearch 5.5.3 (which support multiple types). I have around 10 types in my Elasticsearch and each type has around 10 string fields. What I want to do is make a single search box, that would complete the phrase (of any fields of those 10 types) as user starts typing using completion suggester. What could be the best approach to it? Is using _all field a good idea?

Answer 1

Yes, that's perfectly doable using a "custom all field" field of type completion

First, create the index with all the types and make sure to copy each field in a custom field of type completion:

PUT my_index
{
  "mappings": {
    "type1": {
      "properties": {
        "field1": {
          "type": "text",
          "copy_to": "my_all"
        },
        "field2": {
          "type": "text",
          "copy_to": "my_all"
        },
        "my_all": {
          "type": "completion"
        }
      }
    },
    "type1": {
      "properties": {
        "field1": {
          "type": "text",
          "copy_to": "my_all"
        },
        "field2": {
          "type": "text",
          "copy_to": "my_all"
        },
        "my_all": {
          "type": "completion"
        }
      }
    }
  }
}

Then, you'd query the completion data like this (i.e. without specifying any mapping type and using the common my_all field):

POST my_index/_search
{
  "suggest": {
    "my-suggest": {
      "prefix": "bla",
      "completion": {
        "field": "my_all"
      }
    }
  }
}