Elasticsearch completion suggester on multifield with different weighting

Question

I'm using the Completion Suggester in Elasticsearch to allow partial word matching queries. In my index (products_index), I'd like to be able to query both the product_name field and the brand field. Here are my mappings:

POST /product_index

mappings: {
  products: {
    properties: {
      brand: {
        type: "string",
        analyzer: "english"
      },
      product_name: {
        type: "string",
        analyzer: "english"
      },
      id: {
        type: "long"
      },
      lookup_count: {
        type: "long"
      },
      suggest: {
        type: "completion",
        analyzer: "simple",
        payloads: true,
        preserve_separators: true,
        preserve_position_increments: true,
        max_input_length: 50
      },
      upc: {
        type: "string"
      }
    }
  }
}

Here is my data:

POST /product_index/products/2
{
  id: 2,
  brand: "Coca-Cola",
  product_name: "Classic Coke",
  suggest: {
    input: [
      "Classic Coke",
      "Coca-Cola"
    ],
    output: "Classic Coke - Coca-Cola",
    payload: {
      id: 2,
      product_name: "Classic Coke",
      brand: "Coca-Cola",
      popularity: 10
    },
    weight: 0
  }
}

And here is my query:

POST /product_index/_search

"suggest": {
  "product_suggest": {
    "text": 'coca-co',
    "completion": {
      "field": 'suggest'
    }
  }
}

This works great except that I'd like to give the product_name field a higher weighting than the brand field. Is there any way I can achieve this? I have looked into this article on using bool queries but I'm quite new to Elasticsearch and unsure how I can apply that in the case of completion suggester.

Thanks a lot!

Answer 1

The Completion Suggester is actually pretty limited in term of scoring: you cannot do that. The only thing you can do is boost some entries but not the attributes inside an entry (see the weight options http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/search-suggesters-completion.html#indexing).

That's because the Completion Suggester doesn't do a "real search" -> it doesn't use the index. It's a simple "dictionary" designed to do "prefix" expansions faster than with an index + inverted lists.

You should give a try to Algolia -> the engine is designed to answer to prefix searches in realtime + having different "weights" per attribute. Here is a tutorial to implement auto-complete menu targeting several fields