Define Synonym Mappings in Your Atlas Search Index

Format of Synonyms Source Collection Documents

You must configure each document with the following fields:

The documents in the collection can contain other fields. The documents in the collection are additive, and mappings are deduplicated. Atlas Search synonyms are stored as a separate Atlas collection, which counts against the same storage quota as any other collection in Atlas. Atlas Search might use more compute resources to apply synonyms from larger synonyms source collections.

Changes to Synonyms Source Collection Documents

If you make changes to your synonyms source collection:

• You don't need to reindex because Atlas Search watches for changes and automatically updates its internal synonym map.

• The time it takes Atlas Search to update the synonym mappings increases with the synonym source collection size. Note that the changes to synonym documents are reflected in your Atlas Search query results eventually.

mappingType Examples

Atlas provides the documents for the following Atlas Search mapping type examples in a collection named sample_synonyms. You can load these documents on your cluster in the same database as your collection. To load these documents on your cluster, when you create the index for your collection, do the following:

1. When you select the Configuration Method, select the Visual Editor.

2. When you Add synonym mapping to your index, select Load sample collection from the Synonym source collection dropdown.

{
  "mappingType": "equivalent",
  "synonyms": ["car", "vehicle", "automobile"]
}

{
  "mappingType": "explicit",
  "input": ["beer"],
  "synonyms": ["beer", "brew", "pint"]
}

Collection Example

user_feedback.comments contains the following documents:

{
  "type": "car dealer",
  "comments": "Blue four-door sedan, lots of trunk space in the car."
}

{
  "type": "winery",
  "comments": "Beer and skittles for all."
}

{
  "type": "apparel store",
  "comments": "Beautiful apparel for the bride."
}

{
  "type": "recreation rental",
  "comments": "Sails as well as the day it was made."
}

Synonym Source Collection Example

The following collection titled user_feedback.synonyms is an example synonym source collection for the user_feedback.comments collection.

user_feedback.synonyms contains the following documents:

{
  "mappingType": "equivalent",
  "synonyms": ["car", "vehicle", "automobile"]
}

{
  "mappingType": "explicit",
  "input": ["beer"],
  "synonyms": ["beer", "brew", "pint"]
}

{
  "mappingType": "equivalent",
  "synonyms": ["dress", "apparel", "attire"]
}

{
  "mappingType": "explicit",
  "input": ["boat"],
  "synonyms": ["boat", "vessel", "sail"]
}

Index Definition Examples

The following examples for the user_feedback.comments collection show the index definitions using static and dynamic mappings.

{
  "mappings": {
    "dynamic": false,
    "fields": {
      "comments": {
        "type": "string",
        "analyzer": "lucene.english"
      }
    }
  },
  "synonyms": [
    {
      "analyzer": "lucene.english",
      "name": "mySynonyms",
      "source": {
        "collection": "synonyms"
      }
    }
  ]
}

{
  "mappings": {
    "dynamic": true
  },
  "synonyms": [
    {
      "analyzer": "lucene.standard",
      "name": "mySynonyms",
      "source": {
        "collection": "synonyms"
      }
    }
  ]
}