Configure an Autocomplete Search Index

how-to

Create a Search index with the Couchbase Server Web Console or the REST API to start using autocomplete with the Search Service.

Prerequisites

You have the Search Service enabled on a node in your database. For more information about how to deploy a new node and Services on your database, see Manage Nodes and Clusters.
You have a bucket with scopes and collections in your database. For more information about how to create a bucket, see Create a Bucket.
Your user account has the Search Admin role for the bucket where you want to create the index.
You have logged in to the Couchbase Server Web Console.

Procedure

You can create a compatible Search index with the Web Console or the REST API.

Create the Autocomplete Search Index with the Web Console

To create the Search index with the Web Console:

Go to Search.
Click Add Index.

In the Index Name field, enter a name for the new index.

Your index name must start with an alphabetic character (a-z or A-Z). It can only contain alphanumeric characters (a-z, A-Z, or 0-9), hyphens (-), or underscores (_).

For Couchbase Server version 7.6 and later, your index name must be unique inside your selected bucket and scope. You cannot have 2 indexes with the same name inside the same bucket and scope.

In the Bucket list, select the bucket where you want to create the index.
Expand Customize Index.
Select Use non-default scope/collection(s).
In the Scope list, select the scope where you want to create the index.
Create a Custom Analyzer with the following settings:
1. In the Name field, enter keyword_to_lower.
2. In the Tokenizer list, select single.
3. In the Token Filters list, select and add the to_lower token filter.
Expand Custom Filters.
Create a custom token filter with the following settings:
1. In the Name field, enter edge_ngram_2_8.
2. In the Type list, select edge_ngram.
3. In the Min field, enter 2, or the minimum number of characters you want the Search index to use for autocomplete.
4. In the Max field, enter 8, or the maximum number of characters you want the Search index to use for autocomplete.
Create another custom analyzer with the following settings:
1. In the Name field, enter edge_ngram.
2. In the Tokenizer list, select unicode.
3. In the Token Filters list, select and add the to_lower and your custom edge_ngram_2_8 token filter.
Under Mappings, clear the default type mapping.
Create a Type Mapping with the following settings:
1. Clear index all contained fields.
(Optional) If the field you want to search with autocomplete is nested inside a JSON object in your documents, Create a Child Mapping for the JSON object with the following settings:
1. Clear index all contained fields.
Under the type mapping or child mapping, Create a Child Field with the following settings:
1. In the field field, enter the name of a text field in a document from your selected scope and collection.
2. In the analyzer list, select your edge_ngram analyzer.
3. Select index.
4. Select store.
5. Select include in _all field.
Expand Advanced.
In the Default Analyzer list, select your keyword_to_lower analyzer.
Click Create Index

You can use the generated index definition JSON payload from the UI to create a Search index with the REST API.

Create an Autocomplete Search Index with the REST API

To create an autocomplete Search index from the REST API:

Create a Search Index with the REST API and curl/HTTP with the following JSON payload, replacing all placeholder values that start with a $:

{
    "type": "fulltext-index",
    "name": "e-ngram-2-8",
    "uuid": "$GENERATED_INDEX_UUID",
    "sourceType": "gocbcore",
    "sourceName": "$BUCKET_NAME",
    "sourceUUID": "$BUCKET_UUID",
    "planParams": {
      "maxPartitionsPerPIndex": 1024,
      "indexPartitions": 1
    },
    "params": {
      "doc_config": {
        "docid_prefix_delim": "",
        "docid_regexp": "",
        "mode": "scope.collection.type_field",
        "type_field": "type"
      },
      "mapping": {
        "analysis": {
          "analyzers": {
            "edge_ngram": {
              "token_filters": [
                "to_lower",
                "edge_ngram_2_8"
              ],
              "tokenizer": "unicode",
              "type": "custom"
            },
            "keyword_to_lower": {
              "token_filters": [
                "to_lower"
              ],
              "tokenizer": "single",
              "type": "custom"
            }
          },
          "token_filters": {
            "edge_ngram_2_8": {
              "back": false,
              "max": 8,
              "min": 2,
              "type": "edge_ngram"
            }
          }
        },
        "default_analyzer": "keyword_to_lower",
        "default_datetime_parser": "dateTimeOptional",
        "default_field": "_all",
        "default_mapping": {
          "dynamic": true,
          "enabled": false
        },
        "default_type": "_default",
        "docvalues_dynamic": false,
        "index_dynamic": true,
        "store_dynamic": false,
        "type_field": "_type",
        "types": {
          "$SCOPE_NAME.$COLLECTION_NAME": {
            "dynamic": false,
            "enabled": true,
            "properties": {
              "$FIELD_NAME": {
                "dynamic": false,
                "enabled": true,
                "fields": [
                  {
                    "analyzer": "edge_ngram",
                    "include_in_all": true,
                    "index": true,
                    "name": "$FIELD_NAME",
                    "store": true,
                    "type": "text"
                  }
                ]
              }
            }
          }
        }
      },
      "store": {
        "indexType": "scorch",
        "segmentVersion": 15
      }
    },
    "sourceParams": {}
  }

Next Steps

To add an autocomplete feature to your application, see Add Autocomplete to Your Application for example code.