Sort processor
- Request fields
- Example

Sort processor

Introduced 2.16

The sort processor sorts an array of items in either ascending or descending order. Numeric arrays are sorted numerically, while string or mixed arrays (strings and numbers) are sorted lexicographically. The processor throws an error if the input is not an array.

Request fields

The following table lists all available request fields.

Field	Data type	Description
`field`	String	The field to be sorted. Must be an array. Required.
`order`	String	The sort order to apply. Accepts `asc` for ascending or `desc` for descending. Default is `asc`.
`target_field`	String	The name of the field in which the sorted array is stored. If not specified, then the sorted array is stored in the same field as the original array (the `field` variable).
`tag`	String	The processor’s identifier.
`description`	String	A description of the processor.
`ignore_failure`	Boolean	If `true`, then OpenSearch ignores any failure of this processor and continues to run the remaining processors in the search pipeline. Optional. Default is `false`.

Example

The following example demonstrates using a search pipeline with a sort processor.

Setup

Create an index named my_index and index a document with the field message that contains an array of strings:

POST /my_index/_doc/1
{
  "message": ["one", "two", "three", "four"], 
  "visibility": "public"
}

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Creating a search pipeline

Create a search pipeline with a sort response processor that sorts the message field and stores the sorted results in the sorted_message field:

PUT /_search/pipeline/my_pipeline
{
  "response_processors": [
    {
      "sort": {
        "field": "message",
        "target_field": "sorted_message"
      }
    }
  ]
}

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Using a search pipeline

Search for documents in my_index without a search pipeline:

GET /my_index/_search

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The response contains the field message:

Response

{
  "took": 1,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": {
      "value": 1,
      "relation": "eq"
    },
    "max_score": 1,
    "hits": [
      {
        "_index": "my_index",
        "_id": "1",
        "_score": 1,
        "_source": {
          "message": [
            "one",
            "two",
            "three",
            "four"
          ],
          "visibility": "public"
        }
      }
    ]
  }
}

To search with a pipeline, specify the pipeline name in the search_pipeline query parameter:

GET /my_index/_search?search_pipeline=my_pipeline

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The sorted_message field contains the strings from the message field sorted alphabetically:

Response

{
  "took": 3,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": {
      "value": 1,
      "relation": "eq"
    },
    "max_score": 1,
    "hits": [
      {
        "_index": "my_index",
        "_id": "1",
        "_score": 1,
        "_source": {
          "visibility": "public",
          "sorted_message": [
            "four",
            "one",
            "three",
            "two"
          ],
          "message": [
            "one",
            "two",
            "three",
            "four"
          ]
        }
      }
    ]
  }
}

You can also use the fields option to search for specific fields in a document:

POST /my_index/_search?pretty&search_pipeline=my_pipeline
{
    "fields": ["visibility", "message"]
}

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In the response, the message field is sorted and the results are stored in the sorted_message field:

Response

{
  "took": 2,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": {
      "value": 1,
      "relation": "eq"
    },
    "max_score": 1,
    "hits": [
      {
        "_index": "my_index",
        "_id": "1",
        "_score": 1,
        "_source": {
          "visibility": "public",
          "sorted_message": [
            "four",
            "one",
            "three",
            "two"
          ],
          "message": [
            "one",
            "two",
            "three",
            "four"
          ]
        },
        "fields": {
          "visibility": [
            "public"
          ],
          "sorted_message": [
            "four",
            "one",
            "three",
            "two"
          ],
          "message": [
            "one",
            "two",
            "three",
            "four"
          ]
        }
      }
    ]
  }
}