opensearch-docs-cn/_api-reference/document-apis/multi-get.md

layout	title	parent	nav_order
default	Multi-get document	Document APIs	30

Multi-get documents

Introduced 1.0 {: .label .label-purple }

The multi-get operation allows you to execute multiple GET operations in one request, so you can get back all documents that match your criteria.

Example without specifying index in URL

GET _mget
{
  "docs": [
  {
    "_index": "sample-index1",
    "_id": "1"
  },
  {
    "_index": "sample-index2",
    "_id": "1",
    "_source": {
      "include": ["Length"]
    }
  }
  ]
}

Example of specifying index in URL

GET sample-index1/_mget

{
  "docs": [
    {
      "_id": "1",
      "_source": false
    },
    {
      "_id": "2",
      "_source": [ "Director", "Title" ]
    }
  ]
}

Path and HTTP methods

GET _mget
GET <index>/_mget

URL parameters

All multi-get URL parameters are optional.

Parameter	Type	Description
<index>	String	Name of the index to retrieve documents from.
preference	String	Specifies the nodes or shards OpenSearch should execute the multi-get operation on. Default is random.
realtime	Boolean	Specifies whether the operation should run in realtime. If false, the operation waits for the index to refresh to analyze the source to retrieve data, which makes the operation near-realtime. Default is true.
refresh	Boolean	If true, OpenSearch refreshes shards to make the multi-get operation available to search results. Valid options are true, false, and wait_for, which tells OpenSearch to wait for a refresh before executing the operation. Default is false.
routing	String	Value used to route the multi-get operation to a specific shard.
stored_fields	Boolean	Specifies whether OpenSearch should retrieve documents fields from the index instead of the document's _source. Default is false.
_source	String	Whether to include the _source field in the query response. Default is true.
_source_excludes	String	A comma-separated list of source fields to exclude in the query response.
_source_includes	String	A comma-separated list of source fields to include in the query response.

Request body

If you don't specify an index in your request's URL, you must specify your target indices and the relevant document IDs in the request body. Other fields are optional.

Field	Type	Description	Required
docs	Array	The documents you want to retrieve data from. Can contain the attributes: _id, _index, _routing, _source, and _stored_fields. If you specify an index in the URL, you can omit this field and add IDs of the documents to retrieve.	Yes if an index is not specified in the URL
_id	String	The ID of the document.	Yes if docs is specified in the request body
_index	String	Name of the index.	Yes if an index is not specified in the URL
_routing	String	The value of the shard that has the document.	Yes if a routing value was used when indexing the document
_source	Object	Specifies whether to return the _source field from an index (boolean), whether to return specific fields (array), or whether to include or exclude certain fields.	No
_source.includes	Array	Specifies which fields to include in the query response. For example, "_source": { "include": ["Title"] } retrieves Title from the index.	No
_source.excludes	Array	Specifies which fields to exclude in the query response. For example, "_source": { "exclude": ["Director"] } excludes Director from the query response.	No
ids	Array	IDs of the documents to retrieve. Only allowed when an index is specified in the URL.	No

Response

{
  "docs": [
    {
      "_index": "sample-index1",
      "_id": "1",
      "_version": 4,
      "_seq_no": 5,
      "_primary_term": 19,
      "found": true,
      "_source": {
        "Title": "Batman Begins",
        "Director": "Christopher Nolan"
      }
    },
    {
      "_index": "sample-index2",
      "_id": "1",
      "_version": 1,
      "_seq_no": 6,
      "_primary_term": 19,
      "found": true,
      "_source": {
        "Title": "The Dark Knight",
        "Director": "Christopher Nolan"
      }
    }
  ]
}

Response body fields

Field	Description
_index	The name of the index.
_id	The document's ID.
_version	The document's version number. Updated whenever the document changes.
_seq_no	The sequnce number assigned when the document is indexed.
primary_term	The primary term assigned when the document is indexed.
found	Whether the document exists.
_routing	The shard that the document is routed to. If the document is not routed to a particular shard, this field is omitted.
_source	Contains the document's data if found is true. If _source is set to false or stored_fields is set to true in the URL parameters, this field is omitted.
_fields	Contains the document's data that's stored in the index. Only returned if both stored_fields and found are true.