Get

The get API allows to get a typed JSON document from the index based on its id. The following example gets a JSON document from an index called twitter, under a type called tweet, with id valued 1:

$ curl -XGET 'http://localhost:9200/twitter/tweet/1'

The result of the above get operation is:

{
    "_index" : "twitter",
    "_type" : "tweet",
    "_id" : "1",
    "_source" : {
        "user" : "kimchy",
        "postDate" : "2009-11-15T14:12:12",
        "message" : "trying out Elastic Search"
    }
}

The above result includes the _index, _type, and _id of the document we wish to retrieve, including the actual source of the document that was indexed.

Fields

The get operation allows to specify a set of fields that will be returned (by default, its the _source field) by passing the fields parameter. For example:

$ curl -XGET 'http://localhost:9200/twitter/tweet/1?fields=title,content'

The returned fields will either be loaded if they are stored, or fetched from the _source (parsed and extracted). Note, certain “json sub objects” can be returned by explicitly prefixing them with _source., for example: _source.obj1.obj2.

Routing

When indexing using the ability to control the routing, in order to get a document, the routing value should also be provided. For example:

$ curl -XGET 'http://localhost:9200/twitter/tweet/1?routing=kimchy'

The above will get a tweet with id 1, but will be routed based on the user. Note, issuing a get without the correct routing, will cause the document not to be fetched.

Preference

Controls a preference of which shard replicas to execute the get request on. By default, the operation is randomized between the each shard replicas.

The preference can be set to:

• _primary: The operation will go and be executed only on the primary shards.
• _local: The operation will prefer to be executed on a local allocated shard is possible.
• Custom (string) value: A custom value will be used to guarantee that the same shards will be used for the same custom value. This can help with “jumping values” when hitting different shards in different refresh states. A sample value can be something like the web session id, or the user name.

Refresh

The refresh parameter can be set to true in order to refresh the relevant shard before the get operation and make it searchable. Setting it to true should be done after careful thought and verification that this does not cause a heavy load on the system (and slows down indexing).

Distributed

The get operation gets hashed into a specific shard id. It then gets redirected to one of the replicas within that shard id and returns the result. The replicas are the primary shard and its replicas within that shard id group. This means that the more replicas we will have, the better GET scaling we will have.