本地英文版地址: ../en/docs-get.html
Get APIedit
Retrieves the specified JSON document from an index.
GET twitter/_doc/0
Requestedit
GET <index>/_doc/<_id>
HEAD <index>/_doc/<_id>
GET <index>/_source/<_id>
HEAD <index>/_source/<_id>
Descriptionedit
You use GET to retrieve a document and its source or stored fields from a
particular index. Use HEAD to verify that a document exists. You can
use the _source
resource retrieve just the document source or verify
that it exists.
Realtimeedit
By default, the get API is realtime, and is not affected by the refresh
rate of the index (when data will become visible for search). In case where
stored fields are requested (see stored_fields
parameter) and the document
has been updated but is not yet refreshed, the get API will have to parse
and analyze the source to extract the stored fields. In order to disable
realtime GET, the realtime
parameter can be set to false
.
Source filteringedit
By default, the get operation returns the contents of the _source
field unless
you have used the stored_fields
parameter or if the _source
field is disabled.
You can turn off _source
retrieval by using the _source
parameter:
GET twitter/_doc/0?_source=false
If you only need one or two fields from the _source
, use the _source_includes
or _source_excludes
parameters to include or filter out particular fields.
This can be especially helpful with large documents where partial retrieval can
save on network overhead. Both parameters take a comma separated list
of fields or wildcard expressions. Example:
GET twitter/_doc/0?_source_includes=*.id&_source_excludes=entities
If you only want to specify includes, you can use a shorter notation:
GET twitter/_doc/0?_source=*.id,retweeted
Routingedit
If routing is used during indexing, the routing value also needs to be specified to retrieve a document. For example:
GET twitter/_doc/2?routing=user1
This request gets the tweet with id 2
, but it is routed based on the
user. The document is not fetched if the correct routing is not specified.
Preferenceedit
Controls a preference
of which shard replicas to execute the get
request on. By default, the operation is randomized between the shard
replicas.
The preference
can be set to:
-
_local
- The operation will prefer to be executed on a local allocated shard if 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.
Refreshedit
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).
Distributededit
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 have, the better GET scaling we will have.
Versioning supportedit
You can use the version
parameter to retrieve the document only if
its current version is equal to the specified one.
Internally, Elasticsearch has marked the old document as deleted and added an entirely new document. The old version of the document doesn’t disappear immediately, although you won’t be able to access it. Elasticsearch cleans up deleted documents in the background as you continue to index more data.
Path parametersedit
-
<index>
- (Required, string) Name of the index that contains the document.
-
<_id>
- (Required, string) Unique identifier of the document.
Query parametersedit
-
preference
- (Optional, string) Specifies the node or shard the operation should be performed on. Random by default.
-
realtime
-
(Optional, boolean) If
true
, the request is real-time as opposed to near-real-time. Defaults totrue
. See Realtime. -
refresh
-
(Optional, Boolean) If
true
, the request refreshes the relevant shard before retrieving the document. Defaults tofalse
. -
routing
- (Optional, string) Target the specified primary shard.
-
stored_fields
-
(Optional, boolean) If
true
, retrieves the document fields stored in the index rather than the document_source
. Defaults tofalse
. -
_source
-
(Optional, string) True or false to return the
_source
field or not, or a list of fields to return. -
_source_excludes
-
(Optional, string) A comma-separated list of source fields to exclude from the response.
You can also use this parameter to exclude fields from the subset specified in
_source_includes
query parameter.If the
_source
parameter isfalse
, this parameter is ignored. -
_source_includes
-
(Optional, string) A comma-separated list of source fields to include in the response.
If this parameter is specified, only these source fields are returned. You can exclude fields from this subset using the
_source_excludes
query parameter.If the
_source
parameter isfalse
, this parameter is ignored. -
version
- (Optional, integer) Explicit version number for concurrency control. The specified version must match the current version of the document for the request to succeed.
-
version_type
-
(Optional, enum) Specific version type:
internal
,external
,external_gte
.
Response bodyedit
-
_index
- The name of the index the document belongs to.
-
_type
-
The document type. Elasticsearch indices now support a single document type,
_doc
. -
_id
- The unique identifier for the document.
-
_version
- The document version. Incremented each time the document is updated.
-
_seq_no
- The sequence number assigned to the document for the indexing operation. Sequence numbers are used to ensure an older version of a document doesn’t overwrite a newer version. See Optimistic concurrency control.
-
_primary_term
- The primary term assigned to the document for the indexing operation. See Optimistic concurrency control.
-
found
-
Indicates whether the document exists:
true
orfalse
. -
_routing
- The explicit routing, if set.
- _source
-
If
found
istrue
, contains the document data formatted in JSON. Excluded if the_source
parameter is set tofalse
or thestored_fields
parameter is set totrue
. - _fields
-
If the
stored_fields
parameter is set totrue
andfound
istrue
, contains the document fields stored in the index.
Examplesedit
Retrieve the JSON document with the _id
0 from the twitter
index:
GET twitter/_doc/0
The API returns the following result:
{ "_index" : "twitter", "_type" : "_doc", "_id" : "0", "_version" : 1, "_seq_no" : 10, "_primary_term" : 1, "found": true, "_source" : { "user" : "kimchy", "date" : "2009-11-15T14:12:12", "likes": 0, "message" : "trying out Elasticsearch" } }
Check to see if a document with the _id
0 exists:
HEAD twitter/_doc/0
Elasticsearch returns a status code of 200 - OK
if the document exists, or
404 - Not Found
if it doesn’t.
Get the source field onlyedit
Use the <index>/_source/<id>
resource to get
just the _source
field of a document. For example:
GET twitter/_source/1
You can use the source filtering parameters to control which parts of the
_source
are returned:
GET twitter/_source/1/?_source_includes=*.id&_source_excludes=entities
You can use HEAD with the _source
endpoint to efficiently
test whether or not the document _source exists. A document’s source is not
available if it is disabled in the mapping.
HEAD twitter/_source/1
Get stored fieldsedit
Use the stored_fields
parameter to specify the set of stored fields you want
to retrieve. Any requested fields that are not stored are ignored.
Consider for instance the following mapping:
PUT twitter { "mappings": { "properties": { "counter": { "type": "integer", "store": false }, "tags": { "type": "keyword", "store": true } } } }
Now we can add a document:
PUT twitter/_doc/1 { "counter" : 1, "tags" : ["red"] }
And then try to retrieve it:
GET twitter/_doc/1?stored_fields=tags,counter
The API returns the following result:
{ "_index": "twitter", "_type": "_doc", "_id": "1", "_version": 1, "_seq_no" : 22, "_primary_term" : 1, "found": true, "fields": { "tags": [ "red" ] } }
Field values fetched from the document itself are always returned as an array.
Since the counter
field is not stored, the get request ignores it.
You can also retrieve metadata fields like the _routing
field:
PUT twitter/_doc/2?routing=user1 { "counter" : 1, "tags" : ["white"] }
GET twitter/_doc/2?routing=user1&stored_fields=tags,counter
The API returns the following result:
{ "_index": "twitter", "_type": "_doc", "_id": "2", "_version": 1, "_seq_no" : 13, "_primary_term" : 1, "_routing": "user1", "found": true, "fields": { "tags": [ "white" ] } }
Only leaf fields can be retrieved with the stored_field
option. Object fields
can’t be returned—if specified, the request fails.