The bulk API makes it possible to perform many index/delete operations in a single API call. This can greatly increase the indexing speed.

The REST API endpoint is /_bulk, and it expects the following newline delimited JSON (NDJSON) structure:

action_and_meta_data\n
optional_source\n
action_and_meta_data\n
optional_source\n
....
action_and_meta_data\n
optional_source\n

NOTE: The final line of data must end with a newline character \n. Each newline character may be preceded by a carriage return \r. When sending requests to this endpoint the Content-Type header should be set to application/x-ndjson.

The possible actions are index, create, delete, and update. index and create expect a source on the next line, and have the same semantics as the op_type parameter to the standard index API (i.e. create will fail if a document with the same index exists already, whereas index will add or replace a document as necessary). delete does not expect a source on the following line, and has the same semantics as the standard delete API. update expects that the partial doc, upsert and script and its options are specified on the next line.

If you’re providing text file input to curl, you must use the --data-binary flag instead of plain -d. The latter doesn’t preserve newlines. Example:

$ cat requests
{ "index" : { "_index" : "test", "_id" : "1" } }
{ "field1" : "value1" }
$ curl -s -H "Content-Type: application/x-ndjson" -XPOST localhost:9200/_bulk --data-binary "@requests"; echo
{"took":7, "errors": false, "items":[{"index":{"_index":"test","_type":"_doc","_id":"1","_version":1,"result":"created","forced_refresh":false}}]}

Because this format uses literal \n's as delimiters, please be sure that the JSON actions and sources are not pretty printed. Here is an example of a correct sequence of bulk commands:

POST _bulk
{ "index" : { "_index" : "test", "_id" : "1" } }
{ "field1" : "value1" }
{ "delete" : { "_index" : "test", "_id" : "2" } }
{ "create" : { "_index" : "test", "_id" : "3" } }
{ "field1" : "value3" }
{ "update" : {"_id" : "1", "_index" : "test"} }
{ "doc" : {"field2" : "value2"} }

The result of this bulk operation is:

{
   "took": 30,
   "errors": false,
   "items": [
      {
         "index": {
            "_index": "test",
            "_type": "_doc",
            "_id": "1",
            "_version": 1,
            "result": "created",
            "_shards": {
               "total": 2,
               "successful": 1,
               "failed": 0
            },
            "status": 201,
            "_seq_no" : 0,
            "_primary_term": 1
         }
      },
      {
         "delete": {
            "_index": "test",
            "_type": "_doc",
            "_id": "2",
            "_version": 1,
            "result": "not_found",
            "_shards": {
               "total": 2,
               "successful": 1,
               "failed": 0
            },
            "status": 404,
            "_seq_no" : 1,
            "_primary_term" : 2
         }
      },
      {
         "create": {
            "_index": "test",
            "_type": "_doc",
            "_id": "3",
            "_version": 1,
            "result": "created",
            "_shards": {
               "total": 2,
               "successful": 1,
               "failed": 0
            },
            "status": 201,
            "_seq_no" : 2,
            "_primary_term" : 3
         }
      },
      {
         "update": {
            "_index": "test",
            "_type": "_doc",
            "_id": "1",
            "_version": 2,
            "result": "updated",
            "_shards": {
                "total": 2,
                "successful": 1,
                "failed": 0
            },
            "status": 200,
            "_seq_no" : 3,
            "_primary_term" : 4
         }
      }
   ]
}

The endpoints are /_bulk and /{index}/_bulk. When the index is provided, it will be used by default on bulk items that don’t provide it explicitly.

A note on the format. The idea here is to make processing of this as fast as possible. As some of the actions will be redirected to other shards on other nodes, only action_meta_data is parsed on the receiving node side.

Client libraries using this protocol should try and strive to do something similar on the client side, and reduce buffering as much as possible.

The response to a bulk action is a large JSON structure with the individual results of each action that was performed in the same order as the actions that appeared in the request. The failure of a single action does not affect the remaining actions.

There is no "correct" number of actions to perform in a single bulk call. You should experiment with different settings to find the optimum size for your particular workload.

If using the HTTP API, make sure that the client does not send HTTP chunks, as this will slow things down.

Optimistic Concurrency Control

Each index and delete action within a bulk API call may include the if_seq_no and if_primary_term parameters in their respective action and meta data lines. The if_seq_no and if_primary_term parameters control how operations are executed, based on the last modification to existing documents. See Optimistic concurrency control for more details.

Versioning

Each bulk item can include the version value using the version field. It automatically follows the behavior of the index / delete operation based on the _version mapping. It also support the version_type (see versioning).

Routing

Each bulk item can include the routing value using the routing field. It automatically follows the behavior of the index / delete operation based on the _routing mapping.

Wait For Active Shards

When making bulk calls, you can set the wait_for_active_shards parameter to require a minimum number of shard copies to be active before starting to process the bulk request. See here for further details and a usage example.

Refresh

Control when the changes made by this request are visible to search. See refresh.

Only the shards that receive the bulk request will be affected by refresh. Imagine a _bulk?refresh=wait_for request with three documents in it that happen to be routed to different shards in an index with five shards. The request will only wait for those three shards to refresh. The other two shards that make up the index do not participate in the _bulk request at all.

Update

When using the update action, retry_on_conflict can be used as a field in the action itself (not in the extra payload line), to specify how many times an update should be retried in the case of a version conflict.

The update action payload supports the following options: doc (partial document), upsert, doc_as_upsert, script, params (for script), lang (for script), and _source. See update documentation for details on the options. Example with update actions:

POST _bulk
{ "update" : {"_id" : "1", "_index" : "index1", "retry_on_conflict" : 3} }
{ "doc" : {"field" : "value"} }
{ "update" : { "_id" : "0", "_index" : "index1", "retry_on_conflict" : 3} }
{ "script" : { "source": "ctx._source.counter += params.param1", "lang" : "painless", "params" : {"param1" : 1}}, "upsert" : {"counter" : 1}}
{ "update" : {"_id" : "2", "_index" : "index1", "retry_on_conflict" : 3} }
{ "doc" : {"field" : "value"}, "doc_as_upsert" : true }
{ "update" : {"_id" : "3", "_index" : "index1", "_source" : true} }
{ "doc" : {"field" : "value"} }
{ "update" : {"_id" : "4", "_index" : "index1"} }
{ "doc" : {"field" : "value"}, "_source": true}

Security

See URL-based access control.

Partial responses

To ensure fast responses, the multi search API will respond with partial results if one or more shards fail. See Shard failures for more information.