The bulk operation lets you add, update, or delete many documents in a single request. Compared to individual OpenSearch indexing requests, the bulk operation has significant performance benefits. Whenever practical, we recommend batching indexing operations into bulk requests.
Specifying the index in the path means you don't need to include it in the [request body]({{site.url}}{{site.baseurl}}/opensearch/rest-api/document-apis/bulk/#request-body).
OpenSearch also accepts PUT requests to the `_bulk` path, but we highly recommend using POST. The accepted usage of PUT---adding or replacing a single resource at a given path---doesn't make sense for bulk requests.
{: .note }
## URL parameters
All bulk URL parameters are optional.
Parameter | Type | Description
:--- | :--- | :---
pipeline | String | The pipeline ID for preprocessing documents.
refresh | Enum | Whether to refresh the affected shards after performing the indexing operations. Default is `false`. `true` makes the changes show up in search results immediately, but hurts cluster performance. `wait_for` waits for a refresh. Requests take longer to return, but cluster performance doesn't suffer.
require_alias | Boolean | Set to `true` to require that all actions target an index alias rather than an index. Default is `false`.
routing | String | Routes the request to the specified shard.
timeout | Time | How long to wait for the request to return. Default `1m`.
type | String | (Deprecated) The default document type for documents that don't specify a type. Default is `_doc`. We highly recommend ignoring this parameter and using a type of `_doc` for all indices.
wait_for_active_shards | String | Specifies the number of active shards that must be available before OpenSearch processes the bulk request. Default is 1 (only the primary shard). Set to `all` or a positive integer. Values greater than 1 require replicas. For example, if you specify a value of 3, the index must have two replicas distributed across two additional nodes for the request to succeed.
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## Request body
The bulk request body follows this pattern:
```
Action and metadata\n
Optional document\n
Action and metadata\n
Optional document\n
```
The optional JSON document doesn't need to be minified---spaces are fine---but it does need to be on a single line. OpenSearch uses newline characters to parse bulk requests and requires that the request body end with a newline character.
All actions support the same metadata: `_index`, `_id`, and `_require_alias`. If you don't provide an ID, OpenSearch generates one automatically, which can make it challenging to update the document at a later time.
- Create
Creates a document if it doesn't already exist and returns an error otherwise. The next line must include a JSON document.
This action deletes a document if it exists. If the document doesn't exist, OpenSearch doesn't return an error, but instead returns `not_found` under `result`. Delete actions don't require documents on the next line.
This action updates existing documents and returns an error if the document doesn't exist. The next line must include a full or partial JSON document, depending on how much of the document you want to update. It can also include a script or upsert for more complex document updates.
In the response, pay particular attention to the top-level `errors` boolean. If true, you can iterate over the individual actions for more detailed information.
```json
{
"took": 11,
"errors": true,
"items": [
{
"index": {
"_index": "movies",
"_type": "_doc",
"_id": "tt1979320",
"_version": 1,
"result": "created",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"_seq_no": 1,
"_primary_term": 1,
"status": 201
}
},
{
"create": {
"_index": "movies",
"_type": "_doc",
"_id": "tt1392214",
"status": 409,
"error": {
"type": "version_conflict_engine_exception",
"reason": "[tt1392214]: version conflict, document already exists (current version [1])",