Split index

Split index

Introduced 1.0

The split index API operation splits an existing read-only index into a new index, cutting each primary shard into some amount of primary shards in the new index.

Example

PUT /sample-index1/_split/split-index1
{
  "settings": {
    "index": {
      "number_of_shards": 4,
      "number_of_replicas": 2
    }
  },
  "aliases": {
    "sample-alias1": {}
  }
}

copy

Path and HTTP methods

POST /<source-index>/_split/<target-index>
PUT /<source-index>/_split/<target-index>

Index naming restrictions

OpenSearch indexes have the following naming restrictions:

All letters must be lowercase.
Index names can’t begin with underscores (_) or hyphens (-).
Index names can’t contain spaces, commas, or the following characters:

:, ", *, +, /, \, |, ?, #, >, or <

Path parameters

Parameter	Type	Description
<source-index>	String	The source index to split.
<target-index>	String	The index to create.

Query parameters

Your request must include the source and target indexes. All split index parameters are optional.

Parameter	Type	Description
<source-index>	String	The source index to split.
<target-index>	String	The index to create.
wait_for_active_shards	String	The number of active shards that must be available before OpenSearch processes the 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 operation to succeed.
cluster_manager_timeout	Time	How long to wait for a connection to the cluster manager node. Default is `30s`.
timeout	Time	How long to wait for the request to return. Default is `30s`.
wait_for_completion	Boolean	When set to `false`, the request returns immediately instead of after the operation is finished. To monitor the operation status, use the Tasks API with the task ID returned by the request. Default is `true`.
task_execution_timeout	Time	The explicit task execution timeout. Only useful when wait_for_completion is set to `false`. Default is `1h`.

Request body

The split index API operation creates a new target index, so you can specify any index settings and aliases to apply to the target index.

Example response

{
    "acknowledged": true,
    "shards_acknowledged": true,
    "index": "split-index1"
}

Index codec considerations

For index codec considerations, see Index codecs.