How to do it...

The HTTP method to reindex an index is POST. The URL format to get a mapping is http://<server>/_reindex.

To reindex the data between two indices, we will perform the following steps:

1. If we want to reindex data from myindex to the myindex2 index, the call will be as follows:

POST /_reindex?pretty=true
{
  "source": {
    "index": "myindex"
  },
  "dest": {
    "index": "myindex2"
  }
}

1. The result returned by Elasticsearch should be as follows:

{
  "took" : 20,
  "timed_out" : false,
  "total" : 0,
  "updated" : 0,
  "created" : 0,
  "deleted" : 0,
  "batches" : 0,
  "version_conflicts" : 0,
  "noops" : 0,
  "retries" : {
    "bulk" : 0,
    "search" : 0
  },
  "throttled_millis" : 0,
  "requests_per_second" : -1.0,
  "throttled_until_millis" : 0,
  "failures" : [ ]
}