This processor executes a delete operation against one or more indices using the _delete_by_query handler. The query should be a valid ElasticSearch JSON DSL query (Lucene syntax is not supported). An example query:

        {
            "query": {
                "match": {
                    "username.keyword": "john.smith"
                }
            }
        }
    

To delete all of the contents of an index, this could be used:

        {
            "query": {
                "match_all": {}
            }
        }