This processor executes an update operation against one or more indices using the _update_by_query handler. The query should be a valid Elasticsearch JSON DSL query (Lucene syntax is not supported). An optional Elasticsearch script can be specified to execute against the matched documents. An example query with script:

            {
                "script": {
                    "source": "ctx._source.count++",
                    "lang": "painless"
                },
                "query": {
                    "match": {
                        "username.keyword": "john.smith"
                    }
                }
            }

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

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