我的管道是这样的：couchdb->logstash->elasticsearch。每次更新couchdb中的字段值时，elasticsearch中的数据都会被覆盖。我的要求是，在couchdb中更新字段中的数据时，我希望在elasticsearch中创建一个新数据，而不是覆盖现有数据。
我当前的logstash.conf如下所示：

input {
    couchdb_changes {
        host => "<ip>"
        port => <port>
        db => "test_database"
        keep_id => false
        keep_revision => true
        initial_sequence => 0
        always_reconnect => true
        #sequence_path => "/usr/share/logstash/config/seqfile"
    }
}

output {
    if([doc][doc_type] == "HR") {
        elasticsearch {
            hosts => ["http://elasticsearch:9200"]
            index => "hrindex_new_1"
            document_id => "%{[doc][_id]}"
            user => elastic
            password => changeme
        }
    }
    if([doc][doc_type] == "SoftwareEngg") {
        elasticsearch {
            hosts => ["http://elasticsearch:9200"]
            index => "softwareenggindex_new"
            document_id => "%{[doc][_id]}"
            user => elastic
            password => changeme
        }
    }
}

怎么做？