The fields are stored in a Ruby hash or a Java map (I think; I'd expect it to depend on the Logstash implementation). The order of the keys in such data structures is typically undefined so even if it looks like they're alphabetical now you shouldn't rely on it. It could also be the case that it's the JSON serializer that's sorting the keys, but since it obtains the keys from the internal hash/map it's not possible to maintain the original order.
it's important because i need to exclude some specifics params from the string, so i delete some keys in the array before implode on '&' to rebuild a "similar" string
Apache, Apache Lucene, Apache Hadoop, Hadoop, HDFS and the yellow elephant
logo are trademarks of the
Apache Software Foundation
in the United States and/or other countries.