# Serial difference of timestamps between documents
**URL:** https://discuss.elastic.co/t/serial-difference-of-timestamps-between-documents/173318
**Category:** Elasticsearch
**Created:** [March 21, 2019, 1:37pm UTC](https://discuss.elastic.co/t/serial-difference-of-timestamps-between-documents/173318 "2019-03-21T13:37:44Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@nandrik](https://discuss.elastic.co/u/nandrik)
#### Post date: [March 21, 2019, 1:37pm UTC](https://discuss.elastic.co/t/serial-difference-of-timestamps-between-documents/173318/1 "2019-03-21T13:37:44Z")
I'm trying to calculate the time difference between two specific types of messages coming out of Logstash. I've read the post: [Calculate the time difference between consecutive documents](https://discuss.elastic.co/t/calculate-the-time-difference-between-consecutive-documents/128282) and I've successfully implemented a ruby script in my logstash filter configuration that achieves that.
However, I wonder if all of this could have been achieved with an aggregation query within Kibana.
Which is the most efficient way of doing this?
By adding to Logstash's filter configuration, I have the feeling that I'm doing something wrong, adding meta information at that time.
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [April 18, 2019, 1:37pm UTC](https://discuss.elastic.co/t/serial-difference-of-timestamps-between-documents/173318/2 "2019-04-18T13:37:50Z")
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