I have an index in Kibana which has two date fields (start_date, end_date) and a datasource field and some others.
I want to create a barchart visualisation which counts the documents for a time period grouped by the datasource.
However for the time period there is a complication that I want to count the documents where either the start_date or the end_date fits into the period.
So how can I do that? Can I do somehow an "or" date histogram for two fields? (and add a terms subbucket for the datasource field)
I'm using Kibana 5.5