Imagine that we have to analyse a big amount of users data. At this article there will be a data in CSV format.
For example, we can have a data in next format:
First column is user’s phone number, second column is date in YYMMDD format, third is a city, and the last one is a billed amount for this phone number for this day.
It would be great to get some aggregated info by data/cities/etc. To perform this aggregations for a huge amount of data we can use ELK-stack.