Insert/Update operations makes queries slow?

[JF2018 (Jens Fogh)]

For future reference:

I narrowed the problem down to queries with aggregations.
The solution to my problem is mentioned here:

Aggregations slow after inserts/updates

What kind of hardware do you have? Are you using doc_values? Can you upgrade? We are now on 7.2 and so many things happened in the last 3 or 4 years... Including in the JVM itself.