So just a summary from our environment
12GB RAM for elastic
all production settings were made like mlockall, etc.
13GB total documents in index
2 shards assigned for index
In favor of speed we removed the match for description in our query.
are there any values you need to know from kibana?
any suggestions what to investigate to find the issue
search speed, no matter what the input is under 3 mio documents ~20ms (constant)
search speed for 10 mio documents ~12000ms for the first query
afterwards (when elastic cached the search) it is around 500ms
I Hope anyone can help.