As a user, some time back I was able to generate Response Time graphs (Average and pct95) from apache logs. X axis was time, In Y axis there were 2 lines, pct95 and average. So I would assume I know how to do them.
Now, as a sysadmin, I just setup ELK system and I'm trying to do simmilar graphs. So I chose to create a "Line" Visualization. In there for X-axis I chose Date Histogram, no problem. But in Y axis, I chose: Aggregation = Average, However for Field value, I cannot pickup any field from the Apache logs, they do not show in the list. All I can chose is "offset" which doesn't help.
The question here is, what is the configuration I need to do so that in the Filed choice of the Line visualizations I can see and chose say response_time coming from apache logs?