I am using _stats API for collecting cluster metrics.
I cannot find enough information on details of each metrics, and so having trouble to use those on a monitoring server.
I assumed certain fields are accumulative (e.g. query_total, query_time_in_millis) and didn't concern about those values decreasing. As I was applying derivatives to those fields, I was getting minus values and couldn't interpret further. In which case does query_time_millis reset? or decrease?
Is there an alternative field to calculate request latencies?
I was using query_total divided by query_time_in_millis, but couldn't resolve the case when query_time_in_millis decreases.
What does merge_docs indicate?
If there is a document or reference explaining details on each stat metrics, it would be a great help.