query performance varies very much on different intervals (topN, granularity=all)
interval of 2 days ago to current: > 1 seconds
interval of 2 years ago to current: about 10 seconds
It is apparently that the historical nodes are loading segments: from deep-storage to disk / from disk to memory repeatedly.
the data retention period is 2-years.
no query cache allowed, for data consistency.
What is the general guide to tune historical nodes so that to gain performance?