How to read the cassandra nodetool histograms percentile and other coulmns?
Percentile SSTables Write Latency Read Latency Partition Size Cell Count
(micros) (micros) (bytes)
50% 1.00 14.24 4055.27 149 2
75% 35.00 17.08 17436.92 149 2
95% 35.00 24.60 74975.55 642 2
98% 86.00 35.43 129557.75 770 2
99% 103.00 51.01 186563.16 770 2
Min 0.00 2.76 51.01 104 2
Max 124.00 36904729.27 12359319.16 924 2
They show the distribution of the metrics. For example, in your data the write latency for 95% of the requests were 24.60 microseconds or less. 95% of the partitions are 642 bytes or less with 2 cells. The SStables column is how many sstables are touched on a read, so 95% or read requests are looking at 35 sstables (this is fairly high).
来源：https://stackoverflow.com/questions/34688069/how-to-read-the-cassandra-nodetool-histograms-percentile-and-other-columns