How to read the cassandra nodetool histograms perc

问题:

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

回答1:

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).