nodetool cfhistograms 

Provides statistics about a table that could be used to plot a frequency function.

Provides statistics about a table that could be used to plot a frequency function.

Synopsis 

$ nodetool <options> cfhistograms -- <keyspace> <table>
Options
Short Long Description
-h --host Hostname or IP address
-p --port Port number
-pwf --password-file Password file path
-pw --password Password
-u --username User name
-- Separates an option from an argument that could be mistaken for a option.
Other options are:
  • keyspace is the name of a keyspace.
  • table is the name of a table.

Description 

The nodetool cfhistograms command provides statistics about a table, including read/write latency, partition size, column count, and number of SSTables. The report is incremental, not cumulative. It covers all operations since the last time you ran nodetool cfhistograms in this session. The use of the metrics-core library in Cassandra 2.1 makes the output more informative and easier to understand.

Example 

For example, to get statistics about the libout table in the libdata keyspace on Linux, use this command:

$ install_location/bin/nodetool cfhistograms libdata libout

Output is:

libdata/libout histograms
Percentile  SSTables     Write Latency      Read Latency    Partition Size        Cell Count
                              (micros)          (micros)           (bytes)                  
50%             0.00             39.50             36.00              1597                42
75%             0.00             49.00             55.00              1597                42
95%             0.00             95.00             82.00              8239               258
98%             0.00            126.84            110.42             17084               446
99%             0.00            155.13            123.71             24601               770
Min             0.00              3.00              3.00              1110                36
Max             0.00          50772.00            314.00            126934              3973

The output shows the percentile rank of read and write latency values, the partition size, and the cell count for the table.