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cfhistograms <keyspace> <cfname>- This command provides statistics about a table, including number of SSTables, read/write latency, partition size and column count. cfhistograms covers all operations since the last time you ran the nodetool cfhistograms command. Note that this command can also be used for tablehistograms. This command uses the following syntax:
nodetool cfhistograms keyspaces cfname
For example: to get statistics about the standard1 table in the keyspaces1 keyspace, use this command:
nodetool cfhistograms keyspaces1 standard1
Percentile |
SSTables value |
Write Latency |
Read Latency |
Partition Size |
Cell Count |
|---|---|---|---|---|---|
50% |
10.00 |
42.00 |
20.00 |
210 |
5 |
75% |
20.00 |
42.00 |
24.00 |
280 |
5 |
95% |
25.00 |
42.00 |
42.00 |
300 |
5 |
98% |
25.00 |
42.00 |
770.00 |
310 |
5 |
99% |
26.00 |
42.00 |
2759.00 |
310 |
5 |
Min |
00.00 |
36.00 |
7.00 |
210 |
5 |
Max |
26.00 |
42.00 |
35425.00 |
310 |
5 |
In this example, 95% of the write latency measurements were 42 microseconds (μs) or less, 95% of the read latencies were 42 μs or less, and 95% of the partitions are 300 bytes or less. The SSTables column means that the 95% of all single-key read requests touched at most 25 SSTables.
Parameter |
Description |
|---|---|
SSTables |
Distribution number of sstable per read |
Write Latency |
Distribution of the Write Latency |
Read Latency |
Distribution of the Read Latency |
Partition Size |
Estimated row size |
Cell Count |
Estimated column count |
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