Nodetool cfhistograms (tablehistograms)

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% read request refers to 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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