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From Narendra Sharma <>
Subject Re: Understanding cfhistogram output
Date Fri, 01 Apr 2011 19:48:23 GMT
There are 6 columns in the output.
*- Offset*
>> This is the buckets. Same as values on X-axis in a graph. The unit is
determined based on the other columns.
*- SSTables*
>> This represents the number of sstables accessed per read. For eg if a
read operation involved accessing 3 sstables then you will find a +ve
against offset 3. Most of the times the values will be against lower offset
*- Write Latency *
>> This represents the number of operations and their latency (micro
seconds). If 100 operations took say 5 ms then you will find an entry
against offset 5. This shows the distribution of number of operations across
a range of latency
*- Read Latency*
>> Similar to write latency. The unit is microseconds.
*- Row Size*
>> This represents the number of rows with given size. How many rows of
given size exist.
*- Column Count*
>> Similar to row size. This represents the column count. How many rows with
given number of columns exist.

1. Note that these are estimates and not exact numbers.
2. The values ofcourse change over period of time.

On Fri, Apr 1, 2011 at 10:21 AM, Anurag Gujral <>wrote:

> Hi All,
>             I ran nodetool with cfhistogram I dont fully understand the
> output.Can someone please shower some light on it.
> Thanks
> Anurag

Narendra Sharma
Solution Architect

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