What is OneMinuteRate in Write Latency?

[AI Rumman <ru...@gmail.com>]

Hi,

I am trying to calculate the Read/second and Write/Second in my Cassandra
2.1 cluster. After searching and reading, I came to know about JMX bean
"org.apache.cassandra.metrics:type=ClientRequest,scope=Write,name=Latency".
Here I can see oneMinuteRate. I have started a brand new cluster and
started collected these metrics from 0.
When I started my first record, I can see

Count = 1
> OneMinuteRate = 0.01599111...


Does it mean that my write/s is 0.0159911? Or does it mean that based on 1
minute data, my write latency is 0.01599 where Write Latency refers to the
response time for writing a record?

Please help me understand the value.

Thanks.

Re: What is OneMinuteRate in Write Latency?

[Chris Lohfink <cl...@gmail.com>]

Its from the metrics library Meter
<https://github.com/dropwizard/metrics/blob/3.1-maintenance/metrics-core/src/main/java/com/codahale/metrics/Meter.java>
object which tracks the exponentially weighted moving average
<https://en.wikipedia.org/wiki/Moving_average#Exponential_moving_average>
of events.

Chris

On Thu, Nov 2, 2017 at 12:10 PM, AI Rumman <ru...@gmail.com> wrote:

> Hi,
>
> I am trying to calculate the Read/second and Write/Second in my Cassandra
> 2.1 cluster. After searching and reading, I came to know about JMX bean
> "org.apache.cassandra.metrics:type=ClientRequest,scope=
> Write,name=Latency".
> Here I can see oneMinuteRate. I have started a brand new cluster and
> started collected these metrics from 0.
> When I started my first record, I can see
>
> Count = 1
>> OneMinuteRate = 0.01599111...
>
>
> Does it mean that my write/s is 0.0159911? Or does it mean that based on 1
> minute data, my write latency is 0.01599 where Write Latency refers to the
> response time for writing a record?
>
> Please help me understand the value.
>
> Thanks.
>
>
>
>
>

Re: What is OneMinuteRate in Write Latency?

[Nicolas Guyomar <ni...@gmail.com>]

Hi,

OneMinuteRate is the mean rate of write/s over a minute bucket of data
AFAIK.

You can find Latencies on every attributes whose name does not end with
"Rate"



On 2 November 2017 at 18:10, AI Rumman <ru...@gmail.com> wrote:

> Hi,
>
> I am trying to calculate the Read/second and Write/Second in my Cassandra
> 2.1 cluster. After searching and reading, I came to know about JMX bean
> "org.apache.cassandra.metrics:type=ClientRequest,scope=
> Write,name=Latency".
> Here I can see oneMinuteRate. I have started a brand new cluster and
> started collected these metrics from 0.
> When I started my first record, I can see
>
> Count = 1
>> OneMinuteRate = 0.01599111...
>
>
> Does it mean that my write/s is 0.0159911? Or does it mean that based on 1
> minute data, my write latency is 0.01599 where Write Latency refers to the
> response time for writing a record?
>
> Please help me understand the value.
>
> Thanks.
>
>
>
>
>