What are 99 percentile and 95 percentile?

[schsnnice]

What are 99th percentile and 95 percentile?

Where are these values of percentile come from?

What do these percentile will tell developer?

Thank you

[deboraelkin]

Percentiles are standard concept in statistics. You can find more about them in https://en.wikipedia.org/wiki/Percentile

The 50th percentile is so widely used that it has its own name: Median.

In the context of these reports (eg: Response Time) you should interpret

99th percentile = 850ms

as "99% percent of the requests had a response time of 850ms or less"

[schsnnice]

Why does 99th equal 850 ms?

[schsnnice]

It mean 99 th percentile is point of data that is maximum value?

[deboraelkin]

Please read the definition of percentiles. It means what I just said. 99% of all requests had a processing time less than or equal to the value shown as 99th percentile.

(And 850ms was just an example. Your report shows that the values should be around there for one of the periods. Hover over the report and it'll show the actual value for a given period)