關於graphite的幾個function

scale

至關於乘法.好比15,scale(10)以後是150,sacle(10)以後是-150

Takes one metric or a wildcard seriesList followed by a constant, and multiplies the datapoint by the constant provided at each point.

scaleToSeconds

好比9,scaleToSeconds(60)=54(好比默認是10s採樣一次)

Takes one metric or a wildcard seriesList and returns 「value per seconds」 where seconds is a last argument to this functions.Useful in conjunction with derivative or integral function if you want to normalize its result to a known resolution for arbitrary retentions

derivative

「導數」的概念，求變化值，不根據時間規範化，好比原來是56，後來是9，那麼變化就是-47

This is the opposite of the integral function. This is useful for taking a running total metric and calculating the delta between subsequent data points.This function does not normalize for periods of time, as a true derivative would.

nonNegativeDerivative

非負求導數，好比原來是56，後來是9，那麼差值爲-47，爲負數會被忽略掉。可是能夠給nonNegativeDerivative傳參數，好比nonNegativeDerivative(100)就至關於-47+100+1=54

Same as the derivative function above, but ignores datapoints that trend down. Useful for counters that increase for a long time, then wrap or reset. (Such as if a network interface is destroyed and recreated by unloading and re-loading a kernel module, common with USB / WiFi cards.)

integral

「積分」的概念，至關於不斷累加值

This will show the sum over time, sort of like a continuous addition function. Useful for finding totals or trends in metrics that are collected per minute.

persecond

至關於scaleToSeconds(nonNegativeDerivative(metric),1)

NonNegativeDerivative adjusted for the series time interval This is useful for taking a running total metric and showing how many requests per second were handled.

該操做對於累積的counter metric很是有用，能夠算出每秒的變更值，好比

加上persecond以後就能夠把累積的count值轉換爲變化的曲線

doc

• functions

• What does integrate() do? Or, what's the inverse of deriv()?

• How to do Graphite Derivatives correctly