使用Flux创建直方图
本页介绍了InfluxDB OSS的早期版本。 InfluxDB OSS v2 是最新稳定版本。 查看等效的 InfluxDB v2 文档： 使用Flux创建直方图。
直方图可以提供关于您的数据分布的有价值见解。本指南介绍了如何使用Flux的 histogram() 函数将数据转换为 累积直方图。
histogram() 函数
histogram() 函数 通过对一系列“桶”中的数据频率进行计数来近似数据集的累积分布。一个 桶 仅仅是一个数据点所在的范围。所有小于或等于边界的点都被计入了该桶。在直方图输出中，添加了一个表示每个桶的边界的列（le）。桶计数是累积的。
from(bucket:"telegraf/autogen")
|> range(start: -5m)
|> filter(fn: (r) =>
r._measurement == "mem" and
r._field == "used_percent"
)
|> histogram(bins: [0.0, 10.0, 20.0, 30.0])
histogram函数输出的值代表随时间聚合的数据点。由于值不代表单一时间点，输出表中没有_time列。
桶辅助函数
Flux提供了两个辅助函数用于生成直方图桶。每个函数都生成并输出一个浮点数数组，该数组设计用于在 histogram() 函数的 bins 参数中使用。
linearBins()
linearBins() 函数 生成一系列线性分隔的浮点数。
linearBins(start: 0.0, width: 10.0, count: 10)
// Generated list: [0, 10, 20, 30, 40, 50, 60, 70, 80, 90, +Inf]
logarithmicBins()
logarithmicBins() 函数 生成一系列指数分隔的浮点数。
logarithmicBins(start: 1.0, factor: 2.0, count: 10, infinity: true)
// Generated list: [1, 2, 4, 8, 16, 32, 64, 128, 256, 512, +Inf]
示例
使用线性桶生成直方图
from(bucket:"telegraf/autogen")
|> range(start: -5m)
|> filter(fn: (r) =>
r._measurement == "mem" and
r._field == "used_percent"
)
|> histogram(
bins: linearBins(
start:65.5,
width: 0.5,
count: 20,
infinity:false
)
)
输出表
Table: keys: [_start, _stop, _field, _measurement, host]
_start:time _stop:time _field:string _measurement:string host:string le:float _value:float
------------------------------ ------------------------------ ---------------------- ---------------------- ------------------------ ---------------------------- ----------------------------
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 65.5 5
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 66 6
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 66.5 8
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 67 9
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 67.5 9
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 68 10
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 68.5 12
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 69 12
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 69.5 15
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 70 23
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 70.5 30
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 71 30
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 71.5 30
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 72 30
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 72.5 30
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 73 30
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 73.5 30
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 74 30
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 74.5 30
2018-11-07T22:19:58.423658000Z 2018-11-07T22:24:58.423658000Z used_percent mem Scotts-MacBook-Pro.local 75 30
使用对数桶生成直方图
from(bucket:"telegraf/autogen")
|> range(start: -5m)
|> filter(fn: (r) =>
r._measurement == "mem" and
r._field == "used_percent"
)
|> histogram(
bins: logarithmicBins(
start:0.5,
factor: 2.0,
count: 10,
infinity:false
)
)
输出表
Table: keys: [_start, _stop, _field, _measurement, host]
_start:time _stop:time _field:string _measurement:string host:string le:float _value:float
------------------------------ ------------------------------ ---------------------- ---------------------- ------------------------ ---------------------------- ----------------------------
2018-11-07T22:23:36.860664000Z 2018-11-07T22:28:36.860664000Z used_percent mem Scotts-MacBook-Pro.local 0.5 0
2018-11-07T22:23:36.860664000Z 2018-11-07T22:28:36.860664000Z used_percent mem Scotts-MacBook-Pro.local 1 0
2018-11-07T22:23:36.860664000Z 2018-11-07T22:28:36.860664000Z used_percent mem Scotts-MacBook-Pro.local 2 0
2018-11-07T22:23:36.860664000Z 2018-11-07T22:28:36.860664000Z used_percent mem Scotts-MacBook-Pro.local 4 0
2018-11-07T22:23:36.860664000Z 2018-11-07T22:28:36.860664000Z used_percent mem Scotts-MacBook-Pro.local 8 0
2018-11-07T22:23:36.860664000Z 2018-11-07T22:28:36.860664000Z used_percent mem Scotts-MacBook-Pro.local 16 0
2018-11-07T22:23:36.860664000Z 2018-11-07T22:28:36.860664000Z used_percent mem Scotts-MacBook-Pro.local 32 0
2018-11-07T22:23:36.860664000Z 2018-11-07T22:28:36.860664000Z used_percent mem Scotts-MacBook-Pro.local 64 2
2018-11-07T22:23:36.860664000Z 2018-11-07T22:28:36.860664000Z used_percent mem Scotts-MacBook-Pro.local 128 30
2018-11-07T22:23:36.860664000Z 2018-11-07T22:28:36.860664000Z used_percent mem Scotts-MacBook-Pro.local 256 30
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