Left join using two table but the right table not showing any value in result

InfluxDB 2
, ,
1

Hello,
I am new to InfluxDB 2.0, I have collected disk used/free data from my linux and i am trying to get estimation of days left for the disk to be full.

i have created this query to get daily growth of my disk and get the max value for the last seven days:

growth = from(bucket: "virtual_machines")
  |> range(start: -7d)
  |> filter(fn: (r) => r["_measurement"] == "disk")
  |> filter(fn: (r) => r["_field"] == "used")
  |> filter(fn: (r) => r["host"] == "app_v11")
  |> filter(fn: (r) => r["path"] == "/")
  |> aggregateWindow(every: 1d, fn: last, createEmpty: false)
  |> drop(columns: ["_measurement", "_field", "_start", "_stop", "_time", "fstype","mode","device"])
  |> difference()
  |> max()
  |> toFloat()
  |> yield(name: "grow")

then next is getting the last saved total/used/free disk using this query:

data = from(bucket: "virtual_machines")
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => r["_measurement"] == "disk")
  |> filter(fn: (r) => r["host"] == "app_v11")
  |> filter(fn: (r) => r["path"] == "/")
  |> filter(fn: (r) => r["_field"] == "used"  or r["_field"] == "total" or r["_field"] == "free")
  |> last()
  |> toFloat()
  |> pivot(rowKey:["_time"], columnKey: ["_field"], valueColumn: "_value")
  |> drop(columns: ["_measurement", "_field", "_start", "_stop", "_time", "fstype","mode","device"])
  |> group(columns: ["_measurement"], mode:"by")
  |> yield(name:"data")

both result seems correct when i checked to my linux server.

but when i tried to use growth value (first table) to left join into data table, the result is empty, the query i use is:

join.left(
  left: data,
  right: growth,
  on: (l, r) => (l.host == r.host and l.path == r.path),
  as: (l, r) => ({l with growth_value: r._value}),
)
  |> yield(name:"data")

result for all three query:

image
image2338×679 62.6 KB

please help me for the correct query for this, and what is the query to calculate free and growth_value measurement to get estimation days left for disk to be full. i think it should be free / growth_value is good enough to get days left. how to translate this to flux query

Thank you!

2

You can use map function to perform calculations in flux:

import "array"
import "join"

data = array.from(rows:[{free : 51552239616.0, host :  "app_v11", label : "ubuntu--vg--ubuntu--lv", path : "/", total : 265080094720.0, used : 202495074304.0}])
yield(tables : data, name : "data")

growth = array.from(rows:[{_value : 333168640.0, host :  "app_v11", label : "ubuntu--vg--ubuntu--lv", path : "/"}])
yield(tables : growth, name : "growth")

join.left(
  left: data,
  right: growth,
  on: (l, r) => (l.host == r.host and l.path == r.path),
  as: (l, r) => ({l with growth_value: r._value}),
)
|> map(fn: (r) => ({r with days_left: int( v: r.free / r.growth_value)}))
|> yield(name:"join")

зображення
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