Fill function not working

[dan-hughes]

I have a measurement being updated every 9 minutes. I have tried using the fill function to replicate the IFQL fill(previous) behavior but it doesn't seem create the data specified by the window.

Expected: start and stop should be for every minute in the range (not just a minute when there is a value stored) with the value using the previous value if missing.

Flux script tested on 2.0 Alpha1:

from(bucket: "test")
  |> range(start: -1d )
  |> filter({filter removed})
  |> window(every: 1m)
  |> fill(usePrevious:true)
  |> last()

[reichunter1656]

I have a scenario like this.

I want to sum the points of both (or more) symbols each 20 seconds (or any other interval). Below are the raw points stored in a single measurement grouped by symbol. The second query is the one I came up with to calculate sum(sum() gives me same issue as well).

select last(bs) from table where symbol=<1> or symbol=<2> and time>=1592833320000ms and time<=1592833440000ms group by symbol, time(20s)

name: table
tags: symbol=<1>
time last

2020-06-22T13:42:00Z 84
2020-06-22T13:42:20Z 94
2020-06-22T13:42:40Z 95
2020-06-22T13:43:00Z 87
2020-06-22T13:43:20Z 76
2020-06-22T13:43:40Z 77
2020-06-22T13:44:00Z

name: table
tags: symbol=<2>
time last

2020-06-22T13:42:00Z 288
2020-06-22T13:42:20Z 286
2020-06-22T13:42:40Z 282
2020-06-22T13:43:00Z
2020-06-22T13:43:20Z 312
2020-06-22T13:43:40Z 330
2020-06-22T13:44:00Z

check out how 13:43:00Z has no value; fill(previous) works if this was a single query and will copy over 282 from above. But when I group by both symbols the value will just be 0 for this time stamp and the mean value will go way down at this time.

select mean(lbs) from (select last(bs) as lbs from table where symbol=<1> or symbol=<2> and time>=1592833320000ms and time<=1592833440000ms group by symbol, time(20s)) group by time(20s) limit 10
name: table
time mean

2020-06-22T13:42:00Z 372
2020-06-22T13:42:20Z 380
2020-06-22T13:42:40Z 377
2020-06-22T13:43:00Z 87
2020-06-22T13:43:20Z 388
2020-06-22T13:43:40Z 407
2020-06-22T13:44:00Z

Having a fill(previous) in the inner query does not work. Question is, how can I take the last value of the missing groups into the mean calculation.

I even tried using FLUX with the following query, but still see same issue.
from(bucket: "db/rp")
|> range($range)
|> filter(fn: (r) => r._measurement == "table" and (r._field == "") and r.symbol=~ /^[[Symbol]]$/)
|> aggregateWindow(every: 1m, createEmpty: true, fn:sum) |> fill(usePrevious: true)
|> group(columns: ["_time", "_field"]) |> sum() |> group(columns: ["_measurement", "_field"])

Let me know if there is any workaround for this issue. Thanks!

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