Unable to perform math on derivative

[jessetan]

This works:

> SELECT derivative(last(value)) FROM "processes_user" WHERE time > now() - 2m GROUP BY time(10s) fill(0)
name: processes_user
--------------------
time            derivative
1454927430000000000 30000
1454927440000000000 30000
1454927450000000000 30000
1454927460000000000 20000
1454927470000000000 40000
1454927480000000000 30000
1454927490000000000 20000
1454927500000000000 30000
1454927510000000000 30000
1454927520000000000 30000
1454927530000000000 -1.41353e+09
1454927540000000000 3.2173e+09

This does not work:

> SELECT derivative(last(value)) / 10  FROM "processes_user" WHERE time > now() - 2m GROUP BY time(10s) fill(0)
name: processes_user
--------------------
time
1454927440000000000 0
1454927450000000000 0
1454927460000000000 0
1454927470000000000 0
1454927480000000000 0
1454927490000000000 0
1454927500000000000 0
1454927510000000000 0
1454927520000000000 0
1454927530000000000 0
1454927540000000000 0
1454927550000000000 0

Seems similar to #4849
Observed on InfluxDB 0.9.6.1 running on Centos 7.2.

[jwilder]

This should be working now that #5196 is merged.

select derivative(value) * 10 from cpu where host='server-1' and time > '2006-01-01'

seems to work, but derivative w/ an aggregate seems to have regressed so math does not work:

select derivative(sum(value), 1s) from cpu where host='server-1' and time > '2006-01-01' group by time(1h)

[jsternberg]

I'm able to get this working, although more work is still needed on getting the fill iterator in the correct place.

> select mean(value) from cpu where time >= 1455204070s and time < 1455204090s group by time(10s)
name: cpu
---------
time                    mean
1455204070000000000     1
1455204080000000000     2

> select derivative(mean(value), 1s) from cpu where time >= 1455204070s and time < 1455204090s group by time(10s)
name: cpu
---------
time                    derivative
1455204080000000000     0.1

> select derivative(mean(value), 1s) * 10 from cpu where time >= 1455204070s and time < 1455204090s group by time(10s)
name: cpu
---------
time
1455204080000000000     1

This was tested based on two points in two adjacent intervals off of 8d7a4a9.