advanced cumulative_sum() syntax fails in combination with derivative()

[gsauthof]

Bug report

System info: Influxdb 1.2.2, RHEL 6

Steps to reproduce:

select derivative(cumulative_sum(sum(events)), 1m) from measurement
    where $timeFilter group by $interval

Expected behavior: Same result as with this select statement that uses a sub-query instead of nesting:

select derivative(x, 1m) from (select cumulative_sum(sum(events)) as x
    from measurement
    where $timeFilter group by $interval)

Actual behavior:

ERR: error parsing query: expected field argument in cumulative_sum()

Additional info:

background/use-case: the events could originate from a - say - process manager that reports at irregular intervals how many processes it has started since the last time. The objective is then to get a start-rate normalized over a certain interval - here 1 minute - with varying resolution (here $interval) for varying periods (here $timeFilter).

[Tomcat-Engineering]

Function nesting basically not supported except for a few combinations.

The documentation is not very clear on what is legal, but in general if a combination isn't mentioned in a documentation example it will probably be rejected by the query parser - though it is always worth trying things just in case they work!

I raised a more general issue for this (#7438) but the conclusion seemed to be that we should use subqueries rather than nested function calls.

[jsternberg]

I believe the primary problem here is that cumulative_sum() does not support function nesting. I'm going to close this since using a subquery is possible instead. It doesn't appear to be a bug.

Thanks.