Derivation returns -9999

[alexheilig]

Steps to Reproduce

When running this derivation, it just inputs -9999 instead of the sum of the values from the two datastreams. https://hydroserver.waterrights.utah.gov/orchestration/aggregation/details/derivation?workspace_id=019eb774-8b9d-74fe-b6be-b33ab48cfabe&site_id=019f4db1-366b-77f8-9e0f-98acf09bb17a&task_id=019f6654-3869-77e9-b18b-94c438ccc40b

Expected Behavior

It should have the correct value, not an error value.

Actual Behavior

It returns -9999 as the sum.

Any additional comments?

No response

[kjlippold]

It looks like this is being caused by a bug in how the output datastream time spacing is being calculated. We have two options.

1. Fix the bug by adding a output interval anchor setting.
2. Remove the output interval setting and require that all input datastreams exactly align on their timestamps.

I'd prefer option 2 if you don't anticipate needing to perform calculations on datastreams whose timestamps don't align. Option 2 would also let us drop the distinction between "expression" and "derivation" entirely, we'd just have one "expression" type that can use one or more input datastreams in an expression.

@alexheilig @amabdallah Let me know what your preference is or if you have any questions.

[alexheilig]

@kjlippold We agree to go ahead with option 2. Thanks