Investigate and reduce runtime type coercion in aggregates like sum

[alamb]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.
There is casting logic in aggregates that handles coercing inputs to aggregates

https://github.com/apache/arrow-datafusion/blob/6b4bbd0/datafusion/physical-expr/src/aggregate/sum.rs#L224-L316

On the surface doing these casts in sum.rs appears to duplicates some non trivial amount of the logic in plan timecoercion -- maybe it would be possible to make this code cleaner / consolidate more of the coercion logic.

Describe the solution you'd like
Ensure types are known prior to executing the aggregate so that the input and aggregate types are known aprior

Describe alternatives you've considered
Not sure (maybe the code is needed, it just "feels" a bit wrong)

Additional context

#2405 (comment)
cc @WinkerDu

[comphead]

@alamb I can take this if you dont mind

[andygrove]

I added this to #2355

[comphead]

the same pattern used in min_max.rs.
The common approach to get the underlying value from ScalarValue is through patmatch, and that causes a lot of similar code branches to operate with underlying values supporting different datatypes.

I'm trying to figure out if sum_batch function can be reused instead of boilerplate sum. In fact sum is specific case of sum_batch

[alamb]

I wonder if we can take inspiration from @yjshen 's approach in #2375 (using row formats, etc). I don't have any specific suggestions but thought it might be interesting to look

[comphead]

@alamb sorry for delay, I stuck investigating all that datatypes.
Please check the draft #2516
So idea is to reuse sum_batch function instead of boilerplate sum.
I have to do type casting to ensure all types are the same. it might be looking a concern for the performance. Please let me know your thoughts

[alamb]

I think this I think this ticket is no longer tracking anything actionable -- I expect more performance improvements from #4973