feat: support decimal for math functions: log #17140
Description
Is your feature request related to a problem or challenge?
Math functions in datafusion-functions do not support Decimal128, Decimal256 directly, casting the input to floats. Since #14612 is near, it's reasonable to add first-class support for decimals.
Describe the solution you'd like
In a linked PR, I decided to start from the explicitly defined log function in math/log.rs. It's not trivial because of the optional argument with base and combinations.
Later, it'd be worth introducing a similar support to the make_math_unary_udf! macro – a subject of future work.
Describe alternatives you've considered
Not handling Decimals explicitly decreases precision and disallows using math on large decimals.
Additional context
No response