What do you want to know... SQL support is excellent including creating arrays during GROUP BY, unnesting them in SELECT, converting to strings and passing to/from user defined functions in JS/python/etc.

Arrays scale as you'd expect, i.e. even if it's allowed, I don't recommend 1MM values in an array because some/many of the aforementioned features aren't tested to scale. AFAIK array operations are single threaded and not vectorized or parallelized.