Does Order by Formula use the field index?

so... does the order by formula command make use of the index on an index field?

quick answer is: it is supposed to...


here are some tests in 4d v11.3 on 1 million records to show it...

ORDER BY (non-indexed field): 7095 ms
ORDER BY (indexed field): 294 ms

ORDER BY FORMULA (non-indexed field): 19720 ms
ORDER BY FORMULA (indexed field): 19743 ms

QUERY BY FORMULA (non-indexed field): 22498 ms
QUERY BY FORMULA (indexed field): 22419 ms

it's getting faster :m)