mysql - Creating rows vs. columns performance

Question

I built an analytics engine that pulls 50-100 rows of raw data from my database (lets call it raw_table), runs a bunch statistical measurements on it in PHP and

Answer 1

You have a 140 data items to return every time, each of type double.

It makes no practical difference whether this is 1x140 or 20x7 or 7x20 or 4x35 etc. It could be infinitesimally quicker for one shape of course but then have you considered the extra complexity in the PHP code to deal with a different shape.

Do you have a verified bottleneck, or is this just random premature optimisation?