Edit: In case anyone is wondering why I did that, I wanted a simple visualization of ping-location results for thousands of IPv4 from several hundred ping-probe locations. So that meant aggregating (getting minimum rtt for) millions of observations, and displaying min(rtt) in a IPv4 by probe location cross-tab. MySQL did a great job at the aggregation, but choked (as in, errored out) with several hundred numeric columns. Even if I converted them all to SMALLINT.