[blt]

Wondering why they chose row-major storage. I think it's far more common to only care about a subset of columns than a subset of rows.

[nostrademons]

FTA:

"First, we knew we only cared about row-by-row access over the entire file; we do not need things like random row or column reads."

It sounds like they don't care about subsets of either columns or rows, and are looking to optimize table size and time for full table scans.