Loads bypass a few steps that typically a query would go through (a query goes through plan generation, optimization, and transaction management). Loads are done in terms of “sets” and this set is based on underlying table structure (thus loads for two different tables are different as their sets are based on table structures). Data is processed to check the format and distribution of records calculated very quickly (in one step), fills into the ‘set’ structure, and writes to the storage structure. Storage also performs space availability and other admin tasks, all these operations go pretty quick (think of them as UNIX named pipes that streams data, and SPU stores these records).
