> By definition, the changes will also be small Even if all you're updating is an int32 column from 1 to 2, the RDBMS is still writing much more data than 4 by

> By definition, the changes will also be small Even if all you're updating is an int32 column from 1 to 2, the RDBMS is still writing much more data than 4 bytes. At a minimum it's making a copy of the full page the data is in prior to the update (so 8k for pg, 16k for mysql) and usually multiples of that (mysql writes both before/after).