How a Sort's order is lost before it is used. nodeId is the node that
loses it: for a full loss, the first whose rows hold none of the Sort's
keys; for a partial one, the first that loses some. A partial loss also
gives each node that removes some of the Sort's columns (removals), and
the columns a node keeps but no longer orders by, as they came after a
removed one (cutColumns), each as the Sort names them, in its order.
How a Sort's order is lost before it is used.
nodeIdis the node that loses it: for a full loss, the first whose rows hold none of the Sort's keys; for a partial one, the first that loses some. A partial loss also gives each node that removes some of the Sort's columns (removals), and the columns a node keeps but no longer orders by, as they came after a removed one (cutColumns), each as the Sort names them, in its order.