Because smallserial, serial and
- bigserial are implemented usings sequences, there may
+ bigserial are implemented using sequences, there may
be "holes" or gaps in the sequence of values which appears in the
- column, even if no rows are ever deleted. This is a value allocated
+ column, even if no rows are ever deleted. A value allocated
from the sequence is still "used up" even if a row containing that
value is never successfully inserted into the table column. This
may happen, for example, if the inserting transaction rolls back.