Library Version 11.2.5.2
void resize(size_type n, T t=T())
Resize this container to specified size n, insert values t if need to enlarge the container.
This function supports auto-commit.
The value to insert when enlarging the container.
The number of elements in this container after the call.
http://www.cplusplus.com/reference/stl/vector/resize/
db_vector