SAVEPOINT name– Marks a savepoint within the current transaction, there can be multiple savepoints in a transaction.
ROLLBACK TO SAVEPOINT name
-ROLLBACK TO SAVEPOINT rolls back the current transaction to the specified savepoint, so it discards any changes and or savepoints created after the savepoint to which you are rolling back.
So in your problem, it will rollback to the point created after the insertion of 4,tera. So the value 5, omega will be discarded. So the select query will give
customername ------------- alpha beta gamma tera