I read that savepoints in Oracle global temporary tables delete all the data, but when I tested on Oracle 11g they worked like heap tables. Can anybody explain?

```
insert into table_1 values('one');
insert into table_1 values('two');
savepoint f1;
insert into table_1 values('three');
insert into table_1 values('four');

rollback to f1;

-- the records in table are 2 records just like heap tables, but I read that
-- savepoints in GTT truncates all the data

```