A table with this name must already exists, which will be overwritten. When a table with this name exists, it will be overwritten. When a table with this name already exists, an exception is thrown. This means that the underlying table gets deleted when it is actually destructed. This means the underlying table does not get deleted when destructed.
Synchronization means that the size of the table is synchronized.
This may be needed when the table is filled by an external proces, e.g. the data acquisition system of a telescope. Also a flag is set telling if more rows can be expected. Synchronization means that the size of the table is synchronized. This may be needed when the table is filled by an external proces, e.g. when a data acquisition system of a telescope extends a table, another process reading that table needs to call sync now and then to update its number of rows. This is unsynchronized.