|Range of values||
READ_ONLY_OPEN_DELAYED determines when datafiles in read-only tablespaces are accessed.
The datafiles are accessed for the first time only when an attempt is made to read data stored within them.
The datafiles are accessed at database open time.
You can use this parameter to speed up some operations (primarily opening the database) for very large databases when substantial portions of the database are stored in read-only tablespaces. Consider setting this parameter to
true for such databases, especially if portions of the read-only data are stored on slow-access devices or hierarchical storage.
See Also:Oracle Database Administrator's Guide for information on the consequences of delaying access of datafiles in read-only tablespaces