READ_ONLY_OPEN_DELAYED

READ_ONLY_OPEN_DELAYED determines when datafiles in read-only tablespaces are accessed.

Values:

• true

  The datafiles are accessed for the first time only when an attempt is made to read data stored within them.

• false

  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.