You may need to extend a segment if the database object or objects assigned to the segment run out of space. sp_extendsegment adds database devices to an existing segment.
Before you can extend a segment:
The database device must be listed in sysdevices,
The database device must be available to the database you are extending, and
The segment name must exist in the current database.
The following example adds the database device pubs_dev2 to an existing segment named bigseg:
sp_extendsegment bigseg, pubs2, pubs_dev2
To extend the default segment in your database, place the word “default” in quotes:
sp_extendsegment "default", mydata, newdevice
See Reference Manual: Procedures.