SAS(R) 9.1.3 Companion for z/OS

334 RELEASE Procedure Chapter 16
provided a secondary space allocation is given for the data set in the control language
or SAS statement, and provided all free space on the volume is not subsequently
allocated to other data sets.
PROC RELEASE Statement
PROC RELEASE DDNAME=file-specification ;
DDNAME=file-specification
specifies either a physical file name (enclosed in quotation marks), a fileref that
refers to the physical file from which to release unused space, or a libref referring
to an unopened SAS data library. If multiple librefs are currently assigned to a
SAS data library, you must specify the libref which was assigned first. DDNAME=
is required.
options
specify how much unused space to keep or release, and specify the unit boundary
on which the data set should end.
TOTAL=number | TRACKS=number
specifies the total number of tracks that the data set should contain after
unused space is released, that is, after PROC RELEASE has executed. For
example, the following statement releases all but ten tracks for the data set
that is referenced by the fileref SURVEY:
proc release ddname=survey total=10;
The procedure calculates the amount of space to release as follows:
amount of space allocated − (value of TOTAL= option) = amount of unused
space released
If the value that you specify is smaller than the amount of used space in
the data set, then SAS releases only the unused space at the end of the data
set.
UNUSED=number
specifies the number of tracks of unused space that the data set should
contain after PROC RELEASE has executed. The procedure calculates the
amount of unused space to release as follows:
amount of space allocated − (used space + value of UNUSED= option) =
amount of unused space released
If the value that you specify is greater than the amount of unused space at
the end of the data set, then no space is released at the end of the data set.
RELEASE=number
specifies how many tracks of unused space to release. If the value that you
specify is greater than the amount of unused space at the end of the data set,
then SAS releases all the unused space at the end of the data set.
EXTENTS | EXTENT | EX
tells SAS to release only the space that is allocated to completely unused
secondary extents. After the procedure releases unused space from the data
set, the size of the data set is the sum of the primary extent plus all used
secondary extents.
If you do not specify one of these options in the PROC RELEASE statement,
then all unused space at the end of the data set is released.