4. EXCEPTIONS › 4.3 Detailed Exception Descriptions › 09016: Large Data Set Not Cylinder Allocated

09016: Large Data Set Not Cylinder Allocated

    FILE:             DAA Data Set Allocation File
    SAS FILE NAME:    DETAIL.VCADAA01
    SOURCE LOCATION:  prefix.MICS.USER.SOURCE(DYVCAEXC)

    SEVERITY:         Warning       (SEVERITY='W')
    MANAGEMENT AREA:  Performance   (MGMTAREA='PERFORMANCE')

    PURPOSE:  Identifies large data sets that are not
cylinder allocated.

    RATIONALE:  Because of the implementation of data
security on DASD devices, overhead increases significantly
when multiple-track data processing is performed on data sets
that are track-allocated instead of cylinder-allocated.  For
track-allocated data sets, the system must interrupt
processing each time an attempt is made to access a different
track.  A check is made to see if the new track request falls
within the bounds of the data set.  For cylinder-allocated
data sets this check is performed only when an attempt is
made to access a different cylinder.  If the data set being
accessed is large and is track allocated, this overhead value
can become significant.

    DEFINITION:  The exception is detected when a data set's
allocation exceeds the specified value and the type of
allocation for the data set is not cylinder.

    EXCEPTION STATEMENTS:  The SAS statements identifying the
exception situation and describing the condition are stored
in the source member named in SOURCE LOCATION and are
described below:

/*---------------------------------------------------------*/
/*                                                         */
/*  09016                                                  */
/*  LARGE DATA SET NOT CYLINDER ALLOCATED                  */
/*                                                         */
/*---------------------------------------------------------*/
SPACA = spaca;
IF DAASPACA GE SPACA AND DAAALTYP NE 'CYL' THEN DO;
  EXCCODE='09016'; SEVERITY='W'; MGMTAREA='PERFORMANCE';
  EXCDESC1='LARGE DATA SET NOT CYLINDER ALLOCATED';
  EXCDESC2='VOL=' || VOLSER || ', DSN=' || DSNAME;
  LINK HIT;
END;

    THRESHOLD MODIFICATION:  The user should modify the spaca
value according to the following convention:

    spaca - The number of allocated tracks that is considered
         a large allocation.  An allocation of 1000 tracks
         would be specified as:

         SPACA = 1000;