Rule Definition
The internal COBOL sort function is known as being inefficient on zOS environment (this is the same problem with the merge function). It is often recommended to use external sort tools to process files which can contain a large number of records. Usually required in batch processing the sort tools are generally called by a previous step in the JCL running the program. Using the internal Cobol sort function rather than external sort tool can affect perceptibly the performance of applications in terms of data manipulation.

Remediation
Remove all unnecessary SORT action and replace them by external SORT.

Violation Code Sample

IDENTIFICATION DIVISION.
       PROGRAM-ID. COBFUNC1.
...
           SORT SORT-FILE
            ON ASCENDING KEY WORKDEPT
                USING EMPDATA
                GIVING OUTFILE
...

Fixed Code Sample

//SORGDG  EXEC PGM=SORT
//SYSOUT     DD  SYSOUT=*
//SORTIN      DD  DISP=SHR,DSN=MYTELCO.COBDYNSQ.GDG(0)
//SORTOUT  DD  DSN=MYTELCO.SORTOUT,DISP=(NEW,PASS,DELETE),
//                             DCB=(LRECL=80,BLKSIZE=0,DSORG=PS,RECFM=FB),
//                             SPACE=(CYL,(5,5) 
//SYSIN          DD  *
  SORT FIELDS=(1,6,CH,A)
  SUM FIELDS=NONE
/*
//COBOL1  EXEC PGM=COBFUNC1
//STEPLIB  DD  DSN=APPCAST.SOURCE.LOADLIB
//SORT01   DD  DSN=MYTELCO.SORTOUT
//VSAMF      DD  DSN=MYTELCO.EMPDATA.VSAM,DISP=SHR  
//SEQTF      DD  DSN=MYTELCO.COBFUNC1.SEQ1,DISP=(NEW,CATLG,DELETE),
//                           DCB=(LRECL=120,BLKSIZE=0,DSORG=PS,RECFM=FB)
//                           SPACE=(TRK,(5,5))