Lock Release

Sometimes a SAS data set can get locked such that you can read it but no longer update it. Of course, it is best to attempt to find out who is holding the lock and on simple systems you can use things like the UNIX fuser command to find the process id and then kill that process. However, things are not that easy on a SAS grid environment with many possible servers.

One way to free up the file is to move the data set (and its index file) to another folder then move it back to release the pointer. The below macro makes it very easy to accomplish those actions. The only required argument is the data set name (dsn). The libref is used to obtain the path via the pathname function. A unique sub-folder is created by using the UUIDGEN() function.

The advantage of this technique versus an X command is that it does not rely on the XCMD setting and provides a return code to verify things behaved as expected. You can read thru the below code to see how this is all handled. The %getattr() macro is simply a wrapper of the ATTRN() function. The source code for the %movefile(), %copyfile() and deletefile() macros can be found here.

/*******************************************************************************
     Program: lockrelease.sas
      Author: Tom Bellmer
     Created: 04/25/2020 @ 8:17:58 PM
 SAS Version: SAS 9.4 (TS1M3)
          OS: LIN X64
     Purpose: Moves data set (and index) to sub-folder then back.  This is 
              needed as data sets get locked and this releases it
       Usage: %let x = %lockrelease(dsn = mylib.mymem);
       Notes: Better to see if anyone has file locked but if no other option
              then use this.  It works by changing the file pointer.  

                             Modifications in descending order
FL-YYYYMMDD                             Description
----------- --------------------------------------------------------------------

         1    1    2    2    3    3    4    4    5    5    6    6    7    7    8
....5....0....5....0....5....0....5....0....5....0....5....0....5....0....5....0
*******************************************************************************/

%macro lockrelease(dsn = );
  %local
    libref 
    path
    memname
    guid
    starttime
    temppath
    indexed
    rc
  ;
  %let starttime = %sysfunc(datetime());

  %if not %sysfunc(exist(&dsn)) %then %do;
    %put %str(E)RROR: The dsn: &dsn does not exist;
    %return;
  %end;

  %if not %index(&dsn, .) %then %do;
    %put %str(E)RROR: This only supports two level (permanent) data sets;
    %return;
  %end;

  %let libref   = %scan(&dsn, 1, .);
  %let memname  = %scan(&dsn, 2, .);
  %let guid     = %sysfunc(uuidgen());
  %let path     = %sysfunc(pathname(&libref));
  %let temppath = %sysfunc(dcreate(&guid, &path));

  %if %isblank(&temppath) %then %do;
    %put %str(E)RROR: Unable to create sub-folder.;
    %return;
  %end;
  %else %do;
    %let indexed = %getattr(dsn = &dsn, attr = isindex);

    /********   Move dataset (and index) to sub-folder   *********************/
    %let rc = %movefile(infile = &path/&memname..sas7bdat
                 , outfile = &temppath/&memname..sas7bdat);
    %if &indexed and &rc %then %do;
      %let rc = %movefile(infile = &path/&memname..sas7bndx
                 , outfile = &temppath/&memname..sas7bndx);
    %end; 

    /*****   Move dataset (and index) from sub-folder back to original   *****/
    %if &rc %then %do;
      %let rc = %movefile(infile = &temppath/&memname..sas7bdat
                          , outfile = &path/&memname..sas7bdat);
      %if &indexed and &rc %then %do;
        %let rc = %movefile(infile = &temppath/&memname..sas7bndx
                    , outfile = &path/&memname..sas7bndx);
      %end; 
    %end;

    %if &rc %then %let rc = %deletefile(&temppath);    
  %end;

  %put %str(N)OTE Elapsed Time: %left(%sysfunc(putn(%sysevalf(%sysfunc(
     datetime()) - &starttime), mmss12.3)));

  &rc
%mend;

/*EOF: lockrelease.sas */