topic Re: Hold lock for dataset for specified time in SAS Programming

Hold lock for dataset for specified time

RajasekharReddy — Wed, 07 Jun 2017 04:55:08 GMT

Dear all,

I want hold Lock for specific dataset in specifed time period like in below program i have written lock statment and lock clear stament

want to run lock clear stament after specified time in windows(SAS EG) and unix

is any wayt to hold the lock for specified time and when use the same dataset in menioned perios want get error as data set was locked by user

data work.test01;
input @01 employee_id   6.
        @08 last_name     $10.
        @19 birthday      date7.;
format employee_id   6.
         last_name     $10.
         birthday      date7.;
datalines;
1247 Garcia     04APR54
1078 Gibson     23APR36
1005 Knapp      06OCT38
1024 Mueller    17JUN53
;
run;

lock AccesChk.test01 ;

/*wiat for 10 min after lock need to be clear*/
/*and mean while i will use this dataset for other program and i want get error */
/*as data set was locked by user*/

/*is any options for holding some time in windoiws and unix ?*/

lock AccesChk.test01 clear ;

Re: Hold lock for dataset for specified time

Shmuel — Wed, 07 Jun 2017 05:15:50 GMT

I'm using SAS UE and tried the LOCK staement.

Pay attention: I could rewrite the - so called locked dataset - and sort it without any error:

data test;
    input id;
cards;
111
222
333
; run;

lock work.test;

data test;
   input id;
cards;
555
222
333
; run;

lock work.test;  /* log msg: dataset is already locked by me */

proc sort data=test; by id; run;  /* output order: 222 333 555 */

I cannot check do other users can access the dataset.

The LOCK seems not to be usefull for the locking user.

Re: Hold lock for dataset for specified time

Kurt_Bremser — Wed, 07 Jun 2017 07:21:22 GMT

When you issue a lock() (or whatever the system call is in any given operating system), the system sets the lock for the calling process. As long as you try to modify the file from the same process (read: same workspace server instance), the lock will not be effective; it just blocks other processes from accessing the file.

If you want to see the effect of a lock on another process, just add a sleep call in your code:

lock AccesChk.test01 ;

data _null_;
x1 = sleep(600,1);
run;

lock AccesChk.test01 clear ;

Now you can test if the file is prevented from access in the other session.