Sharing variables when parallel processing

Question

I have setup a process that parallel processes 8 programs to pull a lot of data. However, I have to maintain all of the variables in each one going forward (this is a monthly thing).

Is there a way to create 1 master program with all of the variables and share them across programs when running? I understand each program uses its own instance of SAS so I am thinking no.

hmmm...so I can create a permanent library (MYLIB) and assign a bunch of %let variables (MONTH, etc). How do I call them in my other programs? &MYLIB.MONTH? — Jeff M, Aug 03 '19 at 14:04
Describe the variables in each of the 8 programs, and what you want as the final result. %LET variables are macro variables and can be considered more a parameters for controlling flow, code generation and data filtering values. Do you want to each of the 8 program to use the same macro variable values ? — Richard, Aug 03 '19 at 14:19
I work for a data company and I am pulling down millions of records. I have to split the pulls into 8 different programs by product type so I do need all 8 programs to use the same %Let MONTH variable. I would love to do this once but it is more annoying than deal breaking if I can't. — Jeff M, Aug 03 '19 at 14:22
Store the parameter values, like MONTH, in a dataset that is in the shared library. Each branch can then convert the value(s) from the parameter dataset into macro variable(s) if that helps the code. — Tom, Aug 03 '19 at 16:08

score 2 · Accepted Answer · answered Aug 03 '19 at 19:07

As you correctly notice, the different SAS programs do not share variables automatically, but you can pass them explicitly:

By passing them through environment variables (this is especially useful when you have few parameters, like the report date).
- The launcher program in this case can be a simple shell script, e.g. in *nix:
```
export REPORT_DATE=20190701
sas -sysin program_a.sas
```
- Or, from SAS, you can use systask command to execute the child SAS session
- From the child session you can retrieve the parameter value via %sysget:
```
%let REPORT_DATE = %sysget(REPORT_DATE);
```

As suggested in the comments, by storing the parameters in a shared location (e.g. in a dataset).

In the parent session:

data sharedlib.params;
    REPORT_DATE = "&REPORT_DATE";
run;

In the child session:

proc sql noprint;
    select REPORT_DATE /*format XXX. as necessary*/ into :REPORT_DATE
    from sharedlib.params;
quit;

If you use SAS/CONNECT to manage the child sessions (i.e. signon and rsubmit), you can pass the variables via %sysrput

Sharing variables when parallel processing

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