topic Re: Frequent Overwriting of Temporary Data Sets in New SAS User

Frequent Overwriting of Temporary Data Sets

trevand — Sat, 17 Aug 2024 00:51:31 GMT

Can it be problematic to overwrite temporary data sets? I use multiple data set and proc sql steps to create various variables and the final data set. Proc sql gives a warning if you use the same data recursively. I read here and there that it could be problematic but just wanted to double check and know why it could be problematic?

data temp;
set temp;
run;

proc sql;
create table temp as select * from temp;
run;

Re: Frequent Overwriting of Temporary Data Sets

Astounding — Sat, 17 Aug 2024 01:51:41 GMT

The biggest problem is that these programs replace the original version of TEMP. If you need it (such as if you kater discover a logic error), you no longer have the original input available.

Depending on the size of the data sets, you can be running up the bill. Each step needs to read the entire data set and output all the observations. It's easy to get into bad habits, such as using more steps that you actually need. Typically, input and output are much more costly than data manipulation statements.

Re: Frequent Overwriting of Temporary Data Sets

Ksharp — Sat, 17 Aug 2024 07:51:28 GMT

Nope. That would not be a problem.

If you want to get rid of this WARNING info ,you need option "undo_policy=".

data temp;
set sashelp.class;
run;
proc sql  UNDO_POLICY=none;
create table temp as select * from temp;
quit;

Re: Frequent Overwriting of Temporary Data Sets

trevand — Mon, 19 Aug 2024 14:15:29 GMT

@Ksharp What about overwriting using a data set statement? I read here and there that it could cause problems and I should avoid it.

Re: Frequent Overwriting of Temporary Data Sets

PaigeMiller — Mon, 19 Aug 2024 14:25:02 GMT

@trevand wrote:

@Ksharp What about overwriting using a data set statement? I read here and there that it could cause problems and I should avoid it.

@Astounding already explained this.

Re: Frequent Overwriting of Temporary Data Sets

Ksharp — Tue, 20 Aug 2024 01:47:04 GMT

If you are using a data step statement, that WARNING info would not appeared.
They are doing the same thing I think.