Tagsort reads each observation of the data set twice.

[GN0001]

Hello team,

I am reviewing a log for the program I ran. I can see this:

Tagsort reads each observation of the input data set twice.

Is this a mechanism in SAS that tagsort reads each observation two times?

Respectfully,

blue blue

[Astounding]

Yes.

Do you have access to documentation about PROC SORT?

[ballardw · Accepted solution]

That is normal. The procedure gets the BY variables and the record identifiers, sorts those, then matches to the full data set by record identifier. There may be a time penalty to reduce the disk usage.

You are trading off time for disk space as normally Proc Sort makes two additional copies of the data, roughly, before overwriting the source set (if not creating a different output data set) and removing the temporary data.