SAS advance exam question 3: Space required to run PROC SORT

shiyiming

A quick rule of thumb for the space required to run PROC SORT is:
A. two times the size of the SAS data set being sorted.
B. three times the size of the SAS data set being sorted.
C. four times the size of the SAS data set being sorted.
D. five times the size of the SAS data set being sorted

I am not sure which one is correct. Would you please kindly explain the reason? Whick chapters of the SAS book, The SAS Certification Prep Guide: Advanced Programming for SAS 9, should I read to get this knowledge? Thanks in advance.

^_^

shiyiming

Multi-threaded processing for PROC SORT will effect which of these system resources?
A.
CPU time will decrease,
wall clock time will decrease

B.
CPU time will increase,
wall clock time will decrease

C.
CPU time will decrease,
wall clock time will increase

D.
CPU time will increase,
wall clock time will increase

shiyiming

[quote:37efa4y8]The multiplier 4 applies only to utility files used in releases prior to SAS 9, when PROC SORT needs to use disk space in order to sort the data. For in-memory sorting and sorting with SAS 9 and later, the multiplier is 2 or less.[/quote:37efa4y8]

[quote:37efa4y8]Threaded processing takes advantage of multiple CPUs by executing multiple threads in parallel (parallel processing). Threaded procedures are completed in less real time than if each task were handled sequentially, although the CPU time is generally increased.  
When a threaded sort is used, the observations in the input data set are divided into equal temporary subsets, based on how many processors are allocated to the SORT procedure. Each subset is then sorted on a different processor. The sorted subsets are then interleaved to recreate the sorted version of the input data set.[/quote:37efa4y8]

shiyiming

It is a good idea to read the Prep Guide seriously.

shiyiming

Thanks millions!

^_^