TECHNIQUES FOR EFFICIENTLY ACCESSING AND MANAGING DATA

This paper explores a number of SAS System data management and coding techniques for improving efficiency. After efficiency is defined and a number basic efficiency techniques are summarized, some SAS Version 6.07 + features are discussed from an efficiency viewpoint. These features include PROC SQL, SAS data set compressing, the Stored Program Facility, and SAS Data Views. INTRODUCTION - Efficiency Defined Efficient coding is more than being able to code a program that will run the quickest. Efficiency can be broadly defined as completing a task while utilizing the minimum resources. Since there are many different resources used in completing a programming task, there are many aspects to efficiency. These include elapsed time, CPU time, memory usage, data storage, and 1/0 operations. Also very important, and too frequently ignored, is the expenditure of programmer time for design, coding, and maintenance. All these factors should be considered when measuring efficiency. Saving programmer time is the major advantage of the SAS System over all third generation language (3GLI programs. Compared to 3GL programs, the SAS System greatly reduces the expenditure of programmer time while substantially increasing CPU costs. This reduction in programmer time helps avoid the large application backlogs and high program maintenance costs that are endemic in 3GL shops. To measure efficiency within the SAS System, various SAS System Options can be used to obtain performance statistics. Often used system options are indicated below. Some options are platform specific, as noted. OPTIONS NOTES MPRINT SOURCE SOURCE2 /* Log source */ STIMER FULLSTIMER /* Usage stats*/ MSGLEVEL=I