Improving I/O

Although SAS has created many features to improve data warehousing, it is still necessary to improve I/O through the strategic use of SAS code. This section will cover the following:

• Features for warehousing that have been developed by SAS

• The importance of using the WHERE rather than the IF clause in data processing

• How sorting and indexing can be done to improve I/O in SAS

Developing warehouse environments

The 1990s saw people working with SAS and big data to find creative solutions to improve data I/O. In his 1997 SAS white paper (available under Further reading), Ian Robertson describes the benefits of his case study migrating the Wisconsin Department of Transportation Traffic Safety and Record-keeping System (TSRS) from a mainframe SAS setup to one where data was served up to analysts through a local area network (LAN).

By this time, SAS had been reconfigured to run on their LAN's operating system, OS/2, so his team was able to save...