Deciding Whether to Create an Index
In previous sections, you learned how SAS determines
whether sequential access or direct access is likely to be most efficient
for WHERE processing. You also learned about a variety of factors
that you can assess to determine which access method is most efficient.
After you have made your determination, you can use the following
guidelines to decide whether it is efficient to create an index.
Guidelines for Deciding Whether to Create an Index
-
Minimize the number of indexes to reduce disk storage and update costs. Create indexes only on variables that are often used in queries or (when data cannot be sorted) in BY-group processing.
Get SAS Certification Prep Guide, 4th Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
