If you have already applied optimization techniques but still experience lengthy processing times or excessive memory usage, the size of your data sets might be very large, in which case, further improvement might not be possible.
You can estimate the size of a data set by creating a dummy data set that contains the same variables as your data set. Run the CONTENTS procedure, which shows the size of each observation. Multiply the size by the number of observations in your data set to obtain the total number of bytes that must be processed . You can compare processing statistics with smaller data sets to determine if the performance of the large data sets is in proportion to their size. If not, further optimization might still be possible.
When you use this technique to calculate the size of a data set, you obtain only an estimate. Internal requirements, such as the storage of variable names , might cause the actual data set size to be slightly different.