When the MEMCACHE system
option is 4 or 1, SAS file cache places data in memory as it is processed.
This data is then available for future references by SAS. Files in
the cache are kept until SAS is shut down, caching is terminated,
or more space is required for new files. Memory is reclaimed on a
least recently used basis. Cached data is written to permanent storage.
You can control which SAS libraries use the cache by using the MEMCACHE
system option in the OPTIONS statement. Memory usage can be monitored
using the performance tools.