2. USAGE GUIDELINES › 2.1 Work File Compression

2.1 Work File Compression

The SAS system gives you the option to create variable-length
or fixed-length observations in a SAS data set.
Variable-length observations differ from fixed-length
observations in that the former are usually smaller because
the blank spaces used to pad fixed-length observations are
removed.
 
You instruct SAS to create variable length observations by
specifying the COMPRESS= option.  SAS data set compression
can be implemented for individual data sets or across the
entire SAS system by specifying COMPRESS= on either a DATA
statement (for the individual data set named on the DATA
statement) or an OPTIONS statement (for the entire system).
 
For more information on the COMPRESS= option, see the SAS
Institute documentation.


In deciding whether or not to implement compression for a SAS
data set, CA's research indicates the following:

 o Compressed data sets generally require fewer IOs than
   uncompressed data sets.

 o Observations in a compressed data set cannot be accessed
   by observation number.

 o Compressed data sets use more TCB CPU time than
   uncompressed data sets.  (TCB time is the amount of time
   spent executing application code.)

The CICS Analyzer supports compression for files in the
CA MICS data base as well as the work files used during daily
operational processing.  If you choose to implement data
compression for the CICS Analyzer's work files, elapsed times
may be prolonged in the DAY040 step of the DAILY job.