The SPD Engine automatically
determines the optimal process to use to evaluate observations for
qualifying criteria specified in a WHERE statement. WHERE statement
efficiency depends on such factors as whether the columns in the expression
are indexed. A SAS configuration validation program that measures
I/O scalability with respect to WHERE processing can help you determine
whether your system is properly configured for performing WHERE processing
with the SPD Engine. The program performs these tasks:
-
It creates a table with
two numeric columns.
-
It repeatedly reads
the entire table, each time doubling the number of threads used until
the maximum number is reached. The maximum number of threads is determined
by the CPUCOUNT= SAS system option and is specified when SAS is started.
The resulting log file
shows timing statistics for each cycle. You can examine this information
to determine whether your system is configured correctly. The program
is available at
http://support.sas.com/rnd/scalability/spde/valid.html.