THREADNUM= enables you
to specify the maximum number of
I/O threads that the
SPD Engine spawns for processing an
SPD Engine data set. The THREADNUM= value applies to any of the following SPD Engine
I/O processing:
-
-
-
I/O requested by
thread-enabled applications
Adjusting THREADNUM= enables the system administrator to adjust the level of CPU resources
the SPD Engine can use for any process. For example, in a 64-bit processor system,
setting THREADNUM=4
limits the process to, at most, four CPUs, thereby enabling greater throughput for
other users or applications.
When THREADNUM= is greater than 1,
parallel processing is likely to occur. Therefore, physical order might not be retained in the output.
You can also use this option to explore
scalability for WHERE expression evaluations.
The SPDEMAXTHREADS=
system option imposes an upper limit on the consumption of system
resources and constrains the THREADNUM= value.
Note: The SAS system option NOTHREADS
does not affect the SPD Engine.
Note: Setting THREADNUM=1 means
that no parallel processing occurs, which is behavior consistent with
the default Base SAS engine.