THREADNUM= Table Option

Specifies the maximum number of I/O threads the SPD Engine can spawn for processing an SPD Engine data set.

Category: Table Control
Data source: SPD Engine data set

Syntax

THREADNUM= n

Arguments

n

specifies the number of threads. The default is the value of the SPDEMAXTHREADS= system option, if set. Otherwise, the default is two times the number of CPUs on your computer.

Details

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:
  • WHERE expression processing
  • parallel index creation
  • 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. Setting THREADNUM=1 means that no parallel processing occurs
You can also use this option to explore scalability for WHERE expression evaluations.
SPDEMAXTHREADS=, a configurable system option, imposes an upper limit on the consumption of system resources and therefore constrains the THREADNUM= value.
Last updated: February 23, 2017