The Export operator will connect one main (control) SQL session in addition to the data sessions. The main SQL session is responsible for executing SQL statements pertaining to utility work.
A minimum and a maximum number of sessions (the session limits) can be specified for the Export operator.
Consider the following usage notes:
- The maximum sessions connected can never exceed the number of available AMPs in the system, even if a larger number is specified.
- The default is one session per available AMP.
- For the MinSessions attribute, the minimum specification is one.
- The MaxSessions attribute can be set to a number smaller than the number of AMPs on the database server if fewer sessions are suitable for the job.
- Network protocol software might also impose limits on workstation-attached systems.
- Platform limits for maximum sessions per application differ:
- On a mainframe-attached z/OS client system, use the TDP SET MAXSESSIONS command to specify a platform limit.
- On workstation-attached client systems for UNIX, Linux, and Windows systems, this value is defined in the CLI file, clispb.dat, under the max_num_sess variable.
- On mainframe-attached z/OS client systems, this value is defined in the HSHSPB parameter under the IBCSMAX setting.
The max_num_sess value in the clispb.dat file (or HSHSPB) specifies the total number of sessions allowed to be connected by a single application at one time. The max_num_sess pertains to all sessions connected, both SQL and data loading.