Environment variables for the parallel engine

Set the listed environment variables depending on whether your environment meets the conditions stated in each variable.

For a complete listing of environment variables that you can set, see Environment Variables.

Network settings

APT_IO_MAXIMUM_OUTSTANDING: If the system connects to multiple processing nodes through a network, set the APT_IO_MAXIMUM_OUTSTANDING environment variable to specify the amount of memory, in bytes, to reserve for the parallel engine on every node for TCP/IP communications. The default value is 2 MB.
If TCP/IP throughput at that setting is so low that there is idle processor time, increment it by doubling the setting until performance improves. If the system is paging, however, or if your job fails with messages about broken pipes or broken TCP connections, the setting is probably too high.
APT_RECVBUFSIZE: If any of the stages within a job has a large number of communication links between nodes, specify this environment variable with the TCP/IP buffer space that is allocated for each connection. Specify the value in bytes.
The APT_SENDBUFSIZE and APT_RECVBUFSIZE values are the same. If you set one of these environment variables, the other is automatically set to the same value. These environment variables override the APT_IO_MAXIMUM_OUTSTANDING environment variable that sets the total amount of TCP/IP buffer space that is used by one partition of a stage.
APT_SENDBUFSIZE: If any of the stages within a job has a large number of communication links between nodes, specify this environment variable with the TCP/IP buffer space that is allocated for each connection. Specify the value in bytes.
The APT_SENDBUFSIZE and APT_RECVBUFSIZE values are the same. If you set one of these environment variables, the other is automatically set to the same value. These environment variables override the APT_IO_MAXIMUM_OUTSTANDING environment variable that sets the total amount of TCP/IP buffer space that is used by one partition of a stage.
APT_TIMESTAMP_DEFAULT_INVALID: If defined, the timestamp descriptor class will clear timestamps with a default that is set to invalid.
By default the field value is set to a value equal to what the time and date fields use.

Transform library

If you are working on a non-NFS MPP system, set the following environment variables:

Set the APT_COPY_TRANSFORM_OPERATOR environment variable to true. This environment variable is set to false by default. IBM® InfoSphere® DataStage® and QualityStage® Administrator users must have the appropriate privileges to create project directory paths on all the remote nodes at runtime.
Set the APT_DISABLE_TRACKER_STARTUP environment variable to 1. The value '1' allows the job to run without starting the Resource Tracker. You can set this environment variable in the Administrator client Projects tab, on the Parallel page. You must have the appropriate level of administrator privilege to set the environment variable.

Job monitoring

By default, the job monitor uses time-based monitoring. The job monitor window is updated every five seconds. You can also specify that the monitoring is based on size. For example, the job monitor window is updated based on the number of new entries. To base monitoring on the number of new entries, set a value for the APT_MONITOR_SIZE environment variable. If you override the default setting for the APT_MONITOR_TIME, the setting of the APT_MONITOR_SIZE environment variable is also overridden.

Detailed information about jobs

To produce detailed information about jobs as they run, set the APT_DUMP_SCORE value to True. By default, this environment variable is set to False.

C++ compiler

The environment variables APT_COMPILER and APT_LINKER are set at installation time to point to the default locations of the supported compilers. If your compiler is installed on a different computer from the parallel engine, you must change the default environment variables for every project by using the Administrator client.

Temporary directory

By default, the parallel engine uses the /tmp directory for some temporary file storage. If you do not want to use this directory, assign the path name to a different directory by using the environment variable TMPDIR.