Setting Db2 for z/OS subsystem parameters for Data Gate on Cloud

You can set the Db2 for z/OS subsystem parameters that are required for Data Gate on Cloud on the DSNTIP82 installation panel in Db2 for z/OS or customize and run the DSNTIJUZ sample job.

About this task

You must set the following Db2 subsystem parameters:

ACCEL
Set this subsystem parameter to the value AUTO (ACCEL=AUTO). This means that Data Gate on Cloud is started automatically by Db2 for z/OS.
AUTH_COMPATIBILITY
Set this subsystem parameter to SELECT_FOR_UNLOAD to ensure proper privileges for the initial load of data into Data Gate on Cloud.
CMTSTAT
Set this to CMTSTAT=INACTIVE, which is also the default. So you have to change the parameter value just in case the current value is ACTIVE. You need not change the setting if the parameter is not set at all.

The CMTSTAT subsystem parameter controls whether in-use database access threads (DBATS) can be pooled, for use by other connections, after they successfully commit or roll back. For more information, see DDF THREADS field (CMTSTAT subsystem parameter).

The setting CMTSTAT=ACTIVE is rarely used these days and has not been recommended for a long time. In the past, a performance improvement could be achieved by using it in a controlled environment with a fixed (known) number of connections.

However, the use of this setting leads to a drawback if the number of connections varies. To restrict or control the number of connections, you need to set the MAXDBAT parameter, which defines a maximum for the number of connections. For example, if you want 10000 client connections, you have to set MAXDBAT to 10000. The use of such a limit is very resource-intensive.

Another drawback is that HTTP sessions cannot be reused. This means that every single HTTP request requires an SSL handshake. This is true for both, the HTTP application programming interface (API) and the log reader API of Db2 for z/OS. The higher demand for SSL handshakes binds AT-TLS resources unnecessarily.

TCPKPALV
Set this parameter to the integer value 120 or ENABLE. The value 120 is also the default. The value ENABLE means that the TCP/IP KeepAlive configuration value is used and not overridden with the TCPKPALV value instead (see the TCPCONFIG code sample). Change the parameter value just in case it is set to DISABLE. You need not change the setting if the parameter is not set at all.

The TCPKPALV subsystem parameter determines whether the TCP/IP KeepAlive value in the TCP/IP configuration is to be overridden with a different value. For more information, see TCP/IP KEEPALIVE field (TCPKPALV subsystem parameter)

POOLINAC
Set this parameter to the integer value 120, which is also the default. So you have to change this parameter just in case it is set to a different value. You need not change the setting if the parameter is not set at all.

The POOLINAC subsystem parameter specifies the approximate time, in seconds, that a database access thread (DBAT) can remain idle in the pool before it is terminated. For more information, see POOL THREAD TIMEOUT field (POOLINAC subsystem parameter)

Procedure

  1. Set the ACCEL subsystem parameter. You have the following options:
    • Set the ACCELERATOR STARTUP field (ACCEL subsystem parameter) to the value AUTO on the DSNTIP82 installation panel.
    • Add or change the ACCEL parameter in the DSN6SPRM macro, which is used to provide input to the DSNTIJUZ sample job in your working libraries.
  2. Add or change the AUTH_COMPATIBILITY parameter to the value of SELECT_FOR_UNLOAD in the DSN6SPRM macro, which is used to provide input to the DSNTIJUZ sample job in your working libraries.
  3. If one or more of the following parameters are set to a different value, change the values as shown below. You need not change the setting if one or more parameters are not set at all.
    • CMTSTAT=INACTIVE
    • TCPKPALV=120 or TCPKPALV=ENABLE
    • POOLINAC=120
  4. Stop Db2 for z/OS.
  5. If you chose the sample job in step 1, submit DSNTIJUZ to assemble the new subsystem parameter load member.
  6. Restart Db2 for z/OS so that the changes can take effect.