Configuring IBM z/OS parameters
IBM® z/OS® configuration parameters needed to run CICS® Transaction Gateway
Unlike EXCI connections, IPIC provides the ability to use more than 250 worker threads in a single Gateway. To enable this function the Gateway daemon must be started with environment variable CTG_EXCI_INIT=NO. If CTG_EXCI_INIT=NO is not set, EXCI support is loaded at Gateway daemon startup which restricts the maximum number of threads to the maximum EXCI LOGONLIM of 250.
The JVM runs within the CICS Transaction Gateway address space. This means that, if your application requires CICS Transaction Gateway to create large numbers of threads, for example, connection manager threads, you might need to increase the region size. You define the region size with the REGION parameter in the EXEC statement in the CICS Transaction Gateway start JCL. See Region size considerations for more information on this parameter.