4.8.1 MAXDISPATCHTHREADS

The MAXDISPATCHTHREADS parameter determines the maximum number of concurrently dispatched threads that each server process can spawn. When specifying this parameter, consider the following:

• The value for MAXDISPATCHTHREADS determines the maximum size that the thread pool can grow to be, as it increases in size to accommodate incoming requests.
• The default value for MAXDISPATCHTHREADS is 1. If you specify a value greater than 1, the system creates and uses a special dispatcher thread. This dispatcher thread is not included in the number of threads determining the maximum size of the thread pool.
• Specifying a value of 1 for the MAXDISPATCHTHREADS parameter indicates that the server application must be configured as a single-threaded server. A value greater than 1 indicates that the server application must be configured as a multithreaded server.
• The value you specify for the MAXDISPATCHTHREADS parameter must not be less than the value you specify for the MINDISPATCHTHREADS parameter.
• The operating system resources limit the maximum number of threads that can be created in a process. MAXDISPATCHTHREADS must be less than that limit, minus the number of application managed threads that your application requires.

The value of the MAXDISPATCHTHREADS parameter affects other parameters. For example, the MAXACCESSORS parameter controls the number of simultaneous accesses to the Oracle Tuxedo system, and each thread counts as one accessor. For a multithreaded server application, you must account for the number of system-managed threads that each server is configured to run. A system-managed thread is a thread that is started and managed by the Oracle Tuxedo software, as opposed to threads started and managed by an application. Internally, Oracle Tuxedo manages a pool of available system-managed threads. When a client request is received, an available system-managed thread from the thread pool is scheduled to execute the request. When the request is completed, the system-managed thread is returned to the pool of available threads.

For example, if that you have 4 multithreaded servers in your system and each server is configured to run 50 system-managed threads, the accessor requirement for these servers is the sum total of the accessors, calculated as follows:

50 + 50 + 50 + 50 = 200 accessors