10.2.5.2.1 How Server-Dispatched Threads Are Used

In response to clients’ requests for a service, the server dispatcher creates multiple threads (up to a configurable maximum) in one server that can be assigned to various client requests concurrently. A server cannot call tpinit().

Each dispatched thread is associated with a separate context. This feature is useful in both conversational and RPC servers. It is especially useful for conversational servers which otherwise sit idle, waiting for the client side of a conversation while other conversational connections are waiting for service.

This functionality is controlled by the following parameters in the SERVERS section of the UBBCONFIG(5) file and the TM_MIB(5).

UBBCONFIG Parameter	MIB Parameter	Default
MINDISPATCHTHREADS	TA_MINDISPATCHTHREADS	0
MAXDISPATCHTHREADS	TA_MAXDISPATCHTHREADS	1
THREADSTACKSIZE	TA_THREADSTACKSIZE	0 (representing the OS default)

• Each dispatched thread is created with the stack size specified by THREADSTACKSIZE (or TA_THREADSTACKSIZE). If this parameter is not specified or has a value of 0, the operating system default is used. On a few operating systems on which the default is too small to be used by the Oracle Tuxedo system, a larger default is used.
• If the value of this parameter is not specified or is 0, or if the operating system does not support setting a THREADSTACKSIZE, then the operating system default is used.
• MINDISPATCHTHREADS (or TA_MINDISPATCHTHREADS) must be less than or equal to MAXDISPATCHTHREADS (or TA_MAXDISPATCHTHREADS).
• If MAXDISPATCHTHREADS (or TA_MAXDISPATCHTHREADS) is 1, then the dispatcher thread and the service function thread are the same thread.
• Initially, the system boots MINDISPATCHTHREADS (or TA_MINDISPATCHTHREADS) server threads.
• The system never boots more than MAXDISPATCHTHREADS (or TA_MAXDISPATCHTHREADS) server threads.