OAs with SPPs, OpenTP1 schedules messages to MHPs by creating a schedule queue for each MHP service group.

First MCF converts the MCF-application name included in the message into the service group name and the service names, and then catalogs the received message into the input queue. When the last segment of a received message is stored in the input queue, MCF catalogs the messages into the proper schedule queue depending on the correspondence between the MCF application and the service group name and service names defined in the application attribute definition. Scheduling fails unless the MHP service group and the MCF that received the message are located on the same node.

Messages to an MHP are taken out from the schedule queue by the FIFO method.

Figure 3-46 shows MHP scheduling.

Figure 3-46 Scheduling messages for an MHP

(a) Shutting down scheduling using OpenTP1 commands

An OpenTP1 administrator can use commands to shut down scheduling of service requests to an MHP, and to release such scheduling shutdowns. As shown in the following table, these commands can apply to the scheduling of service requests to MCF applications, services, or service groups.

• Commands for shutting down scheduling
  mcfadctap: Shut down scheduling of service requests to a specific MCF application
  mcftdctsg: Shut down scheduling of service requests to a specific service group
  mcftdctsv: Shut down scheduling of service requests to a specific service
  
• Commands for releasing scheduling-shutdown status
  mcfaactap: Release the scheduling-shutdown status of a specific MCF application
  mcftactsg: Release the scheduling-shutdown status of a specific service group
  mcftactsv: Release the scheduling-shutdown status of a specific service
  

The user can specify whether the service group will become active or remain shut down after complete recovery from an abnormal termination. The user can make this decision either when the user uses the mcftdctsg command to shut down the service group, or when using the status inheritance definition to create the system.

• Using mcfadctap to shut down scheduling for MCF application
  The scheduling-shutdown status of an MHP shut down with mcfadctap can be reproduced at a full recovery after a stoppage of the online system. In the status inheritance definition, you can specify whether the scheduling-shutdown status is to be inherited.
  Table 3-9 shows the two types of scheduling shutdown possible by specifying an MCF-application name.
  

  Table 3-9 Shutting down scheduling of service requests to MCF-applications

  Type of scheduling shutdown	Processing of messages that arrived after the shutdown	Processing of messages already cataloged in the input queue before the shutdown
  Preventing both entry to input queue and output from schedule queue	The message is cataloged in the input queue for the MHP for ERREVT2 (an MCF event).	The message is recataloged in the input queue for the MHP for ERREVT2 (an MCF event).
  Preventing entry to input queue only	The message is cataloged in the input queue for the MHP for ERREVT2 (an MCF event).	The relevant MHP is started normally.
  Preventing only scheduling	The message is cataloged in the input queue for the MHP for ERREVT2 (an MCF event).	The message is recataloged in the input queue for the MHP for ERREVT2 (an MCF event).

  For each communication protocol, you can assign a different MCF-application name for a service name. By the use of different MCF-application names in different protocols, you can ensure that when an MCF-application name is used for a shutdown, only the service requests from one specific protocol will be refused. Figure 3-47 illustrates scheduling shutdown by specifying the MCF-application name.
  

  Figure 3-47 Shutting down scheduling by specifying an MCF application name

  

• Using mcftdctsv to shut down scheduling for services
  The two types of scheduling shutdown (i.e., preventing entry to the input queue or output from the schedule queue) are also possible when shutting down scheduling of service requests to services. Table 3-10 shows the methods for shutting down scheduling of service requests to MHP services.
  Even if an MHP service is shut down, other services in the service group are still usable.
  

  Table 3-10 Shutting down scheduling of service requests to MHP services

  Type of scheduling shutdown	Processing for messages that arrived after the shutdown	Processing for messages already cataloged in the input queue before the shutdown
  Preventing both entry to input queue and output from schedule queue	The message is cataloged in the input queue for the MHP for ERREVT2 (an MCF event).	The message is recataloged in the input queue for the MHP for ERREVT2 (an MCF event).
  Preventing entry to input queue only	The message is cataloged in the input queue for the MHP for ERREVT2 (an MCF event).	The MHP is started normally.
  Preventing only scheduling	The message is cataloged in the input queue for the MHP for ERREVT2 (an MCF event).	The message is recataloged in the input queue for the MHP for ERREVT2 (an MCF event).

• Using mcftdctsg to shut down scheduling for service groups
  The shutting down of scheduling of service requests to a service group can be classified into two types depending on whether the input queue is a disk queue or a memory queue. Each of these two types of scheduling shutdown can be further classified into three subtypes. Table 3-11 shows the scheduling shutdown of service requests to MHP service groups.
  

  Table 3-11 Shutdown of MHP service group

  Type of scheduling shutdown		Processing for messages that arrived after the shutdown	Processing for messages already cataloged in the input queue before the shutdown
  Input queue is disk queue	Preventing both entry to input queue and output from schedule queue	The message is cataloged in the input queue for the MHP for ERREVT2 (an MCF event).	The message is placed in the schedule wait state. After the scheduling shutdown is released, the MHP is started normally.
  	Preventing entry to input queue only	The message is cataloged in the input queue for the MHP for ERREVT2 (an MCF event).	The MHP is started normally.
  	Preventing output from schedule queue only	The message is cataloged in the input queue and the message is placed in the schedule wait state.#	The message is placed in the schedule wait state. After the scheduling shutdown is released, the MHP is started normally.
  Input queue is memory queue	Preventing both entry to input queue and output from schedule queue	The message is cataloged in the input queue for the MHP for ERREVT2 (an MCF event).	The message is cataloged in the input queue for the MHP for ERREVT2 (an MCF event).
  	Preventing entry to input queue only	The message is cataloged in the input queue for the MHP for ERREVT2 (an MCF event).	The MHP is started normally.
  	Preventing output from schedule queue only	The message is cataloged in the input queue for the MHP for ERREVT2 (an MCF event).	The message is recataloged in the input queue for the MHP for ERREVT2 (an MCF event).

  #

  If the number of messages cataloged in the disk input queue exceeds the maximum, the messages that could not be stored are cataloged in the input queue for the MHP for ERREVT2 (an MCF event).

  
  

(b) Shutting down scheduling automatically

In the application attribute definition, you can define whether or not scheduling for an MCF application or service should be shut down if an MHP terminates abnormally while executing a service. Also, in the application attribute definition, you can define that scheduling for an MCF application or service should be shut down after a specified number of abnormal terminations of the MHP. You can specify whether the number of abnormal terminations refers to the number of consecutive MHP abnormal terminations, or the number of MHP abnormal terminations in total.

To shut down in units of applications, use the aplihold command in the application attribute definition. To shut down in units of services, use the servhold command in the application attribute definition. To shut down in units of service groups, use the srvghold command in the application attribute definition.

Note that an abnormal termination includes the situation in which an MHP is rolled back by the rollback function dc_mcf_rollback() that has no-return specified in a parameter. For details of the rollback function, see the OpenTP1 Programming Guide.

When shutting down only the scheduling in units of service groups, you can choose how to handle the received messages if MHP terminates abnormally while executing a service. You can:

• Replace received messages with an error event
• Reschedule received messages at the beginning of the schedule queue. To reschedule, assign r to recvmsg in the application attribute definition.

For automatic shutdown due to abnormal termination, the shutdown status of MHP is not inherited at a full recovery operation after a stoppage of the online system.

When the specification that prevents shutdown at abnormal termination is specified by aplihold, servhold, or srvghold in the application attribute definition, the application, service, or service group will not be shut down. If frequent abnormal terminations occur with this specification, use a command to shut down the application, service, or service group.

(c) Automatic scheduling shutdown caused by inconsistency between the defined MCF-application name and the MHP

When MCF schedules an MHP, it checks for a service group that corresponds to the application name specified in the application attribute definitions. If no such service group exists, OpenTP1 shuts down scheduling for that service group only, and outputs a message to the message log to report that there is no corresponding service group. See Table 3-11 for differences between situations where the input queue is a disk queue and where the input queue is a memory queue.

The MHP scheduling-shutdown status, when scheduling for the MHP was automatically shut down because of an inconsistency between the MCF-application name and the MHP, is not inherited during a full recovery operation after a stoppage of the online system.