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Use the ACMS/MODIFY APPLICATION command to modify the application,
task, or server attributes of an active application. The attributes you
modify are not permanent. If you want a modification to be permanent,
you must modify the application definition.
9.6.1 Modifying Application Attributes
Specify the ACMS/MODIFY APPLICATION command with the /APPLICATION_ATTRIBUTES qualifier to modify the attributes of an active application. Keywords to the /APPLICATION_ATTRIBUTES qualifier specify the application attribute you want to modify. For example, the MAX_PROCESS keyword in the following example sets the maximum number of server processes allowed in application AIR_REGISTER to 5:
$ ACMS/MODIFY APPLICATION AIR_REGISTER - _$ /APPLICATION_ATTRIBUTES=MAX_PROCESS=5 Apply Modifications to Application AIR_REGISTER (Y/[N]): |
Use keywords to the /APPLICATION_ATTRIBUTES qualifier to:
When application-level auditing is enabled, the Audit Trail Logger records any application modifications you make in the Audit Trail Log. See Chapter 12 for an example of an audit trail record for a modified application.
To display the currently defined attributes for an application, specify
the ACMS/SHOW APPLICATION command. Section 9.5.1 describes the
ACMS/SHOW APPLICATION command and provides some sample output.
9.6.2 Modifying Server Attributes
Use the ACMS/MODIFY APPLICATION command with the /SERVER_ATTRIBUTES qualifier to modify the attributes of a server in an application. Keywords to the /SERVER_ATTRIBUTES qualifier specify the server attributes you want to modify.
You can modify the attributes of a particular server in an application, the attributes of all servers in an application, or, if you do not specify an application name, the attributes of all servers in all applications. For example, the NAME and PROCESS_DUMPS keywords in the following example cause ACMS to enable server process dumps for server MYSERV in application SANDAPPL:
$ ACMS/MODIFY APPLICATION SANDAPPL - _$ /SERVER_ATTRIBUTES=(NAME=MYSERV,PROCESS_DUMPS) Apply Modifications to Application SANDAPPL (Y/[N]): |
Use keywords to the /SERVER_ATTRIBUTES qualifier to:
Display currently defined server attributes for an application by specifying the ACMS/SHOW APPLICATION/SERVER_ATTRIBUTES command.
When application-level auditing is enabled, the Audit Trail Logger
records the modification in the Audit Trail Log file. See Chapter 12
for an example of an audit trail record generated by the ACMS/MODIFY
APPLICATION command.
9.6.3 Modifying Task Attributes
The ACMS/MODIFY APPLICATION command with the /TASK_ATTRIBUTES qualifier modifies the attributes of tasks in an application. In the following example, the AUDIT keyword to the /TASK_ATTRIBUTES qualifier enables task-level auditing for all tasks in the application PARTS:
$ ACMS/MODIFY APPLICATION PARTS/TASK_ATTRIBUTES=AUDIT Apply Modifications to Application PARTS (Y/[N]): |
Modify the attributes of a specific task or tasks in an application by specifying the keyword NAME with the /TASK_ATTRIBUTES qualifier. The following command, for instance, disables tasks BI_MONTHLY and YEARLY in the application PARTS:
$ ACMS/MODIFY APPLICATION PARTS - _$ /TASK_ATTRIBUTES=(NAME=(BI_MONTHLY,YEARLY),DISABLE) Apply Modifications to Application PARTS (Y/[N]): |
Use keywords to the /TASK_ATTRIBUTES qualifier to:
If you do not specify a task name or names, all tasks are modified within the selected application with whatever attributes you specify.
When application-level auditing is enabled and you modify the
attributes of a task, the modifications are recorded in the Audit Trail
Log.
9.7 Replacing a Server Image
Use the ACMS/REPLACE SERVER command to replace a server image in an active application with a new version of that image. Application availability and task execution are not affected by the server replacement. The ACMS/REPLACE SERVER command allows the application manager to dynamically make code changes to the code executed by a procedure server. The application manager can make code changes, relink the server image, place the server image in the location specified by the SERVER IMAGE IS statement in the task group definition, and issue the ACMS/REPLACE SERVER command.
The following command, for example, replaces the server image SORT_IMAGE with a new version of that image in the application RULES_REGS. The name of the server image is defined in the application definition.
$ ACMS/REPLACE SERVER SORT_IMAGE/APPLICATION=RULES_REGS Replace Server SORT_IMAGE in Application RULES_REGS (Y/[N]): |
When the application controller receives the ACMS/REPLACE SERVER command, it runs down all free server processes for the specified server and requests all active servers to run down when they are free. A server retaining context does not run down until the context has been released. New server processes are created to meet the minimum and maximum server process requirements of the application. If you attempt to replace an active server image, ACMS replaces it with the new version once it stops executing or is aborted.
If a server image does not stop independently because it contains an infinite loop or some other error, you can force the image to stop. To stop a server image, specify the ACMS/SHOW SERVER command to determine the process ID of the server image, and then issue the DCL command STOP/ID with the server process ID:
$ STOP/ID=22E00563 |
When application-level auditing is enabled and a server is replaced,
the Audit Trail Logger records the event in the Audit Trail Log. See
Chapter 12 for an example of an audit trail record generated by
server replacement.
9.8 Maintaining Application Availability
As system manager, ensure that the processing workload is distributed evenly throughout all nodes in a cluster. If a heavier workload is concentrated more on one node in the cluster than on others, use the ACMS/REPROCESS APPLICATION_SPEC command to redirect application selections to a node other than the node currently being used. This frees up disk space and memory and allow tasks to execute faster.
The ACMS/REPROCESS APPLICATION_SPEC command allows you to take advantage of logical names and search lists to enhance the current ACMS ability to keep applications available in the event of a system failure.
For example, assume that tasks are being selected in an application pointed to by the application specification PAYROLL , and that PAYROLL has been defined as a logical for NODE1::PAYROLL. If PAYROLL is redefined as a logical for NODE2::PAYROLL, and you issue the following command, then all subsequent task selections for PAYROLL are processed on node NODE2 rather than node NODE1.
$ ACMS/REPROCESS APPLICATION_SPEC PAYROLL |
This command is particularly useful to failback to applications when
using search lists for application specifications. Search lists can be
used for application specifications to provide for automatic failover
to one or more backup applications in the event of a system failure.
The ACMS/REPROCESS APPLICATION_SPEC command can be used to failback to
the original application when it becomes available. See Chapter 6
for more information on using search lists in application
specifications.
9.9 Canceling Tasks
There are several situations in which it might be necessary to cancel a task. Cancel one or more tasks when:
To stop either an application or the ACMS system and cancel all active tasks, include a /CANCEL qualifier in the ACMS/STOP SYSTEM or ACMS/STOP APPLICATION command. The /CANCEL qualifier always interrupts any active tasks or users in the system or the application being stopped.
To cancel a task without stopping the ACMS system or application, use the ACMS/CANCEL TASK command. This command results in a non-recoverable exception. However, in distributed transactions the effect of the ACMS/CANCEL TASK command depends upon the task state:
See Compaq ACMS for OpenVMS Writing Applications for complete information about task cancellation and exception handling.
When you use this command without a task name or qualifiers, the command affects all active tasks on the local node, including tasks called by other tasks. By default, ACMS prompts you to confirm the cancellation before canceling a task. However, if you use the /NOCONFIRM qualifier, ACMS cancels all tasks without prompting for confirmation. In either case, include the /LOG qualifier with the ACMS/CANCEL TASK command. The /LOG qualifier displays a message confirming each successful cancellation.
The following command cancels MARKET_TASK1 but not MARKET_TASK2:
$ ACMS/CANCEL TASK Task Name: MARKET_TASK1 Task ID: CARAT::0001000D-00000001 Application: MARKET_APPL User Name: SAMPLE1 Submitter ID: CARAT::0001000D Device: TTB1: Task ID: CARAT::0001000D-00000001 (Y/[N]):Y Task Name: MARKET_TASK2 Task ID: CARAT::00020013-00000001 Application: MARKET_APPL User Name: SAMPLE2 Submitter ID: CARAT::00020013 Device: TTH0: Task ID: CARAT::00020013-00000001 [Y/[N]]:N |
Other qualifiers available with the ACMS/CANCEL TASK command let you
identify which task to cancel by one of several characteristics such as
task name or user name. See the description of the ACMS/CANCEL TASK
command in Chapter 21 for a description of these qualifiers.
9.10 Displaying Task Information
The ACMS/SHOW TASK command displays information about ACMS tasks running on your node. You can display information about tasks that are selected by a local or a remote submitter. You can include one or more task names as parameters. If you include more than one task name, separate the task names with commas. If you do not include a parameter, ACMS displays information about all active tasks. Example 9-4 shows some sample output from the ACMS/SHOW TASK command. Because no task name is specified, ACMS displays information about all active tasks.
| Example 9-4 ACMS/SHOW TASK Command | |||
|---|---|---|---|
$ ACMS/SHOW TASK ACMS V4.0 CURRENT TASKS Time: 1-MAY-1994 20:33:14.93 (1) Task Name: PERS_ADD_TASK (2) State: Active; Executing PROCESSING step WORK (3) Step label: $STEP_1 (4) Task ID: ALLDAY::00010016-0000002 (5) Application: PERS (6) User Name: SWEET (7) Submitter ID: ALLDAY::00010016 (8) Device: TTB4: (9) Called Task: PERS_CALLED_TASK State: Active, executing BLOCK step WORK Step label: $STEP_2 (10) Server(s): PERS_SERVER Executing, PID 0200010B (11) TID: 0012000B-0120-0260-0006-0000050002101 Task ID: ALLDAY::00010016-00000002-00000001 |
The following describes the numbered items in Example 9-4:
| State | Description | |
|---|---|---|
| Starting | Task state while EXC initializes a task instance. Task initialization includes writing a "task start" record to the audit trail log. | |
| Active | Task state when a task is currently executing, is not processing an exception, and has not been cancelled. Additional information further specifies the task state in active status. | |
| Active; Executing BLOCK step WORK | ||
| The task is executing the work part of a block step. Since the work part of a block step involves executing the nested processing, exchange, and subordinate nested block steps within the block, then a task only maintains this state while ACMS initializes the block step. | ||
| Active; Executing BLOCK step ACTION | ||
| The task is executing the action part of a block step. | ||
| Active; Executing BLOCK step ACTION, Committing Transaction | ||
| The task is waiting for notification from DECdtm to commit the transaction as the second step in the 2-phase commit process. | ||
| Active; Executing BLOCK step ACTION, Aborting Transaction | ||
| The task is waiting for notification from DECdtm to abort the transaction. | ||
| Active; Executing PROCESSING step WORK | ||
| The task is calling a step procedure in a procedure server, executing a command in a DCL server, or calling another task. | ||
| Active; Executing PROCESSING step ACTION | ||
| The task is executing the action part of a processing step. | ||
| Active; Executing PROCESSING step ACTION, Committing Transaction | ||
| The task is waiting for notification from DECdtm to commit the transaction as the second step in the 2-phase commit process. | ||
| Active; Executing PROCESSING step ACTION, Aborting Transaction | ||
| The task is waiting for notification from DECdtm to abort the transaction. | ||
| Active; Executing EXCHANGE step WORK | ||
| The task is calling a DECforms form, a TDMS request, or performing stream I/O. | ||
| Active; Executing EXCHANGE step ACTION | ||
| The task is executing the action part of an exchange step. | ||
| Finishing | The task has finished execution and ACMS is completing the task. Task termination processing includes writing a "task end" record to the ACMS Audit Trail Logger. | |
| Completed | A task enters a completed state when it has executed the last step in the task definition and is waiting for a parent task or an agent, such as the QTI, to end or abort the DECdtm transaction in which the task participated. When the transaction completes, EXC frees the servers and ends the task. Additional information further specifies the task state in completed status. | |
| Completed; Waiting to Prepare | ||
| A composed task has completed, but awaits the end of the transaction. ACMS is waiting to receive a prepare message from DECdtm services as the first step in the 2-phase commit process. | ||
| Completed; Waiting to Commit | ||
| A composed task has ended and is stalled pending the end of the transaction. ACMS is wating to receive a commit message from DECdtm as the second step in the 2-phase commit process. | ||
| Completed; Waiting for End of Transaction | ||
| A non-composed task has completed, but awaits the end of the transaction. ACMS is waiting for DECdtm to complete the 2-phase commit process. | ||
| Processing Exception | ||
| A task is processing an exception if it is actively performing the operations necessary to handle a step exception or a transaction exception. Additional information further specifies the task state in processing exception status. | ||
| Processing Exception; Cancelling an EXCHANGE step | ||
| The task is waiting for an exchange step to be cancelled before the exception handling sequence can continue. | ||
| Processing Exception; Cancelling a PROCESSING step | ||
| The task is waiting for a processing step to be cancelled before the exception handling sequence can continue. | ||
| Processing Exception; Aborting a transaction | ||
| ACMS is aborting a DECdtm transaction as part of the exception handling sequence. | ||
| Processing Exception; Calling server cancel procedure(s) | ||
| ACMS is calling one or more server cancel procedures as part of the exception handling sequence. | ||
| Processing Exception; Blocked, Waiting to Commit or Abort | ||
| The task is associated with a blocked transaction. The task remains in this stalled state until communication is reestablished with the transaction coordinator node, or the LMCP Utility or an Rdb or DBMS utility is used to manually resolve the state of the transaction. | ||
| Cancelling | A task is cancelling if it is actively performing the operations necessary to cancel the task following a nonrecoverable exception. Additional information further specifies the task state in cancelling status. | |
| Cancelling; Cancelling an EXCHANGE step | ||
| The task is waiting for an exchange step to be cancelled before the processing sequence can continue. | ||
| Cancelling; Cancelling a PROCESSING step | ||
| The task is waiting for a processing step to be cancelled before the processing sequence can continue. | ||
| Cancelling; Aborting a transaction | ||
| ACMS is aborting a DECdtm transaction as part of the cancel processing sequence. | ||
| Cancelling; Calling server cancel procedure(s) | ||
| ACMS is calling one or more server cancel procedures as part of the cancel processing sequence. | ||
| Cancelling; Auditing task cancel information | ||
| ACMS is writing details about the task cancellation to the ACMS Audit Trail Log. | ||
| Cancelling; BLOCKED, Waiting to Commit or Abort | ||
| The task is associated with a blocked transaction. The task remains in this stalled state until communication is reestablished with the transaction coordinator node, or the LMCP Utility or an Rdb or DBMS utility is used to manually resolve the state of the transaction. | ||
| Cancelling; Executing task cancel action | ||
| The task is executing the cancel action phrase of the task definition. | ||
The /APPLICATION qualifier lets you restrict the search ACMS makes to find a task. When you name an application with the /APPLICATION qualifier, ACMS searches for the tasks you name in the application you specify. The application name is the file name of the application. Do not include the device, directory, or the file type. For example:
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