Compaq ACMS for OpenVMS
Writing Applications

Chapter 6
6	Using the Detached Task Feature
6.1	Overview of Detached Tasks
6.1.1	Detached Tasks
6.1.2	Designing Your Application to Use Detached Tasks
6.1.3	Characteristics of Detached Tasks
6.2	Managing Detached Tasks
6.2.1	Starting a Detached Task
6.2.2	Setting the Retry Limit
6.2.3	Setting the Retry Wait Timer
6.2.4	Showing the Status of Detached Tasks
6.2.4.1	Using the ACMS/SHOW TASK Command
6.2.4.2	Using the ACMS/SHOW APPLICATION/DETACHED_TASKS Command
6.2.5	Stopping a Detached Task
6.2.6	Forcing a Detached Task to Not Retry
6.2.6.1	Task Failures that Cause ACMS Not to Retry a Task
6.2.7	Broadcasting Detached Task Messages
6.3	Using Group Workspaces in a Detached Task
6.4	Concurrent-Use Licensing with Detached Tasks
Chapter 7
7	Defining Distributed Transactions
7.1	Why Use Distributed Transactions
7.2	Including Distributed Transactions Syntax in the Task Definition
7.3	Including Multiple Resource Managers in a Distributed Transaction
7.4	Using Task Sequencing Actions in a Distributed Transaction
7.5	Including a Called Task in a Distributed Transaction
7.6	How Distributed Transactions Affect Server Context
7.7	Excluding a Processing Step from a Distributed Transaction
7.8	Handling Deadlocks and Transaction Failures
Chapter 8
8	Handling Task Execution Errors
8.1	Why Use Exception Handling
8.2	What is an Exception
8.2.1	Step Exceptions
8.2.2	Transaction Exceptions
8.2.3	Nonrecoverable Exceptions
8.3	Using the RAISE EXCEPTION Clause
8.4	Using Exception Handler Actions
8.5	Examples of Exception Handling
8.5.1	Recovering from a DECforms Time-Out Exception
8.5.2	Recovering from a Task-Call-Task Exception
8.5.3	Recovering from a Transaction Exception
8.6	How ACMS Performs Exception Handling
8.6.1	Executing a Step Exception Outside of a Distributed Transaction
8.6.2	Executing a Step Exception Within a Distributed Transaction
8.6.3	Executing a Transaction Exception
8.6.4	Executing Nonrecoverable Exceptions
8.7	How Exceptions Affect Server Cancel Procedures
8.7.1	Step Exceptions and Server Cancel Procedures
8.7.2	Nonrecoverable Exceptions Raised by Action Clauses
8.7.3	Other Nonrecoverable Exceptions and Transaction Exceptions
Chapter 9
9	Queuing ACMS Tasks
9.1	Understanding the ACMS Queuing Facility
9.2	Using ACMS Queuing with Distributed Transactions
9.3	Steps in Using ACMS Queuing
9.4	Defining Queue Security
9.5	Using the ACMS Queue Services to Queue and Dequeue Tasks
9.5.1	Queuing Tasks Using the ACMS$QUEUE_TASK Service
9.5.2	Dequeuing Task Elements Using the ACMS$DEQUEUE_TASK Service
9.6	Using the QTI to Dequeue Tasks
9.6.1	Characteristics of Queued Tasks That are Processed by the QTI
9.6.2	Setting ACMSGEN Parameters for the QTI Process
9.6.2.1	Assigning a User Name to the QTI Process
9.6.2.2	Assigning a Priority to the QTI Process
9.6.2.3	Controlling Submitter Sign-Ins
9.6.2.4	Setting the Retry Time for Failed Tasks
9.6.2.5	Setting the Polling Time for Task Queues
9.6.3	Auditing Done by the QTI Process
9.6.4	How the QTI Handles Errors
9.7	Processing Error Queues
9.8	Debugging Queued Tasks
9.9	Online Backup of Task Queue Files
9.10	Queuing Example
9.11	Procedure Parameter Notation for Programming Services
Command 1	ACMS$DEQUEUE_TASK
Command 2	ACMS$QUEUE_TASK
Chapter 10
10	Defining Task Groups
10.1	Defining a Task Group
10.2	Identifying Which Tasks Belong to the Task Group
10.3	Identifying Which Servers Are Required in the Group
10.3.1	Assigning Server Attributes
10.4	Naming Request Libraries
10.5	Identifying Which Message Files Are Used in the Group
10.6	Naming Workspaces in a Task Group Definition
10.7	Naming the Task Database for a Task Group
10.8	Changing Characteristics of Task Argument Workspaces
Chapter 11
11	Defining Applications
11.1	Defining a Simple Application
11.2	Describing the Application Environment
11.2.1	Naming Task Groups
11.2.2	Naming a User Name for the Application Execution Controller
11.2.3	Assigning Characteristics to Tasks and Servers
11.3	Controlling Tasks
11.3.1	Controlling Access to Tasks
11.3.2	Auditing Task Events
11.3.3	Controlling What Happens When a Task Ends
11.3.4	TASK ATTRIBUTES and TASK DEFAULTS Clauses
11.3.4.1	Using the TASK ATTRIBUTES Clause
11.3.4.2	Using the TASK DEFAULTS Clause
11.3.4.3	Defaulting Task and Task Group Names
11.3.4.4	Positioning TASK ATTRIBUTES and TASK DEFAULTS Clauses
11.3.5	Enabling and Disabling Tasks in the Application Definition
11.3.6	Controlling Transaction Timeouts in the Application Definition
11.4	Controlling Servers
11.4.1	Assigning a Server User Name
11.4.2	Assigning a Dynamic or Fixed Server User Name
11.4.3	Assigning Server Default Directories
11.4.4	Assigning Server Logical Names
11.4.5	Creating Logical Name Tables for Application Servers
11.4.6	Controlling the Number of Server Processes
11.4.7	Creating and Deleting Server Processes
11.4.8	Replacing an Active Server
11.4.9	SERVER ATTRIBUTES and SERVER DEFAULTS Clauses
11.4.10	Defaulting Server and Task Group Names
11.4.11	Positioning SERVER ATTRIBUTES and SERVER DEFAULTS Clauses
11.4.12	Auditing Servers
11.4.13	Enabling Procedure Server Process Dumps
11.5	Controlling Applications
11.5.1	Assigning an Application Execution Controller User Name
11.5.2	Auditing Applications
11.5.3	Assigning Application Default Directories
11.5.4	Assigning Application Logical Names
11.5.5	Assigning Application Database Files
11.5.6	Controlling the Number of Server Processes
11.5.7	Controlling the Number of Task Instances
11.6	Modifying an Active Application
11.7	Controlling Application Failover