EasyManua.ls Logo

IBM SC34-7012-01 User Manual

IBM SC34-7012-01
268 pages
To Next Page IconTo Next Page
To Next Page IconTo Next Page
To Previous Page IconTo Previous Page
To Previous Page IconTo Previous Page
Page #153 background imageLoading...
Page #153 background image
Chapter 13. Programming for recovery
When you are designing your application programs, you can include recovery
facilities that are provided by CICS; for example, you can use global user exits for
backout recovery.
This section covers the following topics:
v “Designing applications for recovery”
v “Program design” on page 143
v “Managing transaction and system failures” on page 149
v “Locking (enqueuing on) resources in application programs” on page 154
v “User exits for transaction backout” on page 160
Designing applications for recovery
In this context, application refers to a set of one or more transactions designed to
fulfill the particular needs of the user organization. A transaction refers to a set of
actions within an application which the designer chooses to regard as an entity. It
corresponds to a unit of execution, which is typically started in a CICS region by
invoking the transaction by its identifier from a terminal attached to CICS.
As an application designer, you must decide how (if at all) to subdivide an
application into transactions, and whether the transactions should consist of just
one unit of work, or more than one.
Ideally, but not necessarily, a transaction would correspond to a unit of work.
Dividing the business application into units of work that correspond to
transactions simplifies the entire recovery process.
An example of a typical business application is an order-entry system. A typical
order-entry application includes all the processes needed to handle one order from
a customer, designed as a set of processing units, as follows:
1. Check the customer’s name and address and allocate an order number.
2. Record the details of ordered items and update inventory files.
3. Print the invoice and shipping documents.
Depending on the agreed recovery requirements statement, you could design
noting details of ordered items and updating files either as one large transaction or
as several transactions, with one transaction for each item within the order.
Splitting the application into transactions
Specify how to divide the application into transactions.
About this task
Procedure
1. Name each transaction, and describe its function in terms that the terminal user
can understand. Your application could include transactions to recover from
failures, such as:
© Copyright IBM Corp. 1982, 2011 141

Table of Contents

Question and Answer IconNeed help?

Do you have a question about the IBM SC34-7012-01 and is the answer not in the manual?

IBM SC34-7012-01 Specifications

General IconGeneral
BrandIBM
ModelSC34-7012-01
CategoryServer
LanguageEnglish

Summary

Recovery and Restart Guide

Part 1. CICS recovery and restart concepts

Chapter 1. Recovery and restart facilities

Details CICS's core recovery and restart mechanisms, including data integrity and failure minimization.

Chapter 2. Resource recovery in CICS

Units of work

Explains the fundamental concept of a unit of work (UOW) in CICS backout mechanisms.

Locks

Details how CICS manages locks for recoverable resources and their states (active/retained).

Synchronization points

Describes how CICS indicates the end of a UOW and the role of syncpoints in recovery.

Chapter 3. Shutdown and restart recovery

Normal shutdown processing

Describes the stages of a normal CICS shutdown, including quiesce stages and warm keypoints.

Warm keypoints

Explains the warm keypoint information used for warm or emergency restarts.

Part 2. Recovery and restart processes

Chapter 4. CICS cold start

Explains the CICS startup process for a cold start, including data set and resource recovery.

Chapter 5. CICS warm restart

Details the CICS startup process for a warm restart, focusing on state rebuilding.

Chapter 6. CICS emergency restart

Covers CICS startup after a failure, including system log recovery and backout.

Chapter 7. Automatic restart management

Explains how CICS utilizes the MVS Automatic Restart Management (ARM) component.

Chapter 8. Unit of work recovery and abend processing

Details how CICS handles unit of work failures, abends, and recovery processes.

Chapter 9. Communication error processing

Covers processing for terminal errors and intersystem communication failures.

Part 3. Implementing recovery and restart

Chapter 10. Planning aspects of recovery

Focuses on planning considerations for CICS recovery, including application design and requirements.

Chapter 11. Defining system and general log streams

Explains the definition and management of system and general log streams for CICS logging.

Chapter 12. Defining recoverability for CICS-managed resources

Details how to define recovery attributes for CICS-managed resources like transactions and files.

Chapter 13. Programming for recovery

Covers programming techniques to include recovery facilities in CICS applications.

Chapter 14. Using a program error program (PEP)

The CICS-supplied PEP

Details the CICS-supplied PEP's functions and limitations for abend handling.

Your own PEP

Guides the creation and implementation of custom Program Error Programs.

Chapter 15. Resolving retained locks on recoverable resources

Quiescing RLS data sets

Describes the process of quiescing RLS data sets for access management.

The RLS quiesce and unquiesce functions

Explains the RLS quiesce/unquiesce functions and their impact on data set access.

Switching from RLS to non-RLS access mode

Details switching data sets from RLS to non-RLS mode for batch operations.

Resolving retained locks before opening data sets in non-RLS mode

Provides steps to resolve retained locks prior to opening data sets in non-RLS mode.

Choosing data availability over data integrity

Discusses trade-offs between data availability and integrity during lock resolution.

Chapter 16. Moving recoverable data sets that have retained locks

Procedure for moving a data set with retained locks

Outlines procedures for moving VSAM data sets, ensuring retained locks are preserved.

Using the REPRO method

Explains the REPRO utility for moving VSAM data sets and preserving locks.

Using the EXPORT and IMPORT functions

Describes using EXPORT/IMPORT for moving VSAM data sets.

Rebuilding alternate indexes

Covers rebuilding alternate indexes and preserving locks.

Chapter 17. Forward recovery procedures

Forward recovery of data sets accessed in RLS mode

Covers preserving retained locks during RLS mode data set forward recovery.

Forward recovery of data sets accessed in non-RLS mode

Provides procedures for forward recovery of non-RLS mode data sets.

Procedure for failed RLS mode forward recovery operation

Details steps to resolve failures during RLS mode forward recovery.

Procedure for failed non-RLS mode forward recovery operation

Outlines procedures for resolving failures in non-RLS mode forward recovery.

Chapter 18. Backup-while-open (BWO)

BWO and concurrent copy

Compares BWO dump types and the role of concurrent copy.

BWO requirements

Lists the necessary components and configuration for BWO support.

Which data sets are eligible for BWO

Identifies eligible data sets for BWO based on storage and access modes.

How you request BWO

Describes methods for defining BWO eligibility for data sets.

Specifying BWO using access method services

Details specifying BWO via DEFINE CLUSTER statements.

Specifying BWO on CICS file resource definitions

Explains defining BWO eligibility through CICS FILE resource definitions.

Removing BWO attributes

Provides procedures for removing BWO attributes from data sets.

Systems administration

Outlines administrator tasks for BWO and forward recovery.

BWO processing

Details how BWO impacts CICS operations like file opening and shutdown.

Chapter 19. Disaster recovery

Why have a disaster recovery plan?

Explains the necessity of a disaster recovery plan for business continuity.

Disaster recovery testing

Highlights the importance and benefits of regularly testing disaster recovery plans.

Six tiers of solutions for off-site recovery

Presents a tiered approach to off-site recovery solutions based on business needs.

Disaster recovery and high availability

Discusses tier 6 solutions for high availability and data currency.

Part 4. Appendixes

Notices

Provides legal notices, warranties, and copyright information.

Trademarks

Lists IBM and other product trademarks.

Bibliography

Lists CICS books and related publications for further reading.

Accessibility

Details accessibility features for CICS system interaction.

Index

An alphabetical index of topics for quick reference.

Related product manuals