DFSMStvs Application Migration Guide

Book description

This IBM Redbooks publication will help you to migrate batch VSAM applications to exploit transactional VSAM. DFSMStvs is available in a z/OS environment and offers the ability for VSAM data to be shared for both read and write operations while maintaining integrity and recoverability. DFSNStvs allows logging of changes to recoverable VSAM data sets. Batch programs can use commit and backout functions.

This book assumes that you are familiar with the material in the companion book DFSMStvs Overview and Planning, SG24-6971, and refers extensively to material published in that book. We also assume some familiarity with CICS Transaction Server and z/OS.

The book is intended for application developers who want to understand how to change applications to make best use of the facilities offered by DFSMStvs and to coexist well with other batch applications and with CICS systems sharing the same VSAM data sets. We assume that you are familiar with the development of batch applications and with the facilities and use of VSAM.

The tasks involved in setting up DFSMStvs and the hardware and software prerequisites are not discussed in this book; they are described in DFSMStvs Overview and Planning, SG24-6971.

Table of contents

  1. Figures
  2. Notices
    1. Trademarks
  3. Preface
    1. The team that wrote this redbook
    2. Become a published author
    3. Comments welcome
  4. Chapter 1: Introduction to DFSMStvs
    1. VSAM sharing without DFSMStvs
      1. Basic VSAM sharing
      2. MVS scheduler and sharing through MVS system services
      3. Record-level sharing
    2. DFSMStvs overview
      1. Recoverable data sets and logging
      2. Two-phase commit
    3. Batch application considerations
      1. Commit frequency
      2. Sharing files beyond today’s batch job structure
      3. Unit of recovery
      4. Application restart
    4. Batch performance observations
      1. Exploiting DFSMStvs with parallel batch programs
      2. Our experiences with parallelizing batch jobs
    5. Value of DFSMStvs
    6. Summary
  5. Chapter 2: Using commit and backout
    1. Unit of recovery
    2. Programming changes
      1. How to commit
      2. How to perform a backout
      3. How often to commit
    3. Rerunning jobs
    4. Summary
  6. Chapter 3: Transactional recovery
    1. Batch application restart
      1. Conventional batch job structure
      2. Using DFSMStvs: unique input
      3. Using DFSMStvs: shared input
    2. Use of forward recovery log
    3. CICSVR overview
    4. Summary
  7. Chapter 4: Defining VSAM data sets for DFSMStvs
    1. Recoverable data sets
    2. IDCAMS definitions
      1. IDCAMS DEFINE CLUSTER parameters
      2. Definition for PL/I example
    3. Storage management considerations
      1. Data class use
      2. Storage class use
      3. Management class use
      4. Backup while open
      5. Reorganization
    4. Summary
  8. Chapter 5: DFSMStvs environment
    1. SMS setup
      1. Data class considerations
      2. Storage class considerations
    2. PARMLIB members
      1. IFAPRDxx
      2. IGDSMSxx
    3. Coupling facility definitions
      1. Log stream names
      2. Log streams and log structures
    4. Summary
  9. Chapter 6: Migrating a COBOL program
    1. The sample program
    2. Changes to the program
    3. Step 1: OPEN
    4. Step 2: Check for deadlocks and time-outs
    5. Step 3: Add commit and backout logic
    6. Step 4: Add restart logic and a positioning data set
    7. Step 5: Remove writes to spool
    8. Summary
  10. Chapter 7: Migrating a PL/I program
    1. The sample program
    2. Changes to the program
    3. Step 1: OPEN
    4. Step 2: Check for deadlocks and time-outs
    5. Step 3: Add commit and backout logic
    6. Step 4: Add restart logic and a positioning data set
    7. Summary
  11. Chapter 8: DFSMStvs experiences
    1. Console log during normal start
    2. Exceptions
      1. Committing without DFSMStvs
      2. DFSMStvs server not registered to RRS
      3. Reestablish connection between SMSVSAM and RRS
    3. Monitoring DFSMStvs
      1. SMSVSAM server connected or not connected to RRS
      2. Display jobs using DFSMStvs
      3. Display a specific cluster and its users
      4. Coupling facility structure utilization
      5. VSAM RLS central locking structure full
      6. Display forward recovery log data sets
      7. RRS failure terminating DFSMStvs
      8. Coupling Facility lock structure
    4. IDCAMS SHCDS examples
      1. Data set list
      2. Subsystem summary
      3. Data sets by subsystem
  12. Appendix A: CICS VSAM recovery (CICSVR) example (1/2)
  13. Appendix A: CICS VSAM recovery (CICSVR) example (2/2)
  14. Appendix B: Example source code
    1. Original COBOL program (1/2)
    2. Original COBOL program (2/2)
    3. Modified COBOL program (1/3)
    4. Modified COBOL program (2/3)
    5. Modified COBOL program (3/3)
    6. Original PL/I program
    7. Modified PL/I program (1/3)
    8. Modified PL/I program (2/3)
    9. Modified PL/I program (3/3)
  15. Glossary
  16. Related publications
    1. IBM Redbooks
    2. Other publications
    3. Online resources
    4. How to get IBM Redbooks
    5. Help from IBM
  17. Index (1/2)
  18. Index (2/2)
  19. Back cover

Product information

  • Title: DFSMStvs Application Migration Guide
  • Author(s): Mary Lovelace, Nigel Morton, Werner Bauer, Mani Pillail
  • Release date: June 2003
  • Publisher(s): IBM Redbooks
  • ISBN: None