DY47407: VSAM PERFORMANCE ISSUES AFTER MIGRATING TO Z/VSE 5.1

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• After migrating to z/VSE 5.1, some customers reported
  incorrect statistics from various monitoring tools. In
  particular were WAITS and VSAM response times of zero.
  Also some DL/I monitoring tools may not have captured any data.
  This was a result of certain I/O EXCPADs not being driven.
  This could also lead to unsatisfactory terminal response times
  (performance) in CICS because CICS does not get control.
  A performance degradation was also reported with the use of
  compressed files.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: all users                                    *
  *                                                              *
  *                                                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: 1. Missing EXCPAD calls for CICS TS     *
  *                         and DL/I                             *
  *                      2. Compression performance degradation  *
  *                         in comparison with 4.2               *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
     Under certan conditions some of EXCPAD calls
     for CICS TS and DL/I are not properly handled
     in IKQIOD and IKQBFC
  

Problem conclusion

• 1. Certain code changes in IKQIOD; IKQBFC; IKQBRP and
     IKQOPN required for proper handling of all types of EXCPAD
     calls including cases for Exit routines in 24bit storage.
  2. Eliminating excessive GETVIS/FREEVIS calls in IKQRCPI to
     improve compression performance.
  

Temporary fix

• *********
  * HIPER *
  *********
  APPLY OFFICIAL PTF
  

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

  DY47403

• APAR is sysrouted TO one or more of the following:

  UD53867

Modules/Macros

• IKQBFC   IKQBRP   IKQIOD   IKQOPN   IKQRCPI
  

Fix information

• Fixed component name

  VSE/VSAM

• Fixed component ID

  5686CF905

Applicable component levels

• R51C PSY UD53867

     UP12/08/27 P E512 Ž

Fix is available

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