PM17542: DB2 PERFORMANCE IMPROVEMENTS

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• DB2 performance improvements
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All DB2 users.                               *
  ****************************************************************
  * PROBLEM DESCRIPTION: DB2 exploits z/OS 1.12 new allocation   *
  *                      functions to improve the performance of *
  *                      allocation, deallocation, open, and     *
  *                      close of the data sets in DB2 page      *
  *                      sets.  It will improve the performance  *
  *                      when opening a large number of data     *
  *                      sets concurrently, especially for DB2   *
  *                      users with high DSMAX.  Significant     *
  *                      reduction in elapsed time has been      *
  *                      observed by DB2 and z/OS performance    *
  *                      test.  DB2 shutdown time may also be    *
  *                      improved.                               *
  *                      z/OS Version 1 Release 12. V1.12. R12.  *
  *                      z/OS APAR OA36101 must be installed.    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  This APAR provides exploitation of new z/OS 1.12 allocation
  functions.  DB2 performance may be improved when opening or
  closing many data sets concurrently.  DB2 shutdown may be
  shortened especially for subsystems with a large DSMAX value.
  

Problem conclusion

• DB2 code exploits z/OS 1.12 new allocation functions.
  Allocation will manage DB2 data set ENQs in memory, and suppress
  certain DB2 DD-level accounting in the SMF records to save
  significant overhead.
  
  ATTENTION to DB2 DBA and system programmers:
  
    To make the APAR effective, if you use z/OS 1.12 or later, you
    should complete one of the following actions:
  
    - Update the ALLOCxx parmlib member to set the SYSTEM
      MEMDSENQMGMT value to ENABLE.  SYSTEM MEMDSENQMGMT(ENABLE).
  
    - Issue system command SETALLOC SYSTEM,MEMDSENQMGMT=ENABLE.
  
    Updating the ALLOCxx parmlib is strongly recommended as it
    remains effective across IPLs.  If the SETALLOC command is
    used to enable SYSTEM MEMDSENQMGMT, a DB2 restart is required
    to make the change effective.
  

Temporary fix

Comments

• ž**** PE11/08/18 FIX IN ERROR. SEE APAR PM46045  FOR DESCRIPTION
  

APAR Information

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

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

  UK60887 UK60888

Modules/Macros

• DSNB1OST DSNB1PMI DSNDAB   DSNTRCKW
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• R810 PSY UK60887

     UP10/10/14 P F010

• R910 PSY UK60888

     UP10/10/14 P F010

Fix is available

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