OA39087: DB2 "LOAD" WITH RESUME TAKES EXCESSIVE TIME LOADING TO A Z/HPF ENABLED DEVICE. MANY ICYTRACE LOGRECS. 12/03/28 PTF PECHANGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Performance Degredatation during  DB2 Utility LOAD RESUME with
  output to a z/HPF enabled device. There are no messages on the
  console, but many logrec ICYTRACE records for the DB2 DBM1
  address space. The logrec records are from ICYNRM showing the
  UCB device that DB2 is writing to, as well as, the output DB2
  data set name.
  There are 3 ICYTRACE records for each event, with the word
  "continued" in the last 2. In the second ICYTRACE record the
  MMPIO31 control block + x'18' shows x'00200108' or x'00200107'
  indicating a device status of program check. It will also show
  the DB2 data set name.
   The 3rd ICYTRACE logrec will show an IOBE control block, with
  IOBE + x'18' = 'xxxx0502'  In our case we repeatedly saw
  IOBE+18 = x'01EC0502'.
  THere is no data loss because MM will redrive the IO with a
  non-zHPF channel program. All that is seen is slow
  performance.
  
  This is also seen when running a BMC Utility to
  LOAD tables. They have noticed that the jobs were very slow
  during a SORT phase. The BMC utilities use a internal SYNCSORT
  solution.
  
  Additional Symptoms:
  ABND0F4 RC20 RSN150A001E IGWBITX1+10F8 / MSGIGW699I from PDSE
  LNKLST validation processing
  Tivoli Storage Manager (TSM) IO timeouts reading Recovery
  Log dataset.
  

Local fix

• disable z/HPF on LPARS running DB2 via the MVS command
  SETIOS ZHPF=NO
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All DFSMS users at HDZ1B10 or higher with    *
  *                 Media Manager apar OA34661 installed,        *
  *                 zHPF capable DASD devices at DS8K microcode  *
  *                 level R6.2 or higher and Ficon Express 8s    *
  *                 channels.                                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: With the DS8K release 6.2 micro code    *
  *                      installed Media Manager will exploit    *
  *                      new functions in the zHPF IO protocol.  *
  *                      Under certain circumstances, the Media  *
  *                      Manager builds the zHPF channel program *
  *                      incorrectly. Failed zHPF channel        *
  *                      programs are rebuilt with CCWs,         *
  *                      therefore a performance degradation can *
  *                      be seen if the number of failed channel *
  *                      programs is large.  For Media Manager   *
  *                      to build the zHPF channel program       *
  *                      incorrectly either reads or update      *
  *                      writes must be requested and there must *
  *                      be between 51 and 80 discontinuities    *
  *                      in the CIs requested.                   *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  

Problem conclusion

• The logic to build a zHPF bidirectional channel program is
  corrected.  The Media Manager will also test that
  the new microcode feature codes are installed to deal
  correctly with zHPF bidirectional channel program
  (TCAX) padding before building such a channel program.
   KEYWORDS: ZHPF/K  TCAX 00200108 00200107
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

• ×**** PE12/08/02 FIX IN ERROR. SEE APAR OA40098  FOR DESCRIPTION
  

APAR Information

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

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

  OA39251 UA64821 UA64822 UA64823

Modules/Macros

• ICYBLD64 ICYPIO64
  

Fix information

• Fixed component name

  DFSMS MEDIA MAN

• Fixed component ID

  5695DF126

Applicable component levels

• RB10 PSY UA64821

     UP12/04/11 P F204 «

• RC10 PSY UA64822

     UP12/04/11 P F204 «

• RD10 PSY UA64823

     UP12/04/10 P F204 «

Fix is available

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