PH66189: ABND04E RC00C90101 DSNKINSL ERQUAL5033 DURING X->SIX PAGESET P-LOCK DOWNGRADE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Db2 receives an ABND04E RC00C90101 DSNKINSL ERQUAL5033 dump
  during X->SIX pageset P-lock downgrade.
  DSNI014I  =DB2A DSNKINSL DATA IN USE DURING ABEND
             REASON 00C90101
             ERQUAL 5033
             TYPE 00000302
             NAME db.ts.X'nnnnnnnn'
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All Db2 12 for z/OS and Db2 13 for z/OS      *
  *                 users of data sharing.                       *
  ****************************************************************
  * PROBLEM DESCRIPTION: ABEND04E RC00C90101                     *
  *                      DSNKINSL ERQUAL5033                     *
  *                                                              *
  *                      ABEND04E RC00C90101                     *
  *                      DSNKTRAV ERQUAL5021                     *
  *                                                              *
  *                      ABEND04E RC00C90101                     *
  *                      DSNKNXT2 ERQUAL5004                     *
  *                                                              *
  *                      In data sharing, page regression can    *
  *                      result in any of the following          *
  *                      symptoms:                               *
  *                       - Incorrect output, INCORROUT.         *
  *                       - ABEND04E RC00C90101, RC00C90102,     *
  *                         RC00C90105, or RC00C902xx in         *
  *                         various CSECTs.                      *
  *                       - Data/index inconsistencies reported  *
  *                         by the CHECK INDEX utility.          *
  *                       - Page regression reported by the      *
  *                         DSN1LOGP utility.                    *
  ****************************************************************
  * RECOMMENDATION: Apply corrective PTF when available          *
  ****************************************************************
  When the pageset P-lock exit was invoked to downgrade
  the pageset P-lock from X to SIX, some pages were not written
  to the GBP as expected. When the pageset P-lock is downgraded
  from X to SIX, the object is converted to GBP-dependent.
  All changed pages in the buffer pool for the object
  need to be written out before allowing another Db2 member
  to read pages for the object. However, the PAGE SET WRITE
  log records showed some of the pages did not get written
  out during the X to SIX downgrade.
  
  This APAR adds diagnostics to verify the pages for the object
  are written out as expected by the pageset P-lock exit.
  If the write engine detects a changed page was not written
  out, an ABEND04E RC00C200F0 DSNB5SCM dump is taken.
  
  In addition, for an object that is not partitioned but
  has multiple pieces, there is a serialization flaw when
  the pageset P-lock exit downgrades the pageset P-lock
  from X to SIX, causing the mainline Setwrite agents to
  modify pages without knowing the object is being converted
  to GBP-dependent.  The pageset P-lock exit was getting
  an X latch for piece one, but the Setwrite agent may not
  be getting the X latch for piece one.
  

Problem conclusion

• Db2 was modified to verify all pages for the piece have been
  written out as expected after the  pageset P-lock exit has
  invoked the write engine to synchronously write the pages
  to the GBP.  If a page is found that was not written out,
  an ABEND04E RC00C200F0 DSNB5SCM dump is taken.
  
  To fix the serialization flaw with the pageset P-lock exit
  and mainline Setwrite agents, Db2 was fixed to acquire
  another X latch that covers all the pieces. This new X latch
  is only acquired if the pageset P-lock exit is active
  and the object has more than one piece.
  

Temporary fix

Comments

• ×**** PE25/09/05 FIX IN ERROR. SEE APAR PH68017  FOR DESCRIPTION
  

APAR Information

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

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

  UO04591 UO04592

Modules/Macros

• DSNB1LRR DSNB1PPP DSNB1SWS DSNB5SCM
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RC10 PSY UO04591

     UP25/08/29 P F508

• RD10 PSY UO04592

     UP25/08/29 P F508

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.