PI50992: QCAPTURE GETS ASN0725W LOG RECORDS OUT OF ORDER ON DB2 V11 BOTH WITH 6 AND 10 BYTE RBA / LRSN.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Qcapture gets ASN0725W log records out of order on DB2 V11 both
  with 6 and 10 byte RBA / LRSN.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All Version 11 users of DB2 for zOS.         *
  ****************************************************************
  * PROBLEM DESCRIPTION: Log read may not return all log         *
  *                      records in the requested log range.     *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When the physical log writer writes the log buffers to the log
  data sets an internal global field is updated with the highest
  LRSN that was written out. This field can be read by other
  threads to check the highest LRSN written to the log data sets.
  
  This internal field is unnecessarily initialized to zero prior
  to each high written LRSN update. The initialization creates
  a timing window where readers of the field could read in zeros
  as the highest LRSN written.
  
  When processing peer log read request DB2 checks the highest
  written LRSN and use it as the end range for the host member
  if it is lower than the requested end range. A high written
  LRSN of zeros could be used due to the initialization.
  This could result in DB2 returning end of data before all log
  records in the requested log range have been returned to the
  application on DB2 11.
  

Problem conclusion

• DB2 has been changed to remove the initialization of the
  internal field before setting the highest written LRSN.
  
  Additional keywords: IFCID306 IFC306 IFI306
  

Temporary fix

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

Comments

APAR Information

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

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

  UI32571

Modules/Macros

• DSNJW107 DSNJW127
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RB10 PSY UI32571

     UP15/11/13 P F511

Fix is available

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