IT23360: DB2READLOG API CAN HANG IN PURESCALE.

Db2 Version 11.1 Mod 3 Fix Pack 3 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod3 Fix Pack3 iFix001 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod3 Fix Pack3 iFix002 for Linux, UNIX, and Windows

APAR status

• Closed as fixed if next.

Error description

• The db2Read API can hang when it is executed concurrently on
  multiple members in pureScale environment.
  In this situation, other EDU updating log records also can
  hang.
  
  Example of stack traces in this problem - there will be one
  stack with UpgradeLock and another with sqloXlatchConflict:
  
  <StackTrace>
  -------Frame------ ------Function + Offset------
  0x0900000000112F14 thread_wait + 0x94
  0x090000000D8EC6E8 sqloWaitEDUWaitPost + 0x2D8
  0x090000000C80F918
  sqlplWaitOnWP__FCP9sqeBsuEduCP14SQLP_LOCK_INFOCP8SQLP_LRBCP15SQL
  P_LTRN_CHAINCbN25 + 0x273C
  0x090000000CCF1F14
  sqlplMakeNewRequestSD__FP9sqeBsuEduP14SQLP_LOCK_INFOP11SQLP_TENT
  RYRP8SQLP_LRBP8SQLP_LRBP15SQLP_LTRN_CHAINbT7CbN29 + 0x160C
  0x090000000C870008
  sqlpUpgradeLock__FP9sqeBsuEduP14SQLP_LOCK_INFO + 0xE7C
  0x09000000098229FC
  sqlpgReadStartUse__FP9SQLP_DBCBP9sqeBsuEduCUiCUsCUlPb + 0x640
  0x090000000E40D74C
  sqlplfrFMOpenLog__FP12SQLPLFR_DBCBUiP21SQLPLFR_REQ_SCAN_NEXTUlPU
  lPP9SQLP_LECB + 0xFE8
  0x090000000E41D0A8
  sqlplfrFMReadLog__FP12SQLPLFR_DBCBP21SQLPLFR_REQ_SCAN_NEXTP17SQL
  PLFR_SCAN_DATA + 0x42AC
  0x090000000DEB492C RunEDU__9sqpLfrEduFv + 0x23BC
  0x090000000DEB0264 RunEDU__9sqpLfrEduFv + 0x364
  0x090000000DEAFFD0 RunEDU__9sqpLfrEduFv + 0xD0
  0x090000000D66B1FC EDUDriver__9sqzEDUObjFv + 0x3F0
  0x090000000C3C0DCC sqloEDUEntry + 0x390
  </StackTrace>
  
  
  <StackTrace>
  -------Frame------ ------Function + Offset------
  0x090000000C8137E4 sqloXlatchConflict + 0x540
  0x09000000098235D4
  sqlpgReadUpdateUseReader__FP9SQLP_DBCBP9sqeBsuEduCUiCUs + 0x63C
  0x090000000E40DD78
  sqlplfrFMOpenLog__FP12SQLPLFR_DBCBUiP21SQLPLFR_REQ_SCAN_NEXTUlPU
  lPP9SQLP_LECB + 0x1614
  0x090000000E41D0A8
  sqlplfrFMReadLog__FP12SQLPLFR_DBCBP21SQLPLFR_REQ_SCAN_NEXTP17SQL
  PLFR_SCAN_DATA + 0x42AC
  0x090000000DEB492C RunEDU__9sqpLfrEduFv + 0x23BC
  0x090000000DEB0264 RunEDU__9sqpLfrEduFv + 0x364
  0x090000000DEAFFD0 RunEDU__9sqpLfrEduFv + 0xD0
  0x090000000D66B1FC EDUDriver__9sqzEDUObjFv + 0x3F0
  0x090000000C3C0DCC sqloEDUEntry + 0x390
  </StackTrace>
  

Local fix

• Execute db2ReadLog API only on one member.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Purescale with more than 3 members.                          *
  * Running readlog application from more than 3 members in      *
  * parallel.                                                    *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Execute db2ReadLog API only on one to two member(s).         *
  *                                                              *
  * Update to fix pack 3.                                        *
  ****************************************************************
  

Problem conclusion

Temporary fix

Comments

APAR Information

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

  IT22567

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

Fix information

Applicable component levels

• RB10 PSN

     UP

• RB10 PSY

     UP