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IT18553: STANDBY CRASHES IF MIRROR LOG PATH IS CHANGED AND DATABASE IS NOT REACTIVATED AFTERWARDS.

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APAR status

  • Closed as program error.

Error description

  • The standby will crash if the mirror log path is changed to NULL
    without reactivating the database on standby and is unmounted
    afterwards.
    
    The issue is seen when -
    1. Setup HADR pair with mirror log path enabled
    2. Constantly running workload on primary
    3. Update the mirror log path to NULL on standby and do not
    reactivate the standby at all
    4. Rename the mirror log path to a different name so standby
    would not find it.
    5. Search for following db2diag.log entry. The message is the
    key as it adds S0000196.LOG to mirfhdr.dualLogError[]. This
    would make sqlpgCheckFileIsGood() return false to the mirror
    path copy.
    (After mirror log path gets renamed, the first file that standby
    writes to would trigger this message.
    The subsequent logs would not trigger this.)
    
    2016-11-18-11.40.48.644243-300 E4741258E985          LEVEL:
    Error
    PID     : 26632                TID : 46913273456960  KTID :
    28761
    PROC    : db2sysc
    INSTANCE: db2inst1              NODE : 000            DB   :
    SAMPLE
    HOSTNAME: hostabc
    EDUID   : 124                  EDUNAME: db2hadrs.0.0 (SAMPLE)
    FUNCTION: DB2 UDB, data protection services, sqlpgStartMfhEntry,
    probe:7520
    MESSAGE : ADM1839W  An error occurred while DB2 was writing log
    data to log
              file "S0000196.LOG" on path
    
    "/home/hostabc/db2inst1/mirrorpath/NODE0000/LOGSTREAM0000/".
    The
              log file is still available on log path
    
    "/home/hostabc/db2inst1/db2inst1//NODE0000/SQL00001/LOGSTREAM
              0000/".  DB2 will attempt to use both paths for
    subsequent log files.
              In the meantime, check that the specified log path in
    which the error
              occurred exists and is accessible.  Also check that
    there is space
              available in the file system.
    
    6. Rename the mirror log path back.
    7. The rename would succeed on active path and failed on mirror
    path. (For example, renamed 196 to 200)
    8. When standby tries to write 200.LOG, it would crash.
    

Local fix

  • Reactivating the database after log mirror path is changed.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to v10.5fp9                                          *
    ****************************************************************
    

Problem conclusion

  • Fixed in v10.5fp9
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT18553

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    A50

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2016-12-22

  • Closed date

    2017-09-27

  • Last modified date

    2017-09-27

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

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

    IT22009

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • RA50 PSN

       UP

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSEPGG","label":"Db2 for Linux, UNIX and Windows"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"10.5","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
27 September 2017