IBM Support

IT30978: MULTIPLE CLP FRONTENDS ISSUED FROM DIFFERENT SHELL SCRIPTS USES THE SAME BACKEND AGENT, CAUSING UNEXPECTED RESULTS OR ERRORS.

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APAR status

  • Closed as program error.

Error description

  • Db2 CLP uses two independent processes, frontend process and
    backend process. Both processes use IPC queues to communicate
    with each other. On Unix and Linux operating systems, it is
    possible that duplicate IPC queue ids to get generated for
    different frontend agents, thus causing various symptoms.
    Possible symptoms include:
    
    1. Intermittent errors returned to CLP.  For example you may
    observe the following error messages :
    
    DB21016E  The Command Line Processor encountered a system error
    while sending the command to the backend process.
    DB21018E  A system error occurred. The command line processor
    could not continue processing.
    
    In addition, following messages may be logged in the
    db2diag.log file:
    
    2018-08-05-09.00.11.071950-300 E146642A659          LEVEL: Error
    (OS)
    PID     : 27590832             TID : 1              PROC : db2
    INSTANCE: db2inst             NODE : 000
    HOSTNAME: hostname
    EDUID   : 1
    FUNCTION: DB2 UDB, oper system services, sqlowqueInternal,
    probe:40
    MESSAGE : ZRC=0x870F00BB=-2029059909=SQLO_QUE_NO_ACCESS
             "do not have the access right"
    CALLED  : OS, -, msgsnd
    OSERR   : EACCES (13) "The file access permissions do not allow
    the  specified action."
    DATA #1 : system V message queue identifier.,
    PD_TYPE_SYSV_QUEUE_ID, 4 bytes
    0x29F000AA
    DATA #2 : Pointer, 8 bytes
    0x09001000a198c1e0
    DATA #3 : unsigned integer, 8 bytes
    4176
    
    2. Script fails with SQLSTATE 42702 / SQLCODE: -204
    
    3. 2 or more frontends use the same backend process, and script
    could cause unexpected data updates or return unexpected
    results.
    
    1 could occur if CLP frontend processes were started by
    different user IDs.
    2 and 3 could occur if CLP frontend processes were started by
    the same user ID.
    
    These issues have been treated with APARs such as IT22632 (fixed
    in 11.1 Mod2 Fix Pack2 iFix002) and IT23909 (fixed in 11.1 Mod4
    Fix Pack4 for non-AIX platforms), but they did not completely
    resolve these issues.
    
    This APAR will be able to avoid issue 3 completely.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * Db2 Version 11.1                                             *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to Db2 Version 11.1 Mod 4 Fix Pack 5.                *
    ****************************************************************
    

Problem conclusion

  • Problem was first fixed in Db2 Version 11.1 Mod 4 Fix Pack 5.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT30978

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    B10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2019-11-18

  • Closed date

    2020-01-08

  • Last modified date

    2020-01-08

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

    IT30470

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

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • RB10 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":"11.1","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
08 January 2020