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When running Db2 commands as root against multiple user instances, the DB21016E error is returned.

Troubleshooting


Problem

When a user that is logged in as super user (su) attempts to run Db2 commands against several Db2 instance users within the same command line processor (CLP) session, the error DB21016E is sometimes returned for one of the commands. This issue occurs on AIX systems running the KornShell (ksh).

Symptom

DB21016E  The Command Line Processor encountered a system error while sending 
the command to the backend process.

Cause

When using su to execute Db2 commands for different user instances, their respective uid%8 (uid MOD 8) values must be unique. Otherwise the DB21016E error is thrown.

Diagnosing The Problem

Db2 traces collected during the incident have the following trace point: 

errtrans DB2 UDB oper system services sqlowqueInternal fnc
(13.3.15.1014.0.40)
    pid 7667932 tid 1 cpid -1 node -1 probe 40
    Error Translation
    Original Error OSERRNO = 13
         New Error ZRC = 0x870F00BB = -2029059909 =
SQLO_QUE_NO_ACCESS

1895        data DB2 UDB RAS/PD component pdLogInternal fnc
(3.3.134.9.0.130)
    pid 7667932 tid 1 cpid -1 node -1 probe 130
    bytes 120

    Data1         (PD_TYPE_BITMASK,8) Bitmask:
    0x0000000000000002
    Data2         (PD_TYPE_ECFID,4) Function:
    DB2 UDB, oper system services, sqlowqueInternal
    Data3         (PD_TYPE_HEXINT,8) Hex integer:
    0xFFFFFFFF870F00BB
    Data4         (PD_TYPE_ECFID,4) Function:
    OS, -, msgsnd
    Data5         (PD_TYPE_HEXINT,8) Hex integer:
    0x000000000000000D
    Data6         (PD_TYPE_UINT,8) unsigned integer:
    40
    Data7         (PD_TYPE_UINT,8) unsigned integer:
    2
    Data8         (PD_TYPE_UINT,8) unsigned integer:
    4
 Also, the db2diag.log file contains results similar to the following: 

2015-04-01-10.21.57.255102-240 E124974A660          LEVEL: Error
(OS)
PID     : 7667932              TID : 1              PROC : db2
INSTANCE: db2inst1             NODE : 000
HOSTNAME: localhost
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
0x00300004
DATA #2 : Pointer, 8 bytes
0x09001000a081d3d8
DATA #3 : unsigned integer, 8 bytes
1
This issue is not the result of users being incorrectly defined, or any access issues. It is the result of the CLP attempting to read a queue that belongs to a different user.
In addition, the UID of the two instance users should have the same UID%8 value.

Resolving The Problem

There are two solutions to this issue:
  • Ensure that the UID values being used in the su command do not evaluate to the same values for UID%8.
  • Run the Db2 commands as a script within the su command.
    For Example:
    su - <user> -c "./script.sh"
    where script.sh contains multiple Db2 commands:
    db2 connect to sample;
    db2 select * from <table>;

Document Location

Worldwide

[{"Type":"MASTER","Line of Business":{"code":"LOB10","label":"Data and AI"},"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSEPGG","label":"Db2 for Linux, UNIX and Windows"},"ARM Category":[{"code":"a8m500000008PmTAAU","label":"Programming Interface->CLP"}],"ARM Case Number":"","Platform":[{"code":"PF002","label":"AIX"}],"Version":"11.5.6;and future releases"}]

Document Information

Modified date:
18 October 2021

UID

ibm16495421

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