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IT32180: HADR STANDBY MAY START UP WITH SYSTEM BUFFER POOLS ONLY, INSTEADOF RETURNING AN SQL1768N ERROR

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APAR status

  • Closed as program error.

Error description

  • When a database is activated, if there is insufficient memory to
    start all the defined user buffer pools, the database will still
    be activated with tiny system buffer pools only (also commonly
    referred to as 'hidden' buffer pools) in order to allow for an
    administrator to rectify the situation. In such a scenario, the
    db2diag.log will contain messages about the insufficient memory
    condition (as seen further below), and the ADM6073W warning
    message will be logged into both the db2diag.log and admin logs.
    
    When this same condition occurs during a START HADR AS STANDBY
    operation or ACTIVATE DATABASE command on a HADR standby
    database, the standby database is incorrectly allowed to start
    with only the system buffer pools.  The command should have been
    rejected with error SQL1768 reason code 13.  It is not desired
    behavior to allow the use of HADR standby database with only
    system buffer pools because it would drastically impact standby
    log replay performance.
    
    Sample messages in db2diag.log:
    FUNCTION: DB2 UDB, SQO Memory Management, sqlogmshr, probe:149
    MESSAGE : ZRC=0x850F00C5=-2062614331=SQLO_NO_INS_MEM
              "Insufficient instance_memory to allocate new memory"
    DATA #2 : String, 56 bytes
    Insufficient INSTANCE_MEMORY to allocate new memory set.
    ...
    
    FUNCTION: DB2 UDB, base sys utilities,
    sqeLocalDatabase::FirstConnect, probe:10000
    MESSAGE : ZRC=0x850F00C5=-2062614331=SQLO_NO_INS_MEM
              "Insufficient instance_memory to allocate new memory"
    DATA #1 : String, 283 bytes
    Failed to allocate the database shared memory set.
    The configured DATABASE_MEMORY plus smaller overflow may have
    exceeded INSTANCE_MEMORY or the maximum shared memory on the
    system.
    Attempting to start up with only the system buffer pools.
    Database shared memory set size is (bytes):
    ...
    
    FUNCTION: DB2 UDB, buffer pool services, sqlbAssignBufferPool,
    probe:2
    MESSAGE : ADM6073W  The table space "SYSCATSPACE" (ID "0") is
    configured to use
              buffer pool ID "1", but this buffer pool is not active
    at this time.
              In the interim the table space will use buffer pool ID
    "4099".  The
              inactive buffer pool should become available at next
    database startup
              provided that the required memory is available.
    ...
    
    With this APAR fix, behavior changes as follows:
    
    If the HADR Standby database encounters the condition
    described above, where there is insufficient memory to allocate
    all buffer pools, it will instead fail with SQL1768N reason code
    13 error.
    
       "SQL1768N Unable to start HADR. Reason code = 13.
       13 - An HADR standby database cannot start without at
       least one regular buffer pool. A buffer pool could not
      be started due to insufficient memory."
    
    On regular db or a HADR primary, a warning message SQL1478W
    will continue to be returned with db activated successfully.
    
      "SQL1478W  The defined buffer pools could not be started.
       Instead, one small buffer pool for each page size
       supported by the database manager has been started."
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to Db2 version 11.1 Mod 4 fixpack 6                  *
    ****************************************************************
    

Problem conclusion

  • Problem was first fixed in Db2 version 11.1 Mod 4 fixpack 6
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT32180

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    B10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2020-03-13

  • Closed date

    2020-04-07

  • Last modified date

    2020-04-07

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

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

    IT32436

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

[{"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:
03 April 2020