IBM Support

IT00315: 11.70.XC1/2 CONVERSION TO XC3 OR HIGHER FAILS TO START UP BTREE SCANNER THREAD(S) IF INSTANCE IS STARTED WITH ONINIT -S

Subscribe to this APAR

By subscribing, you receive periodic emails alerting you to the status of the APAR, along with a link to the fix after it becomes available. You can track this item individually or track all items by product.

Notify me when this APAR changes.

Notify me when an APAR for this component changes.

 

APAR status

  • Closed as program error.

Error description

  • It is expected behavior that when an instance of IDS is started
    with the oninit -s command (or the onmonitor->Mode->Startup
    equivalent), it will not start the btree scanner thread(s).
    When converting an IDS instance from 11.70.xC1/2 to 11.70.xC3 or
    higher, it goes through special conversion code.  When this
    special conversion code is complete, it marks the instance as
    OnLine and starts the dbScheduler threads but it does not start
    the btree scanner thread(s).
    
    The above scenario in and of itself is not fatal.  But because
    it does not start the btree scanner threads, it also does not
    initialize the necessary btree scanner structures in shared
    memory.  And because it does not initialize the btree scanner
    shared memory structures, there are some side effects:
    
    1) Because the btree scanner thread is responsible for removing
    deleted index keys and keeping indices from becoming severely
    bloated and therefore less efficient, this can lead to
    performance problems.
    2) A query of the sysmaster:sysshmhdr pseudo table directly
    references the uninitialized btree cleaner memory structure and
    will segv and crash the IDS instance (example stack is included
    later in the description)
    3) The onstat -C command will not work, reporting only "Changing
    data structure forced command termination".
    
    After the fact, any of these problems can avoided by starting
    the instance before conversion with "oninit" or by taking the
    instance offline after conversion (assuming started with oninit
    -s) and bringing it back up with "oninit".  Simply starting the
    btree scanner thread(s) with onmode -C start will also crash the
    IDS instance.
    
    dbScheduler has a task called mon_profile which is enabled by
    default to run every 4 hours.  This task does a query of the
    sysmaster:sysshmhdr pseudo table which will induce the crash.
    The crash looks something like this:
    
    20:55:10  Assert Failed: Exception Caught. Type: MT_EX_OS,
    Context: mem
    20:55:10   Who: Session(127, informix@, 0, 0x4ddf5088)
    		Thread(141, dbWorker2, 4ddb6e00, 20)
    		File: mtex.c Line: 416
    20:55:10   Action: Please notify IBM Informix Technical Support.
    20:55:10  Raw hex dump of stack located in
    /home/informix/tmp/af.4756d8e.rawstk
    20:55:10  Stack for thread: 141 dbWorker2
    
     base: 0x000000005063f000
      len:   135168
       pc: 0x0000000001317a03
      tos: 0x0000000001c2a030
    state: running
       vp: 20
    
    afstack
    afhandler
    affail_interface
    mt_ex_throw_sig
    afsig_handler
    <signal frame>
    prshmhdr
    pstread
    pst_rsread
    rsread
    fmread
    readseq_single
    gettupl
    scan_next
    insert_next
    doinsert
    excommand
    sq_execute
    mi_exec
    ph_execute
    do_sensor
    db_sch_worker
    udrlm_clang_execute_internal
    udrlm_clang_execute
    udrlm_exec_routine
    udr_execute
    dbsched_start_udr
    th_init_initgls
    startup
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * users converting from 11.70                                  *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Update to IDS-11.70.xC9                                      *
    ****************************************************************
    

Problem conclusion

  • Problem Fixed In IDS-11.70.xC9
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT00315

  • Reported component name

    INFORMIX SERVER

  • Reported component ID

    5725A3900

  • Reported release

    B70

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2014-03-13

  • Closed date

    2016-12-09

  • Last modified date

    2016-12-09

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

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

Fix information

  • Fixed component name

    INFORMIX SERVER

  • Fixed component ID

    5725A3900

Applicable component levels

  • RB70 PSN

       UP

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSGU8G","label":"Informix Servers"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"B70","Edition":"","Line of Business":{"code":"","label":""}}]

Document Information

Modified date:
09 December 2016