Informix

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  • 1.  dbaccess starts eating 100% CPU when terminal session closed abruptly on RedHat

    Posted Mon August 05, 2024 04:16 PM

    Hi everybody,

    When running dbaccess (in interactive menu mode) on RedHat, if you just close the putty terminal window abruptly, dbaccess process keeps running and using up 100% CPU.

    Top output shows:

    The process hierarchy survives pending from process with pid 1,(init) and with no terminal attachment.

    ----------------------------------------------------------------------------------------------

    root     1407447       1  0 09:13 ?        00:00:00 sudo su - informix
    root     1407448 1407447  0 09:13 ?        00:00:00 sudo su - informix
    root     1407449 1407448  0 09:13 ?        00:00:00 su - informix
    informix 1407450 1407449  0 09:13 ?        00:00:00 -bash
    informix 1409593 1407450 84 09:16 ?        00:03:28 dbaccess

    ----------------------------------------------------------------------------------------------

    A "kill 1409593" will just end up the whole hierarchy.

    Closing the terminal window without dbaccess running will end up the ps hierarchy correctly.

    Using strace on the running dbaccess shows it is running an infinite loop doing

    ----------------------------------------------------

    read(0, "", 1)                          = 0
    read(0, "", 1)                          = 0

    read(0, "", 1)                          = 0

    ......
    ----------------------------------------------------

    This is happenning on RedHat only. Tested on SuSE and on HP/UX and dbaccess and everything else gets closed correctly on the linux/unix side.

    I have checked stty -a and terminal config is exactly the same on RedHat and SuSE.

    Any insight here much appreciated,

    Best regards,

    Josem



    ------------------------------
    Jose Ruiz
    ------------------------------


  • 2.  RE: dbaccess starts eating 100% CPU when terminal session closed abruptly on RedHat

    IBM Champion
    Posted Tue August 06, 2024 06:27 AM

    Hi Jose,

    this is a known problem, bugging us too from time to time (test machines getting really slow), only no one so far got around to really fixing it and perform the required regression testing.

     -> if you need this fixed, I'd recommend opening a support case and request the fix

    Also: I cannot confirm this is anyhow RedHat specific, we're seeing it on SuSE too, and I just repro'ed it on AIX.



    ------------------------------
    Andreas Legner
    ------------------------------



  • 3.  RE: dbaccess starts eating 100% CPU when terminal session closed abruptly on RedHat

    Posted Tue August 06, 2024 07:08 AM

    Support case opened. Thanks Andreas.



    ------------------------------
    Jose Ruiz
    ------------------------------



  • 4.  RE: dbaccess starts eating 100% CPU when terminal session closed abruptly on RedHat

    Posted Tue August 13, 2024 02:47 AM

    We have APAR IT46691: INTERACTIVE DBACCESS SURVIVING LOSS OF TERMINAL CONSUMING AN ENTIRE CPU

    https://www.ibm.com/support/pages/apar/IT46691?myns=swgother&mynp=OCSSGU8G&mync=E&cm_sp=swgother-_-OCSSGU8G-_-E



    ------------------------------
    Jose Ruiz
    ------------------------------