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IT18394: MQ channel process amqmrppa or amqcrsta consumes high cpu on Windows systems

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APAR status

  • Closed as program error.

Error description

  • The process status output for the MQ channel process(amqrmppa or
    runmqchl or amqcrsta)  shows
    high CPU or 100% CPU usage for the channel process. MQ trace of
    channel process(amqrmppa/runmqchl/amqcrsta)
    shows a tight loop with repeated send calls failing with the
    error WSAECONNRESET(10054 (0x2746)).
    
    006EF815 14:21:53.457939   4964.9       CONN:971534 -------{
    ccigsk_secure_soc_write
    006EF816 14:21:53.457945   4964.9       CONN:971534 Channel
    Name:TESTCHANNEL       Local:127.0.0.1(1414)
    PeerName:127.0.0.1(55411)
    006EF817 14:21:53.457953   4964.9       CONN:971534
    gsk_secure_soc_write: input: gsk_soc_handle=0x0000000006BB27D0,
    
    pBytesToWrite=0x000000000784E730,nBytesToWrite=0,pnBytesWritten=
    0x000000000784E688
    006EF818 14:21:53.457988   4964.9       CONN:971534 --------{
    cciTcpSslWriteCallback
    006EF819 14:21:53.457996   4964.9       CONN:971534
    cciTcpSslWriteCallback: input: nBytesToWrite=15397
    006EF81A 14:21:53.458002   4964.9       CONN:971534 ---------{
     cciTcpSend
    006EF81B 14:21:53.458007   4964.9       CONN:971534 Sending
    15397 bytes from 0000000007623E30
    006EF81C 14:21:53.458013   4964.9       CONN:971534 ----------{
     send
    006EF81D 14:21:53.458025   4964.9       CONN:971534 ----------}!
    send (rc=Unknown(2746))
    006EF81E 14:21:53.458041   4964.9       CONN:971534 Data:
    0xffffffff
    006EF81F 14:21:53.458053   4964.9       CONN:971534 Sent -1
    bytes
    006EF820 14:21:53.458065   4964.9       CONN:971534 ----------{
     cciTcpGetNameandAddress
    006EF821 14:21:53.458071   4964.9       CONN:971534 Reverse DNS
    lookups: FALSE
    006EF822 14:21:53.458078   4964.9       CONN:971534 Resolved
    name: 127.0.0.1
    006EF823 14:21:53.458085   4964.9       CONN:971534 ----------}
     cciTcpGetNameandAddress (rc=OK)
    006EF824 14:21:53.458089   4964.9       CONN:971534 RetCode
    (rrcE_SEND_FAILED)
    006EF825 14:21:53.458095   4964.9       CONN:971534 ---------}!
    cciTcpSend (rc=rrcE_SEND_FAILED)
    006EF826 14:21:53.458102   4964.9       CONN:971534 --------}!
    cciTcpSslWriteCallback (rc=Unknown(FFFFFFFF))
    006EF827 14:21:53.458202   4964.9       CONN:971534
    gsk_secure_soc_write: output: gsk_soc_handle=0x0000000006BB27D0,
    
    pBytesToWrite=0x000000000784E730,nBytesToWrite=0,pnBytesWritten=
    0x000000000784E688, nBytesWritten=0
    006EF828 14:21:53.458212   4964.9       CONN:971534 -------}!
    ccigsk_secure_soc_write (rc=Unknown(227))
    006EF829 14:21:53.458225   4964.9       CONN:971534 -------{
    xcsWaitFd
    006EF82A 14:21:53.458231   4964.9       CONN:971534 fdcount=1,
    fd[0]=1048 option=2 timeout=(0sec, 0usec)
    006EF82B 14:21:53.458238   4964.9       CONN:971534 timeout=20s
    (+0us)
    006EF82C 14:21:53.458245   4964.9       CONN:971534 --------{
    select
    006EF82D 14:21:53.458258   4964.9       CONN:971534 --------}!
    select (rc=Unknown(1))
    

Local fix

  • Restart the channel(s) being serviced by the affected process.
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users using MQ SSL channels on Windows systems.
    
    
    Platforms affected:
    Windows
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    The MQ channel agent sending code did not correctly handle the
    case where the Windows socket reported the error code EWOULDBLK
    to report a saturated send buffer followed by the error code
    ECONNRESET to report a broken connection. This caused the
    channel process to enter a tight loop, instead of reporting the
    broken connection as expected.
    

Problem conclusion

  • The MQ channel agent logic has been modified to correctly handle
    this connection failure.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v8.0       8.0.0.7
    v9.0 CD    9.0.2
    v9.0 LTS   9.0.0.1
    
    The latest available maintenance can be obtained from
    'WebSphere MQ Recommended Fixes'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
    
    If the maintenance level is not yet available information on
    its planned availability can be found in 'WebSphere MQ
    Planned Maintenance Release Dates'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
    ---------------------------------------------------------------
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT18394

  • Reported component name

    WMQ BASE MULTIP

  • Reported component ID

    5724H7251

  • Reported release

    800

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2016-12-14

  • Closed date

    2017-01-17

  • Last modified date

    2017-06-01

  • 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

    WMQ BASE MULTIP

  • Fixed component ID

    5724H7251

Applicable component levels

  • R800 PSY

       UP

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Document Information

Modified date:
01 June 2017