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PK78543: REGION SLOWDOWN CICS NEEDS TO ISSUE A WARNING MESSAGE

A fix is available

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APAR status

  • Closed as program error.

Error description

  • You are experiencing a region slowdown issue.
    The lock Manager shows most of the lock requests and
    suspends are from SOLOCK and SOTCPIPS.
    This is due to one of your programs issuing an EXEC CICS TCPIP
    CLIENTNAME which results in a GETHOSTBYADDR call, and your
    network has slow response on this GETHOSTBYADDR call.
    CICS needs to measure the elasped time of issuing the call.
    A warning message needs to be issued regarding what program
    is issuing this call and which IP address is being involved
    if the time goes above a certain threshold.
    Additional Symptom(s) Search Keyword(s):
    KIXREVSPW
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All CICS Users                               *
    ****************************************************************
    * PROBLEM DESCRIPTION: EXEC CICS EXTRACT TCPIP CLIENTNAME      *
    *                      results in a TCPIP GETHOSTBYADDR        *
    *                      call which is slow to respond           *
    *                      leading to a back up of CICS tasks.     *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    A CICS slowdown occurred which showed lots of waits on the
    SOTCPIPS lock and the SOLOCK.
    
    A task had issued EXEC CICS EXTRACT TCPIP CLIENTNAME to obtain
    the client name as known by the domain name server. DFHSOIS
    obtains the SOLOCK (SHARED), switches to the SO TCB and then
    issues a GETHOSTBYADDR call. The GETHOSTBYADDR is a blocking
    call. This took several seconds to complete. During this time,
    other tasks back up waiting for the SOLOCK and waiting for the
    SO TCB to become available.
    
    CICS fails to report this occurrence and as such diagnosis of
    this problem is difficult.
    

Problem conclusion

  • DFHSOIS ?get_client_hostname has been updated to issue a
    new message (DFHSO0118) if the GETHOSTBYADDR call takes
    longer than three seconds to complete.
    
    The following message will be added to the CICS Transaction
    Server for z/OS Version 3 Release 1 and Version 3 Release 2
    CICS Messages and Codes manuals (GC34-6442-04,GC34-6827-01)
    in Chapter 1 "DFH messages" under section "DFHSOxxxx" after
    message DFHSO0117 and before message DFHSO0119.
    The message will read:
    
        DFHSO0118 "APPLID" THE GETHOSTBYADDR CALL TO
               RESOLVE IP ADDRESS "IP_ADDRESS" TO A HOST NAME
               TOOK OVER 3 SECONDS TO COMPLETE.
    
        EXPLANATION:  CICS has issued the TCP/IP function
        gethostbyaddr to resolve the IP address "ip_address" to
        a host name. This call took greater than three seconds
        during which time the sockets TCB was blocked. During this
        time no socket IO was possible.
    
        SYSTEM ACTION:  CICS continues.
    
        USER RESPONSE:  The gethostbyaddr function will usually
        perform a name server reverse lookup to resolve the IP
        address into a host name. This call took over three seconds
        to complete.  The gethostbyaddr function is most commonly
        driven by EXEC CICS EXTRACT TCPIP CLIENTNAME.
    
        Check that the name server defined to TCP/IP in the
        /etc/resolv.conf file is valid and responding correctly.
        You can issue the TSO NSLOOKUP command to query the name
        server.  If a SYSTCPD DD name has been defined in the CICS
        job, check that the file it references correctly defines the
        name server.  If the name server is defined correctly to
        CICS then contact the administrator to determine why the IP
        address lookup failed to respond in a timely fashion.  The
        TCP/IP RESOLVERTIMEOUT parameter can be used to control the
        duration of a gethostbyaddr call.
    
        DESTINATION:  Console
    
        MODULE:  DFHSOIS
    
        XMEOUT PARAMETERS: applid, ip_address
    

Temporary fix

  • FIX AVAILABLE BY PTF ONLY
    

Comments

APAR Information

  • APAR number

    PK78543

  • Reported component name

    CICSTS V3 Z/OS

  • Reported component ID

    5655M1500

  • Reported release

    400

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2009-01-14

  • Closed date

    2009-03-18

  • Last modified date

    2009-04-02

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

    PK58814

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

    UK44943 UK44944

Modules/Macros

  •    DESSOAN  DESSOIS  DFHMESOE DFHSOCCC DFHSODCC
    DFHSOIS  DFHSOREC DFH78543 MFHMESOE
    

Publications Referenced
GC34644204GC34682701   

Fix information

  • Fixed component name

    CICSTS V3 Z/OS

  • Fixed component ID

    5655M1500

Applicable component levels

  • R400 PSY UK44943

       UP09/03/21 P F903

  • R500 PSY UK44944

       UP09/03/21 P F903

Fix is available

  • Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.

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Document Information

Modified date:
02 April 2009