IBM Support

PH16111: LOCATION STATISTICS (IFCID 365) ENHANCEMENTS

A fix is available

Subscribe

You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • Multiple issues with location statistics:
    - connection received count is not updated until the request
      has been allocated to a DBAT
    - various location counters in the IFCID 365 record are not
      being serialized when updated which leads to incorrect
      values for those statistics, especially the new connection
      count
    - invalid values are returned for some location entries
      when the maximum entries (95) per ifcid365 record are
      returned during a READS request
    
    Additional keywords and symptoms:
    ***********************************
    DB2DDF DDF IFCID365 QW0165
    

Local fix

  • no local fix or workaround
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All Db2 12 for z/OS Distributed Data                         *
    * Facility (DDF) users. Specifically those                     *
    * who utilize location statistics (IFCID365).                  *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * Update to Db2's location statistics                          *
    * (IFCID365) support, including both                           *
    * defect fixes and new functionality.                          *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Apply corrective PTF when available                          *
    ****************************************************************
    This APAR provides a service update to DB2's location
    statistics (IFCID365) support, including both defect fixes
    and new functionality.  In particular, this service update
    APAR addresses the following issues:
    1.When a new conversation (connection) is received from a
      location, the received connection count does not get updated
      until the connection has been assigned to a DBAT.
    2.Various location statistics counters are not properly
      serialized during their update by multiple concurrent
      connections from the same location leading to inaccurate
      values.
    3.During a READS request to obtain the IFCID365 location
      statistics data for any location with which the Db2
      subsystem has had any activity, invalid data was returned
      to the requesting READS program when the maximum number
      of location entries (95) was generated into the IFCID365
      record.
    4.Not enough information is provided in a location's
      statistics data (QLST) to assist database administrators,
      system administrators, and/or application users on how the
      location impacted a Db2 subsystem.
    

Problem conclusion

  • The following changes have been made:
    1.A location's connection received count will now be updated
      prior to the request being assigned to a DBAT for
      processing.
    2.The update of any location statistic will now be performed
      via zSeries instructions which permit the serialization of
      the update between concurrent tasks.
    3.The program which generates the IFCID365 trace data for a
      statistics trace or READS request has been changed to ensure
      that sufficient storage is available to generate location
      statistics trace data up to the maximum number of entries
      per IFCID365 trace record.
    4.To provide more information about the impact of a remote
      location on a Db2 subsystem when Db2 is a server to the
      location:
      - The IFCID365 location statistics (DSNDQLST) will have new
        fields added and existing fields will be changed.  The
        changes will be described below.
      - Due to the size increase of each location's data, the
        maximum number of location entries in one IFCID365 trace
        record has been changed to 50 from 95.
      - All locations that the Db2 subsystem has had any
        activity with since DDF was started will be included
        in a statistics interval trace record. All locations are
        already reported in a READS request.
    A location entry in an IFCID365 statistics trace record is
    called a QLST and its description for programming purposes is
    provided in macro DSNDQLST which is being changed by this
    APAR. The following existing field is being changed:
    QLSTCNVQ - NUMBER OF CONNECTION REQUESTS QUEUED BY DDF THAT
               ARE WAITING FOR ALLOCATION (REQUESTER) OR WAITING
               FOR A DBAT DUE TO MAXDBAT BEING REACHED (SERVER).
               A LARGE VALUE FOR A REQUESTER INDICATES THAT IN
               THE DB2 VTAM APPL ENTRY FOR THE SUBSYSTEM, THE
               MAXIMUM NUMBER OF SESSIONS FOR COMMUNICATION WITH
               A PARTNER (DSESLIM) MIGHT NEED TO BE INCREASED.
               A LARGE VALUE FOR A SERVER INDICATES THAT THE
               DB2 SUBSYSTEM PARAMETER (MAXDBAT) MIGHT NEED TO
               BE INCREASED.
    The following new fields, which are ONLY updated when Db2 is
    a server to the location, are added after the previously last
    field, QLSTPRLV:
    QLSTNREST - NUMBER OF TIMES THAT A CONNECTION FROM THE REMOTE
                SITE INVOKED A REST SERVICE.
    QLSTNSSR - NUMBER OF TIMES THAT A CONNECTION FROM THE REMOTE
               SITE CAUSED A SYSTEM MONITORING PROFILE TO SET
               SPECIAL REGISTERS.
    QLSTNSGV - NUMBER OF TIMES THAT A CONNECTION FROM THE REMOTE
               SITE CAUSED A SYSTEM MONITORING PROFILE TO SET
               GLOBAL VARIABLES.
    QLSTNWLB - NUMBER OF CONNECTIONS FROM THE REMOTE SITE
               USING SYSPLEX WORKLOAD BALANCING.
    QLSTNTLS - NUMBER OF CONNECTIONS FROM THE REMOTE SITE
               CONFIGURED WITH SSL AND AT/TLS SUPPORT.
    QLSTNTRS - NUMBER OF CONNECTIONS FROM THE REMOTE SITE
               UNDER CONTROL OF A TRUSTED CONTEXT.
    QLSTNAES - NUMBER OF CONNECTIONS FROM THE REMOTE SITE
               USING AES ENCRYPTION.
    QLSTNXA - NUMBER OF CONNECTIONS FROM THE REMOTE SITE
              UNDER CONTROL OF AN XA GLOBAL TRANSACTION.
    QLSTNENC - NUMBER OF CONNECTIONS FROM THE REMOTE SITE
               USING DRDA DATA ENCRYPTION.
    QLSTNPWD - NUMBER OF CONNECTIONS FROM THE REMOTE SITE
               USING USERID AND/OR PASSWORD AUTHENTICATION.
    QLSTNKER - NUMBER OF CONNECTIONS FROM THE REMOTE SITE
               USING KERBEROS AUTHENTICATION.
    QLSTNMFA - NUMBER OF CONNECTIONS FROM THE REMOTE SITE
               USING MULTI-FACTOR AUTHENTICATION.
    QLSTNCCA - NUMBER OF CONNECTIONS FROM THE REMOTE SITE
               USING CLIENT CERTIFICATE AUTHENTICATION.
    QLSTFSEC - NUMBER OF TIMES THAT A CONNECTION FROM THE REMOTE
               SITE HAD SECURITY AUTHENTICATION FAILURES.
    QLSTHCRSR - NUMBER OF TIMES THAT CURSORS DEFINED WITH
                HOLD PREVENTED THREAD POOLING.
    QLSTDGTT - NUMBER OF TIMES WHERE THE EXISTENCE OF ACTIVE
               DECLARED GLOBAL TEMP TABLES PREVENTED THREAD
               POOLING.
    QLSTKPDYN - NUMBER OF TIMES WHERE THE USAGE OF KEEPDYNAMIC
                PACKAGES PREVENTED THREAD POOLING.
    QLSTHIPRF - NUMBER OF TIMES WHERE THE USAGE OF HIGH
                PERFORMANCE DBATS PREVENTED THREAD POOLING.
    QLSTHLOBLOC - NUMBER OF TIMES WHERE THE EXISTENCE OF ACTIVE
                  HELD LOB LOCATORS PREVENTED THREAD POOLING.
    QLSTSPCMT - NUMBER OF TIMES WHERE A STORED PROCEDURE ISSUED
                COMMIT PREVENTED THREAD POOLING.
    QLSTCNVTC - NUMBER OF CONNECTIONS FROM THE REMOTE SITE THAT
                WERE TERMINATED DUE TO CONDBAT BEING REACHED.
    QLSTCNVTP - NUMBER OF CONNECTIONS FROM THE REMOTE SITE THAT
                WERE TERMINATED DUE TO SYSTEM MONITORING PROFILE
                EXCEPTION.
    QLSTCNVTQN - NUMBER OF CONNECTIONS FROM THE REMOTE SITE THAT
                 WERE TERMINATED DUE TO MAXCONQN BEING REACHED.
    QLSTCNVTQW - NUMBER OF CONNECTIONS FROM THE REMOTE SITE THAT
                 WERE TERMINATED DUE TO MAXCONQW BEING REACHED.
    QLSTNTHDPQ - NUMBER OF TIMES WHERE THREADS USED BY CONNECTIONS
                 FROM THE REMOTE SITE WERE QUEUED DUE TO A SYSTEM
                 MONITORING PROFILE EXCEPTION.
    QLSTNTHDPT - NUMBER OF TIMES WHERE THREADS USED BY CONNECTIONS
                 FROM THE REMOTE SITE WERE TERMINATED DUE TO A
                 SYSTEM MONITORING PROFILE EXCEPTION.
    QLSTNTHDA - NUMBER OF TIMES WHERE THREADS USED BY CONNECTIONS
                FROM THE REMOTE SITE ABENDED.
    QLSTNTHDC - NUMBER OF TIMES WHERE THREADS USED BY CONNECTIONS
                FROM THE REMOTE SITE WERE CANCELED.
    QLSTNCNV - CURRENT NUMBER OF ACTIVE CONNECTIONS FROM THIS
               LOCATION.
    QLSTHCNV - HIGHEST NUMBER OF ACTIVE CONNECTIONS FROM THIS
               LOCATION SINCE THE LAST STATISTICS TRACE INTERVAL
               FOR A STATISTICS TRACE REQUEST. FOR A READS
               REQUEST, HIGHEST NUMBER OF ACTIVE CONNECTIONS FROM
               THIS LOCATION SINCE DDF WAS STARTED.
    QLSTNTHD - CURRENT NUMBER OF ACTIVE THREADS IN USE BY THIS
               LOCATION.
    QLSTHTHD - HIGHEST NUMBER OF ACTIVE THREADS IN USE BY THIS
               LOCATION SINCE THE LAST STATISTICS TRACE INTERVAL
               FOR A STATISTICS TRACE REQUEST. FOR A READS REQUEST,
               HIGHEST NUMBER OF ACTIVE THREADS IN USE BY THIS
               LOCATION SINCE SINCE DDF WAS STARTED.
    A new field is being added in a previously unused area of the
    QLST, between fields QLSTLOCN_OFF and QLSTLOCN, which will
    enable IFCID365 trace or READS processing programs to
    determine what fields are present in a QLST entry, as
    follows:
    QLSTVRSN - WHEN FIELD IS SET GREATER THAN OR TO:
                '000001' - THE QLST SECTION CONTAINS FIELDS
                           QLSTLOCN_OFF TO QLSTHTHD.
                OTHERWISE - THE QLST SECTION CONTAINS FIELDS
                            QLSTLOCN_OFF TO QLSTPRLV.
    
    The DSNWMSGS file, which contains full descriptions of all
    fields within a trace record for every IFCID, will be updated
    with changes made by this APAR in a documentation APAR at a
    later date.
    

Temporary fix

Comments

APAR Information

  • APAR number

    PH16111

  • Reported component name

    DB2 OS/390 & Z/

  • Reported component ID

    5740XYR00

  • Reported release

    C10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2019-08-27

  • Closed date

    2020-04-14

  • Last modified date

    2020-05-02

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

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

    UI69010

Modules/Macros

  • DSNLXRSS DSNLBABR DSNLTDCM DSNLXRSQ DSNLIDDC DSNLXRSL DSNLCMT2
    DSNLCMT1 DSNLXXSS DSNLCMSL DSNLTMIN DSNLTSEC DSNLXROP DSNLVPF5
    DSNLCTDR DSNLXMRF DSNLIRTR DSNLTPCM DSNLXRCL DSNLXHPR DSNLTDPR
    DSNLJTIN DSNLVCLM DSNLTSET DSNLVALM DSNLAGNX DSNLVRPL DSNLCDG2
    DSNLAGNT DSNLCDG1 DSNLTCM1 DSNLXCQH DSNLXHSE DSNWVZSA DSNLXRBF
    DSNLCCLO DSNLTPBA DSNLTP1S DSNDQLST DSNLCTRC DSNLXRFT DSNLIRCA
    DSNLXHOC DSNLEDDA DSNLIRSY DSNLQINA DSNLXHSP DSNLQCRP DSNDQW05
    DSNLXHIM DSNLVCIP DSNLTDRB DSNLXRQX DSNLTDRC DSNLTEXC DSNLCDP2
    DSNLCDP1 DSNLILNR DSNLISDA DSNLXCQ7 DSNLXHNO DSNLXRAX DSNLXCQ6
    DSNLVDDC DSNLVSRC DSNWAACT DSNWVZPS DSNLDUMP DSNLTPRC DSNLTRB1
    DSNLCSRR DSNLVSDA DSNWDFDI DSNLQDIS DSNLIASY DSNLTGBK DSNLQACT
    DSNLTPPR DSN3AUCN DSNLXRDT DSNLCRTD DSNLTMSC DSNLQCTL DSNLQXED
    DSNLTBAB DSNLVRFY DSNLTACC
    

Fix information

  • Fixed component name

    DB2 OS/390 & Z/

  • Fixed component ID

    5740XYR00

Applicable component levels

  • RC10 PSY UI69010

       UP20/04/18 P F004

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.

[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSEPEK","label":"Db2 for z\/OS"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
04 May 2020