A fix is available
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
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Document Information
Modified date:
04 May 2020