A fix is available
APAR status
Closed as new function.
Error description
Db2 13 for z/OS System Profile improvements Additional Symptoms and Keywords: db2spm spm profile_sys
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: * * All Distributed Data Facility (DDF) users. * * Specifically those that use profiles to * * monitor threads for remote clients that * * access Db2 using TCP/IP. * * Db2 13 for z/OS (function level V13R1M500 * * or higher). * **************************************************************** * PROBLEM DESCRIPTION: * * System Profile monitor threads * * queuing improvements. * **************************************************************** * RECOMMENDATION: * **************************************************************** When a MONITOR THREADS profile reaches its exception threshold limit, subsequent DBATs monitored by the same profile might be queued waiting for the next available DBAT slot, monitored by the same profile, to terminate or be pooled. When this event occurs, the current Db2 internal mechanism used to queue the DBAT incorrectly affects the system MAXDBAT value. The incorrect behavior might affect the overall performance of Db2 in relation to the system-wide setting of the MAXDBAT subsystem parameter. Also, when the DBATs that are queued because of the profile exception condition, they are misrepresented as being Type1 inactive DBATs being suspended Note: MAXTYPE1 subsystem parameter has been deprecated and it is no longer supported in Db2 13 or later.
Problem conclusion
Temporary fix
Comments
Db2 for z/OS System Profile has been enhanced to provide additional thread status and DDF global system statistics counters related to DBATs that are queued when a profile exception was reached. This improvement will allow the user to clearly distinguish those DBATs that are in this waiting state when a profile exception occurs. Furthermore, this will eliminate the misunderstanding of those DBATs being queued (because of a profile exception) are not related to the deprecated MAXTYPE1 subsystem parameter. The changes introduced by PH47626 become available when function level V13R1M500 or higher is activated in Db2 13. Message DSNV402I from -DISPLAY THREAD command report: A new ST column value, 'RS', is implemented to uniquely identify a thread (DBAT) is being suspended because of a system profile exception condition. Example: DSNV402I -DB2A ACTIVETHREADS NAME ST A REQ ID AUTHID PLAN ASID TOKEN SERVER RS * 2 abc user1. DISTSERV 1234 1 The value of 'RS' is described as follows: RS - A DBAT is servicing a request from a remote client. The thread is suspended because a system profile MONITOR THREADS exception threshold was reached. The threshold is specified in the DSN_PROFILE_ATTRIBUTES ATTRIBUTE2 column value for the associated profile PROFILEID row. The thread is queued until other threads that are monitored by the same profile deallocate or go inactive, providing an available slot. The thread resumes when a slot becomes available, and the thread is next in the queue. Existing value 'RQ' will be updated as follows: RQ - A DBAT is servicing a request from a remote client. The thread is suspended because the maximum number of active DBATs was reached, as specified by the MAXDBAT system parameter. DBATs are queued until other DBATs deallocate or go inactive, providing an available slot. The DBAT resumes when a slot becomes available, and the DBAT is next in the queue. Message DSNL093I from -DISPLAY DDF DETAIL command report: A new counter, PQDBAT, will be added to display the current number of DBATs queued because of a system profile exception threshold being reached. Example: When PQDBAT=0, this means there are currently no DBATs queued because of a system profile exception. -DISPLAY DDF DETAIL ... DSNL093I DSCDBAT=0 INACONN=0 IUDBAT=0 PQDBAT=0 Example: When PQDBAT=1, this means there is currently 1 DBAT being queued because of a system profile exception threshold being reached. -DISPLAY DDF DETAIL ... DSNL093I DSCDBAT=0 INACONN=0 IUDBAT=2 PQDBAT=1 The description of PQDBAT is as follows: PQDBAT - The current number of DBATs queued because a system profile exception threshold was reached. This value increases as more DBATs that match a system profile reach the specified exception threshold. This value decreases as DBATs that match the system profile terminate or the connection becomes inactive. The online product documentation for Db2 is updated for these changes: https://www.ibm.com/docs/en/db2-for-zos The global DDF system section of Db2 statistics which is mapped by DSNDQDST is being updated to include two new fields QDSTDBPQ and QDSTMDPQ. QDSTDBPQ - the current number of DBATs suspended due to system profile exception was reached. QDSTMDPQ - the maximum number of DBATs suspended due to system profile exception was reached since DDF started. A full description of the changes to DSNDQDST is provided in the ++HOLD DOC included with this APAR. 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.
APAR Information
APAR number
PH47626
Reported component name
DB2 OS/390 & Z/
Reported component ID
5740XYR00
Reported release
D10
Status
CLOSED UR1
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2022-06-29
Closed date
2022-08-03
Last modified date
2022-09-01
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI81803
Modules/Macros
DSNLJEMG DSNFLDIR DSNVDTA DSNDQDST DSNLTEXC DSNLTACT DSNWZDG2 DSNWDFDS DSNLIRTR DSNFCDIR DSNLTDDF DSNWAKIS DSNLJTIN DSNWAACT DSNWVZPS DSNLTACC
Fix information
Fixed component name
DB2 OS/390 & Z/
Fixed component ID
5740XYR00
Applicable component levels
RD10 PSY UI81803
UP22/08/12 P F208
Fix is available
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Document Information
Modified date:
01 September 2022