A fix is available
APAR status
Closed as program error.
Error description
When using -START RLIMIT with SCOPE(Group) option, for any INSERT/DELETE/UPDATE to any table in any member, Db2 is possible to invoke -START RLIMIT command internally. When there are many internal control blocks were left as uncleaned under notify exit service tasks, CPU consumption will increase due to the loop in DSNXKAC1 to go through these control blocks. Additional Keywords: DB2RLF LOOPDSNXKAC1 DB2STGLK/K ZSA4
Local fix
To clean these control blocks, Db2 restart is needed. Please take below steps: 1. Issue -START RLIMIT command without SCOPE(GROUP) from all members. This will ensure that all members's internal flag of SCOPE(GROUP) is reset. 2. Restart Db2 member by member to clean these left control blocks Please make sure to complete step 1 on all members and then start to restart Db2. Otherwise, if any member has the internal flag on for SCOPE(GROUP), then the internal -START RLIMIT on this member will bring to all other members.
Problem summary
**************************************************************** * USERS AFFECTED: * * All Db2 12 for z/OS users of the * * START RLIMIT SCOPE(GROUP) command * **************************************************************** * PROBLEM DESCRIPTION: * * High CPU consumption due to loop * * in DSNXKAC1 when using * * -START RLIMIT with the SCOPE(GROUP) * * option * **************************************************************** * RECOMMENDATION: * * Apply corrective PTF when available * **************************************************************** When the -START RLIMIT with SCOPE(Group) option is used, a subsequent INSERT/DELETE/UPDATE to the active RLF table triggers the refresh of the in-memory RLF table in each member of the data sharing group. The auto refresh process in members where the update was not done left internal control blocks when looking up Db2 catalog table to verify the active RLF table. When many of these internal control blocks were left as uncleaned under the notify exit service tasks, CPU consumption will increase due to the loop in DSNXKAC1 to go through these control blocks.
Problem conclusion
Db2 code has been changed to release storage when looking up catalog to refresh the in-memory RLF table in the notify exit. Additional keywords: RLF
Temporary fix
********* * HIPER * *********
Comments
APAR Information
APAR number
PH13905
Reported component name
DB2 OS/390 & Z/
Reported component ID
5740XYR00
Reported release
C10
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2019-06-26
Closed date
2019-09-30
Last modified date
2019-11-01
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI65580
Modules/Macros
DSNTCSRC
Fix information
Fixed component name
DB2 OS/390 & Z/
Fixed component ID
5740XYR00
Applicable component levels
RC10 PSY UI65580
UP19/10/15 P F910 ¢
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"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"12.0","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}},{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SG19M","label":"APARs - z\/OS environment"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"12.0","Edition":"","Line of Business":{"code":"","label":""}}]
Document Information
Modified date:
01 November 2019