A fix is available
APAR status
Closed as program error.
Error description
CICS remains up while DB2 abends and restarts. CICS does not automatically reconnect to DB2 as soon as DB2 is ready to accept connections. There are 2 possible symptoms: 1) CICS does automatically reconnect to DB2 eventually after several (less than 5) minutes. Or 2) CICS never automatically reconnects to DB2 and CICS issues a " DFHDS0001 AN ABEND (CODE 0C4/AKEA) HAS OCCURRED AT OFFSET X'40C6' IN MODULE DFHDSDS4. " less than 5 minutes after DB2 was restarted. In a dump of CICS, either the DFHDS0001 0C4 in DFHDSDS4 dump or a console dump while CICS hasn't yet reconnected to DB2, the 'DB2=1' summary shows the status of the DB2 connection is Disconnecting and there are some transactions showing in the Transaction Summary. Note those transaction numbers and then go to the 'DS=1' summary. In the DS=1 summary, you will find that those transaction numbers are either suspended or dispatchable on an L8 TCB. Go to the bottom of the DS=1 summary and note the MVS TCB for each of the transactions (from the DB2=1 summary) that are shown as Suspended or Dispatchable on an L8 (from the DS=1 summary). . Go to Summ Format. You will find that those MVS TCBs are not in the address space. They are gone, but their corresponding CICS transactions do not know that. The CICS transactions are suspended or dispatchable on an MVS TCB that is gone. . KIXREVSWM
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All CICS users * **************************************************************** * PROBLEM DESCRIPTION: CICS never automatically reconnects * * to DB2 and issues a " DFHDS0001 AN * * ABEND (CODE 0C4/AKEA) HAS OCCURRED AT * * OFFSET X'40C6' IN MODULE DFHDSDS4. " * * message. * **************************************************************** * RECOMMENDATION: * **************************************************************** The 0c4 in DFHDSDS4 occurs if a transaction that has issued a DB2 call is in a CICS dispatcher wait, waiting on an ECB that is located in z/OS storage that is associated with the transactions open TCB. When DB2 crashes that ECB storage will be released when the TCB is deleted. When CICS attempts to terminate this CICS transaction it references the now non-existent ECB which causes an 0c4 to occur in DFHDSDS4. This 0c4 is not handled correctly which results in the CICS transaction hanging forever which prevents CICS reconnecting with DB2. Keywords: abend0C4 abendS0C4 0C4 S0C4
Problem conclusion
CICS has been changed so it now handles this 0c4 correctly and prevents the transaction from hanging. CICS now schedules SMSY to execute immediately instead on waiting for the next scheduled slot. The CICS Transaction Server for z/OS Version 5 Release 1 Diagnosis Reference GC34-2852-00 will be changed to add the following new exceptions to Chapter 83. Kernel Domain (KE) in the section "KEDS gate, FREE_TCBS function" :- "FREE_TCBS_LOCK_HELD TASK_NOT_TERMINATED" and a new section inserted before "KEDS gate, INQUIRE_MVSTCB function" :- "KEDS gate, FREE_TCBS_NOTIFY_IMMED function The FREE_TCBS_NOTIFY_IMMED function of the KEDS gate immediately notifies the Kernel system task that it needs to call function FREE_TCBS. Output Parameters RESPONSE Indicates whether the domain call was successful. For more information, see RESPONSE parameter on domain interfaces." The CICS Transaction Server for z/OS Version 5 Release 1 Trace Entries SC34-2873-00 manual will be changed to add the following trace point to Chapter 19. Kernel domain trace points in Table 159 "Kernel domain trace points" :- "KE 050B DFHKEDS Exc Notify error 1 KEDS parameter list 2 TISR parameter list"
Temporary fix
FIX AVAILABLE BY PTF ONLY
Comments
APAR Information
APAR number
PI23781
Reported component name
CICS TS Z/OS V5
Reported component ID
5655Y0400
Reported release
800
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2014-08-13
Closed date
2014-10-27
Last modified date
2015-03-05
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI22542 UI22543
Modules/Macros
DFHDPWB@
GC34285200 | SC34287300 |
Fix information
Fixed component name
CICS TS Z/OS V5
Fixed component ID
5655Y0400
Applicable component levels
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":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSGMGV","label":"CICS Transaction Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Line of Business":{"code":"LOB35","label":"Mainframe SW"}}]
Document Information
Modified date:
30 April 2020