PI30997: IMS SHUTDOWN HANGS AT OTMA PHASE=3 BECAUSE CM0 TASK WAITING FOR ACK 15/01/16 PTF PECHANGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Customer reported that IMS control region hung after a '/CHE
  DUMPQ' was issued to shutdown IMS. Part of the output from the
  /DIS SHUTDOWN STATUS' showed that a CM0 task was active..
  G58 OTMA PHASE=3
  G59 COMMIT 0  TMEMBER=MEO2        TPIPE=MQM1111
  X99 *14306/053042*
  .
  Analysis from the dump shows the following:
  TSCD: 1FA1F4D0
  +0080  SHUTCM0.. 21FA8738  <- CM0 task holding up shutdown.
  YQAB: 21FA8A08
  +0000 EYECATCH. YQABYQAB NEXTPTR.. 00000000 CLBPTR.. 21FA8738<<
        TPIPEPTR. 21FA7190 LTERM.... MQMPRO01 MTEPTR.. 1F74B180
  +0020 PREFXPTR. 21FA8AB0 ACKTMO... 0078     LTERMOVR. 00000000
        00000000  SYNCAWE. 00000000 SYNCTMO.. FFE2D5C4
                                            x'FF'  ** wait for ACK
                                            x'E2D5C4' ** SND
  +006C  RT_TOKEN. 00000000  00000000
         SENDTIME. 2014306F  000038C2  ==> 11/02/2014 04:02:10
  ********  ******** >time output sent to client
  Note: the 'output send' and 'STOP OTMA' happened at same times.
  00.01.47 STC07625 ---- SUNDAY,    02 NOV 2014 ----
  :
  04.02.10 STC07625  R 016,/STO OTMA
  04.02.10 STC07625  DFS058I 04:02:10 STOP COMMAND COMPLETED
  The '/STOP OTMA' causes IMS to leave XCF group.
  The '/CHE DUMPQ' was issued at 04:02:33 that initiates the
  IMS shutdown process. The CM0 task waiting for ACK/NAK has
  put the shutdown "on hold" and hangs the shutdown.
    Examined the OTMA shutdown code, STOP OTMA code and OTMA XCF
  send code and identified the root cause of the problem.In the
  XCF_send routine DFSYSND0 the YQAB_WAIT_for_CONFIRM flag was
  turned on for OTMA CM0 output send. Right before the routine
  issued the XCF send,OTMA checked the OTMA server token
  ( MTETOKEN ). If the token is zero, DFSYSND0 will IWAIT waiting
  for a non-zero OTMA server token. In customer's case,this server
  token is zero. Because the token was cleared by the STOP OTMA
  command and IMS is about to shutdown. Later OTMA shutdown phase
  3 found this active YQAB. It resets the YQAB_WAIT_FOR_CONFIRM
  and IPOST the IWAIT of DFSYSND0. Since OTMA server token is
  still zero, DFSYSND0 issued another IWAIT. Because this IWAIT
  in DFSYSND0 will always be there our OTMA phase 3 shutdown will
  never complete. IMS then hung forever.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: IMS V13 customers with OTMA APAR PI12922/    *
  *                 PTF UI16341                                  *
  ****************************************************************
  * PROBLEM DESCRIPTION: IMS shutdown hung after /STOP OTMA      *
  ****************************************************************
  * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF      *
  ****************************************************************
  When /STOP OTMA command was issued to prepare for shutdown,
  OTMA server token was then cleared by APAR PI12922. However,
  if there is any OTMA output message to be sent to a client,
  this message could be put into IWAIT and wait for the non-zero
  OTMA server token. A non-zero OTMA server token can be created
  if a /START OTMA command is issued which is not going to happen
  in the IMS shutdown process. Because of this OTMA IWAIT,
  IMS shutdown cannot complete.
  

Problem conclusion

• GEN:
  KEYWORDS:
  
  *** END IMS KEYWORDS ***
  IMS OTMA XCF send routine, DFSYSND0, was enhanced to avoid
  IWAITing for non-zero OTMA server token if we are processing
  shutdown for OTMA messages.
  
  IMS OTMA phase 1 shutdown process in DFSYMOM0 was enhanced
  to avoid calling XCF send if OTMA server token is zero.
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

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

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

  PI32932 UI25352

Modules/Macros

• DFSYMOM0 DFSYSND0
  

Fix information

• Fixed component name

  IMS V13

• Fixed component ID

  5635A0400

Applicable component levels

• R300 PSY UI25352

     UP15/02/24 P F502 «

Fix is available

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