PH34965: CICS REGION SUFFERS DFHIS1015 ERROR CODE (X'0515') DURING CPU SHORTAGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• During a period of high CPU a connection (IPCONN) is dropped by
  TCPIP or a TCPIP Client. This high CPU situation takes away CPU
  resources from other CICS regions. Since the CICS region
  associated with the dropped connection is not getting enough
  CPU there is a window in IPCONN acquire processing where the
  CISS task can get delayed due to the CPU shortage.
  .
  When the inbound connection is closed by the client,
  because the IPIC connection wasn't established in time, CSOL is
  notified but cannot locate the correct IPCONN or CISS task to
  notify of this.  The fact the connection is closed then gets
  lost.  The send of the IPCONN capex (Capability Exchange)
  response is successful even though the client will never receive
  it.
  .
  Inbound only IPCONNs are able to acquire with just a single
  socket so that is why the IPCONN ends up acquired at this point
  even though the connection is closed. Since the IPCONN appears
  as ACQuired in CICS the INITIALIZE_CONNECTION from the client
  fails because you cannot ACQuire an IPCONN that is already
  ACQuired. This results in the DFHIS1015 code (x'0515) message
  being issued.
  .
  Additional Symptom(s) Search Keyword(s): DFHIS1015 0515
  INITIALIZE_CONNECTION , KIXREVRJL
  

Local fix

• The IPCONN can be made to work again by manually releasing it.
  A simple SET IPCONN REL command is enough because the
  client will reconnect successfully on its next retry interval
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS Users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: CICS suffers a DFHIS1015 error code     *
  *                      (X'0515').                              *
  ****************************************************************
  It is possible for CICS to suffer a DFHIS1015 error code
  (X'0515') during times when the CICS region is being CPU
  constrained.
  The error happens when a client system connected
  to a CICS region using an IPCONN does not get a response to its
  capability exchange quickly enough and closes the socket.
  This can result in CICS believing the IPCONN is acquired and the
  client believing it is released, and the client will keep
  sending in CAPEX (Capability Exchange requests) into CICS.
  Each of these CAPEX requests will result in a DFHIS1015 message.
  

Problem conclusion

• CICS has been changed to issue a new message DFHIS1047 and
  an exception trace entry to indicate the client has closed the
  socket.
  
  The CICS TS IBM Documentation has been changed to add a new
  message DFHIS1047:
  
  DFHIS1047 date time applid The capability exchange was abandoned
  for IPCONN ipconn from applid applid because the client has
  closed the connection.
  
  Explanation
  
  During processing of a connection request for an IPIC web
  session IPCONN ipconn, CICS received a capability exchange
  request at the same time the connection was being closed.
  
  System Action
  
  An exception trace is written by IS domain, indicating the
  connection has been unexpectedly closed. The capability exchange
  will fail and the IPCONN is not acquired.
  
  User Response
  
  Investigate why the client has closed the connection.
  
  
  The new exception trace is IS 0550:
  
  IS 0550 DFHSICO Exc CLIENT SOCKET CLOSED 1 ISCO parameter list
  

Temporary fix

Comments

APAR Information

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

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

  UI75535 UI75536 UI75537

Modules/Macros

• DFHCIS4  DFHISAL  DFHISCO  DFHISCOP DFHISCOT DFHISCU  DFHISDM
  DFHISDUF DFHISEM  DFHISEMP DFHISFS  DFHISIC  DFHISIF  DFHISIS
  DFHISJU  DFHISLQ  DFHISLQP DFHISPH  DFHISPHP DFHISPRP DFHISRE
  DFHISREU DFHISREX DFHISRR  DFHISRRP DFHISRS  DFHISRSP DFHISSR
  DFHISST  DFHISTRI DFHISUE  DFHISXF  DFHISXM  DFHISXS  DFHISZA
  DFHMEISC DFHMEISE DFHMEISK DFHMIRS  DFHMNXM  DFHWBAP  DFHWBAPF
  DFHWBCL  DFHWBDM  DFHWBDUF DFHWBSO  DFHWBSV  DFHWBSVT DFHWBXM
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels

• R100 PSY UI75537

     UP21/05/25 P F105

• R200 PSY UI75536

     UP21/05/25 P F105

• R300 PSY UI75535

     UP21/05/26 P F105

Fix is available

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