PH59039: SOS WHEN IDS FEATURE IS TURNED ON AND LONG RUNNING TASK

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Task storage is getmained during many EXEC SEND MAP commands.
  Each SEND MAP issues getmains of length 910, 1110 and 1910. This
  storage would continue to grow and consume EUDSA storage until
  SOS.
  
  
  BMS 3270 Intrusion Detection Service (IDS) feature uses an
  array which starts with an initial size. Elements are then added
  to this and if it eventually fills and more elements need to be
  added, a new area of storage is getmained, the current contents
  are copied over and the new element added. This 'new' array will
  be used and elements added as needed.... if that becomes too
  small the process repeats.
  
  It seems once this array is no longer needed, CICS only frees
  the 'current' array, and not any that were getmained and
  eventually found to be too small. All of these arrays will be
  cleaned up at end of task via an implicit freemain.
  
  
  The fact that this transaction is a long running transaction
  is the reason that this storage leak has been able to occur.
  

Local fix

• Try to avoid long running task or re-start long running task
  constantly in small intervals
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: Long running transaction with EXEC CICS *
  *                      SEND MAP loop caused a SOS condition in *
  *                      EUDSA.                                  *
  *                                                              *
  ****************************************************************
  When Intrusion Detection Services (IDS) feature toggle
  com.ibm.cics.bms.ids=true is ON and an EXEC CICS SEND MAP
  command is executed repeatedly, CICS BMS keeps acquiring
  USER storage from EUDSA to hold the amount of data required for
  IDS. This will normally be freemained at the end of the
  transaction.
  
  If the transaction is long running, then it may consume EUDSA
  storage until it leads a Short-on-storage (SOS) condition.
  

Problem conclusion

• CICS has been changed to FREEMAIN the USER storage if there is a
  subsequent GETMAIN.
  

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:

  UI96957 PH62036

Modules/Macros

• DFHMCP1$ DFHMCPA$ DFHMCPE$ DFHMCX
  

Fix information

• Fixed component name

  CICS TS Z/OS V6

• Fixed component ID

  5655YA100

Applicable component levels

• R400 PSY UI96957

     UP24/05/21 P F405

Fix is available

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