PH67658: ABOVE THE LINE PRIVATE STORAGE EXHAUSTION IN THE EXCI ADDRESS SPACE AFTER CICS TS 6.2 UPGRADE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Starting at CICS TS 6.2 the minimum value that can be specified
  for the internal trace table size has been increased from 1 MB
  to 12 MB. The EXCI has its own internal trace table in the EXCI
  address space where the client program is running. In CTG (CICS
  Transaction Gateway) region that uses EXCI connection to CICS
  and allocates many EXCI pipes over time might lead to above the
  line private storage exhaustion and eventually raise these
  messages:
  
  DFHEX0003  A GETMAIN request in module DFHXCTRI (code X'0901')
  has failed. Reason X'00000004'.
  DFHEX0113  EXCI trace Initialization has failed.
  
  This also can cause abend878 begin to appear leading CTG region
  to crash.
  .
  Additional keywords/symptoms:
  Internal trace table size x'00C00000' x'C00000' C00000 (= 12MB)
  In storage, DFHTRANCHOR block + x'18' shows trace table size.
  e.g.
  2126F000  03286EC4 C6C8E3D9 C1D5C3C8 D6D94040 | ..>DFHTRANCHOR
  2126F010  00000000 00000000 00C00000 00000000 | .........{......
                             ^^^^^^^^
  .
  ip verbx vsmdata 'noglobal,summary' then find on '2126F000' in
  this instance shows:
  -- DQE Listing ..
  ..
  DQE:  Addr 2126F000 Size   1000
                                  FQE: Addr 2126F328 Size CD8
  DQE:  Addr 21541000 Size C00000
  .
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: Above the line private storage          *
  *                      exhaustion in the EXCI address space.   *
  ****************************************************************
  CICS 6.2 base code was changed to make the minimum CICS internal
  trace table size 12Mb (dec) to improve serviceability. It had
  previously been 1Mb. This change also affected the EXCI trace
  table size.
    For environments that utilise EXCI, such as CTG, their "batch
  job" made repeated calls to create and tear down EXCI
  environments. Many STORAGE OBTAINS for 12 Mb were made.
  Eventually the MVS storage usage accumulated so much that an
  878 abend occurred on a GETMAIN.
  

Problem conclusion

• CICS has been changed to revert the default (and minimum) EXCI
  trace table sizes to be 1 Mb.
    The CICS EXCI documentation at:
  https://www.ibm.com/docs/en/cics-ts/6.x?topic=exci-using-
  options-table-dfhxcopt
  will be updated to change the default value for TRACESZE to be
  1024(kb), in both the table showing the format of the DFHXCOPT
  macro and its parameters, and in the description for the
  TRACESZE parameter itself.
  

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:

  UO06050 UO06051 UO06052 UO06053

Modules/Macros

• CJA9DBUG CJB9DBUG CJI9DBUG CJJ9DBUG DFHSMOM  DFHSMON  DFHSMOS
  DFHTRAO  DFHTRDM  DFHTRDUF DFHTRFFE DFHTRFPB DFHTRFT  DFHTRPRA
  DFHTRPT  DFHTRPX  DFHTRSR  DFHTRSU  DFHTRTRI DFHTRXDF DFHXCO
  DFHXCOPT DFHXCPRH DFHXCTRI DFHXCTRP EYU0DVAF EYU9DBUG EYU9XZUT
  

Fix information

• Fixed component name

  CICS TS Z/OS V6

• Fixed component ID

  5655YA100

Applicable component levels

• R500 PSY UO06052

     UP25/12/09 I 1000 ¢

• R50M PSY UO06053

     UP25/12/09 I 1000 ¢

• R600 PSY UO06050

     UP25/12/09 I 1000 ¢

• R60M PSY UO06051

     UP25/12/09 I 1000 ¢

Fix is available

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