PH27375: WHEN USING THE DB2 AUTH EXIT DSNX@XAC, THERE ARE MORE RE SIGNONS TO DB2 THAN NECESSARY

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• If you use the Db2 auth exit DSNX@XAC, CICS, when reusing a Db2
  thread, will match a new CICS transaction to a Db2 thread in
  such a way that there are more calls to Db2 for reSIGNon than
  necessary.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS Users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: A CICS using the Db2 Authorization exit *
  *                      DSNX@XAC may result in more re-signons  *
  *                      to Db2.                                 *
  ****************************************************************
  The use of the Db2 authorization exit DSNX@XAC may result in
  more re-signons to Db2 and a noticeable increase in CPU
  consumption. The increase in CPU consumption is due to the
  extra calls to RACF because of the need to perform a full Db2
  signon. The full signon is being forced because the new thread
  chosen from the free chain, matches against authname but because
  DSNX@XAC is being used it also needs to match against ACEEs.
  As the ACEEs do not match DFHD2D2 will force a Db2 full signon.
  

Problem conclusion

• In DFHD2EX1 get_a_connection where the check is made for any
  free threads, if the DSNX@XAC is in use add a check for the new
  tasks ACEE matches the thread on one of the free chains before
  using it.
  

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:

  UI71809 UI71810 UI71811

Modules/Macros

• DFHD2EX1
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels

• R100 PSY UI71811

     UP20/10/01 P F009

• R200 PSY UI71810

     UP20/09/30 P F009

• R300 PSY UI71809

     UP20/09/30 P F009

Fix is available

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