PI90226: ODBC THREADS DEADLOCK ON THE MUTEX WHEN ODBC APPLICATION TRACE IS ENABLED

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• When ODBC application trace is enabled, the ODBC threads can
  deadlock on the mutex and caused more threads to queue waiting
  for the mutex. Then the applications hung. This problem occurs
  only when the ODBC application trace is enabled.  The hung is
  in application address space. The SVC 1 wait PSW is within LE
  module CEEOPMLR. There is a small window when one ODBC thread
  held H latch and then request AT Latch while the other thread
  held AT Latch and then request H latch, thus the deadlock.
  

Local fix

• Turn off ODBC application trace because the AT latch is
  held only when the ODBC application trace is enabled.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users of DB2 11 and 12 for                               *
  * z/OS ODBC/CLI driver                                         *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * ODBC application may hit a deadlock                          *
  * situation and hang when ODBC                                 *
  * application trace is enabled.                                *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply corrective PTF when available                          *
  ****************************************************************
  When ODBC application trace is enabled and there are multiple
  threads running concurrently, a deadlock situation may
  occur when one thread is attempting to record an SQLAllocEnv()
  call in the application trace, and another thread is writing
  the error information to the application trace.
  

Problem conclusion

• The deadlock situation is resolved.
  

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:

  UI53616 UI53617

Modules/Macros

• DSNAOCLI DSNAOC02 DSNAOG02 DSNAOSDK
  

Fix information

• Fixed component name

  DB2 ODBC/JDBC/S

• Fixed component ID

  5740XYR02

Applicable component levels

• RC17 PSY UI53616

     UP18/02/16 P F802

• RB17 PSY UI53617

     UP18/02/20 P F802

Fix is available

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