PH66304: NEW FUNCTION FOR LOCK TABLE

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• New Function - This apar is for Epic 30823 to improve data
  availability for LOCK TABLE statements in thread-reuse
  situations
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All Db2 13 for z/OS users who are using      *
  *                 universal tablespace and execute LOCK        *
  *                 TABLE statements with the RELEASE            *
  *                 DEALLOCATE duration in effect during         *
  *                 thread-reuse scenarios.                      *
  ****************************************************************
  * PROBLEM DESCRIPTION: A Db2 application or thread that        *
  *                      issues LOCK TABLE statements might      *
  *                      result in partition lock(s) being       *
  *                      acquired with a "RELEASE DEALLOCATE"    *
  *                      duration for universal table space.     *
  *                      As a result, the partition lock(s) can  *
  *                      be held beyond the logical connection   *
  *                      end due to thread reuse. This           *
  *                      condition can result in resource        *
  *                      unavailable or lock contention for      *
  *                      other applications attempting to        *
  *                      access the table's data. This           *
  *                      situation can be observed in a local    *
  *                      or distributed (DDF) environment.       *
  *                                                              *
  *                      The following symptoms have been        *
  *                      observed:                               *
  *                      A new user in a multithreaded           *
  *                      situation might hit timeout and         *
  *                      receive SQLCODE=-913, SQLSTATE=57003,   *
  *                      SQLERRMC=00C9008E                       *
  *                      The reused thread continues to hold     *
  *                      the partition locks from a previous     *
  *                      execution, with a lock-acquired time    *
  *                      that is before the sign-on time. A new  *
  *                      user might inherit a lock from a        *
  *                      previous user.                          *
  *                                                              *
  *                      Additional symptoms: -913 SQLCODE913    *
  *                      00C9008E RC00C9008E                     *
  ****************************************************************
  When a Db2 application issues a LOCK TABLE statement with
  RELEASE DEALLOCATE in effect, partition locks may persist
  beyond the logical connection end in thread-reuse scenarios.
  This issue occurs during connection reuse or new user sign-on,
  whether through Distributed Data Facility (DDF) with
  high-performance database access threads (HIPERF DBAT) or local
  Db2 application connections. As a result, one of the following
  may occur:
  -A new user in a multithreaded environment may encounter
  timeouts, receiving SQLCODE -913, SQLSTATE 57003, SQLERRMC
  00C9008E.
  -A reused thread may retain partition locks from a prior
  execution, with a lock-acquired time predating the new user's
  sign-on, causing the new user to inherit locks from a previous
  user.
  To resolve this, Db2 should release partition locks acquired by
  LOCK TABLE statements upon a new user sign-on or new
  connection, eliminating residual lock side effects.
  

Problem conclusion

Temporary fix

Comments

• This new function APAR provides a solution to release the
  partition lock(s) obtained by a LOCK TABLE statement during a
  new user sign-on or a new connection, thereby eliminating the
  side effects caused by the residual lock.
  

APAR Information

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

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

  UO03449

Modules/Macros

• DSN3AB00 DSN3CMIT DSN3ONLY DSN3PR00 DSN3PRP  DSN3SI30 DSN3SY00
  DSNICMT2 DSNIIEPL DSNIPSFI DSNITCUS DSNIUNWB DSNLIRTR DSNLJXUS
  DSNLQCTL DSNLTACC DSNLTCM1 DSNLTDSR DSNLTRB1 DSNTACT  DSNTANU
  DSNVDTA  DSNWAACT DSNWDFDS
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RD10 PSY UO03449

     UP25/06/07 P F506  

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.