PI31459: MANY DSNT501I AND DSNT376I FOR INDEX CLEANUP DAEMON

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Quite a number of dsnt376i / dsnt501i  messages were being
  received, involving the index clean-up daemon thread when it
  timed out. It doesn't seem to be necessary to externalize
  this information.
  Messages were of the kind:
  DSNT376I  -DSN  PLAN=IDAEMK WITH
          CORRELATION-ID=014.IDAEMKxx
          CONNECTION-ID=DSN
          LUW-ID=xxxxxxxx.xxxxxxxx.xxxxxxxxxxxx
          THREAD-INFO=
  SOPR:..................:................:.......................
  .....
  ....:*:*  :*:*
          IS TIMED OUT. ONE HOLDER OF THE RESOURCE IS
  ..
  DSNT501I  -DSN  DSNILMCL RESOURCE UNAVAILABLE
             CORRELATION-ID=014.IDAEMKxx
             CONNECTION-ID=DSN
             LUW-ID=xxxxxxxx.xxxxxxxx.xxxxxxxxxxxx=0
             REASON 00C9008E
             TYPE 00000D01
             NAME 00000nnn.0000nnnn
  Additional keywords: timeout , time out , rc00C9008E , IDAEMK .
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All DB2 11 for z/OS users using indexes.     *
  ****************************************************************
  * PROBLEM DESCRIPTION: Index pseudo delete cleanup processing  *
  *                      may encounter lock timeouts and issue   *
  *                      many DSNT376I and DSNT501I messages.    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  An index pseudo delete cleanup thread needs to acquire DBD lock
  and table lock before updating the index to remove the pseudo
  deleted entries. If the required locks have already been held by
  other applications, index pseudo delete cleanup thread could
  timeout and issue many DSNT376I and DSNT501I messages. Because
  index pseudo delete cleanup threads tend to give other
  applications higher priority, normally they are the victims in
  the timeout situation. Index pseudo delete cleanup threads are
  designed to run in the background and to not block other
  applications, issuing a large amount of timeout messages. This
  can be alarming to the users while there is no real contention
  in the system.
  

Problem conclusion

• DB2 code has been changed to not issue DSNT376I and DSNT501I
  messages if an index pseudo delete cleanup thread timed out
  while waiting for the necessary locks in order to remove the
  pseudo deleted entries from an index. If, however, the index
  pseudo delete cleanup threads are the lock holders and caused
  other applications to timeout, DSNT376I and DSNT501I messages
  will continue to be issued.
  Additional keywords: MSGDSNT501I MSGDSNT376I INDEXDAEMON
  

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:

  UI26612

Modules/Macros

•    DSNILMCL DSNTLSUS
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RB10 PSY UI26612

     UP15/04/23 P F504

Fix is available

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