IC67064: READ_RECORD DELETED ROWID ASSERTION FAILURE IS POSSIBLE WHEN 1 U SER IS TRYING TO DO A ISFIRST BTPOSITION LOOKUP AND A 2ND USER I

APAR status

• Closed as program error.

Error description

• The test case for this defect currently depends on the existence
  of idsdb203632 which is due to the fact that the chkparent call
  does a sqisread call with a mode of ISFIRST.
  
  The issue appears to be that in btposition if the very 1st item
  in an index gets deleted and the positioning user waits for the
  lock (and the delete is committed), when a user is attempting to
  do the sqisread with the mode of ISFIRST, btposition doesn't
  seem to correctly detect that the slot has been deleted (after
  being woken up when the lock is released) and lets the
  read_record() call attempt to read the row, which results in the
  read_record assertion failure.
  
  If the very 1st item in the index has already been deleted and
  we don't need to wait on the lock, we correctly see the slot as
  deleted and get into a btnext() call.  In this case, if we have
  to wait for a lock for the next lowest item, we will correctly
  tell that the slot was deleted when we are woken up on the lock,
  and do another btnext to get to the next non-deleted item.
  
  Only in the case where we need to position to the very 1st entry
  in the index, in slot 1, do we seem to fail to detect the item
  was deleted out from under us after we wait for the lock.
  
  The stack for the test case looks like the following:
  afstack()
  afhandler()
  affail_interface()
  read_record()
  gather_records()
  rsread()
  fmread()
  chkparent()
  chkrowcons()
  addone()
  insone_next()
  doinsert()
  excommand()
  sq_execute()
  sqmain()
  listen_verify()
  spawn_thread()
  startup()
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users                                                    *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * An assertion will be seen.                                   *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to 11.50.xc7 and above.                              *
  ****************************************************************
  

Problem conclusion

• Problem first fixed in 11.50.xc7.
  

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:

Fix information

• Fixed component name

  IBM IDS ENTRP E

• Fixed component ID

  5724L2304

Applicable component levels

• RB15 PSN

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