IV64314: WHEN INTRA_PARALLEL ENABLED, SQL STATEMENT WITH IN PREDICATE MIGHT RETURN INCORRECT RESULTS

DB2 Version 10.1 Fix Pack 6 for Linux, UNIX, and Windows

APAR status

• Closed as program error.

Error description

• An incorrect result set might be produced when INTRA_PARALLEL is
  enabled for a SQL statement if all of the following conditions
  are met:
  (a) the statement contains an IN predicate referencing a numeric
  column type that is not an integer
  (b) the values list of the IN predicate contains integer values
  (c) the optimizer produces an access plan with a MSJOIN to apply
  the IN predicate as a join
  (d) the query degree of the access plan is > 1
  
  For example, if the column DECCOL is of type decimal, then the
  following IN predicate satisfies conditions (a) and (b):
  DECCOL IN (1,2,3)
  
  You can collect an EXPLAIN of the statement to confirm if a
  MSJOIN operation is performed and the query degree of the access
  plan is a value > 1.
  

Local fix

• You can attempt to avoid the MSJOIN operation by using an
  optimization guideline to request a different join alternative,
  such as NLJOIN or HSJOIN.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users                                                    *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to DB2 version 10.1.0.5.                             *
  ****************************************************************
  

Problem conclusion

• The problem is first fixed in DB2 version 10.1.0.5.
  

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:

  IT04924

Fix information

• Fixed component name

  DB2 FOR LUW

• Fixed component ID

  DB2FORLUW

Applicable component levels

• RA10 PSN

     UP