IT28596: QUERY WITH INDEX SCAN ON A COLUMNAR TABLE WHICH IS UNDER A UNIONMAY GET INCORRECT RESULT

APAR status

• Closed as program error.

Error description

• If Query has a Plan where UNION has a leg with Index Scan on a
  Columnar Table, then it is possible to get incorrect result.
  Example problem portion of the Plan:
  
                           UNION
                                |
                     /-------+-------\
             TBSCAN                     FETCH
             from                         /----+-----\
            Table A                  IXSCAN   CO-TABLE: Table B
                                              |
                                      INDEX: Index_Table_B
  

Local fix

• db2set  DB2_REDUCED_OPTIMIZATION="COL_IXSCAN_ALL_V1133 OFF"
  -im option can be used, BUT Static sql will need to be reboud
  and already compiled dynamic sql re-compiled as well.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * COLUMNAR TABLES WITH INDEXES ONLY                            *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Please, See Error Description and Install this Fix.          *
  ****************************************************************
  

Problem conclusion

• Please, See Error Description and Install this Fix.
  

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

  DB2 FOR LUW

• Fixed component ID

  DB2FORLUW

Applicable component levels

• RB10 PSY

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