IT07789: IWA: SELECT CAN MISS RESULT ROWS FROM DATA MARTS WITH A N:M CARDINALITY REFERENCE

APAR status

• Closed as program error.

Error description

• The problem is with a snowflake schema, where a reference on the
  second level (or beyond) is not a 1:n cardinality reference.
  
  Consider the following join examples:
  
  a)   fact table  ---- 1:n reference  ---->  dimension 1 table
  ---- n:m reference ---->  dimension 2 table :
  
      A query on such a data mart can miss result rows, because
  not all the non-unique rows from the
      dimension 2 table are gathered for the join with the
  dimension 1 table.
  
  b)   fact table  ---- n:m reference ---->  dimension table :
  
      A query on such a data mart produces correct results.
  
  c)   fact table  ---- n:m reference  ----> dimension 1 table
  ---- n:m reference ----> dimension 2 table :
  
      A query on such a data mart produces correct results.
      Here, the reference from fact table to dimension 1 table
  simply was made an n:m reference as well
      (even though dimension 1 table has unique keys and would
  satisfy the requirements for a 1:n reference).
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users having data marts with n:m cardinality references.     *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Update to IBM Informix Server 12.10.xC6                      *
  ****************************************************************
  

Problem conclusion

• Problem Fixed In IBM Informix Server 12.10.xC6
  

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

  INFORMIX SERVER

• Fixed component ID

  5725A3900

Applicable component levels

• RC10 PSY

     UP