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IZ43788: DB2 MAY ISSUE SQL0901N EXECUTING A QUERY WITH CORRELATED REFERENCES TO A TABLE FROM AN OUTER JOIN

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • An SQL0901N may be issued when executing a query containing a
    LEFT or RIGHT OUTER JOIN (LOJ) if correlation exists to the
    table from the row-preserving (RP) side of the LOJ.
    
    The following conditions must be satisfied for the scenario to
    occur:
    - The RP table has a unique key associated with it
    - 2 or more levels of correlation exist to the RP table
    - All correlated constructs are inner-joined after the LOJ
    (either directly or via transitivity) on the correlated column
    
    An example scenario follows:
    
    -- Table DDL
    CREATE TABLE RP (PK_C CHAR(2) NOT NULL PRIMARY KEY);
    CREATE TABLE NP (J_C CHAR(2));
    
    -- Table Function DDL
    CREATE FUNCTION F1(IN_C CHAR(2))
    RETURNS TABLE   (OUT_C CHAR(2))
    LANGUAGE SQL
    DETERMINISTIC
    NO EXTERNAL ACTION
    BEGIN ATOMIC
     DECLARE DUMMY CHAR(2);--
    SET (DUMMY) = (IN_C);--
    RETURN VALUES(IN_C);--
    END;
    
    CREATE FUNCTION F2(IN_C CHAR(2))
    RETURNS TABLE   (OUT_C CHAR(2))
    LANGUAGE SQL
    DETERMINISTIC
    NO EXTERNAL ACTION
    READS SQL DATA
    RETURN
    SELECT  A.J_C
    FROM  (VALUES(IN_C)) AS A(J_C)
    LEFT OUTER JOIN NP AS B
    ON  B.J_C = A.J_C;
    
    -- Query that will issue the SQL0901N
    SELECT A.PK_C
    FROM   RP AS A,
          TABLE(F1(A.PK_C)) AS B, -- First level of correlation
         TABLE(F2(B.OUT_C)) AS C   -- Second level of correlation
    WHERE A.PK_C = B.OUT_C   -- Explicit inner-join
    AND   B.OUT_C = C.OUT_C   -- Inner-join via transitivity
    ;
    
    -- SQLCODE issued
    SQL0901N  The SQL statement failed because of a non-severe
    system error.
    Subsequent SQL statements can be processed.  (Reason "Bad Plan;
    Unresolved QNC
    found".)  SQLSTATE=58004
    
    This problem will be first fixed in DB2 Verson 9.1 Fix Pack 9.
    

Local fix

  • No workaround exists aside from manually rewriting the query in
    question.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * EE or EEE                                                    *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description.                                       *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 Version 9.1 Fix Pack 9 or later.              *
    ****************************************************************
    

Problem conclusion

  • First Fixed in DB2 Version 9.1 Fix Pack 9.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IZ43788

  • Reported component name

    DB2 UDB ESE AIX

  • Reported component ID

    5765F4100

  • Reported release

    910

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2009-02-13

  • Closed date

    2010-04-21

  • Last modified date

    2010-04-21

  • APAR is sysrouted FROM one or more of the following:

    IZ43786

  • APAR is sysrouted TO one or more of the following:

Fix information

  • Fixed component name

    DB2 UDB ESE AIX

  • Fixed component ID

    5765F4100

Applicable component levels

  • R910 PSN

       UP

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Document Information

Modified date:
21 April 2010