PK58914: PRUNE UN-REFERENCED COLUMNS FROM XMLTABLE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• 1. utilize XML Index even when parent axis is involved.
  2. prune un-referenced Columns from XML table.
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All DB2 users who use XMLTABLE               *
  *                 function, or parent axis in the              *
  *                 XPath predicate.                             *
  ****************************************************************
  * PROBLEM DESCRIPTION: This APAR improves the performance      *
  *                      of queries that have unreferenced       *
  *                      columns in XMLTABLE function,           *
  *                      or have parent axis in XPath            *
  *                      predicates.                             *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  This APAR improves the performance of queries that have
  unreferenced columns in XMLTABLE function, or have parent axis
  in XPath predicates.
  
  For example,
  
  SELECT X.C0
  FROM T1,
    XMLTABLE('/a/b/c' PASSING T1.XMLCOL
       Columns C0 VARCHAR(10) PATH 'd',
               C1 VARCHAR(10) PATH 'e'
       ) X;
  
  CREATE INDEX IDX_STR   ON T1(XMLCOL)
  GENERATE KEYS USING
         XMLPATTERN   '/a/b/str'  AS SQL VARCHAR(10);
  
  SELECT X.*
  FROM T1,
    XMLTABLE('/a/b/c' PASSING T1.XMLCOL
       Columns C0 VARCHAR(10) PATH 'd',
               C1 VARCHAR(10) PATH 'e'
       ) X
  WHERE XMLEXISTS('/a/b/c ../str="IBM" '
            PASSING T1.XMLCOL);
  

Problem conclusion

• DB2 is modified to optimize queries using XMLTABLE functions,
  or parent axis in XPath predicates.
  

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:

  UK37755

Modules/Macros

• DSNXNTRY DSNXOSO2 DSNXOW2H DSNXQFNR DSNXQPER
  DSNXQRWC DSNXQRWR DSNXQUTL
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• R910 PSY UK37755

     UP08/08/29 P F808

Fix is available

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