JR28835: HIGH2KEY AND LOW2KEY ARE TRUNCATED IN DB2 FOR LUW NICKNAMES ON D B2 FOR Z/OS TABLES WITH DECIMAL(14) OR LARGER COLUMNS

APAR status

• Closed as fixed if next.

Error description

• When you create a nickname on a DB2 for z/OS table that has a
  DECIMAL column with a precision of 14 or greater, the values of
  HIGH2KEY and LOW2KEY that DB2 for LUW puts into SYSCAT.COLUMNS
  might be truncated.
  
  For example, suppose that the DB2 for z/OS table has the
  following columns with the following values for HIGH2KEY and
  LOW2KEY:
  
  NAME           CHAR(HEX(HIGH2KEY)) CHAR(HEX(LOW2KEY))
  -------------- ------------------- ------------------
  DEC14_COL      F012345678912345    F011345678912345
  DEC15_COL      F123456789123456    F113456789123456
  
  DB2 for LUW will put the following in SYSCAT.COLUMNS.  Note that
  the last two digits of the HIGH2KEY and LOW2KEY values are
  incorrectly set to 0.
  
  COLNAME         HIGH2KEY           LOW2KEY
  --------------- ------------------ -----------------
  DEC14_COL       +12345678912300.   +11345678912300.
  DEC15_COL       +123456789123400.  +113456789123400.
  
  The fix will be as follows:
  
  - For columns with a precision of 14 or 15, DB2 for LUW will put
  the correct values of HIGH2KEY and LOW2KEY into SYSCAT.COLUMNS.
  
  - If the data source is DB2 for z/OS Version 7 and the precision
  is 16 or greater, then DB2 for LUW will not set HIGH2KEY and
  LOW2KEY.  This is necessary because DB2 for z/OS Version 7
  stores only 8 bytes for HIGH2KEY and LOW2KEY.  Therefore when
  the decimal column has a precision of 16 or greater, DB2 for LUW
  cannot get accurate values for HIGH2KEY and LOW2KEY.
  

Local fix

• Either of the following:
  
  (1) Run NNSTAT on the nickname column using data-based
  statistics collection (METHOD parameter = 2).  SYSPROC.NNSTAT is
  described in the DB2 V9.1 Info Center at
  http://publib.boulder.ibm.com/infocenter/db2luw/v9/index.jsp?top
  ic=/com.ibm.websphere.ii.federation.query.doc/administering/rfps
  ts08.html
  
  (2) Update the statistics manually, for example:
  
  UPDATE SYSSTAT.COLUMNS
     SET (high2key, low2key) =
        ('high2key_value', 'low2key_value')
     WHERE tabschema = 'nickname_schema' AND
        tabname = 'nickname' AND
        colname = 'nickname_column';
  
  This requires knowing the correct values for HIGH2KEY and
  LOW2KEY.
  

Problem summary

• Users affected:
     Users of the DB2 for LUW Homogeneous Federation Feature or
  InfoSphere Federation Server
  Problem description and summary:
     See error description.
  The problem is fixed in Future release
  

Problem conclusion

Temporary fix

Comments

APAR Information

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

  JR28556

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

Fix information

Applicable component levels

• R820 PSN

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