PI77633: CHANGE CRC32 ALGORITHM.

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• Change CRC32 algorithm.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All DB2 12 for z/OS users of the HASH_CRC32 built-in         *
  * function.                                                    *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * The HASH_CRC32 built-in function uses a CKSUM calculation to *
  * return a result.                                             *
  * This result can be considered to be incorrect if a CRC32     *
  * result is expected.                                          *
  * The HASH_CRC32 built-in function should use a CRC32          *
  * algorithm.                                                   *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply corrective PTF when available                          *
  ****************************************************************
  The HASH_CRC32 built-in function uses a CKSUM calculation to
  return a result. This is not a CRC32 algorithm.
  The result can be considered to be incorrect if a CRC32 result
  is expected.
  The HASH_CRC32 built-in function should use a CRC32 algorithm.
  

Problem conclusion

• The HASH_CRC32 built-in function is being replaced and will now
  use a standard CRC32 algorithm to compute a result.
  The results will differ from those returned prior to this apar.
  The use of the function has not changed.
  
  It should be noted that in order to be consistent, the result
  for the HASH_CRC32 function for a given string will now differ
  from that provided prior to this apar.
  
  For example, using the documented example.
  
  Prior to this apar,
  
  SELECT HEX(HASH_CRC32('ABCDEFGHIJKLMNOPQRZTUVWXYZ'))
  FROM SYSIBM.SYSDUMMYU;
  
  The result returned should be:  x1D23D6D6
  
  
  After this apar,
  
  SELECT HEX(HASH_CRC32('ABCDEFGHIJKLMNOPQRZTUVWXYZ'))
  FROM SYSIBM.SYSDUMMYU;
  
  The result returned should be:  xB4B86309
  
  The DB2 12 for z/OS SQL Reference publication will be updated to
  reflect this change for the HASH_CRC32 built-in function.
  
  Additionally, it is important to note that existing users of
  this function will need to discard any previous result if saved
  and/or
  used in some way since it is considered to be incorrect. After
  applying this apar, a new value will need to be computed for
  use.
  
  Additional   Keywords: SQLCRC32 SQLFUNCTION DB2INCORR/K
  INCORROUT SQLINCORR SQLINCORROUT
  

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:

  UI46824

Modules/Macros

• DSNXRBIN DSNXRBND DSNXGUDF
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RC10 PSY UI46824

     UP17/05/15 P F705

Fix is available

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