JR58823: Parallel Engine MD5 checksum is computed over a column with an extra | (pipe) character

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APAR status

• Closed as program error.

Error description

• A customer created an application which needed to compute an
  MD5 checksum which used exactly the same
  algorithm and data as was used inside the Information Server
  Parallel Engine Checksum stage. The customer found
  that the Parallel Engine appended an extra | (pipe) character
  to column data before computing the checksum and this made it
  difficult
  for the custom application to get the same result which the
  Checksum stage got.
  The  Checksum stage computes  an  MD5-encryption result based
  which is based on appending a | (pipe) character to the input.
  For  example, an input value of "0402190691182" computes  the
  hex-code
  11dab83edaf431c9db8fdd3c1e8459b1
  The hex-code that was generated by the stage corresponds to to
  the value "0402190691182|", where | is added in the end.
  Instead the hex-code should not have | at the end and generated
  c77b7e301b5b428c5c16472e944977a2
  

Local fix

Problem summary

• The stage Checksum provides as a result a MD5-encryption that
  has delim '|'
  For an example value of "0402190691182" provides the hex-code
  11dab83edaf431c9db8fdd3c1e8459b1
  The hex-code that was generated by the stage corresponds to to
  the value "0402190691182|", where | is added in the end.
  Instead the hex-code should not have | at the end and generated
  c77b7e301b5b428c5c16472e944977a2
  Fix Description
  ==========
  The way the columns are grouped together with the delimiter is
  managed by an underlying module which is used by other
  operators like Sequential export stage etc. Because of multiple
  stages dependency we cannot change the underlying behavior of
  not adding final delimiter.
  On the other side, what is seen is that if space is used as
  delimiter only then the final delimiter is ignored.
  Instead of generating checksum for "aaaaa|...|cccc|" I am
  suggesting the with environment variable the checksum will be
  generated for "aaaaa bbbbb cccc", where space is delimiter and
  final delimiter will be ignored as it is space.
  Customer's requirement for single column will also be met as
  checksum will be generated for "abcde" (not having final
  delimiter if it is single column) and for multiple columns the
  checksum will be generated for "aaaaa bbbbb cccc"
  The fix will be given by environment variable
  APT_CHECKSUM_DELIM_SPACE=1
  

Problem conclusion

• A patch is available which fixes the problem.
  

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:

Modules/Macros

• SERVER
  

Fix information

• Fixed component name

  WIS DATASTAGE

• Fixed component ID

  5724Q36DS

Applicable component levels

• R912 PSY

     UP