IZ59120: INSTANCE MAY ABEND DURING COMPILATION OF A QUERY CONTAINING IMPL ICITLY EQUIVALENT COLUMNS AND A PREDICATE WITH AN EMPTY STRING

DB2 Version 9.1 Fix Pack 9  for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 10  for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 11  for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 12  for Linux, UNIX and Windows

APAR status

• Closed as program error.

Error description

• A query being compiled that has a local predicate (LOCPRD) with
  an empty string literal, i.e., '', may cause the instance to
  abend if the following conditions are satisfied:
  
  1) The column (COMPCOL) in LOCPRD is equivalent to another
  column (OTHCOL), e.g., via a join
  2) OTHCOL is also involved in a local predicate (OTHLOCPRD)
  3) LOCPRD is either an equi-join or non-equi-join predicate
  4) OTHLOCPRD is an equi-join predicate
  5) OTHCOL and COMPCOL are both string-type columns
  
  The stack trace from such an abend will look something like:
  
  sqlrxcp1
  sqlnr_seldel_test
  sqlnr_upddelpd_cond
  sqlnr_seq
  sqlnr_rcc
  sqlnr_magic_detail_action
  ...
  

Local fix

• Manually rewrite the query by adjusting the empty strings in
  the2 predicates involved to have the same length as the columns
   they are being compared against using spaces, e.g.,
  VARCHAR_4_COL = ''
  can be safely adjusted to:
  VARCHAR_4_COL = '    '
  

Problem summary

• A query being compiled that has a local predicate (LOCPRD) with
  
  an empty string literal, i.e., '', may cause the instance to
  abend if the following conditions are satisfied:
  
  1) The column (COMPCOL) in LOCPRD is equivalent to another
  column (OTHCOL), e.g., via a join
  2) OTHCOL is also involved in a local predicate (OTHLOCPRD)
  3) LOCPRD is either an equi-join or non-equi-join predicate
  4) OTHLOCPRD is an equi-join predicate
  5) OTHCOL and COMPCOL are both string-type columns
  
  The stack trace from such an abend will look something like:
  
  sqlrxcp1
  sqlnr_seldel_test
  sqlnr_upddelpd_cond
  sqlnr_seq
  sqlnr_rcc
  sqlnr_magic_detail_action
  ...
  

Problem conclusion

• First fixed in DB2 UDB Version 9.1 FixPak 9.
  

Temporary fix

• Manually rewrite the query by adjusting the empty strings in
  the2 predicates involved to have the same length as the columns
   they are being compared against using spaces, e.g.,
  VARCHAR_4_COL = ''
  can be safely adjusted to:
  VARCHAR_4_COL = '    '
  

Comments

APAR Information

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

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

  IC62780 IC62781 IC71236

Fix information

• Fixed component name

  DB2 UDB ESE SOL

• Fixed component ID

  5765F4102

Applicable component levels

• R910 PSY

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