IT33391: UDR EXPRESSION AGAINST IN CLAUSE WOULD EVALUATE/EXECUTE THE UDR FOR EVERY ELEMENT IN THE IN CLAUSE

APAR status

• Closed as suggestion for future release.

Error description

• Given a condition of the form
  
   "function_name(column) IN (list_of_values)"
  
  the server would execute the function expressions once for each
  of the list values, rather than evaluating this expression once
  only and comparing the result against all list values.
  Consequences would be longer query duration, higher cpu
  consumption and, possibly, higher memory demand.
  
  This behavior occurs regardless of the function being defined as
  NOT VARIANT, one reason being that the IN clause gets re-written
  as a series of OR clauses.
  

Local fix

• Problem was observed with a UDR returning lvarchar
  -> changing this into varchar(255) was possible and avoided the
  problem.
  

Problem summary

Problem conclusion

Temporary fix

Comments

• Defect will be addressed in future releases.
  

APAR Information

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

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

Fix information

Applicable component levels