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  1. IMPALA
  2. IMPALA-10388

Document the limitation on mask functions

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    Details

    • Type: Documentation
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: Impala 4.0
    • Component/s: Docs
    • Labels:
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      Description

      Hive's mask functions are GenericUDFs. Impala currently doesn't support Hive GenericUDFs, so we have our builtin implementation for them. Due to lack of a corresponding framework for GenericUDF in Impala (IMPALA-9271), we implement these mask functions by overloads. However, it may requires hundreds of overloads to cover all possible combinations. We just implement some important overloads, including

      • those used by Ranger default masking policies,
      • those with simple arguments and may be useful for users,
      • an overload with all arguments in int type for full functionality. Char argument need to be converted to their ASCII value.

      If you encountered errors like "No matching function with signature: mask...", it means Impala is lack of the corresponding overload. Use the following query to find the available overloads:

      show functions in _impala_builtins like "mask*";
      

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            • Assignee:
              shajini shajini thayasingh
              Reporter:
              stigahuang Quanlong Huang
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                Updated:
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