UDF Limitations

Impala UDFs have the following limitations:

  • Impala cannot work with UDFs that accept or return composite, nested, or types not available in Impala tables.
  • UDFs must produce the same output each time the same argument value is passed.
  • UDFs cannot spawn other threads or processes.
  • UDFs become undefined when you restart the catalogd process. In this scenario, you must reload the UDFs.
  • You currently cannot include user-defined table functions in Impala queries.