Cloudera Docs

JDBC mode limitations

You must understand the limitations of JDBC mode and what functionality is not supported.

Keep the following limitations of JDBC mode in mind:
  • JDBC_CLUSTER and JDBC_CLIENT are used for reads only, and are recommended for production workloads of 1 GB or less. With larger workload bottlenecks develop in data transfer to Spark.

    Writes through HWC of any size are recommended for production. Writes do not use JDBC mode.

  • In JDBC_CLUSTER mode, HWC fails to correctly resolve queries that use the ORDER BY clause when run as hive.sql(" <query> "). The query returns unordered rows of data even though the query contains an ORDER BY clause.
  • In JDBC read mode, a query of a table having a column of a complex type, such as ARRAY, STRUCT and MAP, incorrectly represents the type as String in the returned DataFrame.