MapR 5.0 Documentation : Impala Limitations

What Impala Does Not Provide

Impala does not replace Hive or other frameworks built on MapReduce for long-running batch-oriented queries.

Impala is not fit as a query layer to support operational/OLTP applications (No update/deletes, not optimized for point look-ups).

Known Limitations in Impala 2.2.0

  • The LOAD DATA statement does not work when the source directory and destination table are in different encryption zones.
  • The Impala configuration option, --disk_spill_encryption, is not supported to secure sensitive data from being observed or tampered with when temporarily stored on disk.
  • Redaction of sensitive data from Impala log files is not supported. 
  • You cannot use the lineage information feature to track who has accessed data through Impala SQL statements.

Known Limitations in Impala 1.1.1

Impala provides limited HBase/MapR-DB support:

 

Impala does not respect memory limits configured in certain scenarios:

 

Impala does not spill to disk if intermediate results being processed on a node exceed the memory reserved for Impala on that node.
Example use cases impacted by this could include large table joins. The joined result set must fit into the aggregated memory of the cluster.