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
Impala has the following known limitations:
- 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.
Impala UDFs (user-defined functions) have the following known limitations:
- Impala does not 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.
- Prior to Impala 2.5.0, UDFs become undefined when you restart the catalog service. You must reload the UDFs.
- You currently cannot include user-defined table functions in Impala queries.