External Table Limitations
The external table feature has the following limitations:
• The Spark Connector is a Spark application running under the user that is the owner of the Analytics Engine installation, typically actian. This means that only data sources for which that user has permissions to access (read or write) can be used in Analytics Engine.
• Operations not supported on external tables are usually reported with explicit errors. The main such unsupported operations are:
– Creating keys (of any type) and creating indexes (of any type) are not supported because they cannot be enforced (that is, they can be violated by the actions of an external entity)
– Adding and dropping columns
– Updates and deletes
• By default, there is only limited support for predicate pushdown or limit pushdown on external tables. This implies that potentially all data could be scanned and processed, regardless of the query. However, this issue can be mitigated by using the Advanced Staging Tables feature.
• It is recommended to use credentials, which is a more secure way to access cloud storage and other external services, instead of passing sensitive credential information in the SQL statement. If you use credential name to access remote objects, then you cannot use other options in the OPTIONS clause. This direct mode of passing sensitive credential information in SQL statements may be deprecated in the future. For more information, see
CREATE CREDENTIAL.
Last modified date: 09/11/2026