An external catalog synchronizes metadata from another catalog implementation and presents the resulting Iceberg tables as read-only to non-owning query engines. It provides centralized visibility without taking control of table writes, supporting architectures that separate storage, metadata, and compute. section 7.4.10 section 7.4.4
External catalogs are useful when organizations need:
- A shared view of Iceberg tables managed by systems such as Snowflake, Glue, or Dremio Arctic. section 7.4.10 section 7.4.4
- Read-only access for engines such as Spark, Flink, Trino, or Dremio while write ownership remains elsewhere. section 7.4.10 section 7.4.4
- Centralized permissions and temporary storage credentials without exposing cloud credentials directly to engines. section 7.4.10 section 7.4.4
