Iceberg Spark Procedure register_table

A Spark SQL procedure in Apache Iceberg used to register an existing metadata JSON file as a table within the active catalog.

The Iceberg Spark Procedure register_table is a administrative utility executed via Spark SQL. It allows data engineers to register an existing Iceberg metadata JSON file (located in cloud or object storage) as a managed table in a different catalog. This procedure is commonly used for migrating tables between catalogs, disaster recovery, or cloning table states to test environments.

Syntax and Implementation

The procedure requires the destination table identifier and the absolute storage path pointing to the target .metadata.json file:

/* Register an existing table using its metadata JSON file path */
CALL prod.system.register_table(
    table => 'db.cloned_logs',
    metadata_file => 's3://my-bucket/db/web_logs/metadata/v12.metadata.json'
);

Architectural Benefits

Catalog Interoperability: Since Iceberg’s state is defined entirely within its metadata files, registering a table is a simple metadata swap that is catalog-independent.
Cloning Snapshot States: Data teams can clone a table at a specific historical state by registering the metadata JSON corresponding to a past snapshot version.
Disaster Recovery: If a catalog database is corrupted, the table state can be reconstructed by searching storage for the latest metadata JSON file and running register_table.

Iceberg Spark Procedure register_table