Delta Direct¶

Delta Direct lets you create a read-only Apache Iceberg™ table in Snowflake from a Delta Lake table in external cloud object storage. Snowflake reads the Delta transaction log (_delta_log/) and registers the table’s Parquet data files without copying or rewriting them, so you can query your Delta Lake data with Snowflake while other engines continue to write to it.

Delta Direct is one type of Direct Iceberg table.

Create a Delta Direct table¶

To create a Delta Direct table, complete the following steps:

1. Create an external volume that points to the cloud storage location of your Delta table. For instructions, see Configure an external volume.
2. Create a catalog integration with CATALOG_SOURCE = OBJECT_STORE and TABLE_FORMAT = DELTA. For instructions, see Delta Lake table files.
3. Create an Iceberg table with CREATE ICEBERG TABLE (Delta files in object storage).

The following example shows these steps:

CREATE ICEBERG TABLE my_delta_iceberg_table
  CATALOG = delta_catalog_integration
  EXTERNAL_VOLUME = delta_external_volume
  BASE_LOCATION = 'relative/path/from/ext/vol/'
  AUTO_REFRESH = TRUE;

Refresh a Delta Direct table¶

To keep the table in sync with your Delta table, set a refresh interval on the catalog integration and use automated refresh, or refresh the table manually with ALTER ICEBERG TABLE … REFRESH. For more information, see Automatically refresh Apache Iceberg™ tables.

Storage access and metadata writes¶

Delta Direct only needs read access to your storage. If your external volume allows writes, Snowflake can also write Iceberg metadata for the table to your storage. For more information, see Delta-based tables and Read-only vs write access for Delta Direct on each storage provider.

Data types¶

For how Delta data types map to Snowflake data types, see Delta data types.

Considerations and limitations¶

For limitations, see the following sections:

• Usage notes
• Refresh