read_delta

Read a Delta Lake table from the local filesystem or supported object store.

Note: read_delta was formerly known as delta_scan

Syntax

-- Single url or path.
read_delta(<url>)
-- Using a cloud credentials object.
read_delta(<url>, <credential_object>)
-- Required named argument for S3 buckets.
read_delta(<url>, <credentials_object>, region => '<aws_region>')
-- Pass S3 credentials using named arguments.
read_delta(<url>, access_key_id => '<aws_access_key_id>', secret_access_key => '<aws_secret_access_key>', region => '<aws_region>')
-- Pass GCS credentials using named arguments.
read_delta(<url>, service_account_key => '<gcp_service_account_key>')

Parameter descriptions and which object store it’s relevant to.

Parameter	Object store	Description
url	All	The URL or path to a delta table to scan.
credential_object	S3 and GCS	A database object storing credentials for accessing the object or objects.
aws_region	S3	If scanning an object in S3, the region of the bucket.
aws_access_key_id	S3	ID of AWS access key with permissions to read from the bucket.
aws_secret_access_key	S3	Secret associated with the AWS access key.
gcp_service_account_key	GCS	A JSON-encoded GCP service account key with access to the bucket.

The path or URL provided to read_delta should be to a directory containing a _delta_log/ directory.

Usage

Local files

Local Delta table can be read with read_delta by passing in a path to the table. Paths may be absolute or relative.

-- Read a relative path.
SELECT * FROM read_delta('./directory/my_delta_table/');

Objects in GCS

Objects in GCS can be read by providing the path to the object and credentials for the object to read_delta. The service account key provided should be JSON encoded.

-- Single object.
SELECT * FROM read_delta('gs://my-bucket/path/delta_table',
                           service_account_key => '<service_account_key>');

Optionally, a credentials object can be created and used in place of providing the service account key directly.

-- Create the credentials.
CREATE CREDENTIALS my_gcp_creds PROVIDER gcp
    ( service_account_key '<service_account_key>' );
-- And use them in the scan.
SELECT * FROM read_delta('gs://my-bucket/path/delta_table', my_gcp_creds);

Objects in S3

Objects in GCS can be read by providing the path to the object and credentials for the object, and the bucket region to read_delta.

SELECT * FROM read_delta('gs://my-bucket/path/delta_table',
                           access_key_id = '<access_key_id>',
                           secret_access_key = '<secret_access_key>',
                           region = 'us-east-1');

Optionally, a credentials object can be created and used in place of providing the service account key directly.

-- Create the credentials.
CREATE CREDENTIALS my_aws_creds PROVIDER aws
    OPTIONS (
        access_key_id = '<access_key_id>',
        secret_access_key = '<secret_access_key>',
    );
-- And use them in the scan. Note that a region still needs to be provided.
SELECT * FROM read_delta('gs://my-bucket/path/delta_table', my_aws_creds, region => 'us-east-1');