Singdata - Documents

Overview

Cross-instance data sharing allows you to securely share tables or views in Lakehouse with users in other instances without copying data. Using CREATE SHARE and GRANT commands, you can precisely control the scope and permissions of sharing. This guide is organized by business scenario to help you quickly master data sharing configuration.

SQL Commands Involved

Command	Purpose	Use Case
`CREATE SHARE`	Create a share object	Define a data sharing container
`GRANT ... TO SHARE`	Grant table/view access to a share	Configure share content
`ALTER SHARE ... ADD INSTANCE`	Add a consumer instance	Specify sharing targets
`SHOW SHARES`	View share list	Monitor share status
`DROP SHARE`	Delete a share	Clean up obsolete shares

Prerequisites

The following examples use a simulated shared table shared_sales:

-- Create test table CREATE TABLE IF NOT EXISTS shared_sales ( sale_id INT, product STRING, amount DOUBLE, sale_date DATE ); -- Insert test data INSERT INTO shared_sales VALUES (1, 'Phone', 5000, '2024-06-01'), (2, 'Laptop', 8000, '2024-06-02');

Use CREATE SHARE to define a share object as a container for data sharing.

-- Create a share CREATE SHARE sales_share;

💡 Tip: A newly created share is empty by default. Use GRANT to add tables or views.

Granting Shared Tables

Use the GRANT command to grant read access on a table or view to a share object.

-- Grant read access on a shared table GRANT SELECT ON TABLE shared_sales TO SHARE sales_share;

Supported permissions:

SELECT: Allows consumer instances to query table data.
READ METADATA: Allows consumer instances to view the table schema.

Adding Consumer Instances

Use ALTER SHARE to add a target Lakehouse instance to the share, enabling it to access the shared data.

-- Add a consumer instance (replace with the actual instance ID) ALTER SHARE sales_share ADD INSTANCE 'consumer_instance_id';

⚠️ Note: Consumer instances must be under the same Singdata platform account, or a cross-account sharing policy must be configured.

Use SHOW SHARES to view all share configurations for the current instance.

-- View share list SHOW SHARES; -- View share details DESC SHARE sales_share;

Returned information:

share_name: Share name
kind: Share type (OUTBOUND / INBOUND)
objects: List of shared tables/views

Use REVOKE or DROP SHARE to remove share permissions.

-- Revoke share permission on a table REVOKE SELECT ON TABLE shared_sales FROM SHARE sales_share; -- Delete the share DROP SHARE sales_share;

💡 Tip: Deleting a share does not affect the source table data; it only cuts off the consumer instance's access channel.

Cleaning Up Test Data

After completing share verification, it is recommended to clean up the test table:

-- Drop test table DROP TABLE IF EXISTS shared_sales; DROP SHARE IF EXISTS sales_share;

💡 Tip: Lakehouse supports UNDROP TABLE, so accidentally dropped tables can be recovered within the retention period.

Notes

Read-only sharing: Shares only support SELECT permission; consumer instances cannot modify source table data.
Real-time access: When a consumer instance queries a shared table, it reads the latest data from the source instance directly with no synchronization delay.
Network policy: Cross-cloud or cross-region sharing requires that network policies (such as PrivateLink) are correctly configured.
Permission inheritance: Row-level permissions or dynamic data masking policies on shared tables also take effect on consumer instances.
Billing: Compute resource consumption from shared queries is borne by the consumer instance; storage costs are borne by the provider.

FAQ

Issue	Cause	Solution
CREATE SHARE reports insufficient permissions	Requires the `instance_admin` role	Contact an administrator to grant `instance_admin`
Consumer cannot see the Share	Provider has not executed ADD INSTANCE	Provider executes `ALTER SHARE <share> ADD INSTANCE <consumer_instance>`
DESC SHARE reports Share not found	`instance_name` is incorrect	Confirm the exact value of the `provider_instance` field via `SHOW SHARES`
Consumer cannot find a table after mounting the Schema	The table was not included in the GRANT	Provider re-executes `GRANT SELECT, READ METADATA ON TABLE ... TO SHARE`
Only want to share certain columns or rows	Sharing the table directly exposes all data	Create a VIEW to filter the required columns/rows first, then add the VIEW to the Share

Lakehouse Cross-Instance Data Sharing Guide (Share)

Overview

SQL Commands Involved

Prerequisites

Creating a Data Share

Granting Shared Tables

Adding Consumer Instances

Viewing Share Information

Revoking a Share

Cleaning Up Test Data

Notes

FAQ

Related Documentation