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Troubleshooting ClickHouse connectivity

Authentication failed​

Error: Authentication failed or password is incorrect or no user with such name

Cause: The username or password provided is incorrect, or the user doesn't exist in the ClickHouse instance.

Solution: Verify the username and password are correct. Connect to ClickHouse directly and confirm the user can authenticate:

SELECT currentUser();

If the user doesn't exist, create it by following the setup guide.

Connection refused​

Error: Connection refused or cannot connect

Cause: The ClickHouse instance isn't reachable from Atlan, or the HTTP interface isn't enabled on the specified port.

Solution:

  • Verify the host and port are correct. ClickHouse uses port 8443 for HTTPS by default.
  • Confirm that the ClickHouse HTTP interface is enabled in your ClickHouse server configuration.
  • Make sure your firewall or security group rules permit inbound connections from Atlan's IP addresses on the specified port.
  • For databases behind a firewall, consider using Self-Deployed Runtime.

Insufficient privileges​

Error: Access denied or insufficient privileges

Cause: The configured user doesn't have the necessary SELECT permissions on ClickHouse system tables.

Solution: Grant the required permissions by following the setup guide. At a minimum, the user needs SELECT access to system.databases, system.tables, and system.columns.