ClickHouse

Connecting to ClickHouse

To connect Semaphor to your ClickHouse instance, use a connection string in the following format.

Connection String Format

clickhousedb://username:password@host

• username – Your database username.
• password – The corresponding password.
• host – The hostname or IP address of your ClickHouse instance.

Example Connection String

If your ClickHouse user is default, your password is mypassword, and your host is instance.us-east-1.aws.clickhouse.cloud, your connection string will be:

clickhousedb://default:mypassword@instance.us-east-1.aws.clickhouse.cloud

Prerequisites

Before you connect Semaphor to ClickHouse, ensure the following requirements are met.

Database Permissions

• The user must have read access to the necessary tables.
• The user must be able to query information_schema table to retrieve metadata.

Network Access

• If your database is private, whitelist the Semaphor IP: 44.199.53.142 to allow connections.
• Make sure your firewall rules and security groups allow inbound connections from Semaphor.

Troubleshooting

If you encounter issues connecting to Clickhouse, review the following:

• Invalid Credentials: Verify your username and password.
• Network Restrictions: Confirm that your server accepts connections from Semaphor’s IP address.
• Incorrect Connection String: Double-check that your connection string matches the required format.
• Database Permissions: Make sure your database user has permission to query the necessary tables and metadata.

If you continue to experience issues, contact Semaphor Support for assistance.