This documentation describes the integration of MindsDB with ClickHouse, a high-performance, column-oriented SQL database management system (DBMS) for online analytical processing (OLAP). The integration allows MindsDB to access data from ClickHouse and enhance ClickHouse with AI capabilities.

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Prerequisites

Before proceeding, ensure the following prerequisites are met:

  1. Install MindsDB locally via Docker or Docker Desktop.
  2. To connect ClickHouse to MindsDB, install the required dependencies following this instruction.

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Connection

Establish a connection to ClickHouse from MindsDB by executing the following SQL command and providing its handler name as an engine.

CREATE DATABASE clickhouse_conn
WITH ENGINE = 'clickhouse', 
PARAMETERS = {
   "host": "127.0.0.1",
    "port": "8443",
    "user": "root",
    "password": "mypass",
    "database": "test_data",
    "protocol" : "https" 
    }

Required connection parameters include the following:

  • host: is the hostname or IP address of the ClickHouse server.
  • port: is the TCP/IP port of the ClickHouse server.
  • user: is the username used to authenticate with the ClickHouse server.
  • password: is the password to authenticate the user with the ClickHouse server.
  • database: defaults to default. It is the database name to use when connecting with the ClickHouse server.
  • protocol: defaults to native. It is an optional parameter. Its supported values are native, http and https.

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Usage

The following usage examples utilize the connection to ClickHouse made via the CREATE DATABASE statement and named clickhouse_conn.

Retrieve data from a specified table by providing the integration and table name.

SELECT *
FROM clickhouse_conn.table_name
LIMIT 10;

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Troubleshooting

Database Connection Error

  • Symptoms: Failure to connect MindsDB with the ClickHouse database.
  • Checklist:
    1. Ensure that the ClickHouse server is running and accessible
    2. Confirm that host, port, user, and password are correct. Try a direct MySQL connection.
    3. Test the network connection between the MindsDB host and the ClickHouse server.

Slow Connection Initialization

  • Symptoms: Connecting to the ClickHouse server takes an exceptionally long time, or connections hang without completing
  • Checklist:
    1. Ensure that you are using the appropriate protocol (http, https, or native) for your ClickHouse setup. Misconfigurations here can lead to significant delays.
    2. Ensure that firewalls or security groups (in cloud environments) are properly configured to allow traffic on the necessary ports (as 8123 for HTTP or 9000 for native).

SQL statement cannot be parsed by mindsdb_sql

  • Symptoms: SQL queries failing or not recognizing table names containing spaces, reserved words or special characters.
  • Checklist:
    1. Ensure table names with spaces or special characters are enclosed in backticks.
    2. Examples:
      • Incorrect: SELECT * FROM integration.travel data
      • Incorrect: SELECT * FROM integration.‘travel data’
      • Correct: SELECT * FROM integration.`travel data`