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Troubleshooting

Installation​

Cannot import GPG keys from keyserver.ubuntu.com with apt-key​

The apt-key feature with the Advanced package tool (APT) has been deprecated. Users should use the gpg command instead. Please refer the install guide article.

Cannot import GPG keys from keyserver.ubuntu.com with gpg​

  1. See if your gpg is installed:

Cannot get deb packages from ClickHouse repository with apt-get​

  1. Check firewall settings.
  2. If you cannot access the repository for any reason, download packages as described in the install guide article and install them manually using the sudo dpkg -i <packages> command. You will also need the tzdata package.

Cannot update deb packages from ClickHouse repository with apt-get​

The issue may be happened when the GPG key is changed.

Please use the manual from the setup page to update the repository configuration.

You get different warnings with apt-get update​

The completed warning messages are as one of following:

To resolve the above issue, please use the following script:

Can't get packages with Yum because of wrong signature​

Possible issue: the cache is wrong, maybe it's broken after updated GPG key in 2022-09.

The solution is to clean out the cache and lib directory for Yum:

After that follow the install guide

Connecting to the server​

Possible issues:

  • The server is not running.
  • Unexpected or wrong configuration parameters.

Server is not running​

Check if server is running​

If the server is not running, start it with the command:

Check the logs​

The main log of clickhouse-server is in /var/log/clickhouse-server/clickhouse-server.log by default.

If the server started successfully, you should see the strings:

  • <Information> Application: starting up. — Server started.
  • <Information> Application: Ready for connections. — Server is running and ready for connections.

If clickhouse-server start failed with a configuration error, you should see the <Error> string with an error description. For example:

If you do not see an error at the end of the file, look through the entire file starting from the string:

If you try to start a second instance of clickhouse-server on the server, you see the following log:

See system.d logs​

If you do not find any useful information in clickhouse-server logs or there aren’t any logs, you can view system.d logs using the command:

Start clickhouse-server in interactive mode​

This command starts the server as an interactive app with standard parameters of the autostart script. In this mode clickhouse-server prints all the event messages in the console.

Configuration parameters​

Check:

  1. Docker settings:

    • If you run ClickHouse in Docker in an IPv6 network, make sure that network=host is set.

  2. Endpoint settings.

    • Check listen_host and tcp_port settings.
    • ClickHouse server accepts localhost connections only by default.

  3. HTTP protocol settings:

    • Check protocol settings for the HTTP API.

  4. Secure connection settings.

    • Check:
    • Use proper parameters while connecting. For example, use the port_secure parameter with clickhouse_client.

  5. User settings:

    • You might be using the wrong user name or password.

Query processing​

If ClickHouse is not able to process the query, it sends an error description to the client. In the clickhouse-client you get a description of the error in the console. If you are using the HTTP interface, ClickHouse sends the error description in the response body. For example:

If you start clickhouse-client with the stack-trace parameter, ClickHouse returns the server stack trace with the description of an error.

You might see a message about a broken connection. In this case, you can repeat the query. If the connection breaks every time you perform the query, check the server logs for errors.

Efficiency of query processing​

If you see that ClickHouse is working too slowly, you need to profile the load on the server resources and network for your queries.

You can use the clickhouse-benchmark utility to profile queries. It shows the number of queries processed per second, the number of rows processed per second, and percentiles of query processing times.