Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure

这个错误通常表示 HiveMetaStore 无法连接到 MySQL 数据库。请确保 MySQL 数据库已正确安装和配置，并且您已经将 HiveMetaStore 配置为连接到正确的数据库。

您可以尝试以下步骤来解决此问题：

1. 确保 MySQL 服务正在运行。您可以使用以下命令来检查 MySQL 服务的状态：

   systemctl status mysql

如果 MySQL 服务未运行，请使用以下命令启动它：

   systemctl start mysql

2. 检查 MySQL 数据库的连接参数是否正确。请确保在 Hive 的配置文件中指定了正确的 MySQL 主机名、端口号、用户名和密码。

3. 确保您正在使用与 MySQL 数据库兼容的 JDBC 驱动程序。如果您使用的是旧版本的 JDBC 驱动程序，请升级到最新版本。

4. 检查网络连接是否正常。请确保 HiveMetaStore 和 MySQL 数据库之间的网络连接正常，并且您可以从 HiveMetaStore 访问 MySQL 数据库。

如果您尝试了以上步骤后仍然无法解决问题，请提供更多的日志信息，以便我能够更好地帮助您解决问题。

相关问题

caused by: com.mysql.cj.exceptions.cjcommunicationsexception: communications link failure

这是一个 MySQL 通信链接错误异常，通常是由于与 MySQL 服务器的连接中断导致的。可能的原因包括 MySQL 服务器暂时不可用、连接超时、用户名或密码错误等。建议检查服务器的连接状态以及配置信息，并确保所有必要的端口都已打开。

Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure The last

This error message usually indicates a problem with the connection between your application and the MySQL database server. Here are a few things you can try to troubleshoot the issue:

1. Check your network connection: Make sure that your application server can communicate with the MySQL server. Ensure that there are no network issues, such as firewalls or network congestion.

2. Check MySQL server status: Verify that the MySQL server is up and running and that it's listening on the correct port. You can use the command "sudo systemctl status mysql" to check the status of the MySQL server.

3. Check MySQL logs: Check the MySQL error logs for any errors that may be causing the connection failure. The logs are usually located at /var/log/mysql/error.log.

4. Check MySQL configuration: Verify that the MySQL configuration is correct and that the connection parameters in your application code are correct. Check that the database name, username, and password are correct.

5. Increase the connection timeout: If the connection is timing out, increase the connection timeout in your application code or MySQL configuration file.

6. Restart MySQL server: Try restarting the MySQL server to clear any cached connections or other issues that may be causing the problem.

I hope this helps you resolve the issue. Let me know if you have any other questions.