Troubleshooting Error Code 2013: Connection Lost Error in MySQL – 10 Reasons and Solution

The Error Code 2013 (CR_SERVER_LOST) indicates a connection lost error in MySQL. Here are 10 possible reasons for this error and how to troubleshoot them:

  1. Network Issues: Check for network connectivity problems, such as network congestion, firewall settings, or intermittent network failures. Verify that the network connection between the client and the MySQL server is stable and reliable.
  2. Server Overload: If the MySQL server is overloaded due to high traffic or resource-intensive queries, it may lead to connection timeouts. Monitor server performance, identify resource bottlenecks, and optimize queries or increase server resources accordingly.
  3. Long-running Queries: Long-running queries can cause connection timeouts if the execution time exceeds the connection timeout setting. Analyze and optimize queries to reduce their execution time or adjust the connection timeout value to accommodate longer query execution times.
  4. InnoDB Configuration: Incorrect or suboptimal InnoDB configuration settings can lead to connection timeouts. Review and tune the InnoDB configuration parameters such as innodb_buffer_pool_size, innodb_log_file_size, and innodb_flush_method to ensure optimal performance and stability.
  5. Server Restart or Crash: A server restart or crash can result in connection loss. Check server logs for any indications of restart or crashes and investigate the cause. Ensure that the MySQL server starts successfully and monitor for any recurring issues.
  6. Server Resource Exhaustion: If the MySQL server runs out of system resources like memory or disk space, it can result in connection loss. Monitor server resources and ensure there is sufficient memory, disk space, and other necessary resources available for the MySQL server.
  7. Idle Connections: Idle connections can be terminated by the server due to connection timeout settings. Consider optimizing connection pooling configurations or using connection keep-alive mechanisms to keep idle connections active and prevent premature termination.
  8. Incorrect Connection Settings: Verify that the connection settings in the application or client configuration files are correct. Ensure that the hostname, port, username, and password are accurate and properly set.
  9. Firewall or Security Restrictions: Check if there are any firewall rules or security settings that may be blocking or terminating connections to the MySQL server. Ensure that the necessary ports are open and that there are no restrictive security policies in place.
  10. Client-Side Issues: In some cases, the connection lost error may be due to issues on the client side. Check the client application or library used to connect to the MySQL server for any compatibility issues, bugs, or limitations. Update the client software, libraries, or drivers to the latest versions if necessary.

To troubleshoot Error Code 2013, it’s essential to analyze the specific circumstances and error logs to identify the root cause. Review the MySQL error log, server and system resource utilization, network connectivity, and application configurations. Investigate each potential reason mentioned above to determine the cause of the connection loss and take appropriate steps to resolve the issue.

About Shiv Iyer 455 Articles
Open Source Database Systems Engineer with a deep understanding of Optimizer Internals, Performance Engineering, Scalability and Data SRE. Shiv currently is the Founder, Investor, Board Member and CEO of multiple Database Systems Infrastructure Operations companies in the Transaction Processing Computing and ColumnStores ecosystem. He is also a frequent speaker in open source software conferences globally.