Error
Error Code:
3169
MySQL Error 3169: Session Terminated Abruptly
Description
This error indicates that an active MySQL client session has been unexpectedly terminated by the server. It means the connection you were using to interact with the database is no longer valid, often due to server-side intervention or critical resource issues.
Error Message
Session was killed
Known Causes
4 known causesAdministrator Termination
A database administrator explicitly killed the session using the 'KILL' command, often to free up resources or stop an errant query.
Inactivity Timeout
The session exceeded the configured 'wait_timeout' or 'interactive_timeout' period, leading the server to automatically close the idle connection.
Server Resource Limits
The MySQL server or underlying system ran out of critical resources like memory, CPU, or available connections, forcing the server to terminate sessions.
Network Instability
An unstable network connection between the client and the MySQL server was disrupted, causing the server to detect a lost client and kill the session.
Solutions
4 solutions available1. Investigate Server Load and Resource Utilization medium
Identify and resolve high CPU, memory, or disk I/O that could be causing the server to kill sessions.
1
Connect to your MySQL server and check the current status of running processes.
SHOW FULL PROCESSLIST;2
Monitor system-level resource usage. On Linux, use tools like `top`, `htop`, `vmstat`, or `iostat`. On Windows, use Task Manager or Performance Monitor.
top
# or
iostat -xz 53
If you identify a specific query or process consuming excessive resources, consider optimizing it or temporarily terminating it.
KILL <process_id>;4
Review MySQL's `innodb_buffer_pool_size`, `key_buffer_size`, `max_connections`, and other relevant configuration parameters to ensure they are appropriately sized for your workload.
SHOW VARIABLES LIKE 'innodb_buffer_pool_size';
SHOW VARIABLES LIKE 'key_buffer_size';
SHOW VARIABLES LIKE 'max_connections';2. Examine MySQL Error Logs for Clues easy
Analyze the MySQL error log for messages indicating the reason for session termination.
1
Locate your MySQL error log file. The location varies by operating system and installation method. Common locations include `/var/log/mysql/error.log` (Linux) or within the MySQL data directory (Windows).
text2
Open the error log file and search for entries around the time the session was terminated. Look for keywords like 'killed', 'killed by administrator', 'out of memory', 'segmentation fault', or specific error codes.
tail -f /var/log/mysql/error.log | grep 'killed'3
If the log indicates a specific query or user action caused the termination, address that directly. For example, if a long-running query is consistently being killed, investigate its performance.
text3. Review `wait_timeout` and `interactive_timeout` Settings easy
Adjust idle connection timeouts to prevent legitimate sessions from being closed prematurely.
1
Check the current values of `wait_timeout` and `interactive_timeout`.
SHOW VARIABLES LIKE 'wait_timeout';
SHOW VARIABLES LIKE 'interactive_timeout';2
If these values are too low, long-running but idle queries or applications might be terminated. Consider increasing them, especially for `wait_timeout` if you have applications that maintain connections for extended periods.
SET GLOBAL wait_timeout = 28800; -- Set to 8 hours (default is 28800)
SET GLOBAL interactive_timeout = 28800; -- Set to 8 hours (default is 28800)3
To make these changes permanent, update your MySQL configuration file (e.g., `my.cnf` or `my.ini`) and restart the MySQL server.
[mysqld]
wait_timeout = 28800
interactive_timeout = 288004. Investigate External Process Killers or Monitoring Tools medium
Determine if an external system or script is intentionally terminating MySQL sessions.
1
Check your server's running processes for any unusual or unexpected scripts or tools that might be monitoring and terminating processes based on certain criteria.
ps aux | grep mysql2
Review any custom scripts, cron jobs, or monitoring agents (e.g., Nagios, Zabbix, Prometheus with specific exporters) that are configured to interact with your MySQL server.
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If a monitoring tool is configured to kill sessions that exceed a certain duration or resource threshold, adjust its configuration or the MySQL server's parameters accordingly.
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