MysqlSlaveSqlThreadNotRunning

MysqlSlaveSqlThreadNotRunning #

MySQL Slave SQL thread not running on {{ $labels.instance }}

Alert Rule
alert: MysqlSlaveSqlThreadNotRunning
annotations:
  description: |-
    MySQL Slave SQL thread not running on {{ $labels.instance }}
      VALUE = {{ $value }}
      LABELS = {{ $labels }}    
  runbook: https://srerun.github.io/prometheus-alerts/runbooks/mysqld-exporter/mysqlslavesqlthreadnotrunning/
  summary: MySQL Slave SQL thread not running (instance {{ $labels.instance }})
expr: ( mysql_slave_status_slave_sql_running and ON (instance) mysql_slave_status_master_server_id
  > 0) == 0
for: 0m
labels:
  severity: critical

Meaning #

The MysqlSlaveSqlThreadNotRunning alert is triggered when the MySQL slave SQL thread is not running on a specific instance. This indicates that the MySQL slave is not replicating data from the master server, which can lead to data inconsistencies and other issues.

Impact #

If this alert is not addressed promptly, it can lead to:

  • Data inconsistencies between the master and slave databases
  • Failure to meet data replication requirements
  • Potential data loss or corruption
  • Downtime or performance degradation of dependent applications

Diagnosis #

To diagnose the issue, follow these steps:

  1. Check the MySQL slave status using the SHOW SLAVE STATUS command to verify that the SQL thread is not running.
  2. Check the MySQL error logs for any errors related to the SQL thread.
  3. Verify that the MySQL slave is configured correctly and that the replication user has the necessary permissions.
  4. Check the network connectivity between the master and slave servers to ensure that there are no connectivity issues.
  5. Verify that the MySQL slave is not in a read-only mode.

Mitigation #

To mitigate the issue, follow these steps:

  1. Check the MySQL slave status and take necessary actions to restart the SQL thread.
  2. Investigate and resolve any underlying issues that may be preventing the SQL thread from running, such as network connectivity issues or configuration errors.
  3. Verify that the MySQL slave is replicating data correctly from the master server.
  4. Consider restarting the MySQL slave service or instance if necessary.
  5. Monitor the MySQL slave status to ensure that the issue does not recur.

Note: For detailed troubleshooting and resolution steps, refer to the runbook provided.

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