Error
Error Code:
3082
MySQL Error 3082: Replication Threads Not Running
Description
This error indicates that an operation requiring active MySQL replication threads cannot proceed because they are not running. It typically occurs when attempting to perform actions on a replication slave that depend on its replication status, such as checking its status or performing a failover, but the slave is either not configured or not started for the specified channel.
Error Message
This operation requires running replication threads; configure slave and run START SLAVE FOR CHANNEL '%s'
Known Causes
4 known causesReplication Threads Not Started
The `START SLAVE` command has not been executed for the relevant replication channel, preventing required replication operations from running.
Incorrect Slave Configuration
The MySQL server is not properly configured as a replication slave, or its configuration details (e.g., master host, user, log file) are incorrect or incomplete.
Replication Threads Stopped Unexpectedly
Replication threads were previously running but have since stopped due to a manual `STOP SLAVE` command or an underlying replication error.
Missing or Incorrect Channel Name
The operation requires a specific replication channel, but it was either omitted from the command or the provided channel name is invalid or not configured on the slave.
Solutions
4 solutions available1. Start Replication Threads easy
Manually start the replication threads if they have stopped unexpectedly.
1
Connect to your MySQL replica server using a MySQL client.
2
Execute the `START SLAVE` command. If you are using named channels, specify the channel name.
START SLAVE FOR CHANNEL 'your_channel_name';
-- Or for the default channel:
START SLAVE;3
Verify the status of replication threads using `SHOW SLAVE STATUS`. Look for `Slave_IO_Running` and `Slave_SQL_Running` to be 'Yes'.
SHOW SLAVE STATUS\G2. Check Replication Configuration medium
Ensure that the replication parameters are correctly configured and that the replica can connect to the source.
1
Connect to your MySQL replica server.
2
Examine the replication configuration using `SHOW REPLICA STATUS` (or `SHOW SLAVE STATUS` for older versions). Pay close attention to:
SHOW REPLICA STATUS\G3
Specifically, check `Master_Host`, `Master_User`, `Master_Port`, and `Master_Log_File`/`Master_Log_Pos`. Ensure these match your source server's details.
4
Verify that the replica can establish a network connection to the source on the specified `Master_Port`.
5
If any parameters are incorrect, stop replication, change the configuration, and restart.
STOP REPLICA FOR CHANNEL 'your_channel_name';
CHANGE REPLICATION SOURCE TO MASTER_HOST='new_master_host', MASTER_USER='new_master_user', MASTER_PORT=new_master_port FOR CHANNEL 'your_channel_name';
START REPLICA FOR CHANNEL 'your_channel_name';3. Restart MySQL Service easy
A full service restart can resolve transient issues preventing replication threads from starting.
1
Log in to your MySQL replica server's operating system.
2
Restart the MySQL service. The command varies depending on your operating system and installation method.
# For systemd-based systems (e.g., Ubuntu 15.04+, CentOS 7+):
sudo systemctl restart mysql
# For SysVinit-based systems (e.g., older Ubuntu, CentOS):
sudo service mysql restart
# For Windows:
# Open Services.msc and restart the MySQL service.3
After the service restarts, connect to MySQL and check replication status.
SHOW REPLICA STATUS\G4
If threads are still not running, you may need to start them manually as per Solution 1.
START REPLICA FOR CHANNEL 'your_channel_name';4. Investigate Source Server Connectivity and Permissions advanced
Ensure the replica has the necessary privileges and network access to the source server.
1
On the source MySQL server, verify that the replication user (`Master_User`) exists and has the `REPLICATION SLAVE` privilege.
SHOW GRANTS FOR 'replication_user'@'replica_ip';
-- If not present:
GRANT REPLICATION SLAVE ON *.* TO 'replication_user'@'replica_ip' IDENTIFIED BY 'password';
FLUSH PRIVILEGES;2
Check the source server's firewall to ensure it allows incoming connections on the MySQL port (default 3306) from the replica's IP address.
3
On the replica, ensure the `Master_Host` is resolvable and reachable from the replica server.
ping source_server_hostname_or_ip4
Review the source server's MySQL error logs for any connection attempts or errors related to the replication user.
5
If connectivity issues are found, adjust firewall rules or MySQL `bind-address` configuration on the source server as needed, then restart the source MySQL service.