Addressing MySQL Error 1190: Resolving Network Issues When Writing to Master

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If you’re working with MySQL replication and encounter Error 1190 (SQLSTATE 08S01), it indicates there’s a network error that prevents the slave from writing to the master server. This error can disrupt replication and data consistency. In this comprehensive guide, we’ll cover how to diagnose and address this issue to maintain a healthy replication setup.

Diagnosing Error 1190 in MySQL

Error 1190 is a network-related error that often arises in a replication setup when a slave server attempts to connect to the master server. Here’s how to approach diagnosing this error:

  1. Check Network Connectivity: Confirm that the slave can reach the master over the network. Use tools like ping or traceroute to diagnose connectivity issues.
  2. Review MySQL Configuration: Ensure that the master host is correctly configured in the slave’s CHANGE MASTER TO statement.
  3. Inspect Error Logs: Both the master and slave MySQL error logs can provide insights into the network error. Look for any relevant messages that could indicate the cause of the issue.
  4. Verify Replication Settings: Check the replication user’s privileges and ensure the user has the necessary permissions to write to the master.

Solutions for Error 1190

Depending on the root cause identified during diagnosis, here are various solutions to fix Error 1190:

Ensuring Proper Network Configuration

Make sure the network settings allow for proper communication between the master and slave:

# Check if the master is reachable from the slave
ping master_host_ip

If there are network issues, you may need to configure firewalls or network routes to allow traffic between the servers.

Configuring Replication User Correctly

Ensure the replication user has the correct privileges and that the master host is specified correctly in the replication settings:

# On the master:
GRANT REPLICATION SLAVE ON *.* TO 'replication_user'@'slave_host' IDENTIFIED BY 'password';
FLUSH PRIVILEGES;

# On the slave:
CHANGE MASTER TO
MASTER_HOST='master_host_ip',
MASTER_USER='replication_user',
MASTER_PASSWORD='password';
START SLAVE;

Checking for Replication Filters

Replication filters on the slave can sometimes cause issues. Ensure that any filters are correctly configured and not inadvertently blocking the necessary data.

Monitoring and Adjusting Server Resources

Check server resources on both the master and slave. Insufficient resources can lead to network timeouts and errors:

# Monitor CPU and memory usage on Linux
top

# Monitor network bandwidth and connectivity
iftop

Adjust server resources as needed to ensure stable replication.

Updating MySQL to the Latest Version

If the error persists, consider upgrading MySQL to the latest version to benefit from bug fixes and improved stability:

# Use your package manager to update MySQL
apt-get update && apt-get upgrade mysql-server

Conclusion

Error 1190 in MySQL replication setups can be a sign of underlying network or configuration issues. By carefully diagnosing the problem and applying the right solution, you can restore the communication between master and slave servers and ensure reliable replication. If these steps do not resolve the issue, further investigation into the network infrastructure or seeking assistance from a network administrator may be necessary.

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