Read replicas are central to many database systems. Keeping your read replicas in sync with their primaries is important to ensure you are getting the most value out of them. However, sometimes changes in your workload can lead to replication lag, causing your read replicas to fall behind. Cloud SQL makes it easy to monitor for replication lag and supports several options to resolve replication lag, such as upgrading the replica.
Cloud SQL for MySQL now supports parallel replication, which gives you another solution to reduce replication lag. Parallel replication works by adding more SQL threads to apply transactions on your replica. You can enable parallel replication by setting parallel replication flags on your MySQL 5.7 and 8.0 replicas. You can set database flags through the Google Cloud Console, the gcloud command line, the REST API, or Terraform. For more information on reducing high replication lag, you can view our documentation.
The Cloud SQL Team