The 'redis failed to refresh slots cache' error occurs when there is an issue with Redis cluster. When Redis cluster starts, it fetches all the slot information from the master node and caches it. However, if for some reason, one or more of the nodes in the cluster fail or the network connection between them breaks, the slots cache may become outdated or invalid. As a result, any attempt to query the cluster will fail, and the error message 'redis failed to refresh slots cache' will be displayed.
To resolve the 'redis failed to refresh slots cache' error, you can try the following solutions:
Restart the Redis cluster: Sometimes, restarting the Redis cluster can help refresh the slots cache and fix the error. You can do this by stopping all the Redis nodes and then starting them again.
Reset the slots cache manually: If restarting the cluster doesn't work, you can try resetting the slots cache manually. To do this, use the command cluster forget <node-id> to remove the incorrect node information from the cluster. Then, run the cluster meet <ip> <port> command to add the correct node information back to the cluster.
Check network connectivity: Ensure that there are no network issues between the nodes in the cluster. Check that all nodes are reachable and that there are no firewalls blocking communication.
Upgrade Redis version: If you're using an older version of Redis, upgrading to the latest stable release may help resolve the error. The newer versions have better error handling and reporting mechanisms that can help diagnose and fix such issues.
Dragonfly is fully compatible with the Redis ecosystem and requires no code changes to implement.