MySQL Bugs: #96606: InnoDB Cluster - Prevents reads on Failed Primary Node

Bug #96606	InnoDB Cluster - Prevents reads on Failed Primary Node
Submitted:	21 Aug 2019 16:58	Modified:	30 Oct 2019 12:36
Reporter:	Pedro Pinheiro	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Group Replication	Severity:	S4 (Feature request)
Version:	8.0	OS:	Any
Assigned to:		CPU Architecture:	Any
Triage:	Needs Triage: D5 (Feature request)

Description:
Use Case:
3 Node Single-Primary Cluster

Event:
Current Primary changes (Failed, leave the cluster, intentional  changed to another node)

OnGoing:
Application is connected to the Primary node, and as no way to know the primary node did change (it's only performing reads).

Problem:
How to prevent the application from continue to read from the failed primary? We don't want to read from a node that is not part of the cluster.
 Is there any setting on Group Replication or MySQL Router, to kill all the ongoing connections to the failed node? Assuming it's working and but not in the cluster. Or any other way to prevent the stale readings?

Note:
This would be a very desired feature to make InnoDB Cluster a reliable High Availability Solution.

How to repeat:
please check the description.

Hello Pedro,

Thank you for the feature request.

regards,
Umesh

Posted by developer:
 
Implemented on WL#12895: "Group Replication: Add OFFLINE_MODE to group_replication_exit_state_action" released on 8.0.18