Bug #92110 Errors when joining on start may lead to a stale view of the group
Submitted: 21 Aug 2018 18:02 Modified: 11 Mar 2019 16:05
Reporter: Pedro Gomes Email Updates:
Status: Closed Impact on me:
None 
Category:MySQL Server: Group Replication Severity:S3 (Non-critical)
Version:8.0.13 OS:Any
Assigned to: CPU Architecture:Any

[21 Aug 2018 18:02] Pedro Gomes 
Description:
When joining a member on a server restart, if the join process fails because the server is incompatible with the group, we can have a situation where the state of group is:

SELECT * FROM performance_schema.replication_group_members;
CHANNEL_NAME MEMBER_HOST	MEMBER_PORT	MEMBER_STATE
group_replication_applier 127.0.0.1 13000 ONLINE 
group_replication_applier 127.0.0.1 13001 OFFLINE		

In the offline member we still see another member as being online.

How to repeat:
Go to

  group_replication.gr_lower_case_table_names_different

print the members after the member fails to join the group on boot

  

Suggested fix:
No suggestion
[11 Mar 2019 16:05] David Moss 
Posted by developer:
 
Thank you for your feedback, this has been fixed in upcoming versions and the following was added to the 8.0.16 changelog:
When a member joined a group on server start, if the join process failed, for example because the server was incompatible with the group, there was a possibility that the offline member could still see another member as being online. Now, in such a situation the information shown in the performance_schema.replication_group_members table is restricted to the local member when it is OFFLINE.