MySQL Bugs: #101178: The variable group_replication_force_members is better to be case insensitive

Bug #101178	The variable group_replication_force_members is better to be case insensitive
Submitted:	15 Oct 2020 6:55	Modified:	28 Oct 2021 7:19
Reporter:	Richard Hao	Email Updates:
Status:	No Feedback	Impact on me:	None
Category:	MySQL Server: Group Replication	Severity:	S4 (Feature request)
Version:	8.0.21	OS:	CentOS (7.5.1804)
Assigned to:	MySQL Verification Team	CPU Architecture:	x86 (Intel(R) Core(TM) i5-8300H CPU @ 2.30GHz)

Description:
A member is specified by the hostname and the port in our GR group, and that is very easy for DBAs to use different case for group_replication_group_seeds，group_replication_group_seeds。such as in our my.cnf file

group_replication_local_address = 'centos7-cerver6:33061'
group_replication_group_seeds ='CentOS7-Server6:33061,Centos7-Server7:33061,CentOS7-Server8:33061'

Sometimes when we encounter a GR error which the Primary node is not able to reach a majority of members in the group,we need to force a new group membership, we do follow steps:
1. use sql "select * from performance_schema.replication_group_members;" to get member's info: member_host, member_port and form the active member list

2. then force a new group membership by setting group_replication_force_members = active member list getting in step 1.

then we will get error:
ERROR 1231 (42000): Variable 'group_replication_force_members' can't be set to the value of 'XXXXXXXX'

We spend a lot of time to find the cause.

How to repeat:
1. group_replication_local_address in lower case
2. group_replication_group_seeds in upper case
3. GR group has five members, kill 3 secondary members at the same time
4. Primary node will block all dml and ddl,
5. use sql "select * from performance_schema.replication_group_members;" to get member's info: member_host, member_port and form the active member list
6.setting group_replication_force_members = active member list getting in step 5.

then you will get the error

> 1. use sql "select * from performance_schema.replication_group_members;" to get member's info : member_host, member_port and form the active member list 

we use sql "select * from performance_schema.replication_group_members;" to get member status and online members' member_host, use this "select @@group_replication_group_seeds" to get active member list,

mysql> select * from replication_group_members;
+---------------------------+--------------------------------------+------------------+-------------+--------------+-------------+----------------+
| CHANNEL_NAME              | MEMBER_ID                            | MEMBER_HOST      | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |
+---------------------------+--------------------------------------+------------------+-------------+--------------+-------------+----------------+
| group_replication_applier | 111284db-f88f-11ea-b10d-0050563c33c4 | CentOS7-Server6  |        3306 | ONLINE       | PRIMARY     | 8.0.21         |
| group_replication_applier | 11b72caa-f88f-11ea-9a5c-0050562c2906 | CentOS7-Server7  |        3306 | ONLINE       | SECONDARY   | 8.0.21         |
| group_replication_applier | 1219c539-f88f-11ea-b979-00505624863e | CentOS7-Server8  |        3306 | UNREACHABLE  | SECONDARY   | 8.0.21         |
| group_replication_applier | 62f8518b-023a-11eb-9228-000c29bbdbd8 | CentOS7-Server9  |        3306 | UNREACHABLE  | SECONDARY   | 8.0.21         |
| group_replication_applier | 62f8518b-023a-11eb-9228-000c29bbdbe9 | CentOS7-Server10 |        3306 | UNREACHABLE  | SECONDARY   | 8.0.21         |
+---------------------------+--------------------------------------+------------------+-------------+--------------+-------------+----------------+
mysql> select @@group_replication_group_seeds;
+-------------------------------------------------------------------------------------------------------------------------------------------------------------+
| @@group_replication_group_seeds                                                                                                                             |
+-------------------------------------------------------------------------------------------------------------------------------------------------------------+
| CentOS7-Server6:33061,centos7-Server7:33061,CentOS7-Server8:33061,CentOS7-Server5:33061,CentOS7-Server9:33061,CentOS7-Server10:33061,CentOS7-Server11:33061 |
+--------------------------------------------------------------
-----------------------------------------------------------------------------------------------+

the active member list is 'CentOS7-Server6:33061,centos7-Server7:33061'

Hi,

Just to be sure, you are talking about the content not the settings name case sensitivity, so you are experiencing issues if you mix the hostname cases (centos7-1 vs CENTOS7-1) ?

Thanks

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".