29.12.11.16 The replication_group_members Table

This table shows network and status information for replication group members. The network addresses shown are the addresses used to connect clients to the group, and should not be confused with the member's internal group communication address specified by group_replication_local_address.

The replication_group_members table has these columns:

• CHANNEL_NAME

  Name of the Group Replication channel.

• MEMBER_ID

  The member server UUID. This has a different value for each member in the group. This also serves as a key because it is unique to each member.

• MEMBER_HOST

  Network address of this member (host name or IP address). Retrieved from the member's hostname variable. This is the address which clients connect to, unlike the group_replication_local_address which is used for internal group communication.

• MEMBER_PORT

  Port on which the server is listening. Retrieved from the member's port variable.

• MEMBER_STATE

  Current state of this member; can be any one of the following:

  • ONLINE: The member is in a fully functioning state.

  • RECOVERING: The server has joined a group from which it is retrieving data.

  • OFFLINE: The group replication plugin is installed but has not been started.

  • ERROR: The member has encountered an error, either during applying transactions or during the recovery phase, and is not participating in the group's transactions.

  • UNREACHABLE: The failure detection process suspects that this member cannot be contacted, because the group messages have timed out.

  See Section 20.4.2, “Group Replication Server States”.

• MEMBER_ROLE

  Role of the member in the group, either PRIMARY or SECONDARY.

• MEMBER_VERSION

  MySQL version of the member.

• MEMBER_COMMUNICATION_STACK

  The communication stack used for the group, either the XCOM communication stack or the MYSQL communication stack.

  This column was added in MySQL 8.0.27.

The replication_group_members table has no indexes.

TRUNCATE TABLE is not permitted for the replication_group_members table.