Replication question


This question is not regarding the Percona build but about MySQL in general. Here is the scenario I have:

Site A → Replication → Site B

On Site A, there is a source database running, denoted as SDB. On Site B, there is a Group Replication cluster (GRC) consisting of three servers: M1 (master), S1 (slave), and S2 (slave).

The replication channel is defined on M1. However, when M1 goes down, a new master is chosen. My goal is to relocate the replication channel from the currently down M1 to the new master. I want to ensure that replication from SDB continues, irrespective of the current master of the GRC.

I can identify the new chosen master using ProxySQL, but the channel metadata is not replicated. There are tables under the MySQL database that contain relevant information:

I believe that the following values need to be preserved to update the replication channel on the new master:

Checkpoint_master_log_name: mysqld-bin.XXX
Checkpoint_master_log_pos: 197
Master_log_name: mysqld-bin.XXX
Master_log_pos: 1600
Do you have any thoughts or suggestions on how to accomplish this?

I can attempt to create a trigger that copies data from the mentioned tables to my replicated table. This would ensure that relevant data is distributed across all GRC members. I am currently exploring this approach. Nevertheless, it’s difficult to believe that no one has encountered this issue before, and I would prefer not to reinvent the wheel.

Ensure you are running with the following variables:


Verify that while replication is running, the metadata is being replicated by GR by checking the contents of mysql.slave_master_info table. If you see the same updated data on each GR member, then that’s all you need to restart replication.

Thank you. I’m in the final stages of setting up the test. The last time I destroyed the cluster, it was because of this issue. I had believed that starting a replica on the new master would be sufficient, but something went wrong. I’ll provide an update once I have the outcome.

According to what I see the table mysql.slave_master_info is not replicated within the group replication.
It get updated only on the master.
So, if master shutdown I would be not able to restart replica properly.

What you think?

There is strange issue.
mysql.slave_worker_info this is the table that holds the information about the replication status.
for example : Master_log_name | Master_log_pos | Checkpoint_master_log_name | Checkpoint_master_log_pos
But for some reason it not get replicated between group replication master and slaves.
I am not sure if this is an BUG or I misconfigured the servers.

Do you have any experience with that?

Thank you very much

I see I forgot to mention important information.
On site A (the source) there is no GTID enabled.
The replication channel defined with ASSIGN_GTIDS_TO_ANONYMOUS_TRANSACTIONS.
Therefore I can’t use SOURCE_AUTO_POSITION (which would be the solution otherwise)