Bug #110155 Improve GR error MY-013780 reporting
Submitted: 21 Feb 2023 14:07 Modified: 21 Feb 2023 14:20
Reporter: Simon Mudd (OCA) Email Updates:
Status: Verified Impact on me:
Category:MySQL Server: Group Replication Severity:S4 (Feature request)
Version:8.0.32 OS:Any
Assigned to: CPU Architecture:Any

[21 Feb 2023 14:07] Simon Mudd
A recent GR failure shows this error message in MySQL logging:

2023-02-21T13:55:23.795665Z 0 [ERROR] [MY-013780] [Repl] Plugin group_replication reported: 'Failed to establish MySQL client connection in Group Replication. Error establishing connection. Please refer to the manual to make sure that you configured Group Replication properly to work with MySQL Protocol connections.'

There's a problem but the logging provides no visibility into why there's a failure.  This therefore requires more work from the DBA to identify the problem and correct it.

How to repeat:
I'm not sure how to repeat this but the problem if this error is seen is as described above.

Suggested fix:
Please provide a better error to indicate not only that the error exists but also why.
- which server/port was GR trying to talk to?
- what was the exact problem / "operation" that took place or was being attempted?
- any other useful information (maybe from the operating sytem)

e.g. compare with a similar synchronous failure:

2023-02-21T13:19:03.433157Z 98344 [ERROR] [MY-010584] [Repl] Slave I/O for channel '': error reconnecting to master 'some_user@host:3306' - retry-time: 60 retries: 1 message: Can't connect to MySQL server on 'host:3306' (111), Error_code: MY-002003

At least by adding the user_name@host:port parts it's clear which server may be causing the problem.
[21 Feb 2023 14:20] MySQL Verification Team
Hello Simon,

Thank you for the feature request!