Add support for more granular Group Replication related metrics

[shayancanonical]

Host operating system: output of uname -a

Linux mysql-k8s-mem-0 5.15.0-112-generic #122-Ubuntu SMP Thu May 23 07:48:21 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

mysqld_exporter version: output of mysqld_exporter --version

mysqld_exporter, version 0.14.0 (branch: debian/sid, revision: 0.14.0-0ubuntu0.22.04.1~ppa2)
  build user:       [email protected]
  build date:       20240404-17:57:16
  go version:       go1.18.1
  platform:         linux/amd64

MySQL server version

mysql Ver 8.0.37-0ubuntu0.22.04.3 for Linux on x86_64 ((Ubuntu))

mysqld_exporter command line flags

    "--collect.perf_schema.replication_group_members"
    "--collect.perf_schema.replication_group_member_stats"

Feature request

It would be helpful to include more granular Group Replication metrics to the exporter. This will allow users to set up more targeted Group Replication related alerts and create richer Group Replication related dashboards.

closed: Issue 362 requests the inclusion of the contents of replication_group_members, however the resulting query is a SELECT * FROM replication_group_members
the resulting gauge looks as follows:

# HELP mysql_perf_schema_replication_group_member_info Information about the replication group member: channel_name, member_id, member_host, member_port, member_state. (member_role and member_version where available)
# TYPE mysql_perf_schema_replication_group_member_info gauge
mysql_perf_schema_replication_group_member_info{channel_name="group_replication_applier",member_communication_stack="MySQL",member_host="mysql-k8s-mem-0.mysql-k8s-mem-endpoints.test-node-port.svc.cluster.local",member_id="304597c5-8655-11ef-a89c-ee4cab64faa8",member_port="3306",member_role="PRIMARY",member_state="ONLINE",member_version="8.0.37"} 1

There is a (relatively cold) fork by Percona that attempts to define more granular queries that would result in easily used metrics

A similar request has been made to add more group replication stats

Would the community be willing to develop or accept contributions that enhance Group Replication related metrics?