Percona input plugin

[xert]

Feature Request

Proposal:

I wish to add Percona user statistics https://www.percona.com/doc/percona-server/5.6/diagnostics/user_stats.html into the mysql input plugin.

I have a working patch for this. Should I add PR?

Current behavior:

Percona user statistics currently not implemented in the mysql plugin

Desired behavior:

Add Percona user statistics to mysql input plugin

Use case: [Why is this important (helps with prioritizing requests)]

Allows to monitor user, client, table and index usage (see the Percona documentation linked above)

[sparrc]

@xert rather than overloading the mysql plugin, I would prefer if we had a separate percona input plugin, unless there is a significant efficiency to be gained from integrating it directly into the mysql plugin.

[xert]

@sparrc That was my initial perspective too and it's still a possible option, of course.

I see this possible solutions:

1. Make separate percona plugin, collecting just userstat metrics (disadvantage - the DSN must be configured twice, telegraf will make unnecessary additional connections to the server)
2. Copy mysql as percona and add userstats to it (DSN needs to be configured just once, but this solution it's not good for maintenance)
3. Extend mysql plugin capabilities (better then 2. for sure, but adds complexity to the plugin)
4. Separate common functionality needed by both plugins to a shared piece of code (generic sql plugin?) and make plugins mysql and percona (maybe mariadb too - I am not sure if mariadb has some differences in performance / information schema)

I think that the best approach is 3. and then work on 4. Currently I see there are opportunities for improvement in the mysql plugin. For example the metric queries are defined as constants at the top of the file and are used later in functions. If You change the SQL it's not obvious which parts of code are affected by this change. I think it lead to missing column in #1647.

What do You think?

[sparrc]

Personally I still prefer (1), because when we're talking about a MySQL database I don't think adding 1 more connection is much overhead. Although percona is obviously closely related to MySQL, it's definitely a separate product and I think it makes sense to collect percona-specific metrics only.

[xert]

Ok, I'll try to make a new plugin collecting just percona specifics.

[akrus]

Is there any update here?

[joelsdc]

Hi @xert, can you share your current working patch please? I'd love to give it a try... :D

[danielnelson]

Closed in #4306