add performance_schema property

[ldangeard-orange]

This PR optionally enables operators to enable performance_schema feature in MariaDB. This requires setting the cf_mysql.mysql.performance_schema_enabled property to true in mysql instance group (default is false)

In MariaDB distribution , by default performance_schema is OFF since 10.0.12. See doc performance_schema

The performance_schema instrument flags (e.g. performance_schema_max_file_handles) are given sensible defaults based on Orange production usage (which sometimes slightly differ from mariadb defaults). Documentation mentions possible memory impact of turning on the feature and ways to measure it.

Background

The Performance Schema is a feature for monitoring server performance, see related mariadb documentation.

Performance_schema database, consists of a number of tables that can be queried with regular SQL statements, returning specific performance information.

Numerous community monitoring tools leverage the Performance Schema feature, such as :

• Collector Flags of prometheus mysql exporter
• Graphana dashboard (e.g. Percona plugin)

This PR replaces #188

[cfdreddbot]

Hey ldangeard-orange!

Thanks for submitting this pull request!

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[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this:

https://www.pivotaltracker.com/story/show/152670917

The labels on this github issue will be updated when the story is started.

[gberche-orange]

Once you've publicized your membership, one of the owners of this repository can close and reopen this pull request, and dreddbot will take another look.

@ldangeard-orange is now covered by Orange CCLA as a public member of https://github.com/orange-cloudfoundry . Should be fine to retrigger the dreddbot by closing & reopening this issue.

[gberche-orange]

@menicosia any update on handling of this pr ?

[gberche-orange]

@menicosia any update on handling of this pr ?

[ldangeard-orange]

New PR