Starting with MySQL 5.7, performance_schema has been enhanced to instrument metadata locks, and can be turned on by adding the following line to your my.cnf file:
(At runtime, it can also be enabled by modifying the setup_instruments table in performance_schema.)
From here, you can now query performance_schema.metadata_locks to reveal all currently open metadata locks on your server:
A modern MySQL server contains a lot of useful meta-data in information_schema and performance_schema, which can help bring visibility into what is happening inside of your database server. However, sometimes this data is quite fine grained and needs finessing in order to get to that point 🙂
MySQL 5.7 includes a new SYS schema installed by default.…
New in MySQL 5.7.7, the MySQL sys schema (originally the ps_helper project) is now included by default within the MySQL server!
For those unfamiliar with the
sys schema project, it is a database schema with a set of objects (views, stored procedures, stored functions, and table with a couple of triggers on it) that were implemented to give easy, human readable, DBA and Developer based use case access to the wealth of instrumentation data implemented primarily within Performance Schema, but also with various INFORMATION_SCHEMA tables as well.…