mysql metadata lock 监控插桩设置

Metadata lock instrumentation uses the wait/lock/metadata/sql/mdl instrument, which is enabled by default.

To control metadata lock instrumentation state at server startup, use lines like these in your my.cnf file:

• Enable:

  [mysqld]
  performance-schema-instrument='wait/lock/metadata/sql/mdl=ON'

• Disable:

  [mysqld]
  performance-schema-instrument='wait/lock/metadata/sql/mdl=OFF'

To control metadata lock instrumentation state at runtime, update the setup_instruments table:

• Enable:

  UPDATE performance_schema.setup_instruments
  SET ENABLED = 'YES', TIMED = 'YES'
  WHERE NAME = 'wait/lock/metadata/sql/mdl';

• Disable:

  UPDATE performance_schema.setup_instruments SET ENABLED = 'NO', TIMED = 'NO' WHERE NAME = 'wait/lock/metadata/sql/mdl';