Error mysql Table 'performance_schema...Solution

<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>5.1.34</version>
</dependency>

Table 'performance_schema.session_variables' doesn't exist

MySQL 5.5 adds a new storage engine: named PERFORMANCE_SCHEMA, which is mainly used to collect database server performance parameters. MySQL users cannot create tables whose storage engine is PERFORMANCE_SCHEMA. performance_schema provides the following functions: 
1. Provide detailed information about process waiting, including locks, mutex variables, and file information; 
2. Save historical event summary information to provide detailed judgment on MySQL server performance; 
3. It is very easy to add and delete monitoring event points, and the monitoring cycle of the MySQL server can be changed at will, for example (CYCLE, MICROSECOND)

With the above information, the DBA can understand in detail the bottlenecks that may be causing the performance degradation.

It is very simple to enable the performance_schema function and the performance function of some tables. Add performanc_schema to [mysqld] in my.cnf and check whether the performance database is started:

SHOW VARIABLES LIKE 'performance_schema';

If the returned value is ON, it means that the performance database is opened normally.