Performance Schema System Variable Tables persisted_variables  has these indexes: The value listed for the variable in  mysqld-auto.cnf . •Primary key on ( VARIABLE_NAME ) TRUNCATE TABLE  is not permitted for the  persisted_variables  table. 27.12.14.2 Performance Schema variables_info Table The  variables_info  table shows, for each system variable, the source from which it was most recently set, and its range of values. The  variables_info  table has these columns: • COMMAND_LINE • VARIABLE_SOURCE • COMPILED • DYNAMIC • EXPLICIT • VARIABLE_NAME • EXTRA • GLOBAL • LOGIN • PERSISTED 5033 The variable was set from a server-specific  mysqld-auto.cnf  option file. No row has this value if the server was started with  persisted_globals_load  disabled. The variable was set from a user-specific login path file ( ~/.mylogin.cnf ). The variable was set from a global option file. This includes option files not covered by  EXPLICIT , EXTRA ,  LOGIN ,  PERSISTED ,  SERVER , or  USER . The variable was set from an option file named with the  --defaults-extra-file  option. The variable was set from an option file named with the  --defaults-file  option. The variable was set at runtime. This includes variables set within files specified using the  init_file system variable. The variable has its compiled-in default value.  COMPILED  is the value used for variables not set any other way. The variable was set on the command line. The source from which the variable was most recently set: The variable name.