21.13. Performance Schema Status Variables

The Performance Schema implements several status variables that provide information about instrumentation that could not be loaded or created due to memory constraints:

mysql> SHOW STATUS LIKE 'perf%';+-------------------------------------------+-------+| Variable_name                             | Value |+-------------------------------------------+-------+| Performance_schema_accounts_lost          | 0     || Performance_schema_cond_classes_lost      | 0     || Performance_schema_cond_instances_lost    | 0     || Performance_schema_file_classes_lost      | 0     || Performance_schema_file_handles_lost      | 0     || Performance_schema_file_instances_lost    | 0     || Performance_schema_hosts_lost             | 0     || Performance_schema_locker_lost            | 0     || Performance_schema_mutex_classes_lost     | 0     || Performance_schema_mutex_instances_lost   | 0     || Performance_schema_rwlock_classes_lost    | 0     || Performance_schema_rwlock_instances_lost  | 0     || Performance_schema_socket_classes_lost    | 0     || Performance_schema_socket_instances_lost  | 0     || Performance_schema_stage_classes_lost     | 0     || Performance_schema_statement_classes_lost | 0     || Performance_schema_table_handles_lost     | 0     || Performance_schema_table_instances_lost   | 0     || Performance_schema_thread_classes_lost    | 0     || Performance_schema_thread_instances_lost  | 0     || Performance_schema_users_lost             | 0     |+-------------------------------------------+-------+

Names for these variables have several forms:

For information on using these variables to check Performance Schema status, see Section 21.5, "Performance Schema Status Monitoring".