For an autoscaled parameter, configuration works like this: •With the value set to -1 (the default), the parameter is autoscaled: •The corresponding internal buffer is empty initially and no memory is allocated. •As the Performance Schema collects data, memory is allocated in the corresponding buffer. The buffer size is unbounded, and may grow with the load. •With the value set to 0: •The corresponding internal buffer is empty initially and no memory is allocated. •With the value set to  N  > 0: •The corresponding internal buffer is empty initially and no memory is allocated. •As the Performance Schema collects data, memory is allocated in the corresponding buffer, until the buffer size reaches  N . •Once the buffer size reaches  N , no more memory is allocated. Data collected by the Performance Schema for this buffer is lost, and any corresponding “lost instance”  counters are incremented. To see how much memory the Performance Schema is using, check the instruments designed for that purpose. The Performance Schema allocates memory internally and associates each buffer with a dedicated instrument so that memory consumption can be traced to individual buffers. Instruments named with the prefix  memory/performance_schema/  expose how much memory is allocated for these internal buffers. The buffers are global to the server, so the instruments are displayed only in the  memory_summary_global_by_event_name  table, and not in other memory_summary_by_ xxx _by_event_name  tables. This query shows the information associated with the memory instruments: 27.18 Performance Schema and Plugins 27.19 Using the Performance Schema to Diagnose Problems Removing a plugin with  UNINSTALL PLUGIN  does not affect information already collected for code in that plugin. Time spent executing the code while the plugin was loaded was still spent even if the plugin is unloaded later. The associated event information, including aggregate information, remains readable in performance_schema  database tables. For additional information about the effect of plugin installation and removal, see Section 27.7, “Performance Schema Status Monitoring” . A plugin implementor who instruments plugin code should document its instrumentation characteristics to enable those who load the plugin to account for its requirements. For example, a third-party storage engine should include in its documentation how much memory the engine needs for mutex and other instruments. 5123 Performance Schema and Plugins performance_schema_max_rwlock_instances performance_schema_max_socket_instances performance_schema_max_table_handles performance_schema_max_table_instances performance_schema_max_table_lock_stat performance_schema_max_thread_instances performance_schema_users_size SELECT * FROM performance_schema.memory_summary_global_by_event_name WHERE EVENT_NAME LIKE ’memory/performance_schema/%’;