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https://dev.mysql.com/doc/refman/8.4/en/performance-schema-events-waits-current-table.html
Assume a join query of the following form that is executed using a table join order of t1, t2, t3: SELECT ... The table stores one row per thread showing the current status of the thread's most recent monitored wait event, so there is no system ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-host-cache-table.html
Because the host_cache table exposes the contents of the host cache, it can be examined using SELECT statements. The MySQL server maintains an in-memory host cache that contains client host name and IP address information and is used to avoid ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-instrumentation-checking.html
It is always possible to determine what instruments the Performance Schema includes by checking the setup_instruments table. Changes to this code occur often, which also affects the set of instruments. It is not practical to list all the ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-keyring-component-status-table.html
The keyring_component_status table provides status information about the properties of the keyring component in use, if one is installed. The table is empty if no keyring component is installed (for example, if the keyring is not being used, or is ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-log-status-table.html
The BACKUP_ADMIN privilege, as well as the SELECT privilege, is required for access to the log_status table. The log_status table provides information that enables an online backup tool to copy the required log files without locking those resources ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-memory-model.html
This query shows the information associated with the memory instruments: SELECT * FROM performance_schema.memory_summary_global_by_event_name WHERE EVENT_NAME LIKE 'memory/performance_schema/%'; . Memory used depends on the load actually seen, not ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-memory-summary-tables.html
Example memory event summary information: mysql> SELECT * FROM performance_schema.memory_summary_global_by_event_name WHERE EVENT_NAME = 'memory/sql/TABLE'\G *************************** 1. Operation counts help to understand or tune the overall ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-ndb-sync-excluded-objects-table.html
Example information about NDB database objects which cannot be synchronized with the MySQL data dictionary: mysql> SELECT * FROM performance_schema.ndb_sync_excluded_objects\G *************************** 1. This table provides information about NDB ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-ndb-sync-pending-objects-table.html
This table provides information about NDB database objects for which mismatches have been detected and which are waiting to be synchronized between the NDB dictionary and the MySQL data dictionary.
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-object-filtering.html
The setup_objects table controls whether the Performance Schema monitors particular table and stored program objects. The OBJECT_TYPE column indicates the type of object to which a row applies. TABLE filtering affects table I/O events ...