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https://dev.mysql.com/doc/refman/8.4/en/derived-table-optimization.html
The optimizer handles derived tables, view references, and common table expressions the same way: It avoids unnecessary materialization whenever possible, which enables pushing down conditions from the outer query to derived tables and produces more ...
https://dev.mysql.com/doc/refman/8.4/en/event-scheduler-thread-states.html
These states occur for the Event Scheduler thread, threads that are created to execute scheduled events, or threads that terminate the scheduler. Clearing The scheduler thread or a thread that was executing an event is terminating and is about to ...
https://dev.mysql.com/doc/refman/8.4/en/example-storage-engine.html
The EXAMPLE storage engine is a stub engine that does nothing. Its purpose is to serve as an example in the MySQL source code that illustrates how to begin writing new storage engines. To enable the EXAMPLE storage engine if you build MySQL from ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-enterprise-backup.html
MySQL Enterprise Backup is a commercially-licensed backup utility for MySQL Server, available with MySQL Enterprise Edition. This section explains how to back up and subsequently restore a Group Replication member using MySQL Enterprise Backup. The ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-connection-control-failed-login-attempts-table.html
This table provides information about the current number of consecutive failed connection attempts per account (user/host combination). CONNECTION_CONTROL_FAILED_LOGIN_ATTEMPTS has these columns: USERHOST The user/host combination indicating an ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-ft-being-deleted-table.html
When OPTIMIZE TABLE is run, the INNODB_FT_BEING_DELETED table is emptied, and DOC_ID values are removed from the INNODB_FT_DELETED table. The INNODB_FT_BEING_DELETED table provides a snapshot of the INNODB_FT_DELETED table; it is used only during ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-ft-config-table.html
The INNODB_FT_CONFIG table provides metadata about the FULLTEXT index and associated processing for an InnoDB table. Before querying it, set the value of the innodb_ft_aux_table system variable to the name (including the database name) of the table ...
https://dev.mysql.com/doc/refman/8.4/en/metadata-locking.html
MySQL uses metadata locking to manage concurrent access to database objects and to ensure data consistency. Metadata locking applies not just to tables, but also to schemas, stored programs (procedures, functions, triggers, scheduled events), ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndbinfo-cluster-locks.html
The cluster_locks table provides information about current lock requests holding and waiting for locks on NDB tables in an NDB Cluster, and is intended as a companion table to cluster_operations. Information obtain from the cluster_locks table may ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndbinfo-server-locks.html
The server_locks table is similar in structure to the cluster_locks table, and provides a subset of the information found in the latter table, but which is specific to the SQL node (MySQL server) where it resides. (The cluster_locks table provides ...