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https://dev.mysql.com/doc/refman/8.4/en/controlling-query-plan-evaluation.html
The task of the query optimizer is to find an optimal plan for executing an SQL query. Because the difference in performance between “good” and “bad” plans can be orders of magnitude (that is, seconds versus hours or even days), most query ...
https://dev.mysql.com/doc/refman/8.4/en/events-privileges.html
To enable or disable the execution of scheduled events, it is necessary to set the value of the global event_scheduler system variable. The EVENT privilege governs the creation, modification, and deletion of events. For example, suppose that ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-change-primary.html
This section explains how to change which member of a single-primary group is the primary, using the group_replication_set_as_primary() function, which can be can be run on any member of the group. When this is done, the current primary becomes a ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-frequently-asked-questions.html
What is the maximum number of MySQL servers in a group? A group can consist of maximum 9 servers. Attempting to add another server to a group with 9 members causes the request to join to be refused. This limit has been identified from testing and ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-functions-for-new-primary.html
The following function enables you to set a member of a single-primary replication group to take over as the primary. The current primary becomes a read-only secondary, and the specified group member becomes the read-write primary. The function can ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-responses-failure.html
Group Replication's failure detection mechanism is designed to identify group members that are no longer communicating with the group, and expel them as and when it seems likely that they have failed. Having a failure detection mechanism increases ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-events-table.html
The EVENTS table provides information about Event Manager events, which are discussed in Section 27.4, “Using the Event Scheduler”. The EVENTS table has these columns: EVENT_CATALOG The name of the catalog to which the event belongs.
https://dev.mysql.com/doc/refman/8.4/en/innodb-information-schema-innodb_cmp.html
The INNODB_CMP and INNODB_CMP_RESET tables provide status information about operations related to compressed tables, which are described in Section 17.9, “InnoDB Table and Page Compression”. These two tables have identical contents, but reading ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-information-schema-innodb_cmpmem.html
The INNODB_CMPMEM and INNODB_CMPMEM_RESET tables provide status information about compressed pages that reside in the buffer pool. Please consult Section 17.9, “InnoDB Table and Page Compression” for further information on compressed tables and ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-online-ddl.html
The online DDL feature provides support for instant and in-place table alterations and concurrent DML. Benefits of this feature include: Improved responsiveness and availability in busy production environments, where making a table unavailable for ...