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https://dev.mysql.com/doc/refman/8.4/en/explain.html
If you have a problem with indexes not being used when you believe that they should be, run ANALYZE TABLE to update table statistics, such as cardinality of keys, that can affect the choices the optimizer makes. In practice, the DESCRIBE keyword is ...
https://dev.mysql.com/doc/refman/8.4/en/extended-show.html
Some extensions to SHOW statements accompany the implementation of INFORMATION_SCHEMA: SHOW can be used to get information about the structure of INFORMATION_SCHEMA itself. Several SHOW statements accept a WHERE clause that provides more ...
https://dev.mysql.com/doc/refman/8.4/en/forcing-innodb-recovery.html
To investigate database page corruption, you might dump your tables from the database with SELECT ... Usually, most of the data obtained in this way is intact. Serious corruption might cause SELECT * FROM tbl_name statements or InnoDB background ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-flow-control.html
MySQL Group Replication ensures that a transaction commits only after a majority of the members in a group have received it and agreed on the relative order amongst all transactions sent concurrently. This approach works well if the total number of ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-observability.html
The entire state of the system (including the view, conflict statistics and service states) can be queried through Performance Schema tables. There is a lot of automation built into the Group Replication plugin. Nonetheless, you might sometimes ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-performance-xcom-cache-reduce.html
If you are considering reducing the cache size limit, you can query the Performance Schema table memory_summary_global_by_event_name using the following statement: SELECT * FROM performance_schema.memory_summary_global_by_event_name WHERE EVENT_NAME ... The minimum setting for the XCom message cache size in MySQL 8.4 is 128 MB, which enables deployment on a host that has a restricted amount of available ...
https://dev.mysql.com/doc/refman/8.4/en/index-hints.html
To see the index names for a table, use the SHOW INDEX statement or the Information Schema STATISTICS table. Index hints give the optimizer information about how to choose indexes during query processing. Index hints, described here, differ from ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-buffer-page-lru-table.html
To avoid impacting performance on a production system, reproduce the issue you want to investigate and query buffer pool statistics on a test instance. The INNODB_BUFFER_PAGE_LRU table provides information about the pages in the InnoDB buffer pool; ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-buffer-page-table.html
To avoid impacting performance on a production system, reproduce the issue you want to investigate and query buffer pool statistics on a test instance. The INNODB_BUFFER_PAGE table provides information about each page in the InnoDB buffer pool. For ...
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 ...