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https://dev.mysql.com/doc/refman/8.4/en/innodb-performance-ro-txn.html
You can still make changes to session-specific temporary tables in a read-only transaction, or issue locking queries for them, because those changes and locks are not visible to any other transaction. InnoDB can avoid the overhead associated with ...
https://dev.mysql.com/doc/refman/8.4/en/invisible-columns.html
An invisible column is normally hidden to queries, but can be accessed if explicitly referenced. As an illustration of when invisible columns may be useful, suppose that an application uses SELECT * queries to access a table, and must continue to ...
https://dev.mysql.com/doc/refman/8.4/en/monitor-alter-table-performance-schema.html
You can monitor ALTER TABLE progress for InnoDB tables using Performance Schema. There are seven stage events that represent different phases of ALTER TABLE. Each stage event reports a running total of WORK_COMPLETED and WORK_ESTIMATED for the ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-disk-data-objects.html
NDB Cluster Disk Data storage is implemented using the following objects: Tablespace: Acts as containers for other Disk Data objects. A tablespace contains one or more data files and one or more undo log file groups. Undo log file: Contains undo ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-log-statistics.html
The NDB management client's CLUSTERLOG STATISTICS command can provide a number of useful statistics in its output. Counters providing information about the state of the cluster are updated at 5-second reporting intervals by the transaction ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndbinfo-config-values.html
You can obtain output that is more specific, more detailed, or both by issuing the proper queries. The config_values table provides information about the current state of node configuration parameter values. Each row in the table corresponds to the ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndbinfo-dict-obj-tree.html
The dict_obj_tree table provides a tree-based view of table information from the dict_obj_info table. This is intended primarily for use in testing, but can be useful in visualizing hierarchies of NDB database objects. This means that you must know ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndbinfo.html
All ndbinfo tables are read-only, and are generated on demand when queried. ndbinfo is a database containing information specific to NDB Cluster. This database contains a number of tables, each providing a different sort of data about NDB Cluster ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-nutshell.html
This release adds two system status variables providing information about accesses to the PROCESSLIST table, listed here: Deprecated_use_i_s_processlist_count provides a count of the number of references to the PROCESSLIST table in queries since the ... This section summarizes what has been added to, deprecated in, changed, and removed from MySQL 8.4 since MySQL ...
https://dev.mysql.com/doc/refman/8.4/en/optimization-indexes.html
You must find the right balance to achieve fast queries using the optimal set of indexes. The best way to improve the performance of SELECT operations is to create indexes on one or more of the columns that are tested in the query. The index ...