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https://dev.mysql.com/doc/refman/8.4/en/performance-schema-memory-summary-tables.html
Allocating a single byte one million times is not the same as allocating one million bytes a single time; tracking both sizes and counts can expose the difference. Memory summary tables do not contain timing information because memory events are not ...Operation counts help to understand or tune the overall pressure the server is putting on the memory allocator, which has an impact on ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndbinfo-disk-write-speed-aggregate.html
The disk_write_speed_aggregate table provides aggregated information about the speed of disk writes during LCP, backup, and restore operations.
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-statement-tables.html
A query that fails to parse differs from a query that parses but fails due to an error during execution. Consequently, there is no parsing at runtime and the type of each statement is known by the time it executes. For additional information about ...Statement events occur at a high level of the event ...
https://dev.mysql.com/doc/mysql-secure-deployment-guide/8.0/en/secure-deployment-firewall.html
MySQL Enterprise Firewall is an application-level firewall that enables database administrators to permit or deny SQL statement execution based on matching against allowlists of accepted statement patterns. MySQL Enterprise Firewall installation is ...This helps harden MySQL against attacks such as SQL injection or attempts to exploit applications by using them outside of their legitimate query workload ...
https://dev.mysql.com/doc/ndbapi/en/mccj-using-clusterj-annotations.html
The implementation of this interface is created dynamically by ClusterJ at runtime. In ClusterJ (as in JPA), annotations are used to describe how the interface is mapped to tables in a database. The annotation @PersistenceCapable(table="employee") ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-message-compression.html
Note that the maximum supported input size for the LZ4 compression algorithm is 2113929216 bytes. This limit is lower than the maximum possible value for the group_replication_compression_threshold system variable, which is matched to the maximum ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-events-stages-current-table.html
For discussion of picoseconds as the unit for event times and factors that affect time values, see Section 29.4.1, “Performance Schema Event Timing”. For example, the events_stages_history and events_stages_history_long tables are collections of ...The table stores one row per thread showing the current status of the thread's most recent monitored stage event, so there is no system variable for configuring the table ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-events-transactions-current-table.html
For discussion of picoseconds as the unit for event times and factors that affect time values, see Section 29.4.1, “Performance Schema Event Timing”. For example, the events_transactions_history and events_transactions_history_long tables are ...
https://dev.mysql.com/doc/workbench/en/wb-configuration-additional.html
Safe Updates: When enabled (default), MySQL Workbench will not execute UPDATE or DELETE statements if a key is not defined in the WHERE clause. For example, DELETE FROM foo is considered unsafe, whereas DELETE FROM foo WHERE id = 1 is safe and will ... Commonly used configuration options and preferences include: Rescan for Local MySQL Instances: Right-click on the home screen, and this option will scan your system for MySQL instances and add connection tiles to the home ...
https://dev.mysql.com/doc/refman/8.4/en/derived-table-optimization.html
When this happens, query execution is quicker by the time needed to perform materialization. This is true for a CTE that is referenced multiple times, so there is no duplication of materialized_from_subquery nodes (which would give the impression ...