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https://dev.mysql.com/doc/refman/8.4/en/performance-schema-examples.html
The following example provides one methodology that you can use to analyze a repeatable problem, such as investigating a performance bottleneck. To begin, you should have a repeatable use case where performance is deemed “too slow” and needs ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-instrument-filtering.html
The setup_instruments table lists the available instruments: mysql> SELECT NAME, ENABLED, TIMED FROM performance_schema.setup_instruments; +---------------------------------------------------+---------+-------+ | NAME | ENABLED | TIMED | ...| ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-startup-configuration.html
Consumer names in the setup_consumers table use underscores, but for consumers set at startup, dashes and underscores within the name are equivalent. The other variables indicate table sizes (number of rows) or memory allocation values. For example, ... To use the MySQL Performance Schema, it must be enabled at server startup to enable event collection to ...
https://dev.mysql.com/doc/refman/8.4/en/primary-key-optimization.html
The primary key for a table represents the column or set of columns that you use in your most vital queries. With the InnoDB storage engine, the table data is physically organized to do ultra-fast lookups and sorts based on the primary key column ...Query performance benefits from the NOT NULL optimization, because it cannot include any NULL ...
https://dev.mysql.com/doc/refman/8.4/en/replication-administration-skip.html
Details of the error and the last successfully applied transaction are recorded in the Performance Schema table replication_applier_status_by_worker. Alternatively, you can issue SHOW RELAYLOG EVENTS on the replica or SHOW BINLOG EVENTS on the ...
https://dev.mysql.com/doc/refman/8.4/en/replication-delayed.html
The replication_applier_configuration Performance Schema table contains the DESIRED_DELAY column which shows the delay configured using the SOURCE_DELAY option. The replication_applier_status Performance Schema table contains the REMAINING_DELAY ...
https://dev.mysql.com/doc/refman/8.4/en/replication-features-create-if-not-exists.html
Similarly, every CREATE TABLE IF NOT EXISTS statement without a SELECT is replicated, whether or not the table already exists on the source. SELECT follows somewhat different rules; see Section 19.5.1.7, “Replication of CREATE TABLE ... IF NOT ...
https://dev.mysql.com/doc/refman/8.4/en/replication-features-views.html
Views are filtered by their own name, not by the tables they refer to. This means that a view can be replicated to the replica even if the view contains a table that would normally be filtered out by replication-ignore-table rules. Care should ...
https://dev.mysql.com/doc/refman/8.4/en/rewriter-query-rewrite-plugin.html
The Rewriter plugin uses a database named query_rewrite containing a table named rewrite_rules. The table provides persistent storage for the rules that the plugin uses to decide whether to rewrite statements. Users communicate with the plugin by ...
https://dev.mysql.com/doc/refman/8.4/en/server-side-help-support.html
This information is stored in several tables in the mysql schema (see Section 7.3, “The mysql System Schema”). Proper operation of the HELP statement requires that these help tables be initialized. For a new installation of MySQL using a binary ... MySQL Server supports a HELP statement that returns information from the MySQL Reference Manual (see Section 15.8.3, “HELP ...