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https://dev.mysql.com/doc/refman/8.4/en/innodb-transaction-isolation-levels.html
The following list describes how MySQL supports the different transaction levels. Record locks for nonmatching rows are released after MySQL has evaluated the WHERE condition. For UPDATE statements, if a row is already locked, InnoDB performs a ...
https://dev.mysql.com/doc/refman/8.4/en/insert-on-duplicate.html
If you specify the CLIENT_FOUND_ROWS flag to the mysql_real_connect() C API function when connecting to mysqld, the affected-rows value is 1 (not 0) if an existing row is set to its current values. If you specify an ON DUPLICATE KEY UPDATE clause ...
https://dev.mysql.com/doc/refman/8.4/en/ipv6-support.html
Support for IPv6 in MySQL includes these capabilities: MySQL Server can accept TCP/IP connections from clients connecting over IPv6. For example, this command connects over IPv6 to the MySQL server on the local host: $> mysql -h ::1 To use this ...
https://dev.mysql.com/doc/refman/8.4/en/keyring-plugin-installation.html
A keyring component must be enabled on the MySQL Server instance if you need to support secure storage for persisted system variable values, rather than a keyring plugin, which do not support the function. MySQL provides these keyring plugin ...
https://dev.mysql.com/doc/refman/8.4/en/merge-storage-engine.html
When you create a MERGE table, MySQL creates a .MRG file on disk that contains the names of the underlying MyISAM tables that should be used as one. The table format of the MERGE table is stored in the MySQL data dictionary. Additional Resources A ... The MERGE storage engine, also known as the MRG_MyISAM engine, is a collection of identical MyISAM tables that can be used as ...
https://dev.mysql.com/doc/refman/8.4/en/nonpersistible-system-variables.html
SET PERSIST and SET PERSIST_ONLY enable global system variables to be persisted to the mysqld-auto.cnf option file in the data directory (see Section 15.7.6.1, “SET Syntax for Variable Assignment”). For example, put these lines in your server ...However, not all system variables can be persisted, or can be persisted only under certain restrictive ...
https://dev.mysql.com/doc/refman/8.4/en/order-by-optimization.html
This section describes when MySQL can use an index to satisfy an ORDER BY clause, the filesort operation used when an index cannot be used, and execution plan information available from the optimizer about ORDER BY. (The resulting sort order may be ...An ORDER BY with and without LIMIT may return rows in different orders, as discussed in Section 10.2.1.19, “LIMIT Query ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-statement-summary-tables.html
Example statement event summary information: mysql> SELECT * FROM performance_schema.events_statements_summary_global_by_event_name\G *************************** 1. For use with MySQL HeatWave Service and MySQL HeatWave, where the PRIMARY engine is ... The Performance Schema maintains tables for collecting current and recent statement events, and aggregates that information in summary ...
https://dev.mysql.com/doc/refman/8.4/en/postinstallation.html
This section discusses tasks that you should perform after installing MySQL: If necessary, initialize the data directory and create the MySQL grant tables. For some MySQL installation methods, data directory initialization may be done for you ...
https://dev.mysql.com/doc/refman/8.4/en/replication-features.html
The following sections provide information about what is supported and what is not in MySQL replication, and about specific issues and situations that may occur when replicating certain statements. If you use a feature on the source server that is ...Statement-based replication depends on compatibility at the SQL level between the source and ...