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https://dev.mysql.com/doc/refman/8.4/en/optimizer-issues.html
MySQL uses a cost-based optimizer to determine the best way to resolve a query. In many cases, MySQL can calculate the best possible query plan, but sometimes MySQL does not have enough information about the data at hand and has to make ...
https://dev.mysql.com/doc/refman/8.4/en/pam-pluggable-authentication.html
Note PAM pluggable authentication is an extension included in MySQL Enterprise Edition, a commercial product. MySQL Enterprise Edition supports an authentication method that enables MySQL Server to use PAM (Pluggable Authentication Modules) to ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-filtering.html
Events are processed in a producer/consumer fashion: Instrumented code is the source for events and produces events to be collected. The setup_instruments table lists the instruments for which events can be collected, whether they are enabled, and ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-stage-tables.html
The Performance Schema instruments stages, which are steps during the statement-execution process, such as parsing a statement, opening a table, or performing a filesort operation. Stages correspond to the thread states displayed by SHOW ...
https://dev.mysql.com/doc/refman/8.4/en/proxy-users.html
The plugin that authenticates a given connection may request that the connecting (external) user be treated as a different user for privilege-checking purposes. This enables the external user to be a proxy for the second user; that is, to assume the ...
https://dev.mysql.com/doc/refman/8.4/en/replication-features-invoked.html
Replication of invoked features such as loadable functions and stored programs (stored procedures and functions, triggers, and events) provides the following characteristics: The effects of the feature are always replicated. The following ...
https://dev.mysql.com/doc/refman/8.4/en/replication-options-replica.html
This section explains the server options and system variables that apply to replica servers and contains the following: Startup Options for Replica Servers System Variables Used on Replica Servers Specify the options either on the command line or ...
https://dev.mysql.com/doc/refman/8.4/en/row-constructor-optimization.html
For example, these two statements are semantically equivalent: SELECT * FROM t1 WHERE (column1,column2) = (1,1); SELECT * FROM t1 WHERE column1 = 1 AND column2 = 1; In addition, the optimizer handles both expressions the same way. The optimizer is ...
https://dev.mysql.com/doc/refman/8.4/en/secure-client-programming.html
Client applications that access MySQL should use the following guidelines to avoid interpreting external data incorrectly or exposing sensitive information. Handle External Data Properly Handle MySQL Error Messages Properly Handle External Data ...
https://dev.mysql.com/doc/refman/8.4/en/security-against-attack.html
When you connect to a MySQL server, you should use a password. All other information is transferred as text, and can be read by anyone who is able to watch the connection. If the connection between the client and the server goes through an ...