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https://dev.mysql.com/doc/refman/8.4/en/select-optimization.html
You can use the EXPLAIN statement to determine which indexes are used for a SELECT. Queries, in the form of SELECT statements, perform all the lookup operations in the database. Tuning these statements is a top priority, whether to achieve ...NDB ...
https://dev.mysql.com/doc/refman/8.4/en/create-trigger.html
CREATE [DEFINER = user] TRIGGER [IF NOT EXISTS] trigger_name trigger_time trigger_event ON tbl_name FOR EACH ROW [trigger_order] trigger_body trigger_time: { BEFORE | AFTER } trigger_event: { INSERT | UPDATE | DELETE } trigger_order: { FOLLOWS | ...
https://dev.mysql.com/doc/refman/8.4/en/repair-table.html
Although normally you should never have to run REPAIR TABLE, if disaster strikes, this statement is very likely to get back all your data from a MyISAM table. If the server exits during a REPAIR TABLE operation, it is essential after restarting it ...[QUICK] [EXTENDED] [USE_FRM] REPAIR TABLE repairs a possibly corrupted table, for certain storage engines ...
https://dev.mysql.com/doc/refman/8.4/en/alter-event.html
(See Section 15.1.13, “CREATE EVENT Statement”.) Any user can alter an event defined on a database for which that user has the EVENT privilege. When a user executes a successful ALTER EVENT statement, that user becomes the definer for the ...The ...
https://dev.mysql.com/doc/refman/8.4/en/declare-handler.html
statement handler_action: { CONTINUE | EXIT | UNDO } condition_value: { mysql_error_code | SQLSTATE [VALUE] sqlstate_value | condition_name | SQLWARNING | NOT FOUND | SQLEXCEPTION } The DECLARE ... HANDLER statement specifies a handler that deals ...
https://dev.mysql.com/doc/refman/8.4/en/set-transaction.html
transaction_characteristic: { ISOLATION LEVEL level | access_mode } level: { REPEATABLE READ | READ COMMITTED | READ UNCOMMITTED | SERIALIZABLE } access_mode: { READ WRITE | READ ONLY } This statement specifies transaction characteristics. In ...It ...
https://dev.mysql.com/doc/refman/8.4/en/show-processlist.html
For a comparison of this statement with other sources, see Sources of Process Information. Without the FULL keyword, SHOW PROCESSLIST displays only the first 100 characters of each statement in the Info field. The SHOW PROCESSLIST statement is very ... SHOW [FULL] PROCESSLIST Important The INFORMATION SCHEMA implementation of SHOW PROCESSLIST is deprecated and subject to removal in a future MySQL ...
https://dev.mysql.com/doc/refman/8.4/en/sys-statements-with-runtimes-in-95th-percentile.html
These views list statements with runtimes in the 95th percentile. The statements_with_runtimes_in_95th_percentile and x$statements_with_runtimes_in_95th_percentile views have these columns: query The normalized statement string. db The default ...
https://dev.mysql.com/doc/refman/8.4/en/call.html
CALL sp_name([parameter[,...]]) CALL sp_name[()] The CALL statement invokes a stored procedure that was defined previously with CREATE PROCEDURE. When the procedure returns, a client program can also obtain the number of rows affected for the final ...Stored procedures that take no arguments can be invoked without ...
https://dev.mysql.com/doc/refman/8.4/en/reset-replica.html
This statement is meant to be used for a clean start; it clears the replication metadata repositories, deletes all the relay log files, and starts a new relay log file. It also resets to 0 the replication delay specified with the SOURCE_DELAY option ... RESET REPLICA [ALL] [channel_option] channel_option: FOR CHANNEL channel RESET REPLICA makes the replica forget its position in the source's binary ...