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https://dev.mysql.com/doc/refman/8.4/en/optimizer-issues.html
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 “educated” guesses about the data. MySQL uses a cost-based optimizer to determine the ...Use ANALYZE TABLE tbl_name to update the key distributions for the scanned ...
https://dev.mysql.com/doc/refman/8.4/en/range-optimization.html
MySQL tries to extract range conditions from the WHERE clause for each of the possible indexes. MySQL performs an additional check to filter out rows that satisfy the range condition but not the full WHERE clause. MySQL does not support merging ...
https://dev.mysql.com/doc/refman/8.4/en/rebuilding-tables.html
This section describes how to rebuild or repair tables or indexes, which may be necessitated by: Changes to how MySQL handles data types or character sets. Required table repairs or upgrades reported by CHECK TABLE or mysqlcheck. Methods for ...For ...
https://dev.mysql.com/doc/refman/8.4/en/replication-formats.html
This is called statement-based replication (which can be abbreviated as SBR), which corresponds to the MySQL statement-based binary logging format. You can also configure MySQL to use a mix of both statement-based and row-based logging, depending on ... Replication works because events written to the binary log are read from the source and then processed on the ...
https://dev.mysql.com/doc/refman/8.4/en/replication-solutions-backups-rawdata.html
To guarantee the integrity of the files that are copied, backing up the raw data files on your MySQL replica should take place while your replica server is shut down. If the MySQL server is still running, background tasks may still be updating the ...With InnoDB, these problems should be resolved during crash recovery, but since the replica server can be shut down during the backup process without affecting the execution of the source it makes sense to take advantage of this ...
https://dev.mysql.com/doc/refman/8.4/en/replication-solutions-backups-read-only.html
Note The instructions in this section place the server to be backed up in a state that is safe for backup methods that get the data from the server, such as mysqldump (see Section 6.5.4, “mysqldump — A Database Backup Program”). You should not ...
https://dev.mysql.com/doc/refman/8.4/en/set-password.html
SET PASSWORD [FOR user] auth_option [REPLACE 'current_auth_string'] [RETAIN CURRENT PASSWORD] auth_option: { = 'auth_string' | TO RANDOM } The SET PASSWORD statement assigns a password to a MySQL user account. The password may be either explicitly ...The statement may also include a password-verification clause that specifies the account current password to be replaced, and a clause that manages whether an account has a secondary ...
https://dev.mysql.com/doc/refman/8.4/en/set-variable.html
Like SET GLOBAL, SET PERSIST sets the global variable runtime value, but also writes the variable setting to the mysqld-auto.cnf file (replacing any existing variable setting if there is one). To persist a global system variable to the ...SET ...
https://dev.mysql.com/doc/refman/8.4/en/spatial-geojson-functions.html
MySQL also supports a native JSON data type and a set of SQL functions to enable operations on JSON values. mysql> SELECT ST_AsGeoJSON(ST_GeomFromText('POINT(11.11111 12.22222)'),2); +-------------------------------------------------------------+ | ... This section describes functions for converting between GeoJSON documents and spatial ...
https://dev.mysql.com/doc/refman/8.4/en/transport-protocols.html
For programs that use the MySQL client library (for example, mysql and mysqldump), MySQL supports connections to the server based on several transport protocols: TCP/IP, Unix socket file, named pipe, and shared memory. For additional information, ...This section describes how to select these protocols, and how they are similar and ...