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https://dev.mysql.com/doc/refman/8.0/en/outer-join-optimization.html
MySQL implements an A LEFT JOIN B join_specification as follows: Table B is set to depend on table A and all tables on which A depends. Table A is set to depend on all tables (except B) that are used in the LEFT JOIN condition. The LEFT JOIN ...If ...
https://dev.mysql.com/doc/refman/8.0/en/subquery-restrictions.html
In general, you cannot modify a table and select from the same table in a subquery. FROM t ...); Exception: The preceding prohibition does not apply if for the modified table you are using a derived table and that derived table is materialized ...
https://dev.mysql.com/doc/refman/8.0/en/backup-policy.html
This backup operation acquires a global read lock on all tables at the beginning of the dump (using FLUSH TABLES WITH READ LOCK). After that, the dump becomes lock-free and does not disturb reads and writes on the tables. It was assumed earlier that ...A full backup (a snapshot of the data at a point in time) can be done in MySQL with several ...
https://dev.mysql.com/doc/refman/8.0/en/change-master-to.html
This option prevents the replication applier from taking actions such as creating temporary tables and executing LOAD DATA INFILE requests, which increases the security of the channel. If you are using statement-based replication and temporary ...] ...
https://dev.mysql.com/doc/refman/8.0/en/optimizing-innodb-ddl-operations.html
Many DDL operations on tables and indexes (CREATE, ALTER, and DROP statements) can be performed online. Online DDL support for adding secondary indexes means that you can generally speed up the process of creating and loading a table and associated ...Use TRUNCATE TABLE to empty a table, not DELETE FROM ...
https://dev.mysql.com/doc/refman/8.0/en/replication-privilege-checks-account.html
It is recommended that you never give any ACL privileges to the PRIVILEGE_CHECKS_USER account, including CREATE USER, CREATE ROLE, DROP ROLE, and GRANT OPTION, and do not permit the account to update the mysql.user table. Executing internal-use ...
https://dev.mysql.com/doc/refman/8.0/en/mysql-cluster-limitations-database-objects.html
In addition, the maximum offset for a fixed-width column of an NDB table is 8188 bytes; attempting to create a table that violates this limitation fails with NDB error 851 Maximum offset for fixed-size columns exceeded. Some database objects such ...In NDB 8.0, the maximum permitted size of any one row is 30000 bytes (increased from 14000 bytes in previous ...
https://dev.mysql.com/doc/refman/8.0/en/function-optimization.html
If a function is tagged nondeterministic, a reference to it in a WHERE clause is evaluated for every row (when selecting from one table) or combination of rows (when selecting from a multiple-table join). MySQL also determines when to evaluate ...A ...
https://dev.mysql.com/doc/refman/8.0/en/identifier-length.html
The following table describes the maximum length for each type of identifier. For constraint definitions that include no constraint name, the server internally generates a name derived from the associated table name. For example, internally ...You ...
https://dev.mysql.com/doc/refman/8.0/en/mysql-cluster-programs-ndb-size-pl.html
If you do not wish to use an existing account, then creating one using GRANT USAGE ON db_name.*—where db_name is the name of the database to be examined—is sufficient for this purpose. Options that can be used with ndb_size.pl are shown in the ... This is a Perl script that can be used to estimate the amount of space that would be required by a MySQL database if it were converted to use the NDBCLUSTER storage ...